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) was injected with 80 mu g of venom. One group of mice (n = 10) received drinking water containing L-arginine (3.75 mg/ml) and another group (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) than in saline-treated (2.230 +/- 478 muscle fibers versus 1.005 +/- 134, respectively) although the level of muscle fiber population of uninjured tibialis anterioris muscle (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. (c) 2006 Elsevier Ltd. All rights reserved.