模拟海拔8000m高原缺氧环境对大鼠脑组织线粒体自噬的影响

目的：研究大型低压氧舱模拟海拔8000 m 高原缺氧环境对大鼠线粒体自噬的影响。方法取30只Wistar 大鼠，随机分为正常、缺氧6 h、12 h、24 h 和48 h 组，每组6只，在大型低压氧舱中模拟海拔8000 m 高原缺氧环境，采集实验大鼠的脑组织进行电镜观察并对线粒体自噬蛋白微管相关蛋白1轻链3（LC3）、Beclin1以及凋亡相关蛋白细胞色素 C（CytC）、Caspase3、Bcl-2相关 X 蛋白（Bax）进行测定。结果电镜结果显示，不同时间缺氧组与正常组相比较，大鼠脑组织空泡增多，细胞间隙增大，细胞膜部分破碎，细胞受损，并且不同缺氧时间自噬发生程度较正常组均增多，缺氧24 h 组自噬程度最强，自噬体数量最多。各缺氧组凋亡相关蛋白 CytC、Caspase3和 Bax 表达水平随着缺氧时间的延长均上调，缺氧24 h 和48 h 组显著高于正常组（ P ﹤0.01）。自噬相关蛋白 LC3和 Beclin1表达随着缺氧时间增加呈现从升高到下降的趋势，其中 LC3在缺氧24 h 组表达程度最高（P ﹤0.05），Beclin1蛋白在缺氧6 h 组表达升高，缺氧12 h 组表达最高（P ﹤0.01）。结论模拟海拔8000 m 缺氧环境会对大鼠造成损伤，促进凋亡相关蛋白的表达，同时促进了大鼠脑组织线粒体自噬的发生。

Effect of Simulated 8000 m Altitude on Mitochondrial Autophagy of Brain Tissues in Rats under Hypobaric Hy-poxia Environment

Objective To study the effect of simulated 8000 m altitude using large scale of low pressure oxygen cabin on mitochondrial autophagy of brain tissues in rats under hypobaric hypoxia environment. Methods A total of 30 Wistar rats were randomly divided into normal group and 6 h,12 h,24 h and 48 h hypoxia groups( n = 6 for each group). Under simulated 8000 m altitude using large scale of low pressure oxygen cabin,brain tissues were collected and observed using transmission electron microscopy(TEM),and mitochondrial autophagy protein light-chain 3(LC3),Be-clin1 and apoptosis related proteins of cytochrome C(CytC),Caspase3 and Bcl-2 related X(Bax)were detected. Re-sults The TEM result showed that more cavitation and intercellular space,the part injury of cells membrane,cells dam-age and higher degrees of autophagosomes incidence in brain tissues of different times of hypoxia groups were found,com-pared with those of normal group,and the most values of autophagosome degree and amount were found in 24 h hypoxia group. Levels of apoptosis related proteins CytC,Caspase3 and Bax expressions were increased with prolonged hypoxia time in different times of hypoxia groups,and the levels of 24 h and 48 h hypoxia groups were significantly higher than those of normal group(P ﹤ 0. 01). Autophagy related protein LC3 and Beclin1 showed a trend from increasing to decrea-sing with prolonged hypoxia time,and the highest LC3 level was found in 24 h hypoxia group(P ﹤ 0. 05);Beclin1 pro-tein level began to increase in 6 h hypoxia group,and the highest Beclin1 level was found in 12 h hypoxia group( P ﹤0. 01). Conclusion Simulated 8000 m anoxic environment can induce damage in rats,promote expressions of apoptosis related proteins and incidence of mitochondrial autophagy in brain tissues at the same time.