运动对糖尿病大鼠骨骼肌细胞葡萄糖运载体4转位机制的影响

Effect of exercise on translocation of skeletal muscle cell GLUT4 in diabetic rats

目的 研究运动对链脲佐菌素 (STZ)引起的糖尿病大鼠骨骼肌细胞葡萄糖运载体 4(Glucosetransporter 4,GLUT4)转位机制的影响。 方法 将实验大鼠分为 3组 :正常对照组、糖尿病组和糖尿病运动组。糖尿病运动组大鼠进行 6周游泳训练。实验到期分离各组大鼠大腿股四头肌 ,制备细胞内、外膜 ,以Western印迹法检测GLUT4蛋白含量 ,同时检测大鼠血清胰岛素和血糖浓度。结果 糖尿病大鼠骨骼肌细胞GLUT4蛋白含量明显减少 ,与正常对照组相比 ,细胞内膜GLUT4蛋白含量减少 2 4.1% (P <0 .0 1) ,细胞外膜减少 48.1% ,(P <0 .0 1)。糖尿病大鼠经过 6周运动训练 ,与糖尿病组大鼠相比 ,骨骼肌细胞内膜GLUT4蛋白含量无明显变化 ,而细胞外膜GLUT4蛋白含量增加 10 8.7% (P <0 .0 1) ,血糖由18.5± 1.9mmol/L降至 14 .0± 3 .3mmol/L(P <0 .0 1)。结论 糖尿病状态下骨骼肌细胞GLUT4蛋白含量明显减少 ,其中以细胞外膜GLUT4蛋白含量的减少更为显著 ,即在糖尿病状态下骨骼肌细胞GLUT4蛋白转位机制出现障碍 ,使肌细胞对葡萄糖的转运发生障碍 ,血糖升高。糖尿病大鼠经过运动训练可增加骨骼肌细胞GLUT4蛋白含量 ,并改善GLUT4蛋白转位机制 ,从而增加肌细胞对葡萄糖的转运和利用 ,降低血糖 ,改善糖尿病大鼠糖代谢紊乱的状况。

Objective To investigate the effect of exercise on translocation of skeletal muscle cell GLUT4 protein in streptozotocin induced diabetic rats. Methods Experimental rats were randomized into three groups: control group, diabetic group and diabetic exercise group. Diabetic exercise rats were submitted to swim for 6 weeks. After skeletal muscle plasma membranes and the intracellular membranes were prepared and separated, GLUT4 protein was detected by Western blot analysis. And plasma glucose and serum insulin concentration of three group rats was detected.Results Western blot analysis showed that intracellular membranes GLUT4 protein of diabetic rats skeletal muscle decreased by 24.1 %(P< 0.01 ) and plasma membranes GLUT4 protein decreased by 48.1 % (P< 0.01 )as compared with the control rats. After 6 weeks of exercise training, the plasma glucose level of diabetic exercise rats decreased form ( 18.5 ± 1.9 ) mmol/L to ( 14.0 ± 3.3 ) mmol/L (P< 0.01 ). Plasma membranes GLUT4 protein of diabetic exercise rats increased 108.7 % (P< 0.01 ) and intracellular membranes GLUT4 protein did not change as compared with the diabetic rats. Conclusion The level of GLUT4 protein in diabetic rats skeletal plasma membranes decreased more than that in intracellular membranes, and this may be one of the causes of hyperglycemia of diabetes. Exercise training can ameliorate translocation of GLUT4 and raise the amount of GLUT4 protein in plasma membranes in diabetic rats, which may increase the utilization of glucose in skeletal muscle and decrease hyperglycemia of diabetes.