Low-level laser therapy (LLLT) (660 nm) alters gene expression during muscle healing in rats

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Introduction: The effects of LLLT were studied during muscle regeneration through gene expression. Methods: It was evaluated 10 and 50 J/cm(2) doses during 7, 14 and 21 days post cryoinjury, through histopathological analysis and mRNA MyoD, Myogenin, Vegf and Cox-2 expression. Results: Irradiated groups presented less inflammatory process than control group after 14 and 21 days. Cox-2 levels were downregulated in all irradiated groups after 7, 14 and 21 days. On day 7, both treated groups had a downregulation of Vegf levels, and an upregulation after 14 and 21 days, mainly with 50 J/cm(2). The MyoD levels were upregulated with high dose in all periods and with low dose after 21 days. Myogenin expression was downregulated in both treated groups after 7 days, and was upregulated with 10 J/cm(2) after 21 days. Conclusion: These responses suggest that LLLT can improve the skeletal muscle regeneration through the gene expression stimulation. (C) 2013 Elsevier B.V. All rights reserved.1202935Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Comparative study using 685-nm and 830-nm lasers in the tissue repair of tenotomized tendons in the mouse

Objective: The objective of this study was to evaluate the effects of 685- and 830-nm laser irradiations, at different fluences on the healing process of Achilles tendon (Tendon calcaneo) of mice after tenotomy. Background Data: Some authors have shown that low-level laser therapy (LLLT) is able to accelerate the healing process of tendinuos tissue after an injury, increasing fibroblast cell proliferation and collagen synthesis. However, the mechanism by which LLLT acts on healing process is not fully understood. Methods: Forty-eight male mice were divided into six experimental groups: group A, tenomized animals, treated with 685 nm laser, at the dosage of 3 J/cm(2); group B, tenomized animals, treated with 685-nm laser, at the dosage of 10 J/cm(2); group C, tenomized animals, treated with 830-nm laser, at dosage of 3 J/cm(2); group D, tenomized animals, treated with 830-nm laser, at the dosage of 10 J/cm(2); group E, injured control (placebo treatment); and group F, non-injured standard control. Animals were killed on day 13 post-tenotomy, and their tendons were surgically removed for a quantitative analysis using polarization microscopy, with the purpose of measuring collagen fibers organization trough the birefringence (optical retardation [OR]). Results: All treated groups showed higher values of OR when compared to injured control group. The best organization and aggregation of the collagen bundles were shown by the animals of group A (685 run, 3 J/cm(2)), followed by the animals of group C and B, and finally, the animals of group D. Conclusion: All wavelengths and fluences used in this study were efficient at accelerating the healing process of Achilles tendon post-tenotomy, particularly after the 685-nm laser irradiation, at 3 J/cm(2). It suggests the existence of wavelength tissue specificity and dose dependency. Further studies are required to investigate the physiological mechanisms responsible for the effects of laser on tendinuos repair.o TEXTO COMPLETO DESTE ARTIGO, ESTARÁ DISPONÍVEL À PARTIR DE AGOSTO DE 2015.24675475

Effects of 660 nm low-level laser therapy on muscle healing process after cryolesion

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)The aim of this study was to evaluate the effects of 660 nm low-level laser therapy (LLLT) on muscle regeneration after cryolesion in rat tibialis anterior muscle. Sixty-three Wistar rats were divided into a control group, 10 J/cm(2) laser-treated group, and 50 J/cm2 laser-treated group. Each group formed three subgroups (n = 7 per group), and the animals were sacrificed 7, 14, or 21 d after lesion. Histopathological findings revealed a lower inflammatory process in the laser-treated groups after 7 d. After 14 d, irradiated animals at both fluences showed higher granulation tissue, new muscle fibers, and organized muscle structure. After 21 d, full tissue repair was observed in all groups. Moreover, irradiated animals at both fluences showed smaller necrosis area in the first experimental period evaluated. MyoD immunoexpression was observed in both treated groups 7 d postinjury. Myogenin immunoexpression was detected after 7 and 14 d. The higher fluence increased the number of blood vessels after 14 and 21 d. These results suggest that LLLT, at both fluences, positively affects injured skeletal muscle in rats, accelerating the muscle-regeneration process.507985995Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)CAPES [20226300

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

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)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.2919196Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES