Photomed Laser Surg. 2007 Jun;25(3):191-6
Effect of low-level laser therapy on healing of medial collateral ligament injuries in rats: an ultrastructural study.
Delbari A, Bayat M, Bayat M.
Avicenna Hospital, Tehran, Iran.
OBJECTIVE: This study sought to investigate whether low-level laser therapy (LLLT) with a helium-neon (He-Ne) laser would increase fibril diameter of transected medial collateral ligament (MCL) in rats.
BACKGROUND DATA: It has been shown that LLLT can increase ultimate tensile strength MCL healing.
METHODS: Thirty rats received surgical transect to their right MCL, and five were assigned as the control group. After surgery, the rats were divided into three groups: group 1 (n = 10) received LLLT with He-Ne laser and 0.01 J/cm(2) energy fluency per day, group 2 (n = 10) received LLLT with 1.2 J/cm(2) energy fluency (density) per day and group 3 (sham-exposed group; n = 10) received daily placebo laser with shut-down laser equipment, while control group received neither surgery nor LLLT. Transmission electron microscope (TEM) examination was performed on days 12 and 21 after surgery and dimension and density of ligament fibrils were measured. The data were analyzed by Student t-test and Mann-Whitney tests, respectively.
RESULTS: On day 12, the fibril dimension of group 2 and their density were higher than of groups 1 and 3.
CONCLUSION: LLLT with He-Ne laser on incised MCL in rats could not significantly increase fibril diameter and their density in comparison with sham-exposed group.
Photomed Laser Surg. 2005 Dec;23(6):556-60
Low-level laser therapy improves early healing of medial collateral ligament injuries in rats.
Bayat M, Delbari A, Almaseyeh MA, Sadeghi Y, Bayat M, Reziae F.
Cell and Molecular Biology Research Center, Medical School, Shaheed Beheshti University of Medical Sciences, Tehran, Iran. email@example.com
OBJECTIVE: This study sought to investigate whether or not low-level laser therapy (LLLT) with a helium-neon laser increased biomechanical parameters of transected medial collateral ligament (MCL) in rats.
BACKGROUND DATA: It has been reported that LLLT can enhance tendon healing.
METHODS: Thirty rats received surgical transection to their right MCL, and five were assigned as the control group. After surgery, the rats were divided into three groups: group 1 (n = 10) received LLLT with 0.01 J/cm(2) energy density per day, group 2 (n = 10) received LLLT with 1.2 J/cm(2) energy density per day, and group 3 (sham = exposed group; n = 10) received daily placebo laser with shut-down laser equipment, while the control group received neither surgery nor LLLT. Biomechanical tests were performed at 12 and 21 days after surgery. The data were analyzed by one-way analysis of variance.
RESULTS: The ultimate tensile strength (UTS) of group 2 on day 12 was significantly higher than that of groups 1 and 3. Furthermore, the UTS and energy absorption of the control (uninjured) group were significantly higher than those of the other groups.
CONCLUSIONS: LLLT with a helium-neon laser is effective for the early improvement of the ultimate tensile strength of medial collateral ligament injuries.
Connect Tissue Res. 2005;46(3):125-30
Combined treatment of therapeutic laser and herbal application improves the strength of repairing ligament.
Fung DT, Ng GY, Leung MC.
Orthopaedic Rehabilitation Research and Microscopy Laboratory, Department of Rehabilitation Sciences, Hong Kong Polytechnic University, Hong Kong, China.
The present study investigated the effects of combined therapeutic laser and herbal medication protocols on injured medial collateral ligaments (MCLs) of rat knees. Fully 36 rats were evenly divided into 9 groups. Right MCLs of groups 1 to 6 and 8 were transected, while that of groups 7 and 9 remained intact. After surgery, group 1 was treated with 1 session of high-dosed laser; group 2 with 9 sessions of low-dosed laser; group 3 with an herbal plaster; groups 4 and 5 received combined treatments of groups 1 and ss and 2, and 3 respectively; groups 6 and 7 received only bandaging; groups 8 and 9 received placebo laser and no treatment, respectively. All MCLs were subjected to biomechanical testing at 3 weeks postsurgery. Results revealed significant differences among groups in ultimate tensile strength (UTS) and stiffness (p < 0.01). Combination of multiple low-dosed laser treatment with herbal treatment (group 5) resulted in higher UTS than either no treatment (groups 6 and 8), single high-dosed laser treatment (group 1), multiple low-dosed laser treatment (group 2), or herbal treatment (group 2) alone. We concluded that combined applications of laser and herb can enhance further biomechanical properties of repairing rat MCLs than separate applications at 3 weeks postinjury.
|Photochem Photobiol. 2005 Feb 1; [Epub ahead of print]|
In vivo Study of the Inflammatory Modulating Effects of Low Level Laser Therapy on in iNOS Expression Using Bioluminescence Imaging.
Moriyama Y, Moriyama EH, Blackmore K, Akens MK, Lilge L.
Ontario Cancer Institute Princess Margaret Hospital.
This study was designed to demonstrate that bioluminescence imaging (BLI) can be used as a new tool to evaluate the effects of low level laser therapy (LLLT) during in vivo inflammatory process. Here, the efficacy of LLLT in modulating inducible nitric oxide synthase (iNOS) expression using different therapeutic wavelengths was determined using transgenic animals with the luciferase gene under control of the iNOS gene expression. Thirty transgenic mice (FVB/N-Tg(iNOS-luc)Xen) were allocated randomly to one of four experimental groups treated with different wavelengths (lambda=635, 785, 808 and 905nm) or a control group (non-treated). Inflammation was induced by intra-articular injection of Zymosan A in both knee joints. Laser treatment (25mW.cm(-2), 200 s, 5 J.cm(-2)) was applied to the knees 15 minutes (or min) after inflammation induction. Measurements of iNOS expression were performed at various times (0, 3, 5, 7, 9 and 24h) by measuring the bioluminescence signal using a highly sensitive charge-coupled device (CCD) camera. The results showed a significant increase in BLI signals after irradiation with 635nm laser when compared to both the non-irradiated animals and the other LLLT treated groups indicating wavelength-dependence of LLLT effects on iNOS expression during the inflammatory process. Histological analysis was also performed and demonstrated the presence of fewer inflammatory cells in the synovial joints of mice irradiated with 635nm compared to non-irradiated knee joints. BLI demonstrated an action spectrum of iNOS gene expression following LLLT in vivo.
Lasers Surg Med. 2004;34(3):285-9.
Comparison of single and multiple applications of GaAlAs laser on rat medial collateral ligament repair.
Ng GY, Fung DT, Leung MC, Guo X.
Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong. firstname.lastname@example.org
BACKGROUND AND OBJECTIVES: To examine single versus multiple applications of the gallium aluminum arsenide (GaAlAs) laser on the healing of surgically injured medial collateral ligaments (MCLs) in rats.
STUDY DESIGN/MATERIALS AND METHODS: Sixteen rats were studied, with 12 receiving surgical transection to their right MCL and 4 receiving a sham injury. Group 1 (n = 4) received a single dose of GaAlAs laser therapy (wavelength 660 nm, average power 8.8 mW, pulse 10 kHz, dosage 31.6 J/cm(2)) directly to their MCL during surgery. Group 2 (n = 4) received 9 doses of GaAlAs laser therapy applied transcutaneously on alternate days (wavelength 660 nm, average power 8.8 mW, pulse 10 kHz, dosage 3.5 J/cm(2)). The controls (Group 3, n = 4) received one session of placebo laser at the time of surgery, with the laser equipment shut down, while the sham injured Group 4 (n = 4) received no treatment. Biomechanical tests for structural stiffness, ultimate tensile strength (UTS), and load-relaxation were done at 3 weeks after injury. The stiffness and UTS data were normalized by expressing as a percentage of the left side of each animal before statistical analysis.
RESULTS: The load-relaxation data did not show any differences between the groups (P = 0.18). The normalized stiffness levels of Groups 2 (81.08+/-11.28%) and 4 (92.66+/-13.19%) were significantly higher (P = 0.025) than that of the control Group 3 (58.99+/-15.91%). The normalized UTS of Groups 2 (81.38+/-5.68%) and 4 (90.18+/-8.82%) were also significantly higher (P = 0.012) than that of the control (64.49+/-9.26%). Although, Group 1 had higher mean stiffness and UTS values than the control, no statistically significant difference was found between these two groups.
CONCLUSIONS: Multiple laser therapy improves the normalized strength and stiffness of repairing rat MCLs at 3 weeks after injury. The multiple treatments seem to be superior to a single treatment when the cumulative dosages are comparable between the two modes of application.
Lasers Surg Med. 2003;32(4):286-93.
Effects of a therapeutic laser on the ultrastructural morphology of repairing medial collateral ligament in a rat model.
Fung DT, Ng GY, Leung MC, Tay DK.
Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
BACKGROUND AND OBJECTIVES: Low energy laser therapy has been shown to enhance mechanical strength of healing medial collateral ligament (MCL) in rats. The present study investigated its effects on the ultrastructural morphology and collagen fibril profile of healing MCL in rats.
STUDY DESIGN/MATERIALS AND METHODS: Thirty-two mature male Sprague-Dawley (SD) rats were used. Twenty-four underwent surgical transection to their right MCLs and eight received only skin wound. Immediately after surgery, eight of the MCL transected rats were treated with a single dose of laser therapy at 63.2 J cm(-2), eight were treated with a single dose of laser therapy at 31.6 J cm(-2), the rest had no treatment and served as control. At 3 and 6 weeks after surgery, the MCLs were harvested and examined with electron microscopy for collagen fibril size, distribution, and alignment.
RESULTS: Significant differences (P < 0.001) were found in fibril diameters from the same anatomical site and time period among different groups. The mass-averaged diameters of the laser-treated (64.99-186.29 nm) and sham (64.74-204.34 nm) groups were larger than the control group (58.66-85.89 nm). The collagen fibrils occupied 42.55-59.78, 42.63-53.94, and 36.92-71.64% of the total cross-sectional areas in the laser-treated, control and sham groups, respectively. Mode obliquity was 0.53-0.84 among the three groups.
CONCLUSIONS: Single application of low energy laser therapy increases the collagen fibril size of healing MCLs in rats.