飞燕草素葡萄糖苷通过Sirt1信号通路抑制内质网应激和增强自噬而减轻2型糖尿病小鼠主动脉内皮损伤OA

AIM:To clarify whether delphinidin-3-glucoside(DPg)alleviates aortic endothelial injury in type 2 diabetes mellitus(T2DM)mice and explore the underlying silent information regulator 1(Sirt1)-mediated endoplasmic reticulum stress(ERS)-autophagy mechanism.METHODS:A T2DM mouse model was established by 4-week high-fat diet combined with intraperitoneal injection of streptozotocin,and mice were randomly divided into the control group,T2DM group and T2DM+DPg group(n=6).The rAAV1 carrying sh Sirt1 or shNC was injected via the tail vein to construct the cardiac Sirt1 knockdown mouse model,and the T2DM model was also established by high-fat diet and STZ,and mice were gavaged with DPg,which were divided into the T2DM+DPg+shNC group and the T2DM+DPg+sh Sirt1 group(n=6).Aortic structure and calcification were assessed by haematoxylin and eosin and von Kossa staining.Apoptosis was detected by TUNEL staining,and endothelial cells were detected by CD31 immunohistochemistry.The expression levels of Sirt1,ERS-related protein[phosphorylated protein kinase R-like endoplasmic reticulum kinase(p-PERK),phosphorylated eu-karyotic translation initiation factor 2α(p-eIF2α),CCAAT/enhancer-binding protein homologous protein(CHOP),acti-vating transcription factor 4(ATF4)],autophagy-related proteins[microtubule-associated protein 1 light chain 3(LC3),beclin-1 and P62],and caspase-3 were evaluated by Western blot,RT-qPCR,and immunofluorescence.For the in vitro studies,human umbilical vein endothelial cells were treated with 45 mmol/L glucose to establish a high-glucose model,fol-lowed by DPg treatment,Sirt1 silencing,or 4-phenylbutyric acid(4-PBA)intervention.Cell injury and signalling changes were assessed by CCK8 assay,reactive oxygen species detection,flow cytometry/TUNEL,Western blot,and RT-qPCR.RESULTS:Compared with control group,the aortic wall thickening and calcification were aggravated in the T2DM group,and the number of CD31+endothelial cells decreased while apoptosis increased(P<0.05).The protein levels of Sirt1 and beclin-1 were down-regulated,while the levels of p-PERK,p-eIF2α,CHOP,ATF4,P62 and caspase-3,and the ratio of LC3-II/I were up-regulated(P<0.05).Knockdown of Sirt1 partially abolished the protective effects of DPg in vivo and in vitro(P<0.05).The DPg combined with 4-PBA further reduced high glucose-induced ERS and apoptosis and improved autophagy compared with either treatment alone(P<0.05).CONCLUSION:Treatment with DPg alleviates aortic endothelial injury in T2DM mice by up-regulating Sirt1,suppressing excessive ERS,and improving autophagy.