微囊蛋白1和葡萄糖转运蛋白4在3T3-L1胰岛素抵抗脂肪细胞模型中的表达及作用

Expression and Function of Caveolin-1 and GLUT4 in the Insulin Resistance Model of 3T3-L1 Differentiated Adipocytes

目的诱导3T3-L1前脂肪细胞分化成熟并建立脂肪细胞胰岛素抵抗模型,探讨微囊蛋白1(caveolin-1)及葡萄糖转运蛋白4(GLUT4)在脂肪细胞胰岛素抵抗时的表达及作用。方法 3T3-L1前脂肪细胞经诱导分化成熟、建立胰岛素抵抗模型成功后进入实验,流式细胞术检测胰岛素抵抗状态下脂肪细胞葡萄糖摄取,Western blot检测细胞GLUT4、caveolin-1、磷酸化微囊蛋白1(p-caveolin-1)蛋白的表达,qRT-PCR检测GLUT4、caveolin-1 mRNA的表达。结果地塞米松成功诱导建立了脂肪细胞胰岛素抵抗模型,葡萄糖氧化酶法检测模型组细胞对胰岛素刺激下葡萄糖摄取率降低,流式细胞术检测诱导胰岛素抵抗后,脂肪细胞摄取荧光葡萄糖量明显减少。诱导3T3-L1胰岛素抵抗后,GLUT4 mRNA、caveolin-1 mRNA表达明显降低(P<0.01);GLUT4、caveolin-1及p-caveolin-1蛋白表达均明显降低(均P<0.01)。结论地塞米松可成功诱导建立脂肪细胞胰岛素抵抗模型,诱导3T3-L1细胞胰岛素抵抗后,细胞的葡萄糖转运能力降低,caveolin-1表达与功能降低。

Objective To investigate the glucose uptake of mature adipocytes and the expression of caveolin-1 and glucose transpoter 4（GLUT4）during insulin resistance status,so as to explore its functions. Methods The 3T3-L1 adipocytes were induced to differentiate into adipocytes,and the insulin resistance model were built up. Flow cytometry method was used to observe the state of the glucose uptake and insulin resistance. Western blot was performed to detect the expression of GLUT4,caveolin-1,and p-caveolin-1. qRT-PCR was adopted to detect GLUT4 and caveolin-1mRNA expression. Results The 3T3-L1 preadipocytes were differentiated and induced the insulin resistance of mature adipocytes. The uptake rate of the 2-NBDG of IR adipocytes sharply decreased. The results of qRT-PCR showed that the mRNA relative expression of caveolin-1 and GLUT4 were less than the normal 3T3-L1 adipocytes（P〈0.01）. Western blot showed that the GLUT4,caveolin-1 and p-caveolin-1 protein expression were decreased in the adipocytes（P〈0.01）. Conclusion The 3T3-L1 preadipocytes cells can differentiated into mature adipocytes,dexamethasone can successfully induce insulin resistance in adipocytes. The glucose uptake rate decreased in the insulin resistance 3T3-L1 adipocytes,caveolin-1 and GLUT4 and phosphorylated protein expression were decreased,which suggests the decreasing function of caveolin-1 may related to the insulin resistance status in adipocytes.