【摘要】 目的研究低氧心肌细胞周期及缺氧过程中细胞周期蛋白D1(cyclinD1)和细胞周期蛋白依赖激酶4(CDK4)表达的变化,探讨缺氧心肌在凋亡前是否存在增殖能力和自身修复。方法采用SD大鼠乳鼠进行心肌细胞培养,建立心肌缺血模型,实验分正常对照、缺血6 h和缺血12 h三组;以四唑盐比色试验(MTT)检测心肌细胞活力,流式细胞术测定细胞周期,免疫组化检测cyclinD1和CDK4表达。结果与对照组比较,心肌细胞缺氧处理6 h后,细胞周期中S 期比例增高(P<0 01),12 h后,S期比例下降(P<0 05);cyclinD1胞浆表达和CDK4 胞核表达增加。结论在缺氧所致死亡、凋亡过程中心肌细胞经历了一定程度的增殖过程,cyclinD1 和CDK4 表达增加参与了细胞增殖,缺氧损伤可刺激心肌细胞增殖能力。更多还原

【Abstract】 Objective To investigate the effects of hypoxia on cell cycle distribution and protein expression of cyclinD1 and CDK4 in neonatal rat cardiac myocytes under hypoxia. Methods Cultured neonatal rat cardiac myocytes（CMs） were divided into three groups, namely normal control and ^hypoxia groups cultured in an incubator 95%N₂ and 5%CO₂ for 6 or 12 hours.The percentage of cells in G₁,S and G₂/M phase was measured by flow cytometer （FCM）,and the expression of cyclinD1 and CDK4 by immunocytochemistry and image analysis. Results Compared with normal controls, the percentage of cells in S phage was significantly increased in 6h group（P<0.01）,decreased in 12h group（P<0.05）. The expression of cyclinD1 and CDK4 was significantly increased under hypoxia for 6 hours than that without hypoxia. Conclusion CMs experience a process of proliferation during the death and the apoptosis due to hypoxia. This finding reveals that CMs, to a certain extent, havea capability of proliferation.更多还原