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

IntroductionThe effects of LLLT were studied during muscle regeneration through gene expression.MethodsIt was evaluated 10 and 50 J/cm2 doses during 7, 14 and 21 days post cryoinjury, through histopathological analysis and mRNA MyoD, Myogenin, Vegf and Cox-2 expression.ResultsIrradiated 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/cm2. 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/cm2 after 21 days.ConclusionThese responses suggest that LLLT can improve the skeletal muscle regeneration through the gene expression stimulation.

► We examine changes in the level of MRFs during muscle regeneration.
► Low-level laser therapy is able to decrease the mRNA Cox-2 levels.
► We report a cell response photo-induced.