乳源性复合益生菌对2型糖尿病大鼠GLP-1的影响及调控机制

目的观察乳源性复合益生菌对2型糖尿病大鼠胰高血糖素样肽-1(glucagon like peptide-1,GLP-1)的影响,并探讨其调控机制。方法采用高脂高糖饲养合并腹腔注射链脲佐菌素(Streptozotocin,STZ,35mg/kg)建立糖尿病大鼠模型(T2DM)。造模成功大鼠随机分为二甲双胍组(200mg/kg)、低剂量复合益生菌组(1×108 CFU/d乳酸菌+1×10^6 CFU/d酵母菌)和高剂量复合益生菌组(1×10^10 CFU/d乳酸菌+1×10^8 CFU/d酵母菌),以同周龄正常大鼠为正常对照组,灌胃4周。尾静脉采血测定空腹血糖、口服葡萄糖耐量;酶联免疫吸附法(ELISA)检测血清GLP-1和肽YY(PYY)水平;蛋白免疫印迹法(Western blot)检测结肠组织GLP-1蛋白表达;荧光定量PCR检测肠道菌群、G蛋白偶联受体(GPR43、GPR41)水平;气相色谱(GC)检测肠道短链脂肪酸(short chain fatty acids,SCFAs)含量。结果与模型组相比,高剂量复合益生菌能降低大鼠空腹血糖和口服糖耐量,增加肠道乳杆菌、双歧杆菌含量,提高肠道SCFAs含量,上调GPR43和GPR41mRNA表达,促进胃肠激素GLP-1、PYY分泌,差异有统计学意义(均P<0.05)。结论乳源性复合益生菌可显著促进T2D大鼠GLP-1的分泌,调节糖代谢,推测与调节肠道菌群-SCFAs-G蛋白偶联受体信号通路有关。

Effect and mechanism of milk borne composite probiotics on GLP 1 in type 2 diabetes rats

Objective To observe the effect of milk-borne composite probiotics on GLP-1level in type 2diabetic rats and explore their regulatory mechanisms.Methods After high fat and high glucose diet,STZ(35 mg/kg)was injected intraperitoneally to establish diabetic rat model.The rats were randomly divided into model group,metformin group(200mg/kg),low dose group(1×10^8 CFU/d Lactobacillus and 1×10^6 CFU/d Saccharomycetes)or high dose group(1×10^10 CFU/d Lactobacillus and 1×10^8 CFU/d Saccharomycetes).Normal rats were used as blank controls.The above components were administered intragastrically for 4weeks.Fasting blood glucose and oral glucose tolerance of rats were detected with tail vein blood samples.Levels of glucagon like peptide-1(GLP-1)and peptide YY(PYY)in serum were determined with enzymelinked immuno sorbent assay.The expression of GLP-1protein was detected using Western blot.The intestinal flora,short chain fatty acid receptor GPR43and GPR41were determined by using fluorescent quantitative PCR.The contents of short chain fatty acids in stool samples were determined with gas chromatography.Results Compared to model group,high dose composite probiotics attenuated the fasting blood glucose and glucose intolerance,enriched the contents of Lactobacillus and Bifidobacterium,upregulated the production of acetate,propionate and butyrate,and increased the expression of GPR43and GPR41and the secretion of GLP-1and PYY(all P<0.05).Conclusion Milk-borne composite probiotics can significantly promote the secretion of GLP-1,regulate glucose metabolism in T2Drats.It is related to the regulation of intestinal flora-SCFAs-GPRs signaling pathway.