The Effect Of Sitagliptin On The Wnt/-beta-catenin Signal Pathway And The Transdifferentiation Of Renal Tubular Epithelial Cells Induced By High Glucose

Objective:To investigate the effect of Wnt/ beta –catenin signaling pathway in the transdifferentiation of renal tubular epithelial cells induced by high glucose and the intervention effect of sitagliptin Method:We obtained rat renal proximal tubular epithelial cells(NRK-52K),and joined them in low sugar DMEM + 10% fetal bovine serum(FBS).Then we let these cells grow under 37℃,5%CO2 condition.When eighty percent of cells were fused,these cells were cultured in media without fetal bovine serum for 24 hours.After growing synchronously,the cells were divided into five groups:(1)Nomal control group:glucose 5.5mmol/l;(2)High glucose group:glucose 25mmol/l;(3)Hypertonic group:mannitol 19.5mmol/l + glucose 5.5mmol/l;(4)Sitagliptin intervention group:10umol/l sitagliptin+ glucose 25mmol/l;(5)XAV939 group:These cells were pretreatment with XAV939(1umol/L)which was Wnt/ beta-catenin pathway inhibitor for 40 min.Then put glucose(25mol/l)in the group.We collected cells after 48 hours.Then the expression of the protein and mRNA of Wnt,beta –catenin and alpha-SMA in each group were detected by Western blotting and fluorescence quantitative PCR method respectively.Results:1.Cytotoxicity test:With the increasing of the concentration of sitagliptin,the optosis rate increased gradually.According to the results of the experiment and the related references,the concentration of 10umol/l sitagliptin was used in this experiment.2.RT-PCR show:After 48 hours,the expression of the mRNA of Wnt,beta –catenin and alpha-SMA was no significant difference between the normal group and the hypertonic group(P>0.05);Compared with the expression of the mRNA of other groups,the expression of the mRNA of Wnt,beta –catenin and alpha-SMA in high glucose group was significantly increased(P<0.05);Compared with the expression of the mRNA of high glucose group,the expression of the mRNA of Wnt,beta –catenin and alpha-SMA in Sitagliptin group and XAV939 group was significantly decreased(P<0.05),and the expression of the mRNA of Wnt,beta –catenin and alpha-SMA decreased more significantly in the XAV939 group.3.Western blot show: After 48 hours,the expression of the protein of Wnt,beta-catenin and alpha-SMA was no significant difference between the normal group and the hypertonic group(P<0.05);Compared with the expression of the protein of other groups,the expression of the protein of Wnt,beta –catenin and alpha-SMA in high glucose group was significantly increased(P<0.05);Compared with the expression of the protein of high glucose group,the expression of the protein of Wnt,beta –catenin and alpha-SMA in Sitagliptin group and XAV939 group was significantly decreased(P<0.05),and the expression of the protein of Wnt,beta –catenin and alpha-SMA decreased more significantly in the XAV939 group.Conclusion:Sitagliptin can reduce the expression of alpha-SMA in tubular epithelial cells by partly inhibiting the activation of Wnt/ beta-catenin pathway,so as to delay transdifferentiation of renal tubular epithelial cells.