左归降糖通脉方对糖尿病合并脑梗死大鼠SCFAs/GPR43/GLP-1/GLP-1R信号通路的影响

Effect of Zuogui Jiangtang Tongmai Prescription on SCFAs/GPR43/GLP-1/GLP-1R Signaling Pathway in Rats with Diabetes Mellitus Complicated with Cerebral Infarction

目的:基于短链脂肪酸(SCFAs)/G蛋白偶联受体43(GPR43)/胰高糖素样肽-1(GLP-1)/胰高糖素样肽-1受体(GLP-1R)信号通路探讨左归降糖通脉方对糖尿病合并脑梗死(DM-CI)大鼠的潜在作用机制。方法:将60只SD大鼠随机分为假手术组、模型组、左归降糖通脉方低、高剂量组(12、24 g·kg^(-1))和西药组(吡格列酮二甲双胍片140 mg·kg^(-1)+阿司匹林肠溶片27 mg·kg^(-1)),除假手术组外,其余各组以高糖高脂饮食喂养4周后联合35 mg·kg^(-1)1%链脲佐菌素腹腔注射合并大脑中动脉闭塞建立DM-CI大鼠模型。分别用蒸馏水、左归降糖通脉方低、高剂量、吡格列酮二甲双胍片和阿司匹林肠溶片进行相应干预,术后进行神经功能缺损(NIHSS)评分,TTC染色测量大鼠脑梗死体积,测量各组大鼠随机血糖浓度,苏木素-伊红(HE)染色观察大鼠脑组织病理学变化,气相色谱法检测盲肠内容物SCFAs含量,酶联免疫吸附测定法(ELISA)检测血清GLP-1含量,蛋白免疫印迹法(Western blot)检测大鼠回肠组织中GPR43和缺血侧脑组织中GLP-1R的蛋白表达。结果:与假手术组比较,模型组大鼠NIHSS评分、随机血糖、脑梗死体积显著升高(P<0.01),SCFAs、GLP-1含量和GPR43、GLP-1R蛋白表达显著降低(P<0.01);与模型组比较,左归降糖通脉方高剂量组和西药组大鼠NIHSS评分、随机血糖、脑梗死体积明显降低(P<0.05,P<0.01),SCFAs、GLP-1含量和GPR43、GLP-1R蛋白表达水平显著升高(P<0.01)。结论:左归降糖通脉方可改善DM-CI大鼠糖代谢紊乱、减轻神经功能损伤,其机制可能与左归降糖通脉方增加SCFAs含量,上调GPR43/GLP-1/GLP-1R信号通路的表达有关。

Objective:To explore the potential mechanism of Zuogui Jiangtang Tongmai prescription(ZJT)in the treatment of diabetes mellitus complicated with cerebral infarction(DM-CI)in rats based on the short-chain fatty acids(SCFAs)/G protein-coupled receptor 43(GPR43)/glucagon-like peptide-1(GLP-1)/GLP-1 receptor(GLP-1R)signaling pathway.Method:Sixty SD rats were randomly divided into sham operation group,model group,low-and high-dose ZJT groups(12,24 g·kg^(-1)),western medicine group(140 mg·kg^(-1)pioglitazone metformin tablets+27 mg·kg^(-1)enteric-coated aspirin tablets).Except for the sham operation group,all other groups were fed a high-sugar high-fat diet for 4 weeks and then subjected to intraperitoneal injection of 1%streptozotocin at 35 mg·kg^(-1)combined with middle cerebral artery occlusion(MCAO)to establish a DM-CI rat model.The corresponding interventions were performed with distilled water,low-dose ZJT,high-dose ZJT,pioglitazone metformin tablets,and enteric-coated aspirin tablets.After surgery,National Institutes of Health Stroke Scale(NIHSS)scoring and triphenyltetrazolium chloride(TTC)staining to measure the rat's cerebral infarct volume were carried out.Random blood glucose levels were measured,and hematoxylin-eosin(HE)staining was used to observe histopathological changes in rat brain tissues.Gas chromatography was employed to detect the content of SCFAs in the cecum contents.Enzyme-linked immunosorbent assay(ELISA)was adopted to measure serum GLP-1 level.Western blot was used to detect the protein expression of GPR43 in rat ileal tissues and GLP-1R in the ischemic brain tissues.Result:Compared with the sham operation group,the model group showed significantly increased NIHSS scores,random blood glucose levels,and cerebral infarct volumes(P<0.01),and significantly decreased SCFAs content,GLP-1 levels,and GPR43 and GLP^(-1)R protein expression(P<0.01).Compared with the model group,the high-dose ZJT group and the western medicine group exhibited significantly reduced NIHSS scores,random blood glucose levels,and cerebral infarct volumes(P<0.05,P<0.01),and significantly increased SCFAs content,GLP-1 levels,and GPR43 and GLP-1R protein expression(P<0.01).Conclusion:ZJT can improve glucose metabolism disorder and reduce neurological damage in DM-CI rats,and its mechanism may be related to the increase in SCFAs content and the upregulation of the GPR43/GLP-1/GLP-1R signaling pathway.