ABSTRACT
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.
ABSTRACT
In the present study, we were to screen the specific microRNA (miRNA) of exercise-induced muscle damage (EIMD) and assess the EIMD-specific miRNAs-regulated target of sarcolemmal damage in rats. Twenty-four male Sprague-Dawley (SD) rats were randomly divided into 3 groups, which included sedentary (C), 24 h post-exercise (E24) and 48 h post-exercise (E48) groups. Rat EIMD model was established by an acute eccentric exercise, i.e., a downhill running treatment at -16º gradient. EIMD characteristics were verified by Evans blue dye staining, differentially expressed miRNAs were detected by microarray assay, EIMD-specific miRNAs expressions were further validated by real-time quantitative RT-PCR (RT-qPCR), and targets of the miRNAs were predicted based on mRNA expressions of associated proteins and related pathway core molecules of sarcolemmal damage. Two EIMD-specific expressed miRNAs, including miR-206-3p and miR-139-3p, were found in the study. There was a significantly negative correlation (P < 0.05) between miR-206-3p expression and dystrophin (r = -0.68), utrophin (r = -0.64), JNK (r = -0.62) or ERK1 (r = -0.68) respectively, but no correlation was found between miR-139-3p and these biomolecules. The results suggest that: i) the expression profile of miRNAs in rat is significantly affected by EIMD, ii) miR-206-3p and miR-139-3p are the EIMD-specific miRNAs, and iii) miR-206-3p may control sarcolemmal damage by regulating dystrophin, utrophin, JNK and ERK1.