黄连素促进2型糖尿病大鼠胰高血糖素样肽分泌的分子机制

Molecular Mechanism of Berberine on GLP-1 Secretion in Type 2 Diabetic Rats

目的探究黄连素对2型糖尿病大鼠胰高血糖素样肽-1(GLP-1)分泌的影响,为进一步明确黄连素抗糖尿病分子机制提供理论基础。方法通过高脂高糖饮食及注射链脲佐菌素的方法构建2型糖尿病大鼠模型。实验分为正常对照组、模型对照组、利拉鲁肽组、小剂量及大剂量黄连素组。血糖仪检测不同时段血糖值。用酶联免疫吸附测定(ELISA)法检测GLP-1及糖化血红蛋白含量。定量多聚酶链反应(Q-PCR)法检测目标菌的含量。苏木精-伊红(HE)染色法观察胰腺组织形态。逆转录-聚合酶链反应(RT-PCR)法检测结肠组织胰高血糖素样肽-1受体(GLP-1R)、短链脂肪酸受体43(GPR43)、G蛋白偶联胆汁酸受体1(TGR5)、胰高血糖素原(GCG)、激素原转化酶1/3(PC1/3)mRNA表达。免疫组化法检测胰腺组织胰岛素及核因子κB(NF-κB)蛋白表达。Western blotting检测GLP-1蛋白表达。结果与模型对照组比较,黄连素显著增加梭杆菌属、乳酸杆菌属含量,改善口服葡萄糖耐受能力,减少糖化血红蛋白含量,上调结肠TGR5、GPR43、GCG、PC1/3基因表达,抑制NF-κB蛋白表达,促进GLP-1及胰岛素分泌。结论黄连素可能是通过增加GPR43及TGR5活性,上调GCG及PC1/3 mRNA表达,促进GLP-1以及胰岛素分泌,降低血糖。

Objective To preliminarily explore effects of berberine on the glucagon-like peptide-1(GLP-1)secretion in type 2 diabetic rats,and to provide the theoretical basis for further clarifying the antidiabetic molecular mechanism of berberine.Methods The model of type 2 diabetic rat was established by a high-fat and high-sugar diet combined with the injection of streptozotocin(STZ).The experiment was divided into normal control group,model control group,liraglutide group,low-dose berberine group,and high-dose berberine group.Blood glucose was measured by blood glucose meter in different periods.The contents of glycosylated hemoglobin(HbA1c)and GLP-1 were detected by enzyme-linked immunosorbent assay(ELISA).The content of the microbiota in feces was detected by quantitative polymerase chain reaction(Q-PCR).The histology of pancreas was observed by hematoxylin-eosin(HE)staining.The mRNA expressions of glucagon-like peptide-1 receptor(GLP-1R),short chain fatty acid receptor 43(GPR43),G protein coupled bile acid receptor 1(TGR5),proglucagon(GCG),and proconvertase 1/3(PC1/3)in colon tissue were assayed by reverse transcriptase polumerase chain reaction(RT-PCR).The protein expressions of insulin and nuclear factor kappa-B(NF-κB)were determined by immunohistochemistry.The protein expression of GLP-1 in colon tissue was assayed by Western blotting.Results Compared with the model control group,berberine increased the levels of Fusobacterium and Lactobacillus,ameliorated the oral glucose tolerance,reduced the level of HbA1c,increased the mRNA expressions of GPR43,TGR5,GCG and PC1/3,downregulated NF-κB protein expression,and upregulated GLP-1 and insulin secretion.Conclusion Berberine can ameliorate blood glucose by increasing the activity of GPR43 and TGR5,upregulating the mRNA expressions of GCG and PC1/3,and promoting GLP-1 and insulin secretion.