电针对糖尿病大鼠腓肠肌中肌球蛋白重链降解的影响

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

目的:观察电针对糖尿病大鼠腓肠肌中肌肉特异性环指蛋白1(MuRF1/Trim63)、肌肉萎缩盒F蛋白32(Fbxo32)、肌球蛋白重链-IIa(Myh2)、肌球蛋白重链-IIb(Myh4)及肌球蛋白重链-I(Myh7)表达的影响,探讨电针延缓糖尿病肌萎缩的机制。方法:Wistar大鼠随机分为对照组、模型组和电针组,每组12只。腹腔注射链脲佐菌素制备大鼠糖尿病肌萎缩模型。电针组造模3周后电针双侧'足三里''阴陵泉''肾俞'穴,每次10 min,每日1次,每周6次,连续干预2周。各组分别在造模第0、1、2、3、4、5周测定大鼠体质量、空腹血糖(FBG)、空腹胰岛素(FINS)水平,计算胰岛素抵抗指数(HOMA-IR)。造模后第5周称取大鼠双侧腓肠肌湿重,HE染色测定腓肠肌纤维横截面积,实时荧光定量PCR检测各组大鼠腓肠肌中MuRF1、Fbxo32、Myh2、Myh4和Myh7 mRNA的相对表达量。结果:与对照组比较,造模后第1至5周,模型组大鼠FBG水平、HOMA-IR显著升高(P<0. 05),FINS水平和体质量显著降低(P<0. 05);与模型组比较,电针组大鼠FBG和HOMA-IR降低(P<0. 05),体质量显著增加(P<0. 05)。造模5周后,与对照组比较,模型组大鼠腓肠肌湿重、肌纤维横截面积,Myh2、Myh4和Myh7 mRNA的相对表达量显著降低(P<0. 05),MuRF1和Fbxo32 mRNA的相对表达量显著升高(P<0. 05);与模型组比较,电针组大鼠腓肠肌湿重、肌纤维横截面积显著增加,Myh2、Myh4和Myh7 mRNA的相对表达量上调(P<0. 05),MuRF1和Fbxo32 mRNA相对表达量降低(P<0. 05)。结论:电针干预大鼠双侧'足三里''阴陵泉''肾俞'穴可能通过调控MuRF1、Fbxo32、Myh2、Myh4和Myh7 mRNA的表达,延缓肌球蛋白重链的降解,进而延缓糖尿病肌萎缩的发展。

Objective 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.Methods 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.staining.The expression of MuRF1,Fbxo32,Myh2,Myh4 and Myh7 mRNAs in the gastrocnemius tissue was tested using quantitative real time-PCR.Results 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).Conclusion 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.