Abstract: Objective To detect expression changes of Sfrp1 in NRK-52E cells after 5-Aza-2'deoxycytidine (5-Aza-CdR) intervention. Methods Sprague-Dawley (SD) rats were divided into normal group (NC group) and diabetic nephropathy group (DN group) randomly. The related biochemical indexes were detected after successfully modeling^[1-2] for 10 weeks;kidney index (KI) was calculated; the expression of Sfrp1 in renal tissue was detected by immunohistochemistry. NRK-52E cells were divided into normal glucose group (NG, 5.5 mmol/L), high glucose group (HG, 30 mmol/L) and high glucose +5-Aza-CdR group(5-Aza-CdR group);the expressions of Sfrp1,Dnmt3a,Dnmt3b,col-Ⅲ and col-Ⅳ were detected by Western blot;the mRNA expression of Sfrp1 was detected by RT-qPCR;pearson test was used to analyze the correlation between Sfrp1 and Dnmt3a,Dnmt3b,col-Ⅲ or col-Ⅳ. Results The level of KI, blood glucose, 24 h urinary protein and creatinine in DN group were all higher than those in NC group.The expression of Sfrp1 in renal tissue of DN group was significantly lower than that of NC group.The results of in vitro experiments showed as follows:the mRNA and protein expression of Sfrp1 were decreased in HG group(P＜0.05),while the protein expressions of Dnmt3a,Dnmt3b,col-Ⅲ and col-Ⅳ in HG group were increased (P＜0.05);compared with HG group,the mRNA and protein expression of Sfrp1 was increased in 5-Aza-CdR group(P＜0.05), the protein expressions of Dnmt3a,Dnmt3b,col-Ⅲ and col-Ⅳ in 5-Aza-CdR group were decreased (P＜0.05); Sfrp1 was negatively correlated with Dnmt3a (r=-0.937, P＜0.05),Dnmt3b (r=-0.965, P＜0.05),col-Ⅲ(r=-0.694, P＜0.05) and col-Ⅳ(r=-0.888, P＜0.05). Conclusions The mechanism through which 5-Aza-2′-deoxycytidine inhibits renal fibrosis is potentially related to the reduction of Dnmt3a and Dnmt3b expression and the increase of Sfrp1 expression.

Key words: 5-Aza-2′ deoxycytidine (5-Aza-CDR), DNA methyltransferase 3a(Dnmt3a), DNA methyltransferase 3b(Dnmt3b), secreted frizzled-related protein 1(Sfrp1), renal fibrosis