雌激素对慢性低灌注大鼠血脑屏障通透性的影响

Effect of estradiol on cerebral vascular permeability following pBCCAO

目的检测大鼠永久性双侧颈总动脉结扎（pBCCAO）早期脑组织伊文思蓝（EB）的含量、大鼠海马和脉络丛ZO-1的表达变化，以及17β-雌二醇（E2）对其影响，旨在揭示血管性痴呆（VD）早期血脑屏障通透性的变化，并探索可能的防治措施。方法成年雌性大鼠去双侧卵巢，7d后制备pBCCAO模型，随机分为控制组，pBCCAO后6h、1d．3d、7d实验组，E2处理组和溶剂对照组，采用比色分析法及激光共聚焦显微镜技术检测脑组织EB含量，Western blot技术及共聚焦显微镜技术观察ZO-1蛋白水平。结果大鼠行pBCCAO后1d脑组织EB渗出量较sham组明显升高，于第3天达到高峰，术后7d明显下降，但仍高于sham组；共聚焦结果显示，pBCCAO后3d大鼠海马槽EB红色荧光较sham组和E2组明显增强；Western blot结果显示，pBCCAO后3d大鼠海马中ZO-1较sham组明显降低，但E2处理组与sham组相似，ZO-1水平明显高于溶剂对照组；共聚焦结果显示，pBCCAO后3d脉络丛ZO-1免疫反应较sham组和E2处理组明显降低。结论pBCCAO早期即可造成大鼠血脑屏障损伤，下调ZO-1的表达；E2可有效改善此病理变化。

Objective To detect the level of evans blue （EB） in brain tissue of rats after early permanent bilateral common carotid artery occlusion （pBCCAO）, ZO -1 expression in both brain tissue and choroid plexus, and further to investigate the effect of 17β - estradiol （E2） in order to reveal the change of blood brain barrier following early phase of pBCCAO and explore the possible therapeutic strategy of vascular dementia. Methods pBCCAO model was induced in ovarieetomized rats at 7 d and the rats were randomly divided into control group, 6 h, 1 d, 3 d, 7 d experimental groups after pBCCAO, and E2 treatment group. Colorimetry and laser scanning confocal microscope were used to detect EB content of brain tissue, Western blot analysis and confocal microscope were used to observe ZO - 1 protein expression. Results Compared to the sham group, EB exudation significantly increased from 1 d after pBCCAO and peaked at 3 d and then markedly decreased at 7 d in brain tissue of ovariectomized female rats. Furthermore, confocal results showed that fluorescence intensity of EB at 3 d after pBCCAO significantly increased in alveus of hippocampus compared to sham group and E2 treatment. Additionally, Western blot results showed ZO - 1 expression at 3 d after pBCCAO in hippocampus of ovariectomized rats significantly reduced compared with sham group, while ZO - 1 expression in E2 treatment group was similar to that in sham group, ZO - 1 levels were significantly higher than in the vehicle group. Importantly, the eonfocal results further showed that ZO - 1 immunoreactivity at 3 d after pBCCAO in the choroid plexus was reduced compared to sham group animals and E2 treatment group. Conclusion pBCCAO can cause blood - brain barrier damage, lowered ZO- 1 expression; E2 can effectively improve the pathological changes.