吡格列酮对高脂饮食诱导的胰岛素抵抗大鼠肝组织蛋白酪氨酸磷酸酶-1B及胰岛素受体底物-2表达的影响

Effect of pioglitazone on the expressions of protein-tyrosine-phosphatase-1 Band insulin receptor substrate-2 in the liver of rats with insulin resistance induced by high-fat-diet

目的观察吡格列酮对高脂饮食诱导的IR大鼠肝组织蛋白酪氨酸磷酸酶-1B(PTP-1B)及胰岛素受体底物-2(IRS-2)表达的影响。方法 40只SD大鼠随机分为高脂饮食(HF)组30只和正常对照(NC)组10只,其中HF组又分为高脂对照(HFN)亚组和吡格列酮(HFP)亚组,每组各15只。喂养12周后,HFP亚组给予吡格列酮灌胃2周,并测定大鼠体重、FPG、FIns、TG、TC、IS。应用免疫组化、免疫印迹、免疫沉淀技术检测肝组织PTP-1B及IRS-2的表达。结果免疫组化:HFN亚组PTP-1B表达较NC组增高(P<0.01),HFP亚组较HFN亚组降低(P<0.01);免疫印迹:HFN、HFP亚组PTP-1B表达均高于NC组(P<0.01或P<0.05),且HFP亚组低于HFN亚组(P<0.01);免疫沉淀:HFN亚组IRS-2磷酸化程度较NC组降低(P<0.01),HFP亚组较HFN亚组增高(P<0.05)。结论吡格列酮能够改善IR,其作用机制可能与抑制PTP-1B表达,从而使胰岛素信号转导分子IRS-2表达增强有关。

Objective To observe the effect of pioglitazone on the expressions of protein tyrosine phosphatase 1B （PTP-1B） and insulin receptor substrate 2 （IRS-2） in the liver of rats with insulin resistance induced by high-fat-diet. Methods Forty SD rats were randomized into normal high fat diet group （HF, n=30）, and normal control group （NC, n=10）. The HF group was subdivided into HFN group and HFP group with 15 rats in each. Twelve weeks later, the HFP group was lavaged with pioglitazone for two weeks. The body weight, fasting blood glucose, fasting insulin （Fins）, triglycerides （TG）, total cholesterol （TC）, and insulin sensitive index were measured, and the expressions of PTP-1B and IRS-2 in the liver tissue were determined with immunohistochemistry, Western-blotting, and immunoprecipitation. Results By immunohistochemistry the PTP-1B expression in the HFN group was significantly increased compared with the NC group （1039.54±53.29） vs （856.37±33.26）, （P〈0.01）, and that in the HFP group was significantly decreased compared with the HFN group （920. 62±85.34） vs （1039.54±53.29）, （P〈0.01）. By Western-blotting assay the PTP-1B expression in the HFN group and HFP group were all significantly increased compared with the NC group （HFN vs NC：157.7 % vs 100%, P〈0. 01; HFP vs NC.. 127.1% vs 100%, P〈0.05）, and that in the HFP group was significantly decreased compared with the HFN group （127.1% vs 157.7%, P〈0.01）. By immunoprecipitation the IRS-2 phosphorylation of the HFN group was lowered compared with the NC group （53% vs 100%, P〈 0. 01）, and that of the HFP group was increased compared with the HFN group （78% vs 53%, P〈0.05）. Conclusion Pioglitazone improves irxsulfia resistance, the mechanism of which is possibly related to the inhibited expression of PTP-1B and the enhanced expression of IRS-2.