Superpulsed Low-Level Laser Therapy Protects Skeletal Muscle of mdx Mice against Damage, Inflammation and Morphological Changes Delaying Dystrophy Progression

Abstract

AimTo evaluate the effects of preventive treatment with low-level laser therapy (LLLT) on progression of dystrophy in mdx mice.MethodsTen animals were randomly divided into 2 experimental groups treated with superpulsed LLLT (904 nm, 15 mW, 700 Hz, 1 J) or placebo-LLLT at one point overlying the tibialis anterior muscle (bilaterally) 5 times per week for 14 weeks (from 6th to 20th week of age). Morphological changes, creatine kinase (CK) activity and mRNA gene expression were assessed in animals at 20th week of age.ResultsAnimals treated with LLLT showed very few morphological changes in skeletal muscle, with less atrophy and fibrosis than animals treated with placebo-LLLT. CK was significantly lower (p = 0.0203) in animals treated with LLLT (864.70 U.l−1, SEM 226.10) than placebo (1708.00 U.l−1, SEM 184.60). mRNA gene expression of inflammatory markers was significantly decreased by treatment with LLLT (p<0.05): TNF-α (placebo-control = 0.51 µg/µl [SEM 0.12], - LLLT = 0.048 µg/µl [SEM 0.01]), IL-1β (placebo-control = 2.292 µg/µl [SEM 0.74], - LLLT = 0.12 µg/µl [SEM 0.03]), IL-6 (placebo-control = 3.946 µg/µl [SEM 0.98], - LLLT = 0.854 µg/µl [SEM 0.33]), IL-10 (placebo-control = 1.116 µg/µl [SEM 0.22], - LLLT = 0.352 µg/µl [SEM 0.15]), and COX-2 (placebo-control = 4.984 µg/µl [SEM 1.18], LLLT = 1.470 µg/µl [SEM 0.73]).ConclusionIrradiation of superpulsed LLLT on successive days five times per week for 14 weeks decreased morphological changes, skeletal muscle damage and inflammation in mdx mice. This indicates that LLLT has potential to decrease progression of Duchenne muscular dystrophy.

Pre-exercise low-level laser therapy improves performance and levels of oxidative stress markers in mdx mice subjected to muscle fatigue by high-intensity exercise

“…Finally, it is important to mention that very recently, a study showed that irradiation of LLLT on successive days five times per week for 14 weeks decreased morphological changes, skeletal muscle damage, and inflammation in mdx mice [30], which indicates that LLLT has the potential to decrease progression of Duchenne muscular dystrophy [30,31]. Therefore, in this perspective, LLLT rises as a new and promising therapeutic tool in treatment of symptoms of DMD.…”

Low intensity 635 nm diode laser irradiation inhibits fibroblast–myofibroblast transition reducing TRPC1 channel expression/activity: New perspectives for tissue fibrosis treatment

“…The beneficial effect of LLLT or photobiomodulation therapy in ameliorating fibrosis has been recently demonstrated in different damaged and diseased organs including kidney, skeletal muscle, skin, heart and tendon, but little is known concerning the cellular and molecular mechanisms by which the laser could exert this action .…”

Laser therapy modulates systemic inflammatory processes and muscle atrophy in an experimental model of sepsis in rats

“…Shen et al [28] demonstrated that LLLT was able to inhibit muscle fiber atrophy and molecular changes in a denervated rat model. In addition, LealJunior et al [29] observed that LLLT has the potential to prevent muscle atrophy, decreasing progression of Duchenne muscular dystrophy. Thus, a lower expression of MuRF-1 and atrogin as was observed in the laser-treated animals led us to infer that LLLT treatment may stimulate muscle metabolism, reducing muscle protein degradation and may culminate in the prevention of muscle atrophy.…”