Effects of Eucommia on TGF-β_1/Smad Signaling Pathway in Renal Interstitial Fibrosis in Rats with Unilateral Ureteral Obstruction

Objective:To study the effects of Eucommia on TGF-β1,Smad2 and Smad7 expressions of renal interstitial fibrosis in Rats with unilateral ureteral obstruction.Methods:Adult male SD rats(n=32) were randomly divided into four groups:Sham operation group (Sham),UUO group,Irbesartan group(10 mg·kg-1·d-1) and Eucommia group(6 g·kg-1·d-1).The rats in normal group were treated with normal saline by intragastric administration,and the other groups were to establish renal interstitial fibrosis model by unilateral ureteral obstruction (UUO).The renal tissues were stained by Masson and HE to observe the renal interstitial fibrosis index.The expression of TGF-β1,smad2 and smad7 were detected by immunohistochemistry 2 weeks after surgery.Results:In comparison with that in Sham operation group,the level of TGF-β1 was significantly decreased after treatment with Eucommia.Meanwhile,the level of Smad2 was also down-regulated.However,the level of Smad7 expression was significantly up-regulated.The pathological changes of renal tissues in Irbesartan groups were also markedly alleviated.Conclusion:Eucommia has significant inhibitory effects on renal interstitial fibrosis in rats with unilateral ureteral obstruction,and its mechanism may be associated with the inhibition of TGF-β1 expression,down-regulation of Smad2 expression and up-regulation of Smad7 expression.