ABSTRACT
Objective To investigate the effects and underlying mechanism of calcitriol on ameliorating podocytes impairment in DN rats.Methods SD rats were randomly divided into four groups:normal control (NC) group,calcitriol treatment (VD) group:calcitriol 0.1μg· kg--1 d-1,diabetic nephropathy (DN) group:streptozocin (STZ) 58 mg/kg,DN treated with calcitriol (DN + VD) group:calcitriol 0.1 μg · kg-1 · d-1 + STZ 58 mg/kg.Rats were sacrificed at the end of 18 weeks.Results Compared with the DN group,the DN + VD group exhibited significantly lower proteinuria by 36％,improved renal histology at the end of the experiment (P ＜ 0.05),and similar levels of blood glucose,serum urea nitrogen as well as body weight (P ＞ 0.05).There were no significant differences in the serum concentrations of creatinine,calcium and phosphorus among the four groups (P ＞ 0.05).In DN group,the expressions of nephrin,podocin,VDR,PI3K-p85 and p-Akt were significantly decreased and the expression of desmin was increased compared to NC group.Calcitriol treatment could attenuate the above changes.Additionally,a positive correlation was observed between the expressions of nephrin and VDR (r=0.776,P ＜ 0.05).Likewise,the expression of nephrin was positively correlated with either PI3K -p85 or p-Akt (r=-0.736,r=0.855,all P ＜ 0.05).Conclusion Calcitriol can ameliorate podocytes injury in DN rats,which might be related with the further up-regulation of PI3K/p-Akt signaling pathway.