The use of suramin, an antifibrotic agent, to improve muscle recovery after strain injury.

BACKGROUND

Muscle strain injuries are extremely common in sports medicine. Muscle healing often is hindered by scar tissue formation after injury.

HYPOTHESIS: Suramin can prevent scar tissue formation and improve muscle healing after injury because of its ability to antagonize transforming growth factor-beta1, a fibrotic cytokine.

STUDY

DESIGN

Controlled laboratory study.

MATERIALS AND

METHODS

In vitro, muscle-derived fibroblasts (a potential cell source of muscle fibrosis) were incubated with suramin and/or transforming growth factor-beta1; a cell growth curve was obtained. In vivo, mouse gastrocnemius muscles were strain injured. Suramin or sham/control intramuscular injections were performed after injury at various time points. Mice were sacrificed at various time points after injury, and skeletal muscle tissue was evaluated by using histological and physiological tests. Statistical analysis was performed by using analysis of variance and Fisher tests.

RESULTS

Suramin decreased the stimulating effect of transforming growth factor-beta1 on the growth of muscle-derived fibroblasts in vitro. Significantly less fibrous scar formation was observed in suramin-treated muscles than in sham-injected muscles. The fast-twitch and tetanus strength of suramin-treated muscles was also significantly greater relative to that of control muscles.

CONCLUSIONS

Suramin blocked the stimulatory effect of transforming growth factor-beta1 on muscle-derived fibroblasts in vitro. Suramin also reduced fibrous scar formation in muscle and enhanced muscle strength in strain-injured skeletal muscle.

CLINICAL RELEVANCE: These results may facilitate the development of strategies to enhance muscle healing after injury.