炎症介质在高原暴露下血脑屏障通透性改变中的作用及相互关系

CORRELATION AND INFLUENCES OF INFLAMMATORY MEDIATORS ON PERMEABILITY OF THE BLOOD-BRAIN BARRIER AT HIGH ALTITUDE EXPOSURE

目的:探讨炎症介质在高原暴露下血脑屏障通透性改变中的作用及与脑含水量的关系。方法:应用放射免疫法测定脑组织内TNFα、ET含量,化学法测定脑内NO含量,应用伊文思蓝(EB)透过率测定血脑屏障(BBB)通透性,脑湿干比重法测定脑含水量百分率。结果:高原暴露下,大鼠脑内TNFα、ET、NO含量随着海拔增高而逐渐增高,随着暴露时间延长而逐渐增高,以暴露于5000m的高海拔区第9d增高最明显。与此同时,脑内EB含量和脑内含水量逐渐增高。脑内TNFα、ET、NO含量与脑含水量之间有明显的正相关关系。结论:TNFα、ET、NO在BBB通透性增高中起了重要作用,是高原环境下BBB通透性增高的重要因素。

Aim：To investigate the influences of inflammatory mediator on permeability of the blood-brain barrier（BBB）at high altitude environmental exposure as well as relationship and water centent in brain.Methods：Wistar rats were exposed to different altitude gradients,then brain tissue homogenate was prepared,and the activities of tumor necrosis factor-alpha（TNFa）and endothelin（ET）in brain tissue homogenate were measured by radioimmunoassay methods.The activities of nitric oxide（NO）in brain tissue homogenate were measured by chemical methods.The evans blue（EB）content in brain tissue was determined by colorimetry and the wet weight/dry weight ratio（W/D）was used to express the water content in brain.Results：With altitude going up,the activities of TNFa,NO and ET in the brain of rats rose,and they also rose gradually with time prolonging under high altitude hypoxia exposure.Their most obvious rise was seen during 9 days after ascending 5 000 m high altitude regions.At the same time,the EB and water content in the brain of mice showed the same change trends.Therefore,the inflammatory mediator activity and EB content as well as water content in brain showed an evitdently linear relationship.Conclusion：The inflammatory mediator plays an important role in the change of permeability of BBB.It＇s a critical inducing factor in the change of permeability of BBB under high altitude exposure.