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

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.