RESUMO
BACKGROUND: Numerous studies concerning dysferlin focus on muscle diseases (such as muscular dystrophy), but the relationship between membrane repair after exercise-induced muscle damage and dysferlin is little reported. OBJECTIVE: To observe the cell membrane permeability and expression levels of dysferlin and calpain3 in the rat gastrocnemius after acute eccentric exercise, so as to provide an theoretical reference for exploring the molecular mechanism of muscle regeneration and the exercise therapy of muscular diseases. METHODS: Thirty-two Sprague-Dawley rats were randomly divided into four groups including control, 24, 48 and 72 hours post exercise groups. The membrane permeability and expression levels of dysferlin and calpain3 were determined by immunohistochemistry, western blot assay and qRT-PCR. RESULTS AND CONCLUSION: The activity of serum creatine kinase, and expression levels of calpain3 mRNA and dysferlin protein, as well as membrane permeability at 24 hours post exercise were significantly greater than those in the control group (P ＜ 0.05 or 0.01). The expression level of dysferlin mRNA at 24 and 48 hours post exercise was significantly higher than that at 72 hours post exercise (P ＜ 0.05). Therefore, the damage to the skeletal muscle cell membrane was the most severe at 24 hours after eccentric exercise. Due to Ca2+influx, expression of calpain3 mRNA was activated, and then the damaged cell membrane was repaired by increasing the expression of dysferlin.