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目的:通过糖皮质激素联合高脂喂养建立2型糖尿病(T2DM)大鼠模型,观察黄芪散及其拆方对T2DM大鼠胰岛素抵抗及肝组织11β-羟基类固醇脱氢酶1(11β-HSD1),磷酸烯醇式丙酮酸羧激酶(PEPCK)mRNA与蛋白表达的影响。方法:SD大鼠适应性饲养1周后,将大鼠随机分为正常组,糖皮质激素组(GC),高脂饮食组(HFD),高脂+糖皮质激素复合模型组(HFD+GC),罗格列酮组,黄芪散处方1组(HQS-1,2.91 g·kg~(-1)),黄芪散处方2组(HQS-2,3.85 g·kg~(-1))和黄芪散原方组(HQS,2.96 g·kg~(-1)),每组8只。正常组和GC组大鼠喂以基础饲料,其他各组喂以高脂饲料。同时除正常组和HFD组给予等体积的生理盐水外,其他各组大鼠灌胃醋酸泼尼松龙(3.5 mg·kg~(-1),每天1次),并于1 h后灌胃相应受试药物。于给药10周后,测定各组大鼠空腹血糖(FBG)及胰岛素(FINS)含量,并计算胰岛素敏感指数(ISI);苏木素-伊红(HE)染色法观察各组大鼠肝脏病理变化;实时荧光定量-聚合酶链式反应(Real-time PCR)和蛋白质免疫印迹(Western blot)法检测肝组织中11β-HSD1,PEPCK mRNA和蛋白表达水平。结果:与正常组比较,HFD+GC复合模型组大鼠表现为高血糖、高胰岛素血症,肝细胞变性,肝11β-HSD1,PEPCK表达显著性升高(P<0.01),病理学检测发现大鼠肝脏组织的病变较为明显。与HFD+GC复合模型组比较,各受试药物均不同程度地降低糖尿病大鼠FBG,FINS水平,提高ISI水平(P<0.05,P<0.01),对肝组织病理学形态也有不同程度的改善。比较HQS-1,HQS-2和罗格列酮的作用幅度,黄芪散原方对FINS水平及肝组织病理形态的改善更明显。HQS及其拆方均可不同程度地降低肝11β-HSD1,PEPCK mRNA和蛋白水平(P<0.05,P<0.01),且黄芪散原方组对11β-HSD1的降低幅度优于其他各组。结论:黄芪散具有提高胰岛素敏感性、改善肝脏病理的作用,其发挥防治糖尿病及改善胰岛素抵抗的作用机制可能与降低11β-HSD1水平有关。
OBJECTIVE: To establish a rat model of type 2 diabetes mellitus (T2DM) through glucocorticoid combined with high-fat diet and observe the effects of Astragalus and its decomposed formulas on insulin resistance and hepatic 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1) , Phosphoenolpyruvate carboxykinase (PEPCK) mRNA and protein expression. Methods: One week after the SD rat was fed adaptively, the rats were randomly divided into normal group, glucocorticoid group (GC), high fat diet group (HFD), high fat + glucocorticoid combined model group (HFD + GC ), Rosiglitazone group, Astragalus prescription group 1 (HQS-1, 2.91 g · kg -1), Astragalus prescription group 2 (HQS-2, 3.85 g · kg -1) Astragalus San Yuan Fang group (HQS, 2.96 g · kg -1), with 8 in each group. The rats in normal group and GC group were fed with basal diet, and the other groups were fed with high-fat diet. At the same time, except the normal group and the HFD group, an equal volume of normal saline was given to the other groups, while other groups were given prednisolone acetate (3.5 mg · kg -1, once a day) Corresponding test drug. After 10 weeks of administration, the fasting blood glucose (FBG) and insulin (FINS) were determined in each group, and the insulin sensitivity index (ISI) was calculated. The pathological changes of liver in each group were observed by hematoxylin-eosin staining Real-time PCR and Western blot were used to detect the mRNA and protein expression of 11β-HSD1 and PEPCK in liver tissue. Results: Compared with the normal group, the expression of 11β-HSD1 and PEPCK in liver increased significantly (P <0.01) in hyperglycemia, hyperinsulinemia and hepatocellular degeneration in HFD + GC combined model group. The pathological examination showed that Rat liver tissue lesions more obvious. Compared with HFD + GC model group, all the tested drugs decreased FBG and FINS, increased ISI (P <0.05, P <0.01), and also improved the pathological morphology of liver in varying degrees . Compared with HQS-1, HQS-2 and rosiglitazone, the effect of Astragalus powder on FINS and pathological changes of liver tissue were more obvious. HQS and its disassembled prescriptions reduced the levels of 11β-HSD1 and PEPCK mRNA and protein (P <0.05, P <0.01) to some extent, and the reduction of 11β-HSD1 in the Astragalus membranaceus group was better than other groups. Conclusion: Astragalus San decoction can improve insulin sensitivity and improve liver pathology. Its mechanism of preventing and treating diabetes and improving insulin resistance may be related to decreasing the level of 11β-HSD1.