The effects of tanshinone II A on transforming growth factor β1-Smads signal pathway in renal interstitial fibroblasts of rats

Objective To study the effects of tanshinone Ⅱ A(TSN)on transforming growth factor 131(TGFβ1)signal transduction in renal interstitial fibroblasts of rats and to investigate its mechanism in prevention of tubulointerstmal fibrosis.Methods Rat renal fibroblasts of the line NRK/49F were cultured in vitro,stimulated with 5ng/mL TGFβ1 and pretreated with 10-6,10-5,and 10-4mol/L TSN,respectively.The mRNA levels of fibronectin(FN)were analyzed by reverse transcriptase polymerase chain reaction(RT-PCR).The protein expression of FN and Srnads were detected by western blot.Results TGFβ1 induced the expression of FN and Smads in a time-dependent manner.Compared with pro-stimulation,the FN mRNA and protein levels increaseel by 1.1 times and 1.5 times respectively(P＜ 0.01),the protein expression of phosphorylated Smad2/3(p-Smad2/3)increflsed by 7 times at the end of TGFβ1 stimulation(P＜0.01).TSN precondition down-regulated FN and p-Smad2/3 expression in a dose-dependent nlannero 10-6mol/L TSN precondition had no effect on FN and p-Smad2/3 expression(P＞0.05).After pretreated with 10-and 10-4mol/L TSN,the FN mRNA levels decreased by 28.1%and 43.8%(P＜0.05 and P＜0.01),the FN protein levels decreased by 40%and 44%(P＜0.05),and the p-Smad2/3 protein expression decreased by 40%and 65%respectively(P＜0.05 and P＜0.01).Conclusions TSN can block TGFβ1-Smads signaling pathway in renal interstitial fibroblasts to inhibit renaIinterstitial fibrosis. Key words: Tanshinone Ⅱ A; Fibroblasts; Transforming growth factor beta; Smad proteins