颅脑损伤后血脑屏障形态学与通透性变化规律的实验研究

Experiment on the regularity in morphology and permeability of blood-brain barrier following traumatic brain injury

目的研究脑损伤后血脑屏障形态结构与通透性并评价其在血管源性脑水肿中所起的作用。方法用电镜观察血脑屏障的超微结构及镧示踪显示紧密连接的开放状态;用干湿重法测定脑组织含水量。结果伤后3～24h见内皮细胞吞饮小泡明显增多及线粒体肿胀模糊、核皱缩,基膜断裂,胶质细胞足突肿胀模糊,血管外隙扩大并液体积聚。伤后48～72h吞饮小泡增多减弱;镧颗粒示紧密连接于伤后3h初步开放,24～48h开放达高峰,72h显著开放;脑组织含水量:与对照组比较,伤后3、24h差异有显著意义(P<0.05),48h差异有非常显著意义(P<0.01),72h差异有显著意义(P<0.05)。结论伤后24h内血脑屏障通透性增高以内皮细胞吞饮活跃为主,伤后24h后以紧密连接开放为主;在血管源性脑水肿的形成过程中,紧密连接开放比吞饮活动所起作用要大。

Objective To evaluate the role of morphologic structure and permeability of BBB after traumatic brain injury in forming vasogenic brain edema. Methods The ultrastructure of BBB was observed with electron microscope and the opening state of tight junction of endotheliocyte was revealed using lanthanum trace labeling with electron microscopy. At the same time, water content of cerebral tissue was gotten by dry-wet weight means. Results On the one hand, the number of pinocytotic vesicle in endotheliocyte was greatly growing in 3h to 24h after injury,simultaneously,tumid and blurry mitochondria, wizened nucleus of endotheliocyte, rifted basilemma, tumid and blurry neurodendrite of gliocyte, extensive space outside capillary vessel and liquid accumulating could be seen in traumatic group. However,the growing in the number of pinocytotic vesicle lessen in 48h to 72h after injury. Moreover, by lanthanum trace we observed tight junction preliminary opening at 3h after trauma,at its top of opening within 24h to 48h after trauma, a large number opening still at 72h after trauma in traumatic group. On the other hand,water content of cerebral tissue in traumatic group aggravated obviously compared with control group, having obvious difference（ P 〈 0.05 ） at 3 h, 24h, 72h after trauma, whenas, having very obvious differenence（ P 〈 0.01 ） at 48h after trauma. Conclusions Within 24h after trauma active pinocytosis of endotheliocyre rakes more important role in inducing high permeability of BBB. Then, its chief station is replaced gradually by opening of tight junction of endotheliocyte after 24h after trauma. In a word, the opening of tight junction of endotheliocyte maybe take greater effect than active pinocytosis of endotheliocyte in forming vasogenic brain edema.