牛磺酸对心肌成纤维细胞细胞周期的影响及其机制的研究

Effect of Taurine on the cell cycle of cardiac fibroblast and its mechanisms

目的研究牛磺酸(taurine,Tau)对血管紧张素Ⅱ(an-giotensinⅡ,AngⅡ)诱导的新生大鼠心肌成纤维细胞(cardiacfibroblast,CFb)增殖的抑制作用,并初步探讨其作用机制。方法用AngⅡ诱导新生大鼠CFb增殖,建立心肌纤维化模型,采用四甲基偶氮唑盐(MTT)法检测细胞增殖;羟脯氨酸测定检测胶原含量;流式细胞仪检测细胞周期及细胞周期蛋白依赖性激酶抑制物p27的变化;免疫细胞化学法测定细胞周期调控蛋白D(cyclin D)及p27蛋白的含量。结果Tau(40、80、160mmol.L-1)可明显抑制AngⅡ诱导的CFb增殖与胶原合成,同AngⅡ组比较差异有显著性(P<0.05或P<0.01),且呈现剂量依赖性。流式细胞仪检测表明Tau在80、160mmol.L-1可促进p27的蛋白表达;细胞G0/G1期百分率随Tau浓度增加而增加,S期细胞百分率随Tau浓度增加而减少,与AngⅡ组相比差异有显著性(P<0.05或P<0.01)。免疫细胞化学染色结合图像分析系统的分析结果也表明Tau可增加p27的蛋白表达,与AngⅡ组相比差异具有统计学意义(P<0.01)。结论牛磺酸通过促进p27的表达,使细胞周期阻滞于G0/G1期,而抑制CFb增殖和胶原含量的增加。

Aim To investigate the effect of taurine（Tau）on the cardiac fibroblast（CFb）cell cycle and its regulatory protein expression,and to explore the underlying mechanism of Tau-inhibiting the proliferation of CFb.Methods The proliferation of cultured neonatal rat CFb was induced by Angiotensin Ⅱ and detected by the thiazole blue（MTT）colorimetric assay.Hydroxyproline measurement was carried out to detect the collagen quantification.The expression of cell cycle regulatory protein cyclin D and p^27 were determined by the combination of immunocytochemical staining and image analysis software.Cell cycle and p^27 were assessed via flow cytometry.Results CFb proliferation and hydroxyproline content in culture medium were markedly inhibited when CFb were treated with taurine at concentrations of 40,80 and 160 mmol·L^-1 for 24 hours（P〈0.05 or P〈0.01）.In the flow cytometry analysis,it was found that taurine could block CFb in the G0/G1 phase from entering the S phase,resulting in more cells in the G0/G1 phase and fewer in the S phase.The percentage of the cells in the G0/G1 phase and the S phase at the dosage of 40,80 and 160 mmol·L^-1 were significantly different in comparison to the model group（P〈0.05 or P〈0.01）.CFb expressed cyclin D1 and p^27.Taurine induced p^27 expression and had no effects on cyclin D1 expression.Conclusions The inhibitory effects of taurine on CFb proliferation might be due to the stimulation of p^27 expression,arresting cells in G0/G1 phase.