模拟飞船应急返回时+Gx暴露后大鼠脑组织细胞凋亡的研究

Study on Apoptosis of Rat Brain Cells after Exposure to +Gx in Simulated Emergent Return of Spacecraft.

目的探讨细胞凋亡在模拟飞船应急返回时高+Gx作用致大鼠脑损伤中的病理作用。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,做石蜡切片。用原位末端标记法(TUNEL)检测大鼠海马、顶叶皮层细胞凋亡情况。结果对照组海马和顶叶皮层偶见凋亡细胞；+15Gx组大鼠海马和顶叶皮层在暴露后1d可见部分凋亡细胞(P<0.01),在暴露后3d改变明显(P<0.01)；7d模拟失重组大鼠海马和顶叶皮层在各时间点均可见部分凋亡细胞(P<0.01),暴露后1d最多(P<0.01)；7d模拟失重后再+15Gx组大鼠海马和顶叶皮层在暴露后各时间点均可见部分凋亡细胞(P<0.01),在暴露后3d改变最明显(P<0.01),较+15Gx组和7d模拟失重组均明显增多(P<0.01)。结论 +15Gx／180s暴露可引起大鼠海马和顶叶皮层细胞凋亡；7d模拟失重可加重+15Gx引起的大鼠脑组织细胞凋亡。

Objective To investigate the role of apoptosis in mechanisms of brain damage induced by ＋ Gx exposure in simulated emergent return of spacecraft in rats. Method Forty male SD rats were randomly divided into control group, ＋ 15 Gx group 7 d simulated weightlessness group,and ＋15 Gx exposure after 7 d simulated weightlessness group,with 10 rats in each group. After the rats were exposed to ＋ Gx stress, brain was removed to make paraffin sections. The apoptosis in cerebral cortex and hippocampus were detected by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling（TUNEL）technique, Result Apoptotic cells were observed in cerebral cortex and hippocampus on the first day after ＋ 15 Gx exposure （P 〈 0.01 ）, and most evidently on the third day （P 〈0. 01）, These changes were also observed after simulated weightlessness for 7 d （P〈0.01 ）, most evidently on the first day （P 〈 0. 01）. It was more obvious on the third day after ＋ 15 Gx exposure following simulated weightlessness （P 〈 0.01 ） and number of apoptotic cells increased significantly （P 〈 0. 01）, as compared with ＋ 15 Gx group or simulated weightlessness group, Conclusion ＋ 15 Gx/180 s exposure may induce apoptotic changes in rat cerebral cortex and hippocampus. Number of apoptotic cells in rat brain may increase after exposure to simulated weightlessness for 7 d.