糖尿病大鼠骨骼肌氧化应激与肌特异性环脂蛋白1表达关系的研究

Effects of Oxidative Stress on MuRF1 Expression in Skeletal Muscle of Diabetic Rats

目的探讨糖尿病大鼠骨骼肌氧化应激水平及其对肌特异性环指蛋白1基因(MuRF1)表达的影响。方法通过高糖高脂饮食联合尾静脉注射链脲佐菌素(STZ)构建2型糖尿病大鼠模型,分别检测大鼠腓肠肌肌纤维面积、脂质过氧化水平、超氧化物歧化酶(SOD)活性以及MuRF1 mRNA的表达水平,同时设对照组;通过体外培养C2C12成肌细胞,不同浓度H2O2(0、0.01、0.05、0.10和0.20 mmol/L)诱导肌管细胞内氧化应激,Westernblot检测不同程度氧化应激下细胞MuRF1的表达水平。结果与对照组大鼠相比较,糖尿病大鼠腓肠肌肌纤维面积减小,脂质过氧化水平增高,MuRF1 mRNA表达上调(P<0.01);体外细胞培养发现0.05、0.10、0.20 mmol/LH2O2诱导的C2C12肌管细胞氧化应激可上调MuRF1的表达(P<0.01)。结论糖尿病大鼠骨骼肌氧化应激水平增高,使MuRF1基因表达上调,从而导致骨骼肌萎缩。

Objective To determine whether muscle-specific RING finger protein 1（MuRF1） expression induced by oxidative stress lead to muscle wasting in diabetes rats.Methods The diabetes rat model was established by high-carbohydrate,high-fat diet and injection of streptozotocin.The expression of MuRF1 in gastrocnemius was detected by immunohistochemistry and real time PCR.The level of lipid peroxidation,SOD and fiber size of gastrocnemius was also detected.Further more,C2C12 myotubes were cultured with different concentration of H2O2（0,0.01,0.05,0.10 and 0.20 mmol/L）,the level of MuRF1 protein was detected by western blot.Results Compared with the control group,the diabetes rats showed higher level of thiobarbituric acid reactive substances（TBARS） and MuRF1 mRNA and lower fiber size in gastrocnemius（P〈0.01）.The oxidative stress induced by H2O2（0.05,0.10 and 0.20 mmol/L）upregulated the expression of MuRF1（P〈0.01）in C2C12 myotube cells.Conclusion Our results indicated that diabetes modulated the expression of MuRF1 leading to muscle wasting,and the mechanism might be involved with oxidative stress.