Electroacupuncture improves denervated gastrocnemius atrophy by regulating expression of fork-head protein 3A，muscle atrophy F-box and myogenic differentiation antigen proteins in sciatic nerve injury rats

Abstract

To observe the effect of electroacupuncture (EA) on morphological changes of denervated gastrocnemius(GS) and the expression of fork-head protein(FOXO3A), muscle atrophy F-box(MAFbx)and myogenic differentiation antigen (Myod1) in sciatic nerve injury rats, so as to reveal its mechanism underlying improvement of myoatrophy. Eighteen male Sprague-Dawley rats were randomly divided into sham operation, model and EA groups (n＝6 per group). The model of gastrocnemius atrophy was established by crushing the right sciatic nerve. Then, EA (2 Hz) was applied to the right "Zusanli" (ST36) and "Huantiao" (GB30) for 10 min, once a day for 14 successive days. The wet weight of the GS on both sides was weighted to calculate the wet weight ratio (the injured side /the healthy side), and the cross-sectional area (CSA) and diameter of GS fibers were measured after H．E. staining. The expressions of FOXO3A, MAFbx and Myod1 protein and mRNA in the GS tissue were tested using Western blot and fluorescence quantitative PCR, separately. Following modeling, the GS wet weight ratio, CSA and fiber diameter were smaller in the model group than those in the sham group (P<0.01), and were significantly higher in the EA group than in the model group (P<0.01). H．E. staining showed that the GS fibers became smaller and the myocyte got round in the model group, while the GS fibers were bigger and the myocyte was relatively regular in morphology in the EA group. After modeling, the expression levels of FOXO3A, MAFbx and Myod1 mRNA and protein were evidently higher in the model group (P<0.01); Moreover, after EA treatment, modeling-induced increasing of expression levels of FOXO3A and MAFbx mRNA and protein were revised (P<0.01), while the increased expression level of Myod1 was further up-regulated relavant to that in the model group (P<0.01)．. EA of ST36 and GB30 can suppress the up-regulated expression of FOXO3A and MAFbx mRNA and protein and further promote the expression of Myod1 mRNA and protein in the GS tissue in rats with denervated GS atrophy, which may contribute to its function in relieving the myoatrophy, promoting the skeletal muscle protein hydrolysis and differentiation of satellite cells.