Low intensity training improves redox status and reduces collagen fibers on dystrophic muscle.

Exercise therapy on skeletal muscle of muscular dystrophies has no defined parameters. The effect of low-intensity treadmill training on the oxidative stress markers and fibrosis on hindlimb muscles was investigated. Sixteen dystrophic male mdx animals were separated in trained (mdxT/n=8) and untrained (mdxNT/n=8) groups. Wild type animals (WT/n=8) were used as healthy control. The mdxT group runned at a horizontal treadmill (9 m/min, 30 min/day, 3 times/wk, 8 weeks). Gastrocnemius and tibial anterior muscles were collected for analysis of enzymatic/non-enzymatic oxidant activity, oxidative damage concentration, collagen fibers area morphometry. The mdxT group presented a lower collagen fiber area compared to mdxNT for gastrocnemius (P=0.025) and tibial anterior (P=0.000). Oxidative damage activity was higher in the mdxT group for both muscles compared to mdxNT. Catalase presented similar activity for tibial anterior (P=0.527) or gastrocnemius (P=0.323). Superoxide dismutase (P=0.003) and total antioxidant capacity (P=0.024) showed increased activity in the mdxT group at tibial anterior with no difference for gastrocnemius. Low-intensity training is considered therapeutic as it reduces collagen deposition while improving tissue redox status.