Photobiomodulation therapy protects skeletal muscle and improves muscular function of mdx mice in a dose-dependent manner through modulation of dystrophin.

Abstract

This study aimed to analyze the protective effects of photobiomodulation therapy (PBMT) with combination of low-level laser therapy (LLLT) and light emitting diode therapy (LEDT) on skeletal muscle tissue to delay dystrophy progression in mdx mice (DMD mdx ). To this aim, mice were randomly divided into five different experimental groups: wild type (WT), placebo-control (DMD mdx ), PBMT with doses of 1J (DMD mdx ), 3J (DMD mdx ), and 10J (DMD mdx ). PBMT was performed employing a cluster probe with 9 diodes (1 x 905nm super-pulsed laser diode; 4 x 875nm infrared LEDs; and 4 x 640nm red LEDs, manufactured by Multi Radiance Medical®, Solon - OH, USA), 3 times a week for 14weeks. PBMT was applied on a single point (tibialis anterior muscle-bilaterally). We analyzed functional performance, muscle morphology, and gene and protein expression of dystrophin. PBMT with a 10J dose significantly improved (p < 0.001) functional performance compared to all other experimental groups. Muscle morphology was improved by all PBMT doses, with better outcomes with the 3 and 10J doses. Gene expression of dystrophin was significantly increased with 3J (p < 0.01) and 10J (p < 0.01) doses when compared to placebo-control group. Regarding protein expression of dystrophin, 3J (p < 0.001) and 10J (p < 0.05) doses also significantly showed increase compared to placebo-control group. We conclude that PBMT can mainly preserve muscle morphology and improve muscular function of mdx mice through modulation of gene and protein expression of dystrophin. Furthermore, since PBMT is a non-pharmacological treatment which does not present side effects and is easy to handle, it can be seen as a promising tool for treating Duchenne's muscular dystrophy.