EFFECT OF PASSIVE MOVEMENT ON EXPRESSION OF miRNA-1 AND DIFFERENTIATION OF MYOBLASTS IN DENERVATION-INDUCED SKELETAL MUSCLE ATROPHY IN RATS / 中国修复重建外科杂志

ABSTRACT

OBJECTIVE: To investigate the expression of miRNA-1 in denervated skeletal muscle at different periods, and to explore effects of passive movement on the expression of miRNA-1 and differentiation of myoblasts in denervation-induced skeletal muscle atrophy in rats. METHODS: Twenty-seven Sprague Dawley rats, weighing (200±10) g, were randomly divided into sham-operated group (group A, n=3), denervated group (group B, n=12), and passive movement group (group C, n=12). After the right sciatic nerve was exposed and dissociated, the sciatic nerve of 1 cm in length was removed in groups B and C; resection was not performed in group A. At 1 day after operation, passive flexion and extension movement was performed on the right hind limb in group C. At 6 hours in group A and at 3, 7, 14, and 28 days in groups B and C, 3 rats were sacrificed to measure the wet weight ratio of gastrocnemius muscle, to observe the diameter of the gastrocnemius muscle cell and evaluate the muscle atrophy by HE staining; RT-PCR was used to detect the mRNA expression of miRNA-1 and myocyte differentiation factor (MyoD), and immunohistochemistry to determine the protein expression of MyoD. RESULTS: Atrophy in various degrees was observed in denervated gastrocnemius muscle of groups B and C. The muscle fiber arranged in disorder and the diameter of the muscle cells decreased gradually with the time, without normal structure and morphology. The wet weight ratio and the cell diameter of the gastrocnemius in groups B and C were significantly less than those in group A (P0.05), and had positive correlation at 14 and 28 days (P<0.05); positive correlation was found between the relative expression of MyoD and miRNA-1 mRNA (P<0.05). CONCLUSIONS: Passive movement can prevent amyotrophy by increasing the expression of miRNA-1 and promoting the differentiation of myoblasts.