急性肝衰竭小鼠Occludin表达与血脑屏障通透性的关系

Relationship between expression of Occludin and blood-brain barrier permeability changes in acute liver failure mice

目的探讨乙酰氨基酚/扑热息痛(acetam inophen/paracetam ol,APAP)导致的急性肝衰竭(acute liverfailure,ALF)小鼠模型中血脑屏障(blood brain barrier,BBB)通透性与脑组织紧密连接(tight junction,TJ)蛋白O ccludin表达的关系。方法应用APAP复制ALF小鼠模型,检测脑中伊文思蓝(evans blue,EB)的含量反映BBB通透性,电镜下观察TJ的结构变化。应用W estern blotting方法检测脑组织中O ccludin蛋白的表达。结果小鼠脑组织EB含量于2 h开始升高(2.29±0.42)μg/g,6 h达到峰值(3.61±0.33)μg/g,脑组织中O ccludin蛋白表达2 h开始下降,6 h表达最低,同时电镜下观察到TJ结构出现破坏。结论在APAP所致的ALF动物模型中,BBB通透性增加,表明血管源性脑水肿机制参与脑水肿形成,与其相反,O ccludin表达呈下降趋势,提示脑水肿的发生与O ccludin表达下降引起TJ结构破坏有关。

【Objective】To investigate the relationship between the expression of tight junction（TJ）-associated protein Occludin in the brain tissue and the permeability of the blood-brain barrier（BBB） during acetaminophen（APAP）-induced acute liver failure（ALF）.【Methods】Male Balb/c mice received acetaminophen to induce ALF.We investigated the blood-brain-barrier（BBB） permeability by Evans blue staining,and the TJ structure by electron microscopy.The expression of Occludin in the brain tissue was determined by western blot.【Results】The concentration of EB in the brain tissue began to increase 2 hours（2.29±0.42 μg/g） after injection and the peak level appeared at 6 hours（3.61±0.33 μg/g）.The Occludin expression in brain tissue was decreased 2 hours after injection and reached minimum at 6 hours.It can be investigated by electron microscopy that the TJ structure was damaged.【Conclusions】In APAP-induced ALF,the BBB permeability was increased,indicate the vasogenic edema mechanism is correlated with the brain edema,on the contrary the Occludin expression was decreased,suggesting that the brain edema is correlated with TJ disruption caused by the decrease of Occludin expression.