非诺贝特对心脏成纤维细胞胶原合成的影响及作用机制

摘要

目的 过氧化物酶增殖物激活受体α(peroxisome proliferator-activated receptor-α,PPARα)具有心血管保护作用,但其对心肌纤维化的影响及作用机制尚不清楚.文中探讨PPARα激动剂非诺贝特(Fenofibrate)对糜酶诱导的心脏成纤维细胞(cardiac fibroblasts,CF)胶原合成的影响及细胞内信号转导机制.方法 用胰酶消化法分离、培养新生SD大鼠的CF,采用RT-PCR检测Ⅰ、Ⅲ型胶原mRNA的表达水平,Western blot检测转化生长因子β1(transforming growth factor-β1,TGF-β1)、p-Smad2/3及Smad7的蛋白表达水平.结果 ①非诺贝特浓度依赖性地抑制糜酶诱导的CF中Ⅰ、Ⅲ型胶原mRNA表达,其中50和100μmol/L组Ⅰ、Ⅲ型胶原mRNA表达水平均较糜酶组显著减少(P<0.01).②不同浓度的非诺贝特预处理组CF的TGF-β1蛋白表达水平呈浓度依赖性减少,其中50和100μmol/L组均较糜酶组明显减少(P<0.05,P<0.01).③不同浓度的非诺贝特预处理后,p-Smad2/3蛋白表达水平呈递减趋势,Smad7蛋白表达水平呈递增趋势.结论 PPARα激动剂非诺贝特可抑制糜酶诱导的大鼠CF胶原合成,其机制可能与其下调TGF-β1和p-Smad2/3、上调Smad7蛋白表达有关.%Objective Peroxisome proliferator-activated receptor-α ( PPARα) has cardiovascular protection, but its effect on myocardial fibrosis and the underlying mechanism remain unclear. To investigate the effect of PPARα agonist fenofibrate on the collagen synthesis of rat cardiac fibroblasts( CF) induced by chymase and its mechanism of cellular signal transduction. Methods Cultured CFs from neonatal SD rats were isolated by trypsinization. The mRNA expressions of Type Ⅰ and Type Ⅲ collagen in CFs were determined by RT-PCR. The protein expressions of transforming growth factor-β1( TGF-β1) , p-Smad2/3 and Smad7 in CFs were evaluated by Western blot. Results Pretreatment with fenofibrate inhibited the mRNA expressions of Type Ⅰ and Type Ⅲ collagen induced by chymase in a concentration-dependent manner. The mRNA expressioas of Type Ⅰ and Type Ⅲ collagen pretreated with 50 and 100 μmol/L fenofibrate were significantly lower than those of the chymase group (P ＜0. 01). The protein expression of TGF-β1 was decreased in fenofibrate pretreated youp in a dose-dependent manner, 50 and 100 μmol/L fenofibrate pretreated groups were significantly lower than that of the chymase group (P ＜ 0. 05 , P ＜ 0. 01). Pretreatment with fenofibrate decreased the p-Smad2/3 protein and increased the Smad7 protein respectively in a dose-dependent manner. Conclusion PPARα agonist fenofibrate can inhibit the collagen synthesis of rat CFs induced by chymase. The mechanism is associated with the downregulation of TGF-β1 , p-Smad2/3 protein and the upregulation of Smad7 protein.