青钱柳叶复方对糖尿病大鼠骨骼肌胰岛素信号通路和GLUT4的影响

Effects of cyclocarya paliurus compound prescription on insulin signal pathway and GLUT4 in skeletal muscle of diabetic rats

目的通过建立高血糖动物模型,研究青钱柳叶复方对糖尿病大鼠骨骼肌胰岛素信号通路和GLUT4的影响及作用机制。方法采用高脂饮食联合小剂量腹腔注射链脲佐菌素(STZ)30 mg/kg建立2型糖尿病模型,造模成功后大鼠随机分为模型组、二甲双胍组、青钱柳叶复方高剂量组(复方高剂量组)、青钱柳叶复方低剂量组(复方低剂量组)。正常对照组和模型组给予蒸馏水,各药物治疗组分别灌胃给予相应剂量药物。给药12周后,氧化酶法检测大鼠空腹血糖(FBG)的变化;ELISA法检测大鼠血清中的空腹胰岛素水平(FINS)的变化;计算各组大鼠胰岛素抵抗指数(HOMA-IR)和胰岛素敏感指数(HOMA-IS);Western-Blot法、RT-PCR法和免疫组织化学检测骨骼肌胰岛素信号通路IRS-1、IRS-2、PI3K、AKT、GLUT4的表达情况。结果复方(高、低)治疗组大鼠血清FBG、糖化血红蛋白(Hb A1c)、FINS均显著降低(P<0.05);HOMA-IR显著降低,HOMA-IS显著升高(P<0.05);其中复方高剂量组大鼠血清FBG、Hb A1c、FINS等含量低于复方低剂量组;但差异无统计学意义(P>0.05)。复方高剂量组糖尿病大鼠骨骼肌IRS-1、IRS-2、PI3K、AKT、GLUT4等蛋白表达量增多。结论青钱柳叶复方能降低2型糖尿病大鼠血糖,改善胰岛素抵抗。此作用是通过增加胰岛素受体底物(IRS-1、IRS-2)数量,激活PI3K途径增加GLUT4转位,增强骨骼肌中GLUT4基因和蛋白表达实现的。

Objective To study the effect of cyclocarya paliurus compound prescription on the insulin signal pathway and GLUT4 in skeletal muscle of diabetic rats and action mechanism. Methods The model of type 2 diabetes mellitus was established by high fat diet combined with low dose intraperitoneal injection of streptozotocin （STZ） of 30 mg/kg. The rat model was randomly divided into model group, metformin group, high dose cyclocarya paliurus compound group and low dose cyclocarya paliurus compound group. Normal control group and model group were given distilled water, the drug treatment group were given the appropriate dose of drugs with garage. After 12 weeks, the changes of fasting blood glucose （FBG） were measured by oxidase method. The changes of FINS in the serum were tested by ELISA. The expression of IRS-1, IRS-2, PI3K, AKT and GLUT4 in skeletal muscle were measured by Western- Blot, RT-PCR and immunohistochemistry. Results The levels of serum FBG, HbA1C, FINS were significantly decreased in the compound treatment group （P 〈0. 05）, HOMA-IR decreased, and HOMA-IS increased（P 〈0. 05） ; and the serum FBG, HbA1C, FINS of high dose group were lower than those in the low dose group. But the difference was not statistically significant （P 〉 0. 05 ）. The expression levels of IRS-1, IRS-2, PI3K, AKT and GLUT4 in skeletal muscle of diabetic rats in the high dose group were significantly increased. Conclusion Cyclocarya paliurus compound prescription can reduce blood glucose and improve insulin resistance in type 2 diabetic rats. This is achieved by increasing the number of insulin receptor substrates （IRS-1, IRS-2）, activating the PI-3K pathway, increasing GLUT4 translocation, and enhancing GLUT4 gene and protein expression in skeletal muscle.