Regulation of gypenosides on TGF-β/Smad signaling pathway and expression of connective tissue growth factor in unilateral ureteral obstruction rats with renal tubulointerstitial fibrosis

Objective To investigate the expression transforming growth factorβ1(TGF-β1),Smad7 and connective tissue growth factor(CTGF) in rats with renal tubulointerstitial fibrosis and the effects of Gypenosides(GPs) treatment on expression of TGF-β,Smad7 and CTGF.Methods Unilateral ureteral Obstruction(UUO) rat animal models were used and the rats were divided into GPs group(Gypenosides 200 mg·Kg~(-1)·d~(-1) by gastric gavage from 3d before the obstruction to 14 days after the induction),model group and sham operated group.The expression of TGF-β1,Smad7 and CTGF in the obstructed kidneys was assessed by RT-PCR,immunohistochemistry and HE staining methods after 3,7,and 14d respectively.The degree of tubulointerstitial damage was scored by Masson staining methods.Results Compared with the sham operated group,the expressions of TGF-β1,CTGF mRNA and protein were markedly increased in UUO group,and the expression of Smad7 mRNA and protein was markedly decreased(all P0.01).Compared with model group,the expression of Smad7 mRNA was markedly increased and the expression of CTGF was markedly decreased in GPs-treated group.The degree of tubulointerstitial damage was increased after unilateral ureteral obstruction.The expression of Smad7 increased and the degree of tubulointerstitial damage decreased with the treatment of GPs.Conclusions The expression of CTGF in UUO rats may be regulated by TGF-β/Smad signaling path.The GPs inhibits the expression of CTGF through up-regulation of Smad7,and inhibits the progression of renal tubulointerstitial fibrosis.