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目的观察游泳训练对Ⅱ型糖尿病大鼠骨骼肌MG53表达的影响,旨在探索游泳训练减轻胰岛素抵抗引起的机制。方法以成年(6周龄)雄性SD大鼠为实验对象,采用经典方法通过高脂高糖饲料加腹腔注射链脲佐菌素(STZ,30 mg/kg)建立Ⅱ型糖尿病胰岛素抵抗大鼠模型(2DMIR)。大鼠分为正常对照组(20只)、2DMIR组(20只),各组再分为非游泳训练组(10只)和游泳训练(10只)。游泳训练组分别给予一定时间和程序对大鼠进行游泳训练。采用血糖测定仪测定测空腹血糖(FBG)、放射免疫法试剂盒测定血清空腹胰岛素(FINS)并计算胰岛素抵抗指数(HOMA-IR)。半自动生化分析仪测定血清总胆固醇与甘油三脂。用鼠尾测压法测定大鼠血压。免疫印迹技术检测腓肠肌MG53及葡萄糖转运蛋白4(GLUT4)的表达,荧光适时定量PCR技术检测MG53基因的表达。结果与对照组大鼠相比,2DMIR大鼠空腹血糖水平和胰岛素抵抗指数显著增加、GLUT4表达降低、腓肠肌MG53表达明显升高(均P<0.01)。游泳训练8周能显著降低2DMIR大鼠的代谢综合症的相关指标(体质量、胆固醇、甘油三酯、血压)、空腹血糖水平、胰岛素抵抗指数及腓肠肌MG53表达显著下降,GLUT4表达也明显上调(P<0.05)。结论游泳训练明显改善2DMIR大鼠胰岛素抵抗和血糖代谢。其机制可能与游泳训练通过降低骨骼肌MG53表达从而降低胰岛素受体降解和增强GLUT4功能有关。
Objective To observe the effect of swimming training on the expression of MG53 in skeletal muscle of type 2 diabetic rats and to explore the mechanism of swimming training in reducing insulin resistance. Methods Adult male (6 weeks old) male Sprague-Dawley rats were used as experimental subjects. Type 2 diabetic rats with insulin resistance were established by high-fat and high-sugar diet and streptozotocin (STZ, 30 mg / kg) (2DMIR). Rats were divided into normal control group (n = 20) and 2DMIR group (n = 20). The rats in each group were divided into non-swimming training group (n = 10) and swimming training group (n = 10). Swim training group were given a certain time and procedures for swimming training rats. Fasting blood glucose (FBG) was measured by blood glucose meter, fasting insulin (FINS) was measured by radioimmunoassay kit, and insulin resistance index (HOMA-IR) was calculated. Semi-automatic biochemical analyzer for determination of serum total cholesterol and triglycerides. Rat tail pressure measurement of blood pressure. The expression of MG53 and glucose transporter 4 (GLUT4) in gastrocnemius muscle was detected by Western blotting, and the expression of MG53 gene was detected by fluorescence quantitative PCR. Results Compared with the control group, the fasting blood glucose level and insulin resistance index of 2DMIR rats were significantly increased, the expression of GLUT4 was decreased and the expression of MG53 in gastrocnemius muscle was significantly increased (all P <0.01). Swimming training for 8 weeks significantly reduced metabolic syndrome (body mass, cholesterol, triglyceride, blood pressure), fasting blood glucose level, insulin resistance index and MG53 expression in gastrocnemius muscle and GLUT4 expression in 2DMIR rats significantly P <0.05). Conclusion Swimming training significantly improves insulin resistance and blood glucose metabolism in 2DMIR rats. The mechanism may be related to swimming training through reducing the expression of skeletal muscle MG53, thereby reducing the degradation of insulin receptor and enhancing the function of GLUT4.