Effect of electroacupuncture on degradation of myosin heavy chain of gastrocnemius muscle in diabetes rats

Abstract

To explore the effect of electroacupuncture（EA）on the expression of muscle-specific ring finger protein 1（MuRF1/Trim63），F-box only protein 32（Fbxo32），myosin heavy chain-IIa（Myh2），myosin heavy chain-IIb（Myh4）and myosin heavy chain-I（Myh7）in diabetes rats. Thirty-six male Wistar rats were equally randomized into control, model and EA groups. The diabetes model was established by intraperitoneal injection of 0.1% Streptozocin (STZ) solution (50 mg/kg). After that, EA (2 Hz, 1 mA) was applied to bilateral "Zusanli" (ST36), "Yinlingquan" (SP9) and "Shenshu" (BL23) for 10 min, once a day, 6 times a week for 2 weeks. The fasting blood glucose (FBG) and fasting serum insulin (FINS) contents were assayed by using ELISA, and the homeostasis model assessment of insulin resistance (HOMA-IR) was calculated. The body weight, and wet weight of bilateral gastrocnemius muscles were measured. The cross-sectional area (CSA) of the gastrocnemius muscle was measured after H.E. stai-ning. The expression of MuRF1, Fbxo32, Myh2, Myh4 and Myh7 mRNAs in the gastrocnemius tissue was tested using quantitative real time-PCR. Compared with the control group, the FBG and HOMA-IR were significantly higher (P<0.05), and the FINS, body weight were significantly lower (P<0.05) after intravenous injection of STZ for 1, 2, 3, 4, 5 weeks respectively. Following EA treatment and compared with the model group, the FBG and HOMA-IR were significantly down-regulated (P<0.05), and the FINS and body weight were considerably increased (P<0.05). Following modeling and compared with the control group, the wet weight of gastrocnemius muscle, CSA, and expression levels of Myh2, Myh4 and Myh7 mRNAs were obviously decreased, and the expression of MuRF1 and Fbxo32 mRNA was obviously increased in the model group (P<0.05). After EA treatment, the gastrocnemius muscle wet weight, CSA, expression levels of Myh2, Myh4 and Myh7 mRNA were significantly up-regulated (P<0.05), and the expression levels of MuRF1 and Fbxo32 mRNA were markedly down-regulated in comparison with those of the model group (P<0.05). EA treatment can delay the atrophy of gastrocnemius muscle (skeletal muscle) in diabetes rats possibly by improving the degradation of myosin heavy chain via regulating the expression of muscular MuRF1, Fbxo32, Myh2, Myh4 and Myh7 mRNAs.