模拟飞船应急返回时+Gx暴露后大鼠脑细胞凋亡相关基因bcl-2、p53的表达

Expression of Apoptosis Related Genes bcl-2 and p53 in Rat Brain after Exposure to +Gx in Simulated Emergent Return of Spacecraft

目的探讨bcl-2、p53在模拟飞船应急返回时高+Gx作用致大鼠脑细胞凋亡中的作用。方法40只雄性SD大鼠随机分为4组,即对照组、+15Gx组、7d模拟失重组、7d模拟失重后再+15Gx组,每组10只。大鼠在动物离心机上承受+Gx作用后,灌注取脑,固定包埋,做石腊切片。用免疫组化方法检测大鼠海马、顶叶皮层相关基因bcl-2和p53表达的变化。结果+15Gx暴露后1d可见bcl-2表达减少,p53表达增加,在暴露后3d改变明显;7d模拟失重组大鼠在暴露后1d可见bcl-2表达减少,p53表达增加;模拟失重后再+15Gx组在暴露后1d可见上述bcl-2、p53表达的变化,在暴露后3d改变最明显,变化比+15Gx组或模拟失重组均明显。结论+15Gx/180s暴露可引起大鼠海马和顶叶皮层细胞凋亡相关基因bcl-2和p53表达的变化;7d模拟失重可加重+Gx引起的大鼠脑组织损伤。

Objective To investigate the role of bcl-2 and p53 in mechanisms of brain apoptosis in rats induced by ＋Gx exposure in simulated emergent return of spacecraft. Method Forty male SD rats were randomly divided into 4 groups： control group, 7 d simulated weightlessness group, ＋ 15 Gx group and ＋15 Gx exposure after 7 d simulating weightlessness group,with 10 rats in each group. After rats were exposed to ＋ Gx stress,brain was removed to make paraffin sections. Expression of apoptosis related genes bcl-2 and p53 in cerebral cortex and hippocampus were imaged by immunohistochemical method. Result Expression changes of bcl-2 and p53 were observed in cerebral cortex and hippocampus on the first day after ＋15 Gx exposure, but most evidently on the third day. Expression of bcl-2 decreased and that of p53 was increased. These changes were also observed after exposure to simulated weightlessness for 7 d, most evidently on the first day. It was more obvious on the third day after ＋ 15 Gx exposure following simulated weightlessness. These changes were more obvious as compared with ＋15 Gx group or simulated weightlessness group. Con- clusion ＋15 Gx/180 s exposure may induce expression changes of bcl-2 and p53 in rat cerebral cortex and hippocampus. Neuron injury in rat brain may be aggravated after simulated weightlessness for 7 d.