CKMB和cTnI在缺氧诱导in vitro心肌细胞中的表达

The Expression of CKMB and cTnI Presented in vitro Myocardial Cells Induced by Hypoxia

目的:研究in vitro心肌细胞在长时间缺氧刺激后,CKMB和cTnI的表达特点,为探讨缺氧诱发心脏高表达CKMB和cTnI的机制提供参考。方法:采用体外培养新生Wister大鼠心肌细胞模型,两步法RT-PCR和Western Blotting分别检测上清和胞内HIF-1α和CKMB、cTnI在缺氧培养40分钟后连续时间点的表达变化。结果:缺氧后15min,上清CKMB表达显著升高,后随时间推移缓慢升高;胞内表达在0min～24h均显著高于上清(P<0.05),1h后达峰值。上清cTnI浓度在缺氧15min后急剧升高,24h后达峰值;胞内cTnI浓度在缺氧45min后达峰值;缺氧心肌细胞内、上清cTnI表达在15min～48h均有显著性变化(P<0.05),且呈近似同步性。胞内cTnI浓度在24h后低于上清。结论:单纯长时间缺氧刺激可引起invitro心肌细胞内高表达CKMB和cTnI,并向胞外释放,推测缺氧导致胞膜渗漏是主要释放机制。

Objective To study the expression character of CKMB and cTnI presented in long-time in vitrohypoxic myocardial cells,and provide theoretical consult in understanding the mechanism of highly expressing CKMBand cTnI induced by hypoxia in hearts. Methods The myocardial cells were sampled from newborn Wister mice.Two-step RT-PCR and Western Blotting were applied to detect the consecutive expression variation of HIF-1α andCKMB,cTnI both in the supernatant and inner of incubating cells after 40-minute hypoxia intervention. Results Therehad CKMB appeared in the supernatant within 15min after hypoxic stimulation,with slow increasing along the time.The intracellular CKMB expression got its peak point within 1h,and then descended. The intracellular CKMBconcentration was significantly higher than that of the supernatant of hypoxic myocardial cells within 0min-24h（P〈0.05）. The cTnI concentration of supernatant steeply increased after 15min,reaching the peak point within 24h. Theintracellular cTnI concentration reached the peak point within 45min. The significant differences always existed for thecTnI expression between intra- and extra-myocardial cells within 15min-48h（P〈0.05）,and their increasing tendenciesnearly showed synchronism. The intracellular cTnI concentration was lower than that of supernatant 24h later.Conclusion The single persistent hypoxic stimulation could induce the intensive intracellular expression and deliveryof CKMB and cTnI in vitro myocardial cells,and the latter probably was caused by the leakage of cell membraneoriginally provoked by hypoxia.