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目的探讨苦瓜总皂苷对2型糖尿病大鼠胰岛素信号转导通路的调节作用并揭示其改善胰岛素抵抗作用的机制。方法用高脂高糖饮食喂养结合小剂量链脲佐菌素(STZ)注射复制2型糖尿病大鼠模型,分别以苦瓜总皂苷低、中、高剂量(100,200,400 mg·kg-1·d-1)和二甲双胍(50 mg·kg-1·d-1)灌胃治疗,共8周。取肝脏组织分别用RT-PCR方法和Western blot方法检测蛋白酪氨酸磷酸酶1B(PTP-1B)、细胞因子信号抑制物3(SOCS-3)和c-Jun氨基末端激酶(JNK)的mRNA和蛋白表达量。结果与模型组比较,苦瓜总皂苷各剂量组SOCS-3和JNK的mRNA和蛋白表达量均降低,PTP-1B m RNA也降低(P<0.01)。而且SOCS-3和JNK的mRNA和蛋白表达量随着苦瓜总皂苷剂量的增加表达量逐渐递减,呈剂量依赖关系。结论苦瓜总皂苷改善胰岛素抵抗作用机制很可能是下调SOCS-3、JNK mRNA和蛋白的表达量进而使胰岛素信号转导通路的作用增强。
Objective To investigate the regulation effect of Momordica charantia total saponins on insulin signal transduction pathway in type 2 diabetic rats and its mechanism of improving insulin resistance. Methods A rat model of Type 2 diabetes mellitus (T2DM) was injected with high fat and high sugar diet combined with low dose streptozotocin (STZ) .Multiple doses of 100, 200 and 400 mg · kg -1 · d -1 ) And metformin (50 mg · kg-1 · d-1) intragastrically for 8 weeks. The liver tissues were harvested for detection of protein tyrosine phosphatase 1B (PTP-1B), cytokine signaling inhibitor 3 (SOCS-3) and c-Jun N-terminal kinase (JNK) mRNA by RT-PCR and Western blot And protein expression level. Results Compared with the model group, the mRNA and protein expressions of SOCS-3 and JNK were decreased and the PTP-1B m RNA was also decreased in each dose group (P <0.01). Moreover, the mRNA and protein expression of SOCS-3 and JNK gradually decreased with dose increasing of Momordica charantia total saponins in a dose-dependent manner. Conclusion The mechanism of improving the insulin resistance of Momordica charantia total saponins is likely to be down-regulation of the expression of SOCS-3, JNK mRNA and protein and thus the effect of insulin signal transduction pathway.