| Objective Diabetic kidney disease(DKD)is a microvascular complication specific to diabetes mellitus that increases the risk of death in patients with type2 diabetes mellitus(T2DM)and is a major cause of ESRD.A growing number of studies have demonstrated the renoprotective effects of GLP-1 receptor agonist(GLP-1RA)in the treatment of DM.Although the renoprotective effect of GLP-1RA on diabetic patients has been demonstrated in both human and animal studies independent of its hypoglycemic effect,little has been reported on the mechanism of GLP-1RA protection on podocytes and glomerular filtration barrier.The aim of this study was to investigate the protective effect of dulaglutide on renal injury in DM mice,and to further investigate the protective effect and mechanism of dulaglutide on high glucose injury in foot cells.Method(1)In vivo experiments: A mouse model of type 2 diabetes mellitus was constructed,and normal control,diabetic control,high-dose and low-dose treatment groups were set up.The mice were dosed according to the groups and random blood glucose and body weight changes were detected during the period.After 4 weeks of drug treatment,the mice were executed and serum was collected for biochemical indexes(e.g.creatinine,urea nitrogen,blood lipids)measurement,kidney tissues were taken for protein immunoblotting,PCR,immunohistochemistry and immunofluorescence to understand the protein expression characteristics of GLP-1R,ROCK1,p-MLC,etc.Transmission electron microscopy was performed to understand the morphological changes of podocyte;(2)In vitro test: a high glucose damage podocyte model was constructed and normal control,mannitol control and high glucose damage control groups were set up.Mannitol control,high glucose injury control,dulaglutide intervention and ROCK inhibitor intervention groups were set up.High glucose injury + drug intervention was given for 48 hours according to the group.Immunofluorescence was performed to characterize the expression of GLP-1R,ROCK1,MYH9 and Nephrin.Result 1.The treatment of Dulaglutide significantly reduced the blood glucose of DM mice(vs DM group,all P<0.05),while the triglycerides of mice in the high-dose group of Dulaglutide peptide decreased significantly compared with the diabetic control group(P<0.05).2.Glomerular stromal hyperplasia in DM mice was alleviated by Dulaglutide treatment,and the effect was better in the high-dose group than in the low-dose group.Transmission electron microscopy showed fusion of podocyte foot process and irregular thickening of basement membrane in the glomeruli of DM mice,and treatment with dulaglutide reduced the fusion of podocyte foot process and thickening of basement membrane.3.In the kidneys of DM mice,GLP-1R expression was decreased,Rho/ROCK signaling was activated,MLC phosphorylation was increased,MYH9 and Nephrin expression was decreased.Dulaglutide improved GLP-1R expression and inhibited Rho/ROCK signaling activation,reduced MLC phosphorylation,and increased MYH9 and Nephrin expression.4.ROCK inhibitor intervention on high glucose damaged podocyte promoted MYH9 and Nephrin expression on podocyte.5.Dulaglutide intervention on high glucose damaged podocyte promoted GLP-1R expression,inhibited Rho/ROCK signaling expression and promoted MYH9 and Nephrin expression.Conclusion Dulaglutide ameliorates glycolipid metabolism disorder and alleviates renal histopathological damage in DM mice.Rho/ROCK signaling pathway may be one of the pathways that Dulaglutide increases Nephrin expression,improves podocyte injury,and protects glomerular filtration barrier. |
