实验性灌注压突破的脑组织电镜表现

Electron Microscopic Observation of Brain Tissue in Experimental Perfusion Pressure Breakthrough

经历了慢性缺血后的脑组织在灌注恢复正常时有可能发生严重的脑水肿甚至脑出血,临床上将这种现象称为"正常灌注压突破"(normal perfusion pressure breakthrough,NPPB。通过在实验动物颈部建立颈总动脉-颈外静脉瘘并饲养14周后快速阻断其瘘口,模拟了临床上引起 NPPB 的条件和过程。通过对实验动物脑组织进行电镜检查,发现慢性缺血可引起脑组织内毛细血管内皮细胞变性等结构缺陷,以及毛细血管周围的水肿样改变,内皮细胞的紧密连接疏松,部份标本中红细胞"逸出"管外被周细胞吞噬,可能是 NPPB 超微结构方面的证据。

After chronic brain ischemia,the malignant brain edema or hemorrhage sometimes will follow the recovery by perfusion.This phenomenon is called'normal perfusion pressure breakthrough'(NPPB).In the present study,a carotid-jugular fistula was created in the experimental animals.The clinic condition and process of NPPB was initiated by abruptly closing the fistula after 14 weeeks.The brain tissues of the animals were examined under transmission electron microscope.Some histological changes of brain tissues caused by chronic ischemia such as degeneration of endothelium of capillary were found.The edema around capillary,the loosened tig- ht junction of the endothelium and the phagocytosed extra-capillary red blood cells by pericytes could be the micro-structure evidence of NPPB.