中文摘要：

目的探讨模拟失重对体外培养大鼠心肌细胞凋亡的影响及其可能的调控机制。方法以原代培养的新生大鼠心肌细胞为研究对象,以细胞回转器模拟失重效应,通过RT-PCR检测心肌细胞凋亡相关分子c-myc mRNA在模拟失重后的变化,以western blot观察模拟失重96 h对心肌细胞c-myc和转录因子GATA-4和MEF2A蛋白表达的影响。结果与对照组相比,模拟失重可致心肌细胞凋亡相关分子c-myc mRNA及蛋白表达显著升高（P〈0.05）,而转录因子GATA-4和MEF2A蛋白表达显著降低（P〈0.05）。结论回转器模拟失重96 h可致心肌细胞的凋亡表达增加,其机制可能与转录因子GATA-4和MEF2A表达降低有关。

英文摘要：

Objective To study the effect of simulated microgravity on apoptosis of in vitro cultured rat myocardiocytes and its mechanism.Methods Primarily cultured new born rat myocardiocytes was used as an experimental material and microgravity effect was simulated with clinostat.Myocardiocyte apoptosis–related molecule c-myc mRNA was detected by RT-PCR after simulated microgravity.Effect of 96 h simulated microgravity on expressions of transcriptional factors c-myc,GATA-4 and MEF2A proteins was detected by western blot.Results The expression level of myocardiocyte apoptosis–related molecule c-myc mRNA and protein was significantly higher whereas the expression level of transcriptional factors GATA-4 and MEF2A was significantly lower in experimental group than in control group after simulated microgravity（P0.05）.Conclusion Clinostat-simulated microgravity up-regulates the apoptosis of cardiomyocytes by down-regulating the expression of transcriptional factors GATA-4 and MEF2A.