Interventional Effect of EGCG on Transdifferentiation of Renal Tubular Epithelial Cells in Rats with Obstructive Nephropathy and Its Mechanism

Objective To explore the mechanism of epigallocatechin-3-gallate(EGCG) and its effect on renal interstitial fibrosis and tubular epithelial cell transdifferentiation.Methods 56 male Wistar rats were randomly divided into three groups:normal control group(n =8),model group of unilateral ureteral obstruction(UUO)(n =24) in which renal interstitial fibrosis model was established by unilateral ureteral ligation and EGCG treatment group(n =24) in which EGCG(5 mg/kg) was injected peritoneally on a daily basis after the unilateral ureteral ligation.8 rats of each group(the UUO model and EGCG treatment groups)were sacrificed on the 3rd,7th and 14th day,respectively.The nephridial histopathology was observed by HE and Masson staining;α-smooth muscle aorta(α-SMA),cytokeratin 18(CK-18),transforming growth factor-β1(TGF-β1) in renal tissue were analyzed with immunohistochemistry;nuclear factor-κB(NF-κB) protein in nucleus of renal tissue was detected with Western blot.Results In UUO group,renal tubule injury and interstitial fibrosis emerged.Decreased expression of CK-18 and increased expression of α-SMA and TGF-β1 in renal tissue,and increased expression of NF-κB in the nucleus of renal tissue were found.But the changes in the EGCG treatment group were less obvious than the UUO model group.Conclusion EGCG can maintain the phenotype of renal tubular epithelial cell and alleviate the transdifferentiation of renal tubular epithelial cell and renal interstitial fibrosis found in UUO model group.In vivo,EGCG can reduce the renal tubular epithelial cell transdifferentiation and renal interstitial fibrosis by down-regulating TGF-β1 expression and decreasing NF-κB activation.