Retn基因表达对3T3-L1脂肪细胞葡萄糖摄取的影响及其机制探讨

Influence of Retn gene expression on glucose uptake by 3T3-L1 cells and the related mechanism

目的:观察Resistin蛋白对3T3-L1脂肪细胞葡萄糖摄取的影响并探讨其引发胰岛素抗性的可能机制。方法:(1)采用放射免疫测定法检测低、正常及高表达Retn基因的3T3-L1脂肪细胞在基础状态及胰岛素刺激下的葡萄糖摄取水平。(2)采用RT-PCR和实时荧光定量RT-PCR法测定低、正常和高表达Retn基因的3T3-L1脂肪细胞中几种葡萄糖转运信号蛋白,包括胰岛素受体底物1(IRS-1)、磷脂酰肌醇3激酶(PI-3K)、丝/苏氨酸激酶2(AKT-2)、葡萄糖转运子4(GLUT-4)、丝裂原活化蛋白激酶p38(p38MAPK)及糖原合成酶激酶3β(GSK-3β)的表达。结果:(1)在基础状态及胰岛素刺激下,3T3-L1脂肪细胞葡萄糖摄取随Retn基因表达的升高而降低。(2)PI-3K和AKT-2两个信号蛋白mRNA的表达随着细胞内Retn基因表达水平的升高而降低;GSK-3β和p38MAPK两个信号蛋白mRNA的表达随着细胞内Retn基因表达水平的升高而升高。结论:(1)Resistin蛋白可以导致脂肪细胞产生胰岛素抗性,其机制可能与胰岛素信号通路中的PI-3K和Ras通路中一些信号蛋白表达的变化有关。

Objective：To investigate the influence of high expression of Retn gene on glucose uptake by 3T3-L1 cells and to study its mechanism in inducing insulin resistance. Methods： （1）Radioimmunoassay was used to determine the glucose uptake hy 3T3-L1 cells with low-, normal- and high-level Retn expression under basal and insulin-stimulated states. （2）RT PCR and real-time RT-PCR were used to determine the mRNA levels of several glucose transport proteins in 3T3-L1 cells with different expression of Retn, including insulin receptor suhstrate-1 （IRS-1）, phosphatidylinositol 3-kinase （PI-3K）, AKT-2, glucose transporter-4 （GLUT-4）, p38 mitogen-activated protein kinase （p38MAPK）, and glycogen synthase kinase-31？（GSK-31？）. Results： The uptake of glucose decreased with the increase of Retn expression under basal and insulin-stimulated conditions. The mRNA expression of 2 signal protein PI-3K and AKT-2 decreased with the increase of Retn expression; and the expression of GSK-31β and p38MAPK increased with the increase of Retn expression. Conclusion： Resistin protein can induce insulin resistance in adipocytes, which might he related to the expression changes of some proteins in PI-3K and Ras pathways.