Laser Photobiomodulation Enhances Cell Viability and Regenerative Gene Expression in Oxidative-Stressed Muscle Cells

Purpose: This study aimed to evaluate the effects of laser photobiomodulation therapy (LPT) on muscle cells subjected to oxidative stress. The primary objective was to determine whether LPT could preserve cell viability and modulate the expression of genes associated with muscle regeneration, specifically MyoD and myogenin , as well as the pro-inflammatory cytokine IL-6. Methods: C2C12 myoblasts were cultured and exposed to oxidative stress using hydrogen peroxide (H₂O₂) at a concentration of 50 µM for 1 h. Cells were then irradiated with LPT at wavelengths of 660 or 808 nm with fluences of 3, 5, and 10 J, applied either before (PRE-OS) or after (POST-OS) oxidative stress induction. Cell viability was assessed by the MTT assay, and gene expression was quantified using RT-qPCR. Results: Oxidative stress significantly reduced cell viability. LPT applied prior to OS with 660 nm (3 J) and 808 nm (3 and 10 J) attenuated this reduction. Notably, 10 J at 808 nm (PRE-OS) increased viability beyond control levels and markedly upregulated MyoD expression. Myogenin expression was also observed under 10 J PRE-OS conditions, while IL-6 expression was detected with 5 J at both wavelengths in PRE- and POST-OS groups. Conclusion: LPT demonstrated protective and regenerative effects on myoblasts under oxidative stress, preserving viability and enhancing regenerative gene expression. These findings support the potential of LPT as a therapeutic strategy for muscle injuries and disorders associated with oxidative stress.