大鼠脑缺血-再灌注损伤对脑微血管通透性的影响

Effect of Brain Ischemia and Reperfusion Injury on Cerebral Microvascular Permeability in Rats

目的 :探讨大鼠脑缺血 -再灌注后脑组织微血管通透性的变化规律 ,为进一步探讨脑缺血及再灌注损伤机制提供参考数据。方法 :应用荧光素钠 (分子量 3 86 ,Fl Na)和 FITC标记的右旋糖苷( FD4,分子量 40 0 0 )为荧光示踪剂 ,以单侧颈总动脉远心端及同侧颈静脉插管并连接二管造成颈总动脉向颈静脉的引流 ,同时用动脉夹夹闭对侧颈总动脉造成脑缺血模型。缺血 1h后松开动脉夹并中断引流造成再灌注模型。测量脑组织荧光强度反映脑微血管通透性的变化。结果 :单纯的脑缺血即可引起脑组织微血管通透性的增强 ,再灌注后对小分子量物质的通透性随再灌注时间的延长有增加的趋势 ,而对较大分子量物质的通透性基本维持在同一水平。结论 :即使是在再灌注损伤最严重时 ,脑微血管对较大分子量的物质通透仍不明显 ,说明血 -脑屏障的存在可以有效地防止有害物质通过微血管壁侵入脑组织 ,但一旦进入脑组织 ,将滞留于脑组织中不易清除。

Objective: The effects of brain ischemia and reperfusion injury on cerebral microvascular permeability in rats was observed. Method: The carotid artery was cannulated and connected with jugular vein located in the same side. An arterial champ was used to stop the blood flow of another carotid artery. Then the brain ischemia model was made. After 1 hour, the arterial champ was removed and connection was canceled. An intravital fluorescence microscopic method was established for observing the changes of fluorescein Sodium(FlNa, MW376) and FITC labeled Dextran(FD4, MW4 000) permeability in the rat cerebral microvascular permeability. A tissue homogenization method was established for measuring brain microvascular permeability. Results: Brain tissue microvascular permeability was increased significantly with single cerebral ischemia. After reperfusion, small molecular weight substance(FINa) could be transported through microvascular wall more quickly. However, large molecular weight substance(FD4) was remained unchanged.