›› 2014, Vol. 32 ›› Issue (5): 471-475.

• Original Article • Previous Articles     Next Articles

Protective effect of vitamin D on high glucose-induced podocyte insulin resistance    

ZOU Minshu1, YU Jian1, NIE Guoming1, LUO Liman1, XU Hongtao1, YIN Xiaoling2, ZHOU Jianhua2   

  1.  (1. Department of pediatrics, Wuhan General Hospital of Guangzhou Command of PLA, Wuhan 430070,China; 2. Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China)
  • Received:2013-12-07 Online:2014-05-15 Published:2014-05-15

Abstract:  Objective To study the protective effects of vitamin D (VitD) on podocyte insulin resistance and its mechanisms. Methods Immortalized mouse podocytes in vitro were randomly divided into 4 groups: podocytes+5mmol/L glucose group (group A); podocytes+5mmol/L glucose+1nmol/L propylene glycol group (group B); podocytes+30mmol/L glucose+1nmol/L propylene glycol group (group C); podocytes+30mmol/L glucose+1nmol/L propylene glycol+1nmol/L VitD group (group D). The percentage of podocyte apoptosis was determined after 48 h of incubation. Podocyte viability was assessed by MTT assay. The mRNA expressions of vitamin D receptor (VDR) and insulin receptor substrate protein 1 (IRS1) in podocyte were detected by RT-PCR. Western blot analysis was performed to measure the protein levels of p-IRS1/IRS, p-Akt/Akt and p-ERK1/2/ERK1/2. Results There were significant differences in apoptosis percentage, viability and the expression of VDR, IRS1, p-ERK1/2 of podoctyes(P<0.05)among 4 groups. There was no difference in p-Akt/Akt expression among 4 groups(P>0.05). Compared with group A, B , and D, the percentage of podocyte apoptosis in group C was significantly increased, the cell viability was decreased, the expressions of VDR and IRS1 mRNA and p-IRS1 and p-Akt proteins were down-regulated, whereas p-ERK1/2 was up-regulated in group C. The levels of p-IRS1/IRS1, p-Akt/Akt, p-ERK1/2 / ERK1/2 had no statistical differences in group A, B, and D (P>0.05). Conclusions VitD-VDR system alleviates podocyte apoptosis induced by high glucose, and activates insulin signaling pathway and counteracts insulin resistance signal to improve podocyte insulin resistance.