大鼠脑水肿模型中大分子物质的清除途径

Clearance of macromolecules in brain edema model of rat

目的:研究脑水肿模型中大分子物质由脑实质的清除途径。方法:将10μl藻红蛋白溶液注射到大鼠右侧尾壳核造成高蛋白性脑水肿,分别于注射后0.5、1、2、5、24h处死动物,取脑组织、双侧颈总动脉和颈部淋巴结,快速冰冻切片,荧光显微镜和共聚焦显微镜观察。结果:大鼠脑切片上,各时间点都可见荧光沿右侧胼胝体弥漫性分布,右侧脑室有微弱荧光信号。从注射后5h开始可见皮层灰质、尾壳核和蛛网膜下腔内的血管周围有荧光聚集,所有时间点的颈部淋巴结和颈总动脉都有荧光分布。共聚焦显微镜下,注射后24h注射侧大脑皮层和尾壳核内的毛细血管内皮细胞浆有强荧光信号,而胞核负染。结论:脑水肿时大分子物质在灰质和白质内的引流方式不同;毛细血管内皮细胞参与血管周围间隙内大分子物质的清除;颈部淋巴系统参与脑内大分子物质的引流。

Objective: To study the clearance pathway of macromolecules from the brain parenchyma in brain edema model. Methods: A dose of 10μl phycoerythrin was injected into the right caudato-putamen of each rat,which was killed by 0.5,1,2,5 and 24 hours after injection. After perfused with 10ml 10% ink gelatin,the brain,the common carotid arteries and the cervical lymph nodes were extracted and made fresh frozen cryostat sections,then observed under fluorescence and confocal fluorescence microscope. Results: The fluorescent signals distributed diffusely in the right corpus callosum,and lightly in the right lateral ventricle. They gathered in the perivascular space in the cortex,the right caudato-putamen and the subarachnoid space 5 hours after injection,they subdued in the brain from 0.5 to 24 hours; they were full of the bilateral cervical lymph nodes and the wall of carotid arteries at any time interval. Under confocal fluorescence microscope,the endothelial cell of capillaries in the gray matter had fluorescence staining cytoplasm and negative staining nucleus by 24 hours. Conclusion: The drainage pathway of macromolecules in the white matter is different from that in the gray matter in brain edema model. The endothelial cell of capillaries has important role in clearing macromolecules from the perivascular space. Cervical lymphtics is involved in draining macromolecules from the rat brain.