The role of nitric oxide during healing of trauma to the skeletal muscle

The role of NO in muscle injury is not clear. We examined the involvement of the NO system in the development of muscle damage in an experimental model of crush injury. The animals were divided into four groups: (1) control (CO), (2) sham trauma, (3) trauma, (4) trauma + l-NAME, in two experimental phases, 24 h and 7 days after injury. Twenty-four hours post-trauma, the crushed muscle was characterized by an intense inflammatory reaction. These changes were accompanied by increased oxidative damage, increased cytokine mRNA transcription, NF-kappa B binding ability and TGF-beta growth factor expression in the gastrocnemius muscle. Treatment with l-NAME markedly decreased these histological and molecular abnormalities at 24 h. However, at 7 days post-trauma, increased collagen formation was observed in the l-NAME group. These findings indicate that NO is involved in the balance between fibrosis and healing with regeneration.