Photomed Laser Surg. 2006 Oct;24(5):601-4
Low-Level Laser Therapy at Different Energy Densities (0.-2.0 J/cm(2)) and Its Effects on the Capacity of Human Long-Term Cryopreserved Peripheral Blood Progenitor Cells for the Growth of Colony-Forming Units.
- Nascimento RX,
- Callera F.
UNIVAP Instituto de Pesquisa e Desenvolvimento (IPD), Universidade do Vale do Paraiba (UNIVAP), Sao Jose dos Campos, Sao Paulo, Brazil.
Objective: The aim of this research was to investigate the effects of low-level laser therapy (LLLT) at different energy densities (0.1-2.0 J/cm(2)) on the capacity of long-term cryopreserved peripheral blood progenitor cell (PBPC) for growth of colony-forming units (CFU) in vitro.
Background Data: There are no data concerning the effects of LLLT on human cryopreserved PBPC.
Methods: Cryopreserved PBPC samples were thawed after 3 years in order to demonstrate the positive effect of LLLT and after 5 years in order to confirm the LLLT’s proliferative effect. Cultures were plated in quadruplicate 35-mm-diameter Petri dishes in methylcellulose medium (2 xx 10(5)/mL final concentration) and incubated for 14 days at 37 degrees C with 5% CO(2). A 685-nm diode laser with 25-mW optical power was used as the source of irradiation. Cultures were exposed to energy densities of 0.1, 0.5, 1.0, 1.5, and 2.0 J/cm(2) before incubation (10 irradiated and 10 controls at each energy density group).
Results: A higher number of CFU was observed at the dose of 1.0 J/cm(2) (control 21.3 +/- 8.5 x 10(5) cells, irradiated 40.1 +/- 10.5 x 10(5) cells, p < 0.001). No differences were observed in cultures exposed to doses of 0.1, 0.5, and 1.5 J/cm(2). A decreased number of CFU was demonstrated in samples exposed to the dose of 2.0 J/cm(2) (control 21.4 +/- 11.9 x 10(5) cells, p = 0.013). PBPC samples cryopreserved for 5 years were thawed for CFU assays and exposed to a single dose of 1.0 J/cm(2); once again the exposed group showed a higher number of CFU (control 8.8 +/- 7.8 x 10(5) cells, irradiated 18.1 +/- 13.1 x 10(5) cells, p = 0.026).
Conclusion: Dependent upon the energy density, LLLT elevates (1.0 J/cm(2)) or decreases (2.0 J/cm(2)) the potential of long-term cryopreserved PBPC for growth of CFU in vitro.
|J Clin Laser Med Surg. 1993 Aug;11(4):185-9.|
Effect of low-power He-Ne laser on deformability of stored human erythrocytes.
Iijima K, Shimoyama N, Shimoyama M, Mizuguchi T.
Department of Anesthesiology, Chiba University School of Medicine, Japan.
This study was designed to investigate the effect of the He-Ne laser (continuous wave, lambda = 632.8 nm, 8.5 mW in power) irradiation on human erythrocyte deformability. Blood samples were obtained from hematologically normal adult donors by venipuncture. Red cells were washed and adjusted to 30% Ht with 0.9% NaCl solution (pH 7.00). Red cell solution samples were assigned to three groups. Each sample was divided into seven 3-ml working aliquots. The aliquots in Group I were irradiated for 0 (control), 1, 3, 5, 10, 15, and 30 min within 2 hr after sampling. The aliquots in Group 2 and Group 3 were stored at 5 degrees C for 24 and 36 hr, respectively, and received similar irradiations after 12 hr (in both groups), 24 hr (in Group 2), and 36 hr (in Group 3) from sampling. Red cell deformability was measured by the Nuclepore filter filtration and presented as the filter filtration rate (FFR). The deformability shown as FFR was unchanged in Group 1 (fresh cell group) from the control value, but improved significantly in Groups 2 and 3 (damaged cell groups) after the irradiation. These results suggested that the irradiation of low-powered He-Ne lasers improved cytoskeletal protein activities in damaged erythrocytes.