急性中、重度低压缺氧对大鼠血脑屏障通透性的影响

Effect of acute moderate and severe altitude hypoxia on blood brain barrier permeability in rats

目的 观察急性中、重度低压缺氧条件下 ,大鼠血脑屏障通透性的变化特点 ,为阐明低压缺氧作用下脑功能障碍的可能机理提供生理学依据。 方法 选择雄性 SD大鼠 18只 ,随机分为对照组、5 0 0 0 m及 80 0 0 m急性低压缺氧暴露组。实验组动物于低压舱内 ,以 2 0 m/ s的速率上升 ,至5 0 0 0 m(或 80 0 0 m) ,停留 5 h,而后以 2 0 m/ s的速率下降至地面。出舱后立即经心脏灌注硝酸镧固定液 ,开颅取脑 ,制成切片 ,置透射电镜下观察。 结果 急性低压缺氧暴露 5 h后即刻 ,即可见镧颗粒通过大鼠脑皮质的毛细血管内皮细胞膜及血管内皮细胞间的紧密连接 ,沉积于毛细血管内皮细胞浆内、细胞核膜上以及血管周围 ,弥漫性地分布于脑间质细胞间隙 ,并附着于神经细胞膜上 ,而对照组大鼠 ,镧颗粒仅滞留于大脑皮质的毛细血管腔内。 结论 5 0 0 0 m以上低压缺氧连续暴露 5 h,可引起大鼠血脑屏障通透性增加。

Objective To explore the changes of blood brain barrier(BBB) permeability following acute altitude hypoxia exposures in rats. Methods Eighteen rats were randomly divided into control group and 2 experimental groups. The experimental groups were separately exposed to 5 000 m and 8 000 m altitude in hypobaric chamber for 5 h. The brain specimens of rats were prepared immediately after hypoxia exposure using lanthanum trace labeling technique, and the BBB permeability of lanthanum was observed by electron microscope. Results In control group, lanthanum could be seen only within the capillary, adhering to the endothelial surface. In the 2 experimental groups, the lanthanum within the endothelial cells and extra cellular space was found. Lanthanum passed through the tight junction of endothelial cells could also be seen. Conclusion It is suggested that the increased BBB permeability after acute altitude hypoxia may play an important role in the development of brain edema and impairment of brain functions.