Muscle Regeneration

Lasers Med Sci. 2015 Feb 27. [Epub ahead of print]

Light-emitting diode therapy (LEDT) before matches prevents increase in creatine kinase with a light dose response in volleyball players.

Ferraresi C1, Dos Santos RV, Marques G, Zangrande M, Leonaldo R, Hamblin MR, Bagnato VS, Parizotto NA.

Author information

  • 1Laboratory of Electrothermophototherapy, Department of Physical Therapy, Federal University of Sao Carlos, Rodovia Washington Luís, km 235, 13565-905, Sao Carlos, SP, Brazil, cleber.ferraresi@gmail.com.

Abstract

Low-level laser (light) therapy (LLLT) has been applied over skeletal muscles before intense exercise (muscular pre-conditioning) in order to reduce fatigue and muscle damage (measured by creatine kinase, CK) in clinical trials. However, previous exercise protocols do not exactly simulate the real muscle demand required in sports. For this reason, the aim of this randomized and double-blind placebo-controlled trial was to investigate whether light-emitting diode therapy (LEDT) applied over the quadriceps femoris muscles, hamstrings, and triceps surae of volleyball players before official matches could prevent muscle damage (CK) with a dose response, establishing a therapeutic window. A professional male volleyball team (12 athletes) was enrolled in this study, and LEDT was applied before 4 matches during a national championship. LEDT used an array of 200 light-emitting diodes (LEDs) arranged in 25 clusters of 4 infrared LEDs (850 ± 20 nm; 130 mW) and 25 clusters of 4 red LEDs (630 ± 10 nm; 80 mW). Athletes were randomized to receive one of four different total doses over each muscle group in a double-blind protocol: 105 J (20 s), 210 J (40 s), 315 J (60 s), and placebo (no light for 30 s). CK in blood was assessed 1 h before and 24 h after each match. LEDT at 210 J avoided significant increases in CK (+10 %; P = 0.993) as well as 315 J (+31 %, P = 0.407). Placebo (0 J) allowed a significant increase in CK (+53 %; P = 0.012) as well as LEDT at 105 J (+59 %; P = 0.001). LEDT prevented significant increases of CK in blood in athletes when applied before official matches with a light dose response of 210-315 J, suggesting athletes might consider applying LEDT before competition.

 
Acta Cir Bras. 2015 Feb;30(2):94-99.

Low-level laser therapy modulates musculoskeletal loss in a skin burn model in rats.

Martins F1, Rennó AC2, Oliveira F2, Minatel NP3, Bortolin JA4, Quintana HT4, Aveiro MC5.

Author information

  • 1Institutional Program for Scientific Initiation, National Council of Scientific and Technological Development, Ministry of Science, Technology and Inovation, Brazil.
  • 2Bioscience Department, UNIFESP, Santos, SP, Brazil.
  • 3School of Medicine, UNIFESP, Santos, SP, Brazil.
  • 4Postgraduate Program in Interdisciplinary Health Sciences, UNIFESP, Santos, SP, Brazil.
  • 5Department of Human Movement Sciences, UNIFESP, Santos, SP, Brazil.

Abstract

PURPOSE:

To investigate the effectiveness of low-level laser therapy (LLLT) on gastrocnemius muscle morphology and Myod imunoexpression in a model of dorsal burn in rats.

METHODS:

Sixteen male Wistar rats were distributed into two groups: control group (CG): rats submitted to scald burn injury without treatment and laser treated group (LG): rats submitted to scald burn injury and treated with laser therapy. Fourteen days post-surgery, gastrocnemius muscle was evaluated being the specimens stained with HE and morphometric data was evaluated. MyoD expression was assessed by immunohistochemistry.

RESULTS:

The results showed that laser treated animals presented more organized tissue morphology compared to the non-treated animals, with a higher number of nucleus in the fibers. Also, the cross sectional area of the fibers and the MyoD immunoexpression in the laser treated groups was higher.

CONCLUSION:

Low-level laser therapy had positive effects on gastrocnemius muscle, improving tissue muscle morphology, increasing cross sectional area and MyoD immunoexpression.

Am J Phys Med Rehabil. 2014 Dec;93(12):1073-85. doi: 10.1097/PHM.0000000000000158.

Effects of low-level laser therapy on skeletal muscle repair: a systematic review.

Alves AN1, Fernandes KP, Deana AM, Bussadori SK, Mesquita-Ferrari RA.

Author information

  • 1From the Postgraduate Program in Rehabilitation Sciences (ANA, KPSF, SKB, RAM-F) and Postgraduate Program in Biophotonics Applied to Health Sciences (KPSF, AMD, RAM-F), Universidade Nove de Julho, São Paulo, Brazil.

Abstract

A review of the literature was performed to demonstrate the most current applicability of low-level laser therapy (LLLT) for the treatment of skeletal muscle injuries, addressing different lasers, irradiation parameters, and treatment results in animal models. Searches were performed in the PubMed/MEDLINE, SCOPUS, and SPIE Digital Library databases for studies published from January 2006 to August 2013 on the use of LLLT for the repair of skeletal muscle in any animal model. All selected articles were critically appraised by two independent raters. Seventeen of the 36 original articles on LLLT and muscle injuries met the inclusion criteria and were critically evaluated. The main effects of LLLT were a reduction in the inflammatory process, the modulation of growth factors and myogenic regulatory factors, and increased angiogenesis. The studies analyzed demonstrate the positive effects of LLLT on the muscle repair process, which are dependent on irradiation and treatment parameters. The findings suggest that LLLT is an excellent therapeutic resource for the treatment of skeletal muscle injuries in the short-term.

 
Braz J Phys Ther. 2014 Aug 29;0:0. [Epub ahead of print]

Morphological aspects and Cox-2 expression after exposure to 780-nm laser therapy in injured skeletal muscle: an in vivo study.

Rodrigues NC1, Brunelli R2, Abreu DC3, Fernandes K4, Parizotto NA1, Renno AC4.

Author information

  • 1Departamento de Fisioterapia, Universidade Federal de São Carlos, São Carlos, SP, Brazil.
  • 2Departamento de Cirurgia, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, SP, Brazil.
  • 3Departamento de Biomecânica, Medicina e Reabilitação do Sistema Locomotor, Universidade de São Paulo, Ribeirão Preto, SP, Brazil.
  • 4Departamento de Biociências, Universidade Federal de São Paulo, Santos, SP, Brazil.

Abstract

Background: The effectiveness of low-level laser therapy in muscle regeneration is still not well known.

Objective: To investigate the effects of laser irradiation during muscle healing.

Method: For this purpose, 63 rats were distributed to 3 groups: non-irradiated control group (CG); group irradiated at 10 J/cm² (G10); and group irradiated at 50 J/cm² (G50). Each group was divided into 3 different subgroups (n=7), and on days 7, 14 and 21 post-injury the rats were sacrificed.

Results: Seven days post-surgery, the CG showed destroyed zones and extensive myofibrillar degeneration. For both treated groups, the necrosis area was smaller compared to the CG. On day 14 post-injury, treated groups demonstrated better tissue organization, with newly formed muscle fibers compared to the CG. On the 21st day, the irradiated groups showed similar patterns of tissue repair, with improved muscle structure at the site of the injury, resembling uninjured muscle tissue organization. Regarding collagen deposition, the G10 showed an increase in collagen synthesis. In the last period evaluated, both treated groups showed statistically higher values in comparison with the CG. Furthermore, laser irradiation at 10 J/cm2 produced a down-regulation of cyclooxygenase 2 (Cox-2) immunoexpression on day 7 post-injury. Moreover, Cox-2 immunoexpression was decreased in both treated groups on day 14.

Conclusions: Laser therapy at both fluencies stimulated muscle repair through the formation of new muscle fiber, increase in collagen synthesis, and down-regulation of Cox-2 expression.

Photonics Lasers Med.  2012 Nov 1;1(4):267-286.

Low-level laser (light) therapy (LLLT) on muscle tissue: performance, fatigue and repair benefited by the power of light.

Ferraresi C, Hamblin MR, Parizotto NA.

Source

Laboratory of Electro-thermo-phototherapy, Department of Physical Therapy, Federal University of São Carlos, São Carlos, São Paulo 13565-905, Brazil; and Department of Biotechnology, Federal University of São Carlos, São Carlos, São Paulo 13565-905, Brazil.

 

Abstract

The use of low level laser (light) therapy (LLLT) has recently expanded to cover areas of medicine that were not previously thought of as the usual applications such as wound healing and inflammatory orthopedic conditions. One of these novel application areas is LLLT for muscle fatigue and muscle injury. Since it is becoming agreed that mitochondria are the principal photoacceptors present inside cells, and it is known that muscle cells are exceptionally rich in mitochondria, this suggests that LLLT should be highly beneficial in muscle injuries. The ability of LLLT to stimulate stem cells and progenitor cells means that muscle satellite cells may respond well to LLLT and help muscle repair. Furthermore the ability of LLLT to reduce inflammation and lessen oxidative stress is also beneficial in cases of muscle fatigue and injury. This review covers the literature relating to LLLT and muscles in both preclinical animal experiments and human clinical studies. Athletes, people with injured muscles, and patients with Duchenne muscular dystrophy may all benefit.

KEYWORDS:

ATP, low level laser therapy, mitochondria, muscle fatigue, muscle injury, reactive oxygen species, satellite cells

Lasers Med Sci.  2013 Feb 14. [Epub ahead of print]

The effects of 780-nm low-level laser therapy on muscle healing process after cryolesion.

Brunelli RM, Rodrigues NC, Ribeiro DA, Fernandes K, Magri A, Assis L, Parizotto NA, Cliquet A Jr, Renno AC, Abreu DC.

Source

Post Graduation Program of Surgery, Faculty of Medical Sciences, State University of Campinas (UNICAMP), Campinas, Brazil.

 

Abstract

The objective of this study was to assess the effects of 780-nm low-level laser therapy at different periods of 7, 14 and 21 days after cryolesion, including the dose (10 or 50 J/cm(2)), to promote a better muscle repair evidenced by histopathological and immunohistochemical analyses. Fifty-four male rats were divided into three groups: injured control group (CG)-injured animals without any treatment; injured 780-nm laser-treated group, at 10 J/cm(2) (G10); and injured 780-nm laser-treated group, at 50 J/cm(2) (G50). Each group was divided into three subgroups (n=6): 7, 14 and 21 days post-injury. Histopathological findings revealed better organised muscle fibres in the G10 and G50 during the periods of 7 and 14 days compared to the CG. The G10 and G50 during the 7 days showed a significant reduction (p<0.05) of lesion area compared to the CG, without differences between groups treated for 14 and 21 days. The G10 showed an increase of the amount of vessels after 14 days compared to the G50, but not in relation to controls. With regard to the immunohistochemical analyses of the MyoD factor, the G10 and G50 during the 7 days showed higher concentrations of immunomarkers than controls. Myogenin immunomarkers were similarly observed at days 7 and 14 in all the three groups analysed, whereas immunomarkers were found in none of the groups after 21 days of laser therapy. The results showed that laser, regardless the applied dose, has positive effects on muscle repair.

 

 

Lasers Med Sci.  2012 Dec 22. [Epub ahead of print]

 

Effect of laser therapy on skeletal muscle repair process in diabetic rats.

França CM, de Loura Santana C, Takahashi CB, Alves AN, De Souza Mernick AP, Fernandes KP, de Fátima Teixeira da Silva D, Bussadori SK, Mesquita-Ferrari RA.

Source

Postgraduate Program in Biophotonics Applied to Health Sciences, Universidade Nove de Julho, São Paulo, São Paulo, Brazil, 01504-001, cristiane321@gmail.com.

 

Abstract

Skeletal muscle myopathy is a common source of disability in diabetic patients. This study evaluated whether low-level laser therapy (LLLT) influences the healing morphology of injured skeletal muscle. Sixty-five male Wistar rats were divided as follows: (1) sham; (2) control; (3) diabetic; (4) diabetic sham; (5) nondiabetic cryoinjured submitted to LLLT (LLLT); (6) diabetic cryoinjured submitted to LLLT (D-LLLT); and (7) diabetic cryoinjured non-treated (D). Diabetes was induced with streptozotocin. Anterior tibialis muscle was cryoinjured and received LLLT daily (780 nm, 5 J/cm(2), 10 s per point; 0.2 J; total treatment, 1.6 J). Euthanasia occurred on day 1 in groups 1, 2, 3, and 4 and on days 1, 7, and 14 in groups 5, 6, and 7. Muscle samples were processed for H&E and Picrosirius Red and photographed. Leukocytes, myonecrosis, fibrosis, and immature fibers were manually quantified using the ImageJ software. On day 1, all cryoinjured groups were in the inflammatory phase. The D group exhibited more myonecrosis than LLLT group (p<0.05). On day 14, the LLLT group was in the remodeling phase; the D group was still in the proliferative phase, with fibrosis, chronic inflammation, and granulation tissue; and the D-LLLT group was in an intermediary state in relation to the two previous groups. Under polarized light, on day 14, the LLLT and D-LLLT groups had organized collagen bundles in the perimysium, whereas the diabetic groups exhibited fibrosis. LLLT can have a positive effect on the morphology of skeletal muscle during the tissue repair process by enhancing the reorganization of myofibers and the perimysium, reducing fibrosis.

 

Lasers Med Sci.  2012 Nov 23. [Epub ahead of print]

 

Effect of photobiomodulation on expression of IL-1B in skeletal muscle following acute injury.

Fernandes KP, Alves AN, Nunes FD, Souza NH, Silva JA Jr, Bussadori SK, Ferrari RA.

Source

Rehabilitation Sciences and Biophotonics, Universidade Nove de Julho-UNINOVE, São Paulo, São Paulo, Brazil, kristianneporta@gmail.com.

 

Abstract

Muscle repair is regulated by growth factors and cytokines. Low-level laser therapy (LLLT) seems to influence acute inflammation and accelerate skeletal muscle repair. This study verifies the effect of LLLT on the expression of IL-1B in the tibialis anterior (TA) muscle of rats following acute injury. Wistar rats (n=35) were allocated into three groups: control (without lesion and LLLT, n=5), injury group (n=15), and injury + LLLT group (n=15). The acute injury was induced by the contact with a cooled metal probe (3 mm in diameter) during 10 s, twice, in the same muscle area. LLLT was used three times a week using the InGaAlP laser (660 nm; beam spot of 0.04 cm(2), output power of 20 mW, power density of 500 mW/cm(2), and energy density of 5 J/cm(2) during 10 s). The animals were analyzed at 1, 7, and 14 days following injury. TA muscles samples were used for obtaining total RNA and performing cDNA synthesis. Real-time polymerase chain reactions were realized using IL-1B primer. There was a decrease in IL-1B expression after 7 days in LLLT group in comparison with the no treated group. In conclusion, LLLT was able to decrease IL-1B expression during the skeletal muscle repair following an acute injury.

Rev Bras Fizioter.  2012 Oct 9. pii: S1413-35552012005000053. [Epub ahead of print]

 

 

Evaluation of muscle regeneration in aged animals after treatment with low-level laser therapy.

Pertille A, Macedo AB, Oliveira CP.

Source

Graduate Program in Physical Therapy, Universidade Metodista de Piracicaba, Piracicaba, SP, Brazil.

 

Abstract

BACKGROUND:

The aging process and its associated morphophysiological changes trigger a reduction in the regenerative ability of the satellite cells, a reduction of vascular tissue and an increase in the production of fibroblasts, developing a cellular environment unfavorable for muscle regeneration.

OBJECTIVE:

The aim of this study was to evaluate the effect of low-level laser therapy on the muscle regeneration of old experimental rat models after contusion.

METHOD:

A total of 25 old rats,18 months old, were divided into three groups: control group (CT) without treatment; injury group (IN) with muscle contusion and without treatment and laser group (LA) with contusion and low-level laser therapy, 830 nm, 30 mW e 4 J/cm². The no invasive contusion was induced in the Tibialis Anterior muscle and the samples were collected after 7 and 21 treatment sessions. The muscle was evaluated by Light Microscopy and Immunoblotting.

RESULTS:

After 21 days of treatment there was a significant reduction in the areas of inflammation/regeneration of the LA 21 group compared to IN 21 group. The cross-sectional area of the fibers in regeneration was not statistically different between the groups. Molecular analysis showed that the content of MyoD was statistically reduced in the IN 21 group compared to the CT group. The Myogenin content was increased in the IN 21 group compared to the CT group. Ultimately, the content of TGF-B1 on the IN 21 group was higher when compared to the CT group.

CONCLUSION:

Considering the parameters used, the laser therapy demonstrated to be effective for muscle regeneration in old rats, however only through its anti-inflammatory effect.

 

Lasers Med Sci.  2012 Sep;27(5):993-1000. Epub 2011 Dec 6.

 

GaAs 904-nm laser irradiation improves myofiber mass recovery during regeneration of skeletal muscle previously damaged by crotoxin.

Silva LH, Silva MT, Gutierrez RM, Conte TC, Toledo CA, Aoki MS, Liebano RE, Miyabara EH.

Source

Department of Anatomy, Biomedical Sciences Institute, University of São Paulo, Lineu Prestes Av., 2415, 05508-000, São Paulo, SP, Brazil.

 

Abstract

This work investigated the effect of gallium arsenide (GaAs) irradiation (power: 5 mW; intensity: 77.14 mW/cm(2), spot: 0.07 cm(2)) on regenerating skeletal muscles damaged by crotoxin (CTX). Male C57Bl6 mice were divided into six groups (n=5 each): control, treated only with laser at doses of 1.5 J or 3 J, CTX-injured and, CTX-injured and treated with laser at doses of 1.5 J or 3 J. The injured groups received a CTX injection into the tibialis anterior (TA) muscle. After 3 days, TA muscles were submitted to GaAs irradiation at doses of 1.5 or 3 J (once a day, during 5 days) and were killed on the eighth day. Muscle histological sections were stained with hematoxylin and eosin (H&E) in order to determine the myofiber cross-sectional area (CSA), the previously injured muscle area (PIMA) and the area density of connective tissue. The gene expression of MyoD and myogenin was detected by real-time PCR. GaAs laser at a dose of 3 J, but not 1.5 J, significantly increased the CSA of regenerating myofibers and reduced the PIMA and the area density of intramuscular connective tissue of CTX-injured muscles. MyoD gene expression increased in the injured group treated with GaAs laser at a dose of 1.5 J. The CTX-injured, 3-J GaAs laser-treated, and the CTX-injured and treated with 3-J laser groups showed an increase in myogenin gene expression when compared to the control group. Our results suggest that GaAs laser treatment at a dose of 3 J improves skeletal muscle regeneration by accelerating the recovery of myofiber mass.

 

 

Lasers Med Sci.  2012 Aug 17. [Epub ahead of print]

Low-level laser therapy (808 nm) contributes to muscle regeneration and prevents fibrosis in rat tibialis anterior muscle after cryolesion.

Assis L, Moretti AI, Abrahão TB, de Souza HP, Hamblin MR, Parizotto NA.

Source

Laboratory of Electrothermophototherapy, Department of Physiotherapy, Federal University of São Carlos, São Carlos, SP, Brazil.

 

Abstract

Muscle regeneration is a complex phenomenon, involving replacement of damaged fibers by new muscle fibers. During this process, there is a tendency to form scar tissue or fibrosis by deposition of collagen that could be detrimental to muscle function. New therapies that could regulate fibrosis and favor muscle regeneration would be important for physical therapy. Low-level laser therapy (LLLT) has been studied for clinical treatment of skeletal muscle injuries and disorders, even though the molecular and cellular mechanisms have not yet been clarified. The aim of this study was to evaluate the effects of LLLT on molecular markers involved in muscle fibrosis and regeneration after cryolesion of the tibialis anterior (TA) muscle in rats. Sixty Wistar rats were randomly divided into three groups: control, injured TA muscle without LLLT, injured TA muscle treated with LLLT. The injured region was irradiated daily for four consecutive days, starting immediately after the lesion using an AlGaAs laser (808 nm, 30 mW, 180 J/cm(2); 3.8 W/cm(2), 1.4 J). The animals were sacrificed on the fourth day after injury. LLLT significantly reduced the lesion percentage area in the injured muscle (p?<?0.05), increased mRNA levels of the transcription factors MyoD and myogenin (p?<?0.01) and the pro-angiogenic vascular endothelial growth factor (p?<?0.01). Moreover, LLLT decreased the expression of the profibrotic transforming growth factor TGF-? mRNA (p?<?0.01) and reduced type I collagen deposition (p?<?0.01). These results suggest that LLLT could be an effective therapeutic approach for promoting skeletal muscle regeneration while preventing tissue fibrosis after muscle injury.

 

Lasers Med Sci.  2011 May;26(3):335-40. Epub 2010 Nov 4.

 

Effects of lowlevel laser therapy on expression of TNF-a and TGF-b in skeletal muscle during the repair process.

Mesquita-Ferrari RA, Martins MD, Silva JA Jr, da Silva TD, Piovesan RF, Pavesi VC, Bussadori SK, Fernandes KP.

Source

Departamento de Pós Graduação, Mestrado em Ciências da Reabilitação, Universidade Nove de Julho – UNINOVE, Av. Francisco Matarazzo, 612, Água Branca, CEP 05001-100, São Paulo, SP, Brazil. raquel.mesquita@gmail.com

 

Abstract

The aim of the present study was to determine the effect of lowlevel laser therapy (LLLT) on the expression of TNF-a and TGF-b in the tibialis anterior muscle of rats following cryoinjury. Muscle regeneration involves cell proliferation, migration and differentiation and is regulated by growth factors and cytokines. A growing body of evidence suggests that LLLT promotes skeletal muscle regeneration by reducing the duration of acute inflammation and accelerating tissue repair. Adult male Wistar rats (n=35) were randomly divided into three groups: control group (no lesion, untreated, n=5), cryoinjury without LLLT group (n=15), and cryoinjury with LLLT group (n=15). The injured region was irradiated three times a week using an AlGaInP laser (660 nm; beam spot 0.04 cm(2), output power 20 mW, power density 500 mW/cm(2), energy density 5 J/cm(2), exposure time 10 s). Muscle remodeling was evaluated at 1, 7 and 14 days (long-term) following injury. The muscles were removed and total RNA was isolated using TRIzol reagent and cDNA synthesis. Real-time polymerase chain reactions were performed using TNF-a and TGF-b primers; GAPDH was used to normalize the data. LLLT caused a decrease in TNF-a mRNA expression at 1 and 7 days following injury and in TGF-b mRNA expression at 7 days following cryoinjury in comparison to the control group. LLLT modulated cytokine expression during short-term muscle remodeling, inducing a decrease in TNF-a and TGF-b.

 

Lasers Med Sci.  2011 May;26(3):349-58. Epub 2010 Nov 18.

Effects of low level laser therapy (808 nm) on physical strength training in humans.

Ferraresi C, de Brito Oliveira T, de Oliveira Zafalon L, de Menezes Reiff RB, Baldissera V, de Andrade Perez SE, Matheucci Júnior E, Parizotto NA.

Source

Laboratory of Electrothermophototherapy, Department of Physical Therapy, Federal University of São Carlos, Rodovia Washington Luís, km 235, 13565-905, São Carlos, SP, Brazil. cleber.ferraresi@gmail.com

 

Abstract

Recent studies have investigated whether low level laser therapy (LLLT) can optimize human muscle performance in physical exercise. This study tested the effect of LLLT on muscle performance in physical strength training in humans compared with strength training only. The study involved 36 men (20.8±2.2 years old), clinically healthy, with a beginner and/or moderate physical activity training pattern. The subjects were randomly distributed into three groups: TLG (training with LLLT), TG (training only) and CG (control). The training for TG and TLG subjects involved the leg-press exercise with a load equal to 80% of one repetition maximum (1RM) in the leg-press test over 12 consecutive weeks. The LLLT was applied to the quadriceps muscle of both lower limbs of the TLG subjects immediately after the end of each training session. Using an infrared laser device (808 nm) with six diodes of 60 mW each a total energy of 50.4 J of LLLT was administered over 140 s. Muscle strength was assessed using the 1RM leg-press test and the isokinetic dynamometer test. The muscle volume of the thigh of the dominant limb was assessed by thigh perimetry. The TLG subjects showed an increase of 55% in the 1RM leg-press test, which was significantly higher than the increases in the TG subjects (26%, P?=?0.033) and in the CG subjects (0.27%, P?<?0.001). The TLG was the only group to show an increase in muscle performance in the isokinetic dynamometry test compared with baseline. The increases in thigh perimeter in the TLG subjects and TG subjects were not significantly different (4.52% and 2.75%, respectively; P?=?0.775). Strength training associated with LLLT can increase muscle performance compared with strength training only.

 

Lasers Med Sci.  2011 Jul 22. [Epub ahead of print]

 

Red (660 nm) and infrared (830 nm) low-level laser therapy in skeletal muscle fatigue in humans: what is better?

de Almeida P, Lopes-Martins RA, De Marchi T, Tomazoni SS, Albertini R, Corrêa JC, Rossi RP, Machado GP, da Silva DP, Bjordal JM, Leal Junior EC.

Source

Post Graduate Program in Rehabilitation Sciences, Nove de Julho University (UNINOVE), Rua Vergueiro, 235, 01504-001, São Paulo, SP, Brazil.

 

Abstract

In animal and clinical trials low-level laser therapy (LLLT) using red, infrared and mixed wavelengths has been shown to delay the development of skeletal muscle fatigue. However, the parameters employed in these studies do not allow a conclusion as to which wavelength range is better in delaying the development of skeletal muscle fatigue. With this perspective in mind, we compared the effects of red and infrared LLLT on skeletal muscle fatigue. A randomized double-blind placebo-controlled crossover trial was performed in ten healthy male volunteers. They were treated with active red LLLT, active infrared LLLT (660 or 830 nm, 50 mW, 17.85 W/cm(2), 100 s irradiation per point, 5 J, 1,785 J/cm(2) at each point irradiated, total 20 J irradiated per muscle) or an identical placebo LLLT at four points of the biceps brachii muscle for 3 min before exercise (voluntary isometric elbow flexion for 60 s). The mean peak force was significantly greater (p?<?0.05) following red (12.14%) and infrared LLLT (14.49%) than following placebo LLLT, and the mean average force was also significantly greater (p?<?0.05) following red (13.09%) and infrared LLLT (13.24%) than following placebo LLLT. There were no significant differences in mean average force or mean peak force between red and infrared LLLT. We conclude that both red than infrared LLLT are effective in delaying the development skeletal muscle fatigue and in enhancement of skeletal muscle performance. Further studies are needed to identify the specific mechanisms through which each wavelength acts.

 

Lasers Med Sci.   2011 Jul 15. [Epub ahead of print]

 

Phototherapy with low-level laser affects the remodeling of types I and III collagen in skeletal muscle repair.

de Souza TO, Mesquita DA, Ferrari RA, Dos Santos Pinto D Jr, Correa L, Bussadori SK, Fernandes KP, Martins MD.

Source

Rehabilitation Sciences, Universidade Nove de Julho – UNINOVE, 612, Avenida Francisco Matarazzo, São Paulo, SP, CEP: 05001-100, Brazil, thais.oricchio@terra.com.br.

 

Abstract

The purpose of this article was to analyze the photobiomodulator role of low-level laser therapy (LLLT) on the skeletal muscle remodeling following cryoinjury in rats, focusing the types I and III collagen proteins. Laser phototherapy has been employed to stimulate repair in different tissues. However, its role in skeletal muscle remodeling is not yet well clarified, especially its effect on the collagen component of the extracellular matrix. Fifty adult Wistar rats were divided into four groups: control, sham, cryoinjury, and laser-treated cryoinjury. Laser irradiation was performed three times a week on the injured region using the InGaAlP (indium-gallium-aluminum-phosphorous) laser (660 nm; beam spot of 0.04 cm(2), output power of 20 mW, power density of 0.5 mW/cm(2), energy density of 5 J/cm(2), 10-s exposure time, with a total energy dose of 0.2 J). Five animals were killed after short-term (days 1 and 7) and long-term (14 and 21) durations following injury. The muscles were processed and submitted to hematoxylin and eosin (H&E) and immunohistochemical staining. The histological slices were analyzed qualitatively, semi-quantitatively, and quantitatively. The data were submitted to statistical analysis using the Kruskal-Wallis test. The qualitative analysis of morphological aspects revealed that the muscle repair were very similar in cryoinjury and laser groups on days 1, 14 and 21. However, at 7 days, differences could be observed because there was a reduction in myonecrosis associated to formation of new vessels (angiogenesis) in the laser-treated group. The analysis of the distribution of types I and III collagen, on day 7, revealed a significant increase in the depositing of these proteins in the laser-treated group when compared to the cryoinjury group. InGaAlP diode laser within the power parameters and conditions tested had a biostimulatory effect at the regenerative and fibrotic phases of the skeletal muscle repairs, by promoting angiogenesis, reducing myonecrosis, and inducing types I and III collagen synthesis, following cryoinjury in rat.

 

Lasers Med Sci.  2011 Jul 8. [Epub ahead of print]

Low-level laser therapy (LLLT) in human progressive-intensity running: effects on exercise performance, skeletal muscle status, and oxidative stress.

De Marchi T, Leal Junior EC, Bortoli C, Tomazoni SS, Lopes-Martins RA, Salvador M.

Source

Laboratory of Oxidative Stress and Antioxidants, Institute of Biotechnology, University of Caxias do Sul, Rua Francisco Getúlio Vargas, 1130, 950070-560, Caxias do Sul, RS, Brazil.

Abstract

The aim of this work was to evaluate the effects of low-level laser therapy (LLLT) on exercise performance, oxidative stress, and muscle status in humans. A randomized double-blind placebo-controlled crossover trial was performed with 22 untrained male volunteers. LLLT (810 nm, 200 mW, 30 J in each site, 30 s of irradiation in each site) using a multi-diode cluster (with five spots – 6 J from each spot) at 12 sites of each lower limb (six in quadriceps, four in hamstrings, and two in gastrocnemius) was performed 5 min before a standardized progressive-intensity running protocol on a motor-drive treadmill until exhaustion. We analyzed exercise performance (VO(2 max), time to exhaustion, aerobic threshold and anaerobic threshold), levels of oxidative damage to lipids and proteins, the activities of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT), and the markers of muscle damage creatine kinase (CK) and lactate dehydrogenase (LDH). Compared to placebo, active LLLT significantly increased exercise performance (VO(2 max) p?=?0.01; time to exhaustion, p?=?0.04) without changing the aerobic and anaerobic thresholds. LLLT also decreased post-exercise lipid (p?=?0.0001) and protein (p?=?0.0230) damages, as well as the activities of SOD (p?=?0.0034), CK (p?=?0.0001) and LDH (p?=?0.0001) enzymes. LLLT application was not able to modulate CAT activity. The use of LLLT before progressive-intensity running exercise increases exercise performance, decreases exercise-induced oxidative stress and muscle damage, suggesting that the modulation of the redox system by LLLT could be related to the delay in skeletal muscle fatigue observed after the use of LLLT.

Izv Akad Nauk Ser Biol. 2010 Sep-Oct;(5):535-46.

Muscle regeneration and the state of the thymus in adult rats under laser irradiation and alloplasty of the gastrocnemius muscles and diaphragm of newborn rats.

[Article in Russian]

Buliakova NV, Azarova VS.

Abstract

The regeneration of gastrocnemius muscles of adult rats under implantation conditions in areas of muscle tissue damage in newborn rats has been studied. Alloplasty was performed using minced gastrocnemius and diaphragm muscles, which differs at birth in animals by degree of differentiation. The rat-recipient area of alloplasty was subjected to He-Ne laser radiation before operation, with the aim of reducing the immune response to allogenic muscle tissue. It has been shown that the number of regenerating myofibers produced in implanted gastrocnemius muscles is more than in alloplants from diaphragms. However, the formation of cartilage, bone, and adipose tissue foci were observed in the alloplastic region throughout the whole regeneration period. After implantation of minced diaphragm muscles, cartilage nodes were observed only in 7-day regenerates. At the end of observation, in the first instance, the area of muscle trauma in adult rat muscles was replaced by adipose tissue, even in the case of initial laser irradiation. During the implantation of diaphragm muscles, the area of trauma was filled with regenerating muscle tissue.

Lasers Med Sci. 2010 Nov 18. [Epub ahead of print]

Effects of low level laser therapy (808 nm) on physical strength training in humans.

Ferraresi C, de Brito Oliveira T, de Oliveira Zafalon L, de Menezes Reiff RB, Baldissera V, de Andrade Perez SE, Júnior EM, Parizotto NA.

Laboratory of Electrothermophototherapy, Department of Physical Therapy, Federal University of São Carlos, Rodovia Washington Luís, km 235, 13565-905, São Carlos, SP, Brazil, cleber.ferraresi@gmail.com.

Abstract

Recent studies have investigated whether low level laser therapy (LLLT) can optimize human muscle performance in physical exercise. This study tested the effect of LLLT on muscle performance in physical strength training in humans compared with strength training only. The study involved 36 men (20.8±2.2 years old), clinically healthy, with a beginner and/or moderate physical activity training pattern. The subjects were randomly distributed into three groups: TLG (training with LLLT), TG (training only) and CG (control). The training for TG and TLG subjects involved the leg-press exercise with a load equal to 80% of one repetition maximum (1RM) in the leg-press test over 12 consecutive weeks. The LLLT was applied to the quadriceps muscle of both lower limbs of the TLG subjects immediately after the end of each training session. Using an infrared laser device (808 nm) with six diodes of 60 mW each a total energy of 50.4 J of LLLT was administered over 140 s. Muscle strength was assessed using the 1RM leg-press test and the isokinetic dynamometer test. The muscle volume of the thigh of the dominant limb was assessed by thigh perimetry. The TLG subjects showed an increase of 55% in the 1RM leg-press test, which was significantly higher than the increases in the TG subjects (26%, P?=?0.033) and in the CG subjects (0.27%, P?<?0.001). The TLG was the only group to show an increase in muscle performance in the isokinetic dynamometry test compared with baseline. The increases in thigh perimeter in the TLG subjects and TG subjects were not significantly different (4.52% and 2.75%, respectively; P?=?0.775). Strength training associated with LLLT can increase muscle performance compared with strength training only.

Lasers Surg Med. 2010 Aug;42(6):577-83.

Evaluation of inflammatory biomarkers associated with oxidative stress and histological assessment of low-level laser therapy in experimental myopathy.

 Servetto N, Cremonezzi D, Simes JC, Moya M, Soriano F, Palma JA, Campana VR.

Cátedra de Física Biomédica, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Santa Rosa 1085, (5000) Córdoba, Argentina.

Abstract

The objective of the present work was to study the effect of helium-neon (He-Ne) and gallium-arsenide (Ga-As) laser upon inflammatory biomarkers associated with oxidative stress: fibrinogen, nitric oxide (NO), L-citrulline, and superoxide dismutase (SOD). These were evaluated through histological assessment, in rats with experimental myopathy.

MATERIALS AND METHODS: The groups studied were: (A) control, (B) injured, (C) injured and treated with He-Ne laser, (D) injured and treated with Ga-As laser, (E) irradiated with He-Ne; and (F) irradiated with Ga-As laser. Myopathy was induced by injecting 0.05 mg/rat/day of adrenaline in the left posterior limb muscle at the same point on 5 consecutive days, in groups B, C, and D. Low-level laser therapy (LLLT) was applied with 9.5 J/cm(2) daily for 7 consecutive days with each laser. The determination of the biomarkers was made by spectrophotometry. The muscles (5/8, single blinded) were stained with Gomori Trichrome and examined by optic microscopy. The quantitative variables were statistically analyzed by the Fisher's test and categorical data by the Axionvision 4.8 program. Pearson's chi-squared test was applied, setting significant difference at P < 0.05 for all cases.

RESULTS: In group B, the biomarkers were significantly increased compared to the other groups (P < 0.001), except for NO which in group B decreased significantly (P < 0.001). In group B, there was a higher inflammatory infiltration level (80.67%) in relation to destroyed fibers.

CONCLUSIONS: LLLT caused significant changes in inflammatory biomarkers and oxidative stress: decreased levels of fibrinogen, L-citrulline and SOD as opposed to the increase of NO in rats with experimental myopathies and significant muscle recovery.

Photodermatol Photoimmunol Photomed. 2010 Aug;26(4):192-7.

Phenotype characterization of pericytes during tissue repair following low-level laser therapy.

 Medrado A, Costa T, Prado T, Reis S, Andrade Z.

Laboratory of Experimental Pathology, Oswaldo Cruz Foundation, Salvador, Brazil.

Abstract

Background/purpose: The action of low-level laser therapy (LLLT) on pericytes during wound healing is not well established. The objective of this study was to identify the effect of laser treatment on pericytes during tissue repair. Methods: Punch biopsies were performed on 40 Wistar rats. Twenty animals had their wounds treated with a dose of 4 J/cm(2) using a 670 nm diode laser (9 mW output, 0.031 W/cm(2)) every other day, while the controls received sham irradiation. Animals were sacrificed 3, 7, 10 and 14 days after punch biopsy. Immunohistochemistry staining with anti-desmin, anti-smooth muscle alpha-actin and anti-NG2 antibodies was used to characterize and count pericytes around blood vessels and myofibroblasts dispersed in the extracellular matrix (ECM). The morphology of pericytes was confirmed by transmission electronic microscopy. Results: The laser group exhibited significantly more smooth muscle alpha-actin-positive staining cells at day 7 and more desmin-positive staining cells at day 10 around blood vessels. Laser treatment was also associated with higher numbers of NG2-positive staining cells, especially on days 3 and 7 post-biopsy (P<0.05). Ultrastructural findings confirmed the presence of pericytes sharing the basal membrane with endothelial cells. Conclusion: LLLT stimulated the proliferation and migration of pericytes to the ECM and their phenotypic modulation to myofibroblasts.

Eur J Appl Physiol. 2010 Jul 3. [Epub ahead of print]

 Low level laser therapy before eccentric exercise reduces muscle damage markers in humans.

 Baroni BM, Leal Junior EC, De Marchi T, Lopes AL, Salvador M, Vaz MA.

Exercise Research Laboratory (LAPEX), Federal University of Rio Grande do Sul (UFRGS), Rua Felizardo, 750-Bairro Jardim Botânico, Porto Alegre, RS, 90690-200, Brazil, bmbaroni@yahoo.com.br.

Abstract

The purpose of the present study was to determine the effect of low level laser therapy (LLLT) treatment before knee extensor eccentric exercise on indirect markers of muscle damage. Thirty-six healthy men were randomized in LLLT group (n = 18) and placebo group (n = 18). After LLLT or placebo treatment, subjects performed 75 maximal knee extensors eccentric contractions (five sets of 15 repetitions; velocity = 60 degrees seg(-1); range of motion = 60 degrees ). Muscle soreness (visual analogue scale-VAS), lactate dehydrogenase (LDH) and creatine kinase (CK) levels were measured prior to exercise, and 24 and 48 h after exercise. Muscle function (maximal voluntary contraction-MVC) was measured before exercise, immediately after, and 24 and 48 h post-exercise. Groups had no difference on kineanthropometric characteristics and on eccentric exercise performance. They also presented similar baseline values of VAS (0.00 mm for LLLT and placebo groups), LDH (LLLT = 186 IU/l; placebo = 183 IU/l), CK (LLLT = 145 IU/l; placebo = 155 IU/l) and MVC (LLLT = 293 Nm; placebo = 284 Nm). VAS data did not show group by time interaction (P = 0.066). In the other outcomes, LLLT group presented (1) smaller increase on LDH values 48 h post-exercise (LLLT = 366 IU/l; placebo = 484 IU/l; P = 0.017); (2) smaller increase on CK values 24 h (LLLT = 272 IU/l; placebo = 498 IU/l; P = 0.020) and 48 h (LLLT = 436 IU/l; placebo = 1328 IU/l; P < 0.001) post-exercise; (3) smaller decrease on MVC immediately after exercise (LLLT = 189 Nm; placebo = 154 Nm; P = 0.011), and 24 h (LLLT = 249 Nm; placebo = 205 Nm; P = 0.004) and 48 h (LLLT = 267 Nm; placebo = 216 Nm; P = 0.001) post-exercise compared with the placebo group. In conclusion, LLLT treatment before eccentric exercise was effective in terms of attenuating the increase of muscle proteins in the blood serum and the decrease in muscle force.

J Orthop Sports Phys Ther. 2010 Apr 12. [Epub ahead of print]

Effects of Low-Level Laser Therapy (LLLT) in the Development of Exercise-Induced Skeletal Muscle Fatigue and Changes in Biochemical Markers Related to Post-Exercise Recovery.

Leal Junior EC, Lopes-Martins RA, Frigo L, De Marchi T, Rossi RP, de Godoi V, Tomazoni SS, da Silva DP, Basso M, Filho PL, de Valls Corsetti F, Iversen VV, Bjordal JM.

Abstract

STUDY DESIGN: Randomized crossover double-blinded placebo-controlled trial. OBJECTIVE: To investigate if low level laser therapy (LLLT) can affect biceps muscle performance, fatigue development, and biochemical markers of post-exercise recovery. BACKGROUND: Cell and animal studies have suggested that LLLT can reduce oxidative stress and inflammatory responses in muscle tissue. But it remains uncertain whether these findings can translate into humans in sport and exercise situations. METHODS: Nine healthy male volleyball players participated in the study. They received either active LLLT (cluster probe with 5 laser diodes, l=810 nm, 200 mW power output, 30 seconds of irradiation, applied in 2 locations over the biceps of the non-dominant arm, 60 J of total energy) or placebo LLLT using an identical cluster probe. The intervention or placebo were applied 3 minutes before the performance of exercise. All subjects performed voluntary elbow flexion repetitions with a workload of 75% of their maximal voluntary contraction force (MVC) until exhaustion. RESULTS: Active LLLT increased the number of repetitions by 14.5% (mean of 39.56, SD +/- 4.33 versus 34.56 +/- 5.64, p=0.037) and the elapsed time before exhaustion by 8.0% (p=0.034), when compared to the placebo treatment. The biochemical markers also indicated that recovery may be positively affected by LLLT as indicated by post-exercise blood lactate levels (p<0.01), Creatine Kinase (CK) activity (p=0.017), and C-Reactive Protein (CRP) levels (p=0.047) showing a faster recovery with LLLT application prior to the exercise. CONCLUSION: We conclude that pre-exercise irradiation of the biceps with an LLLT dose of 6 J per application location, applied in 2 locations, increased endurance for repeated elbow flexion against resistance, and decreased post-exercise levels of blood lactate, CK, and CRP. LEVEL OF EVIDENCE: Therapy, Level 1a. J Orthop Sports Phys Ther, Epub 12 April 2010. doi:10.2519/jospt.2010.3294.

Eur J Appl Physiol. 2010 Apr;108(6):1083-8. Epub 2009 Dec 19.

Effects of low-level laser therapy (GaAs 904 nm) in skeletal muscle fatigue and biochemical markers of muscle damage in rats.

 

Leal Junior EC, Lopes-Martins RA, de Almeida P, Ramos L, Iversen VV, Bjordal JM.

Section for Physiotherapy Science, Department of Public Health and Primary Health Care, University of Bergen (UiB), Kalfarveien 31, 5020 Bergen, Norway. ernesto.leal.junior@gmail.com

Abstract

We wanted to test if pre-exercise muscle irradiation with 904 nm laser affects the development of fatigue, blood lactate levels and creatine kinase (CK) activity in a rat model with tetanic contractions. Thirty male Wistar rats were divided into five groups receiving either one of four different laser doses (0.1, 0.3, 1.0 and 3.0 J) or a no-treatment control group. Laser irradiation was performed immediately before the first contraction for treated groups. Electrical stimulation was used to induce six tetanic tibial anterior muscle contractions with 10 min intervals between them. Contractions were stopped when the muscle force fell to 50% of the peak value for each contraction; blood samples were taken before the first and immediately after the sixth contraction. The relative peak forces for the sixth contraction were significantly better (P < 0.05) in the two laser groups irradiated with highest doses [151.27% (SD +/- 18.82) for 1.0 J, 144.84% (SD +/- 34.47) for 3.0 J and 82.25% (SD +/- 11.69) for the control group]. Similar significant (P < 0.05) increases in mean performed work during the sixth contraction for the 1.0 and 3.0 J groups were also observed. Blood lactate levels were significantly lower (P < 0.05) than the control group in all irradiated groups. All irradiated groups except the 3.0 J group had significantly lower post-exercise CK activity than the control group. We conclude that pre-exercise irradiation with a laser dose of 1.0 J and 904 nm wavelength significantly delays muscle fatigue and decreases post-exercise blood lactate and CK in this rat model.

Lasers Med Sci. 2010 Jan;25(1):115-20. Epub 2009 Jun 25.

 

Low-level laser therapy attenuates creatine kinase levels and apoptosis during forced swimming in rats.

Sussai DA, Carvalho Pde T, Dourado DM, Belchior AC, dos Reis FA, Pereira DM.

Postgraduate Program in Health Science and Development in the Central Western Region, Universidade Federal do Mato Grosso do Sul (UFMS), Carandá Bosque, 79032-423 Campo Grande, MS, Brazil.

Abstract

Studies suggest that high-intensity physical exercise can cause damage to skeletal muscles, resulting in muscle soreness, fatigue, inflammatory processes and cell apoptosis. The aim of this study was to investigate the effects of low-level laser therapy (LLLT) on a decrease in creatine kinase (CK) levels and cell apoptosis. Twenty male Wistar rats were randomly divided into two equal groups: group 1 (control), resistance swimming; group 2 (LLLT), resistance swimming with LLLT. They were subjected to a single application of indium gallium aluminum phosphide (InGaAlP) laser immediately following the exercise for 40 s at an output power of 100 mW, wavelength 660 nm and 133.3 J/cm(2). The groups were subdivided according to sample collection time: 24 h and 48 h. CK was measured before and both 24 h and 48 h after the test. Samples of the gastrocnemius muscle were processed to determine the presence of apoptosis using terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP) nick end labeling. (There was a significant difference in CK levels between groups (P < 0.0001) as well as between the 24 h and 48 h levels in the control group, whereas there was no significant intra-group difference in the LLLT group at the same evaluation times. In the LLLT group there were 66.3 +/- 13.2 apoptotic cells after 24 h and 39.0 +/- 6.8 apoptotic cells after 48 h. The results suggest that LLLT influences the metabolic profile of animals subjected to fatigue by lowering serum levels of CK. This demonstrates that LLLT can act as a preventive tool against cell apoptosis experienced during high-intensity physical exercise.

Photomed Laser Surg. 2009 Dec;27(6):863-9.

Effects of low-level laser irradiation on rat skeletal muscle injury after eccentric exercise.

 

Liu XG, Zhou YJ, Liu TC, Yuan JQ.

Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, China.

Abstract

BACKGROUND AND OBJECTIVE: The effect of photobiomodulation on delayed onset muscle soreness remains unknown. This study represents the first investigation of this treatment using an animal model.

METHODS: Seventy-two Sprague-Dawley rats were randomly divided into five groups: sedentary control group, exercise control group and three exercise-plus-laser groups. Downhill running was used to induce muscle injury in the gastrocnemius muscle. He-Ne laser irradiations were administered to the injured muscles immediately and at 18 and 42 h after exercise in the three exercise-plus-laser groups at 12, 28, and 43 J/cm2, respectively. Histological examination and serum creatine kinase (CK), muscle superoxide dismutase (SOD) and malondialdehyde (MDA) analyses were done at 24 and 48 h after exercise.

RESULTS: The exercise control group exhibited a marked inflammation in the gastrocnemius muscle and significant elevations in serum CK activity and muscle MDA level after downhill running. He-Ne laser irradiation at 43 J/cm2 inhibited muscle inflammation, significantly enhanced muscle SOD activity and significantly reduced serum CK activity and muscle MDA level at both 24 and 48 h after exercise, whereas the irradiation at 12 or 28 J/cm2 slightly inhibited muscle inflammation and significantly reduced serum CK activity at 48 h after exercise only (P<0.05).

CONCLUSIONS: Low-level He-Ne laser therapy could exert therapeutic effects on eccentric exercise-induced rat muscle injury through enhancing muscle anti-oxidative capacity and reducing the inflammatory reaction. The photobiomodulation was dose-dependent, and the 43 J/cm2 dose was the most efficient among the doses used.

Exp Physiol. 2009 Jun 12. [Epub ahead of print]

Low-level laser irradiation promotes the recovery of atrophied gastrocnemius skeletal muscle in rat.

Nakano J, Kataoka H, Sakamoto J, Origuchi T, Okita M, Yoshimura T.

1 Nagasaki University Graduate School of Biomedical Sciences;

Low-level laser (LLL) irradiation promotes proliferation of muscle satellite cells, angiogenesis and expression of growth factors. Satellite cells, angiogenesis and growth factors play important roles in the regeneration of muscle. The objective of this study was to examine the effect of LLL irradiation on rat gastrocnemius muscle recovering from disuse muscle atrophy. Eight-week-old rats were subjected to hindlimb suspension for 2 weeks, after which they were released and recovered. During the recovery period, rats underwent daily LLL irradiation (Ga-Al-As; 830 nm; 60 mW; total, 180 sec) to the right gastrocnemius muscle through the skin. The untreated left gastrocnemius muscle served as the control. In conjunction with LLL irradiation, 5-bromo-2.deoxyuridine (BrdU) was injected subcutaneously for labeling of nuclei of proliferating cells. After 2 weeks, myofiber diameters of irradiated muscle increased in comparison with those of untreated muscle, but did't recover back to normal levels. Additionally, in the superficial region of muscle, the number of capillaries and fibroblast growth factor levels in irradiated muscle exhibited meaningful elevation relative to those of untreated muscle. In the deep region of muscle, BrdU-positive nuclei of satellite cells and / or myofibers of irradiated muscle increased significantly relative to that of the untreated muscle. The results of this study suggested that LLL irradiation can promote recovery from disuse muscle atrophy in association with proliferation of satellite cells and angiogenesis.

Photomed Laser Surg. 2009 Aug;27(4):617-23.

Comparison between single-diode low-level laser therapy (LLLT) and LED multi-diode (cluster) therapy (LEDT) applications before high-intensity exercise.

Leal Junior EC, Lopes-Martins RA, Baroni BM, De Marchi T, Rossi RP, Grosselli D, Generosi RA, de Godoi V, Basso M, Mancalossi JL, Bjordal JM.

Laboratory of Human Movement, University of Caxias do Sul, Caxias do Sul, RS, Brazil. ecplealj@ucs.br

BACKGROUND DATA AND OBJECTIVE: There is anecdotal evidence that low-level laser therapy (LLLT) may affect the development of muscular fatigue, minor muscle damage, and recovery after heavy exercises. Although manufacturers claim that cluster probes (LEDT) maybe more effective than single-diode lasers in clinical settings, there is a lack of head-to-head comparisons in controlled trials. This study was designed to compare the effect of single-diode LLLT and cluster LEDT before heavy exercise.

MATERIALS AND METHODS: This was a randomized, placebo-controlled, double-blind cross-over study. Young male volleyball players (n = 8) were enrolled and asked to perform three Wingate cycle tests after 4 x 30 sec LLLT or LEDT pretreatment of the rectus femoris muscle with either (1) an active LEDT cluster-probe (660/850 nm, 10/30 mW), (2) a placebo cluster-probe with no output, and (3) a single-diode 810-nm 200-mW laser.

RESULTS: The active LEDT group had significantly decreased post-exercise creatine kinase (CK) levels (-18.88 +/- 41.48 U/L), compared to the placebo cluster group (26.88 +/- 15.18 U/L) (p < 0.05) and the active single-diode laser group (43.38 +/- 32.90 U/L) (p < 0.01). None of the pre-exercise LLLT or LEDT protocols enhanced performance on the Wingate tests or reduced post-exercise blood lactate levels. However, a non-significant tendency toward lower post-exercise blood lactate levels in the treated groups should be explored further.

CONCLUSION: In this experimental set-up, only the active LEDT probe decreased post-exercise CK levels after the Wingate cycle test. Neither performance nor blood lactate levels were significantly affected by this protocol of pre-exercise LEDT or LLLT.

Exp Physiol. 2009 Jun 12. [Epub ahead of print]

Low-level laser irradiation promotes the recovery of atrophied gastrocnemius skeletal muscle in rat.

Nakano J, Kataoka H, Sakamoto J, Origuchi T, Okita M, Yoshimura T.

1 Nagasaki University Graduate School of Biomedical Sciences;

Low-level laser (LLL) irradiation promotes proliferation of muscle satellite cells, angiogenesis and expression of growth factors. Satellite cells, angiogenesis and growth factors play important roles in the regeneration of muscle. The objective of this study was to examine the effect of LLL irradiation on rat gastrocnemius muscle recovering from disuse muscle atrophy. Eight-week-old rats were subjected to hindlimb suspension for 2 weeks, after which they were released and recovered. During the recovery period, rats underwent daily LLL irradiation (Ga-Al-As; 830 nm; 60 mW; total, 180 sec) to the right gastrocnemius muscle through the skin. The untreated left gastrocnemius muscle served as the control. In conjunction with LLL irradiation, 5-bromo-2.deoxyuridine (BrdU) was injected subcutaneously for labeling of nuclei of proliferating cells. After 2 weeks, myofiber diameters of irradiated muscle increased in comparison with those of untreated muscle, but did't recover back to normal levels. Additionally, in the superficial region of muscle, the number of capillaries and fibroblast growth factor levels in irradiated muscle exhibited meaningful elevation relative to those of untreated muscle. In the deep region of muscle, BrdU-positive nuclei of satellite cells and / or myofibers of irradiated muscle increased significantly relative to that of the untreated muscle. The results of this study suggested that LLL irradiation can promote recovery from disuse muscle atrophy in association with proliferation of satellite cells and angiogenesis.

Lasers Med Sci. 2009 Jun 25. [Epub ahead of print]

Low-level laser therapy attenuates creatine kinase levels and apoptosis during forced swimming in rats.

Sussai DA, Carvalho PD, Dourado DM, Belchior AC, Dos Reis FA, Pereira DM.

Postgraduate Program in Health Science and Development in the Central Western Region, Universidade Federal do Mato Grosso do Sul (UFMS), Rua Abricó do Pará, 146, Carandá Bosque, 79032-423, Campo Grande, MS, Brazil.

Studies suggest that high-intensity physical exercise can cause damage to skeletal muscles, resulting in muscle soreness, fatigue, inflammatory processes and cell apoptosis. The aim of this study was to investigate the effects of low-level laser therapy (LLLT) on a decrease in creatine kinase (CK) levels and cell apoptosis. Twenty male Wistar rats were randomly divided into two equal groups: group 1 (control), resistance swimming; group 2 (LLLT), resistance swimming with LLLT. They were subjected to a single application of indium gallium aluminum phosphide (InGaAlP) laser immediately following the exercise for 40 s at an output power of 100 mW, wavelength 660 nm and 133.3 J/cm(2). The groups were subdivided according to sample collection time: 24 h and 48 h. CK was measured before and both 24 h and 48 h after the test. Samples of the gastrocnemius muscle were processed to determine the presence of apoptosis using terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP) nick end labeling. (There was a significant difference in CK levels between groups (P < 0.0001) as well as between the 24 h and 48 h levels in the control group, whereas there was no significant intra-group difference in the LLLT group at the same evaluation times. In the LLLT group there were 66.3 +/- 13.2 apoptotic cells after 24 h and 39.0 +/- 6.8 apoptotic cells after 48 h. The results suggest that LLLT influences the metabolic profile of animals subjected to fatigue by lowering serum levels of CK. This demonstrates that LLLT can act as a preventive tool against cell apoptosis experienced during high-intensity physical exercise.

Photomed Laser Surg. 2008 Oct;26(5):419-24

Effect of 655-nm low-level laser therapy on exercise-induced skeletal muscle fatigue in humans.

Leal Junior EC, Lopes-Martins RA, Dalan F, Ferrari M, Sbabo FM, Generosi RA, Baroni BM, Penna SC, Iversen VV, Bjordal JM.

Laboratory of Human Movement, University of Caxias do Sul, Caxias do Sul, RS, Brazil. ecplealj@ucs.br

OBJECTIVE: To investigate if development of skeletal muscle fatigue during repeated voluntary biceps contractions could be attenuated by low-level laser therapy (LLLT).

BACKGROUND DATA: Previous animal studies have indicated that LLLT can reduce oxidative stress and delay the onset of skeletal muscle fatigue.

MATERIALS AND METHODS: Twelve male professional volleyball players were entered into a randomized double-blind placebo-controlled trial, for two sessions (on day 1 and day 8) at a 1-wk interval, with both groups performing as many voluntary biceps contractions as possible, with a load of 75% of the maximal voluntary contraction force (MVC). At the second session on day 8, the groups were either given LLLT (655 nm) of 5 J at an energy density of 500 J/cm2 administered at each of four points along the middle of the biceps muscle belly, or placebo LLLT in the same manner immediately before the exercise session. The number of muscle contractions with 75% of MVC was counted by a blinded observer and blood lactate concentration was measured.

RESULTS: Compared to the first session (on day 1), the mean number of repetitions increased significantly by 8.5 repetitions (+/- 1.9) in the active LLLT group at the second session (on day 8), while in the placebo LLLT group the increase was only 2.7 repetitions (+/- 2.9) (p = 0.0001). At the second session, blood lactate levels increased from a pre-exercise mean of 2.4 mmol/L (+/- 0.5 mmol/L), to 3.6 mmol/L (+/- 0.5 mmol/L) in the placebo group, and to 3.8 mmol/L (+/- 0.4 mmol/L) in the active LLLT group after exercise, but this difference between groups was not statistically significant.

CONCLUSION: We conclude that LLLT appears to delay the onset of muscle fatigue and exhaustion by a local mechanism in spite of increased blood lactate levels.

Lasers Med Sci. 2008 Dec 5. [Epub ahead of print]

Effect of 830 nm low-level laser therapy applied before high-intensity exercises on skeletal muscle recovery in atheletes.

Leal Junior EC, Lopes-Martins RA, Baroni BM, De Marchi T, Taufer D, Manfro DS, Rech M, Danna V, Grosselli D, Generosi RA, Marcos RL, Ramos L, Bjordal JM.

Laboratory of Human Movement (LMH), Sports Medicine Institute (IME), University of Caxias do Sul (UCS), Rua Francisco Getúlio Vargas, 1130, 95070-560, Caxias do Sul, RS, Brazil, ecplealj@ucs.br.

Our aim was to investigate the immediate effects of bilateral, 830 nm, low-level laser therapy (LLLT) on high-intensity exercise and biochemical markers of skeletal muscle recovery, in a randomised, double-blind, placebo-controlled, crossover trial set in a sports physiotherapy clinic. Twenty male athletes (nine professional volleyball players and eleven adolescent soccer players) participated. Active LLLT (830 nm wavelength, 100 mW, spot size 0.0028 cm(2), 3-4 J per point) or an identical placebo LLLT was delivered to five points in the rectus femoris muscle (bilaterally). The main outcome measures were the work performed in the Wingate test: 30 s of maximum cycling with a load of 7.5% of body weight, and the measurement of blood lactate (BL) and creatine kinase (CK) levels before and after exercise. There was no significant difference in the work performed during the Wingate test (P > 0.05) between subjects given active LLLT and those given placebo LLLT. For volleyball athletes, the change in CK levels from before to after the exercise test was significantly lower (P = 0.0133) for those given active LLLT (2.52 U l(-1) +/- 7.04 U l(-1)) than for those given placebo LLLT (28.49 U l(-1) +/- 22.62 U l(-1)). For the soccer athletes, the change in blood lactate levels from before exercise to 15 min after exercise was significantly lower (P < 0.01) in the group subjected to active LLLT (8.55 mmol l(-1) +/- 2.14 mmol l(-1)) than in the group subjected to placebo LLLT (10.52 mmol l(-1) +/- 1.82 mmol l(-1)). LLLT irradiation before the Wingate test seemed to inhibit an expected post-exercise increase in CK level and to accelerate post-exercise lactate removal without affecting test performance. These findings suggest that LLLT may be of benefit in accelerating post-exercise recovery.

Photomed Laser Surg. 2006 Apr;24(2):111-20.

Photoengineering of tissue repair in skeletal and cardiac muscles.

Oron U.

Department of Zoology, The George S. Wise Faculty of Life Sciences, Tel-Aviv University, Israel. oronu@post.tau.ac.il

This review discusses the application of He-Ne laser irradiation to injured muscles at optimal power densities and optimal timing, which was found to significantly enhance (twofold) muscle regeneration in rats and, even more, in the cold-blooded toads. Multiple and frequent (daily) application of the laser in the toad model was found to be less effective than irradiation on alternate days. It was found that in the ischemia/reperfusion type of injury in the skeletal leg muscles (3 h of ischemia), infrared Ga-Al-As laser irradiation reduced muscle degeneration, increased the cytoprotective heat shock proteins (HSP-70i) content, and produced a twofold increase in total antioxidants. In vitro studies on myogenic satellite cells (SC) revealed that phototherapy restored their proliferation. Phototherapy induced mitogen-activated protein kinase/extracellular signal-regulated protein kinase (MAPK/ERK) phosphorylation in these cells, probably by specific receptor phosphorylation. Cell cycle entry and the accumulation of satellite cells around isolated single myofibers cultured in vitro was also stimulated by phototherapy. Phototherapy also had beneficial effects on mouse, rat, dog and pig ischemic heart models. In these models, it was found that phototherapy markedly and significantly reduced (50-70%) the scar tissue formed after induction of myocardial infarction (MI). The phototherapeutic effect was associated with reduction of ventricular dilatation, preservation of mitochondria and elevation of HSP- 70i and ATP in the infarcted zone. It is concluded that phototherapy using the correct parameters and timing has a markedly beneficial effect on repair processes after injury or ischemia in skeletal and heart muscles. This phenomenon may have clinical applications.

J Appl Physiol. 2006 Jul;101(1):283-8. Epub 2006 Apr 20.

Effect of low-level laser (Ga-Al-As 655 nm) on skeletal muscle fatigue induced by electrical stimulation in rats.

Lopes-Martins RA, Marcos RL, Leonardo PS, Prianti AC Jr, Muscará MN, Aimbire F, Frigo L, Iversen VV, Bjordal JM.

Department of Pharmacology, Laboratory of Biochemical Pharmacology of Free Radicals, Institute of Biomedical Sciences, University of São Paulo, Brazil. rmartins@icb.usp.br

We investigated whether low-level laser therapy (LLLT) can reduce muscular fatigue during tetanic contractions in rats. Thirty-two male Wistar rats were divided into four groups receiving either one of three different LLLT doses (0.5, 1.0, and 2.5 J/cm2) or a no-treatment control group. Electrical stimulation was used to induce six tetanic muscle contractions in the tibial anterior muscle. Contractions were stopped when the muscle force fell to 50% of the initial value for each contraction (T50%). There was no significant difference between the 2.5 J/cm2 laser-irradiated group and the control group in mean T50% values. Laser-irradiated groups (0.5 and 1.0 J/cm2) had significantly longer T50% values than the control group. The relative peak force for the sixth contraction in the laser-irradiated groups were significantly higher at 92.2% (SD 12.6) for 0.5 J/cm2, 83.2% (SD 20.5) for 1.0 J/cm2, and 82.9% (SD 18.3) for 2.5 J/cm2 than for the control group [50% (SD 15)]. Laser groups receiving 0.5 and 1.0 J/cm2 showed significant increases in mean performed work compared with both the control group and their first contraction values. Muscle damage was indirectly measured by creatine kinase levels in plasma. A distinct dose-response pattern was found in which 1.0 and 2.5 J/cm2 LLLT groups had significantly lower creatine kinase levels than the 0.5 J/cm2 LLLT group and the control group. We conclude that LLLT doses of 0.5 and 1.0 J/cm2 can prevent development of muscular fatigue in rats during repeated tetanic contractions.

Photomed Laser Surg. 2005 Jun;23(3):273-7

Protection of skeletal muscles from ischemic injury: low-level laser therapy increases antioxidant activity.

Avni D, Levkovitz S, Maltz L, Oron U.

Department of Zoology, The George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, Israel.

OBJECTIVE: The aim of this study was to investigate the effect of low-level laser therapy (LLLT) on ischemic-reperfusion (I-R) injury in the gastrocnemius muscle of the rat.

BACKGROUND DATA: Ischemic injury in skeletal muscle is initiated during hypoxia and is aggravated by reoxygenation during blood reperfusion and accumulation of cytotoxic reactive oxygen superoxides. LLLT has been found to biostimulate various biological processes, such as attenuation of ischemic injury in the heart.

MATERIALS AND METHODS: The injury was induced in the gastrocnemius muscles of 106 rats by complete occlusion of the blood supply for 3 h, followed by reperfusion. Another group of intact rats served to investigate the effect of LLLT on intact nonischemic muscles. Creatine phosphokinase, acid phosphatase, and heat shock protein were determined 7 days after I-R injury and antioxidant levels 2 h after reperfusion.

RESULTS: Laser irradiation (Ga-As, 810 nm) was applied to the muscles immediately and 1 h following blood supply occlusion. It was found that laser irradiation markedly protects skeletal muscles from degeneration following acute I-R injury. This was evident by significantly (p < 0.05) higher content of creatine phosphokinase activity and lower (p < 0.05) activity of acid phosphatase in the LLLT-treated muscles relative to the injured non-irradiated ones. The content of antioxidants and heat shock proteins was also higher (p < 0.05) in the LLLT-treated muscles relative to that of injured non-irradiated muscles.

CONCLUSION: The present study describes for the first time the ability of LLLT to significantly prevent degeneration following ischemia/reperfusion injury in skeletal muscles, probably by induction of synthesis of antioxidants and other cytoprotective proteins, such as hsp-70i. The elevation of antioxidants was also evident in intact muscle following LLLT. The above phenomenon may also be of clinical relevance in scheduled surgery or microsurgery requiring extended tourniquet applications to skeletal muscle followed by reperfusion.

Lasers Med Sci. 2006 Dec;21(4):238-44. Epub 2006 Oct 11

Low-level laser therapy can reduce lipopolysaccharide-induced contractile force dysfunction and TNF-alpha levels in rat diaphragm muscle.

Aimbire F, Lopes-Martins RA, Castro-Faria-Neto HC, Albertini R, Chavantes MC, Pacheco MT, Leonardo PS, Iversen VV, Bjordal JM.

Research Group of Animal Experimental, IP & D UNIVAP R. Shishima Hifumi, 2911, 12240-000, São José dos Campos, SP, Brazil.

Our objective was to investigate if low-level laser therapy (LLLT) could improve respiratory function and inhibit tumor necrosis factor (TNF-alpha) release into the diaphragm muscle of rats after an intravenous injection of lipopolysaccharide (LPS) (5 mg/kg). We randomly divided Wistar rats in a control group without LPS injection, and LPS groups receiving either (a) no therapy, (b) four sessions in 24 h with diode Ga-AsI-Al laser of 650 nm and a total dose of 5.2 J/cm2, or (c) an intravenous injection (1.25 mg/kg) of the TNF-alpha inhibitor chlorpromazine (CPZ). LPS injection reduced maximal force by electrical stimulation of diaphragm muscle from 24.15+/-0.87 N in controls, but the addition of LLLT partly inhibited this reduction (LPS only: 15.01+/-1.1 N vs LPS+LLLT: 18.84+/-0.73 N, P<0.05). In addition, this dose of LLLT and CPZ significantly (P<0.05 and P<0.01, respectively) reduced TNF-alpha concentrations in diaphragm muscle when compared to the untreated control group.

J Cell Sci. 2002 Apr 1;115(Pt 7):1461-9.  

 

Low-energy laser irradiation promotes the survival and cell cycle entry of skeletal muscle satellite cells.

Shefer G, Partridge TA, Heslop L, Gross JG, Oron U, Halevy O.

Department of Animal Sciences, The Hebrew University of Jerusalem, P.O. Box 12, Rehovot 76100, Israel.

Low energy laser irradiation (LELI) has been shown to promote skeletal muscle cell activation and proliferation in primary cultures of satellite cells as well as in myogenic cell lines. Here, we have extended these studies to isolated myofibers. These constitute the minimum viable functional unit of the skeletal muscle, thus providing a close model of in vivo regeneration of muscle tissue. We show that LELI stimulates cell cycle entry and the accumulation of satellite cells around isolated single fibers grown under serum-free conditions and that these effects act synergistically with the addition of serum. Moreover, for the first time we show that LELI promotes the survival of fibers and their adjacent cells, as well as cultured myogenic cells, under serum-free conditions that normally lead to apoptosis. In both systems, expression of the anti-apoptotic protein Bcl-2 was markedly increased, whereas expression of the pro-apoptotic protein BAX was reduced. In culture, these changes were accompanied by a reduction in the expression of p53 and the cyclin-dependent kinase inhibitor p21, reflecting the small decrease in viable cells 24 hours after irradiation. These findings implicate regulation of these factors as part of the protective role of LELI against apoptosis. Taken together, our findings are of critical importance in attempts to improve muscle regeneration following injury.

Anat Rec. 1995 Jan;241(1):123-8.

Regeneration in denervated toad (Bufo viridis) gastrocnemius muscle and the promotion of the process by low energy laser irradiation.

Bibikova A, Oron U.

Department of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Israel.

BACKGROUND: It is known that while denervated skeletal muscles have the ability to regenerate, maturation of regenerated myofibres does not take place under these conditions. Denervation also causes elevation of "invasive" and satellite cells, but the role of these cells in the regeneration process after injury to the denervated muscle is still unknown. Low energy lasers have recently been found to modulate and accelerate physiological processes in cells. The aim of the present study was to compare regeneration in denervated and innervated amphibian muscles and to investigate whether this process in denervated muscles can be stimulated by low energy laser irradiation prior to injury in these muscles.

METHODS: Denervated gastrocnemius muscles of toads were irradiated with He-Ne laser (6.0 mW, 31.2 J/cm2) 7 days postdenervation (control muscle received red light irradiation at the same wavelength). Nine days after denervation cold injury was performed on the site of irradiation of both groups of muscles. At 14 days postinjury all muscles were removed and processed for histology and histomorphometric analysis of mononucleated cells, myotubes, and young myofibres in the regenerated zone.

RESULTS: The volume fraction (percent of total injured zone) of the various histological structures in the injured zones 14 days after cold injury in the denervated (9 days prior to injury) muscles did not differ from innervated injured muscles at the same time interval postinjury. The mononucleated cells and myotubes in the laser irradiated muscles comprised 49 +/- 4% and 6 +/- 1% of the injured area, respectively, which was significantly lower than their volume fraction (67 +/- 2% and 11 +/- 2%, respectively) in the control muscles. The young myofibres populated 34 +/- 4% of the total injured area in the denervated and laser irradiated muscles which was significantly higher than their volume fraction (12 +/- 2%) in control denervated muscles.

CONCLUSIONS: It is concluded that initial stages of regeneration can also take place in skeletal denervated and injured muscles of amphibians. The kinetics of the regeneration process are identical in denervated and innervated muscles. The process of regeneration in denervated muscles can be markedly enhanced if the muscle is irradiated by low energy laser prior to injury, probably by activation (stimulation of proliferation and/or differentiation) cells in the muscles that are "recruited" and participate in the process of regeneration.

Lasers Med Sci. 2001;16(1):44-51

Dose-dependency of low-energy HeNe laser effect in regeneration of skeletal muscle in mice.

Amaral AC, Parizotto NA, Salvini TF.

Departamento de Fisioterapia, Universidade Federal de São Carlos, São Carlos/SP, Brasil.

We evaluated the effect on mice skeletal muscle regeneration of different doses (2.6, 8.4, and 25 J/cm2) of HeNe laser (lambda 632.8 nm; power, 2.6 mW; spot size, 0.007 cm2) applied directly to intact skin of injured muscle. Muscle injury was induced in both right and left Tibialis anterior (TA) muscles by ACL myotoxin (5 mg/kg). Right TA muscles were irradiated daily for 5 days while contralateral muscles received a sham treatment. Only the 2.6 J/cm2 dose resulted in changes such as increased mitochondrial density and muscle fibre in the TA muscles as compared to sham groups (3280 +/- 704 microns 2 versus 2110 +/- 657 microns 2, p = 0.02). We concluded that the HeNe effect on mouse muscle regeneration is dose-specific: only 2.6 J/cm2 increased muscle fibre area and mitochondrial density.

Radiats Biol Radioecol. 2002 May-Jun;42(3):315-21.

[Histogenetic, metabolic, and immunologic aspects of the effect of infrared laser radiation on injured skeletal muscles from irradiated and nonirradiated rats]

[Article in Russian]

Zubkova SM, Buliakova NV, Mikha?lik LV, Varakina NI, Azarova VS.

Russian Research Center of Rehabilitative Medicine and Balneology, Ministry of Health of Russia, Moscow, 121099, Russia.

Using biochemical, histological, morphometric and cytogenetic methods, it was shown that low-intensive infrared laser radiation (total dose 3.6 J/cm2), applied to the injured rat skeletal muscles, stimulated metabolism and regeneration more efficiently in the muscles locally exposed to 20 Gy X-rays compared to the unexposed muscles. The laser irradiation promoted postradiative recovery in bone marrow cells, but did not provide normalization in thymus lymphocyte activity.

Vopr Kurortol Fizioter Lech Fiz Kult. 2000 Nov-Dec;(6):8-11.

[Experimental study of the effect of pulsed infrared laser radiation on skeletal muscle regeneration after mechanical trauma]

[Article in Russian]

Buliakova NV, Zubkova SM, Azarova VS, Mikha?lik LV, Varakina NI.

Impulse infrared laser radiation (0.89 microm) was examined for effect on regeneration of cross-cut musculus gastrocnemius in adult rats (ten 3-min exposures, 2-3 procedures weekly for one month after the operation, modulating frequency 10 Hz, total course dose 3.6 J/cm2). Histological, morphometric and biochemical parameters of muscular regenerates as well as biochemical serum indices show enhanced regeneration of the skeletal muscle. Formation of the muscular organ ends earlier vs untreated muscles. This was accompanied with more active sclerotization of the muscular regenerate.

Vopr Kurortol Fizioter Lech Fiz Kult. 1998 Nov-Dec;(6):11-6.

[A comparative analysis of the action of red and infrared laser radiation and ultrasound on the regeneration of locally irradiated skeletal muscle and on immune system function in the rat]

[Article in Russian]

Subkova SM, Buliakova NV, Mikha?lik LV, Varakina NI, Azarova VS.

The study was made of a regeneration ability of the rat skeletal muscle which had been mechanically injured and exposed to a 20 Gy irradiation, of the thymus and bone marrow condition after local exposure of the muscle to red and infrared laser radiation and ultrasound. These factors were found to stimulate regeneration of the injured soft tissues and to reduce cytogenetic damage to bone marrow cells in the irradiated zone under growing immunosuppression. The stimulation was most potent in prolonged exposure to the ultrasound.

J Clin Laser Med Surg. 1996 Dec;14(6):375-80.

Delayed-onset muscle soreness: lack of effect of combined phototherapy/low-intensity laser therapy at low pulse repetition rates.

Craig JA, Barlas P, Baxter GD, Walsh DM, Allen JM.

Rehabilitation Sciences Research Group, School of Health Sciences, University of Ulster, Jordanstown, N. Ireland.

A double-blind, placebo-controlled study using male subjects (n = 60), was conducted to investigate the efficacy of three different frequencies of combined phototherapy/low-intensity laser therapy (CLILT) in alleviating the signs and symptoms of delayed-onset muscle soreness (DOMS). The study was approved by the University's ethical committee. After screening for relevant pathologies, recent analgesic or steroid drug usage, current pain, diabetes, or current involvement in regular weight-training activities, subjects were randomly allocated to one of five experimental groups: Control, Placebo, or 2.5-Hz, 5-Hz, or 20-Hz CLILT groups (660-950 nm; 31.7 J/cm2; pulsed at the given frequencies for a duration of 12 min; n = 12 all groups). Once baseline measurements were obtained, DOMS was induced in the nondominant arm, which was exercised in a standardized fashion until exhaustion, using repeated eccentric contractions of the elbow flexors. The procedure was repeated twice more to ensure exhaustion was achieved, after which subjects were treated according to group allocation. In the CLILT/placebo groups, the treatment head was applied directly to the affected arm at the level of the musculotendinous junction. Subjects returned on two consecutive days for further treatment and assessment. The range of variables used to assess DOMS included range of movement (universal goniometer), mechanical pain threshold/tenderness (algometer) and pain (visual analogue scale and McGill Pain Questionnaire). Measurements were taken before and after treatment on each day, except for the McGill Pain questionnaire, which was completed at the end of the study. Analysis of results using repeated measures and one-factor analysis of variance with relevant post hoc tests showed significant changes in ranges of movement accompanied by increases in subjective pain and tenderness for all groups over time (p = 0.0001); however, such analysis failed to show any significant differences between groups on any of the days. These results thus provide no convincing evidence for any putative hypoalgesic effect of CLILT upon DOMS at the parameters used here.

Biull Eksp Biol Med. 1989 Mar;107(3):345-7.

[Effect of helium-neon laser rays on the processes of postradiation recovery in the skeletal muscles of old rats]

[Article in Russian]

Buliakova NV.

The present experiments were conducted to determine the stimulant effect of helium-neon laser on the postradiation recovery in irradiated uninjured skeletal muscle of rats aged 2-2.5. This was indicated by a restored ability of the muscle for posttraumatic regeneration. The both hind rat legs were exposed to local irradiation of 20 Gy and following laser therapy (8-9 procedures at 3 min each, impulsive or continuous one). Then both musculus gastrocnemius were cut across 30 days after irradiation. It was shown that laser therapy employed before injury of the irradiated muscle accelerated fibrin resorption and improved connective tissue, but slightly stimulated muscular tissue. Impulse laser therapy was more favourable for state of skin and healing of the skin wound after irradiation.