重复+Gz暴露后大鼠心室肌的细胞凋亡现象

目的:探讨不同水平的1周重复多次的+Gz暴露后大鼠心室肌凋亡的现象及变化规律。方法:12只雄性SD大鼠随机分为+6Gz组,+10Gz组和对照组,每组4只。+Gz组大鼠分别暴露于+6Gz/3min和+10Gz/3min,1次/天,连续暴露1周;对照组大鼠置于离心机室,但不受加速度作用。大鼠于末次暴露后1d,取左心室,采用透射电镜和末端脱氧核苷酸转移酶介导的dUTP缺口标记技术(TUNEL)观察心肌细胞凋亡情况。结果:电镜下,除+10Gz组可观察到心肌细胞核内异染色质增多、浓缩、边集现象外,各组未见典型的凋亡改变。TUNEL染色可见,+6Gz组、+10Gz组心肌细胞凋亡指数较对照组均显著增高(P0.01);+10Gz组大鼠心肌凋亡指数较+6Gz组显著增多(P0.05)。结论:+Gz重复暴露可引起大鼠心肌细胞凋亡,且随着G值的增大,细胞凋亡指数呈增多趋势。

Apoptosis in myocyte after repeated + Gz exposures in rats

Objective： To observe the effects of repeated ＋ Gz exposures on the apoptosis of myocyte in rats. Methods： Twelve male Sprague-Dawley rats were randomly divided into three groups： Control group, ＋ 6Gz group and ＋ 10Gz group. The rats of ＋ Gz groups were exposed to ＋ 6Gz for 3 min, ＋ 10Gz for 3 min respectively, 1 b/d, 1 week. Four control rats were kept at the Earth gravity （IG） in the room with the centrifuge. All animals were anaesthetized and anatomized 1 day after the last exposure. Ventricular myocardium was studied by electron microscopy and terminal deoxynucleotide transferase-mediated dUTP nick end labeling （TUNEL） method. Results： The apoptosis of myocyte in control group and ＋ 6Gz group were scarcely observed by electron microscopy, while heterochromatin concentration and margination were observed in ＋ 10Gz group. The apoptotic index of myocardium increased significantly in ＋ 6Gz and ＋ 10Gz group compared with that of the control group （ P 〈 0.05） and showed the largest value in the ＋ 10Gz group （ P 〈 0.05）. Conclusion： Repeated ＋ Gz exposures may induce apoptosis in myocyte, and the number of apoptosis in myocyte increases gradually with the increase of G value.