牛磺酸对心肌纤维化的抑制作用及机理

Inhibition of taurine on myocardial fibrosis and its mechanism

目的:研究牛磺酸(Tau)对心肌纤维化的抑制作用及机制。方法:体内实验以异丙肾上腺素(Iso)皮下注射建立心肌纤维化模型,分为正常对照组、模型组及Tau治疗组(80、160和320 mg.kg-1.d-1),取心肌组织测定羟脯氨酸含量并进行HE染色。体外实验用血管紧张素Ⅱ(AngⅡ)诱导新生大鼠心肌成纤维细胞(CFb)增殖,分为正常对照组、模型组及Tau治疗组(40、80和160 mmol.L-1)。采用四甲基偶氮唑盐(MTT)法检测细胞增殖程度;ELISA法测定转化生长因子β1(TGF-β1)蛋白的含量;流式细胞仪检测细胞周期素依赖性激酶抑制因子P27的变化。结果:体内实验显示Tau(160和320 mg.kg-1.d-1)组羟脯氨酸含量低于Iso组(P<0.01或P<0.001);HE染色可见Iso组心肌纤维增生、排列紊乱、肌浆肿胀;Tau组明显减轻Iso引起的心肌损伤。体外实验表明,各剂量Tau组CFb增殖程度及TGF-β1蛋白含量均低于AngⅡ组(P<0.05或P<0.01),且呈现剂量依赖性;流式细胞仪检测证实Tau(80和160 mmol.L-1)组P27蛋白表达量高于AngⅡ组(P<0.05或P<0.01)。结论:Tau通过抑制TGF-β1蛋白含量的增多、促进P27的表达,抑制CFb增殖和胶原合成,最终抑制心肌纤维化。

Objective To investigate the effect of taurine （Tau） on the myocardial fibrosis and its mechanism. Methods The rat model of myocardial fibrosis was built by subcutaneous injection of isoprel （Iso）. And the rats were divided into control group, model group and taurine group （80, 160, 320 mg · kg^-1· d^ -1）. Hydroxyproline measurment was carried out for detecting collagen quantification in myocardium tissue. Histopathology changes were detected by HE staining. In vitro, the cultured neonatal rat cardiac fibroblasts （CFb） were divided into control group, model group and taurine group （40, 80, 160mmol · L^-1）. The proliferation of CFh was induced by angiotensin Ⅱ （AngⅡ） and detected by the thiazoleblue （MTT） colorimetric assay. TGF-β1 level was determined by ELISA technique. The expression of cyclin dependent kinase inhibitor p27 was assessed with flow cytometry. Results In vivo, the contents of hydroxyproline were decreased in Tau （160, 320 mg· kg^-1· d^-1）groups as compared with model group （P〈0.01 or P〈0. 001）. HE staining results showed that myocardium fiber appeared hyperplastic and were arranged disorder and kytoplasm swelled in model group and Tau relieved the damage of myocardium induced by Iso. CFh proliferation rate and the level of TGF-β1 were greatly declined when CFb was treated with taurine （40, 80 and 160 mmol· L^-1 ） for 24 h （P〈0. 05 or P〈0. 01）. The P27 expression was significantly increased in Tau groups （80 and 160mmol · L^-1） as compared with model group （P〈0.05 or P〈0. 001）. Conclusion Tau can inhibit the proliferation of CFb and metabolism of collagen and offer protection against the myocardial fibrosis by decreasing the level of TGF-β1 and up-regulating P27 expression.