l-arginine enhances muscle regeneration after experimental envenomation by B. jararacussu: A future for nitric oxide-based therapy?

We investigated whether muscle fiber regeneration would be rescued by exogenous administration of l-arginine, the precursor of endogenous synthesis of nitric oxide. The right tibialis anterioris muscle of adult mice (n=20)(n=20) was injected with 80 μg of venom. One group of mice (n=10)(n=10) received drinking water containing l-arginine (3.75 mg/ml) and another group (n=10)(n=10) did not receive any pharmacological treatment. Two months later, muscle regeneration was evaluated by counting the total number of muscle fibers. We found that in l-arginine-treated mice, muscle regeneration was significantly higher (p<0.05)(p<0.05) than in saline-treated (2.230±4782.230±478 muscle fibers versus 1.005±1341.005±134, respectively) although the level of muscle fiber population of uninjured tibialis anterioris muscle (3.121±102)(3.121±102) was not attained. These results show that muscle regeneration was significantly facilitated by l-arginine and suggest that pharmacological activators of the NO pathway may be potentially useful for improving muscle regeneration in human envenomation by B. jararacussu.