运动增加糖尿病大鼠葡萄糖运载体蛋白含量及基因表达的研究

Exercise induces increased CLUT4 gene expression and protein content in diabetic rats

目的 研究运动对链脲佐菌素所致的糖尿病大鼠骨骼肌细胞胰岛素受体 ,葡萄糖运载体 4(glucosetransporter,GLUT4)基因表达和蛋白含量的作用 ,探讨运动训练改善糖尿病大鼠糖代谢的可能作用机理。方法 实验大鼠分 3组 :糖尿病非运动组 ,糖尿病运动组、正常对照组。糖尿病运动组大鼠进行 6周游泳运动。用Western印迹法检测大鼠骨骼肌细胞GLUT4蛋白含量 ,用斑点印迹杂交法检测骨骼肌细胞内GLUT4mRNA含量。结果 糖尿病大鼠血糖水平明显升高 ,血胰岛素水平明显降低 ,骨骼肌细胞GLUT4蛋白含量和mRNA含量明显减少 ,与正常对照组相比分别减少 30 .7%和5 4 9%。糖尿病运动组大鼠经过 6周运动训练 ,血糖由 18.5mmol/L± 1.9mmol/L降至 14.0mmol/L±3.3mmol/L(P <0 .0 1) ,骨骼肌细胞GLUT4蛋白含量和mRNA含量较糖尿病组大鼠分别增加 6 0 .8%和5 6 % ;但运动训练并不增加糖尿病大鼠骨骼肌细胞胰岛素受体与胰岛素的结合率。结论 运动训练主要增加糖尿病大鼠骨骼肌细胞GLUT4基因表达和GLUT4蛋白含量 ,通过胰岛素受体后机制改善糖尿病大鼠外周组织对胰岛素的抵抗 ,降低血糖。

Objective To investigate the effects of exercise on insulin receptor, glucose transporter 4 (GLUT4) gene expression and protein content in skeletal muscle cells of streptozotocin induced diabetic rats. Methods All rats were randomized into three groups: normal, diabetic and diabetic exercise groups. Diabetic exercise rats were swim trained for 6 weeks. The GLUT4 mRNA of skeletal muscle was determined with dot blot and GLUT4 protein was detected by Western blotting. Results After 6 weeks of exercise training, plasma glucose level of diabetic rats decreased from 18.5 mmol/L±1.9 mmol/L to 14.0 mmol/L±3.3 mmol/L ( P <0.01). The dot blot revealed that GLUT4 mRNA decreased by 54.9% in skeletal muscle cells of diabetic rats compared with the normal rats. The Western blotting showed that GLUT4 protein of skeletal muscle cell in diabetic rats decreased by 30.7% compared with the control rats. GLUT4 mRNA and the protein of skeletal muscle in diabetic exercise group increased by 56% and 60.8% respectively as compared with the diabetic rats. However, the maximum binding of insulin receptor of skeletal muscle cells in diabetic exercise group decreased significantly compared with diabetic group. Conclusion The weaker expression of GLUT4 gene and the lower level of GLUT4 protein may be one of the causes of hyperglycemia in diabetic rats. Exercise training may raise the GLUT4 gene expression and the amount of GLUT4 protein in diabetic rats, contributing to the main mechanism of improved post receptor insulin resistance and decreased hyperglycemia in diabetic rats.