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 animals were separated in trained (T/n=8) and untrained (NT/n=8) groups. Wild type animals (WT/n=8) were used as healthy control. The T 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 T group presented a lower collagen fiber area compared to NT for gastrocnemius (=0.025) and tibial anterior (=0.000). Oxidative damage activity was higher in the T group for both muscles compared to NT. Catalase presented similar activity for tibial anterior (=0.527) or gastrocnemius (=0.323). Superoxide dismutase (=0.003) and total antioxidant capacity (=0.024) showed increased activity in the T 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.