雌二醇对去势大鼠局灶性脑缺血再灌注后Ang-1mRNA表达的影响

The Effects of Estradiol on Angiopoietin-1mRNA Expression in a Castrated Rat with Focal Cerebral Ischemia after Reperfusion

目的:探讨雌二醇对去势大鼠局灶性脑缺血再灌注后Ang-1mRNA表达的影响。方法:利用6月龄健康Wistar's雌性野生(WT)去势大鼠和雌激素α受体基因敲除(ERKO)去势大鼠的脑缺血再灌注模型(MCAO)进行实验研究。实验分为4组,WT去势大鼠安慰剂组(A组)、苯甲酸雌二醇组(B组);ERKO去势大鼠安慰剂组(C组)、苯甲酸雌二醇组(D组)。采用放射免疫分析、激光多普勒血流(LDF)仪、CD34血管内皮标记物免疫组化染色和mRNA的定量分析,分别对各组去势大鼠的血浆雌二醇水平、脑血流量的变化、脑缺血再灌注后脑组织血管密度的改变以及Ang-1、Ang-2、Tie-2、VEGF、VEGFR-1、VEGFR-2mRNA的表达进行了检测。结果:经雌二醇处理的WT和ERKO去势大鼠,其血浆雌二醇水平分别为198.13±87.50pg/ml和209.36±92.73pg/ml,高于各自的对照组(p<0.01)。同时,经雌二醇处理的wtmaco去势大鼠,其脑缺血再灌注后脑血流的变化幅度为42.4+13.9%;大脑基底核、顶叶皮层的毛细血管密度分别为38.3+12.5PU和41.9+14.1PU;脑组织中Ang-1mRNA呈6.1+1.8的高表达。这些结果均高于各自的对照组(p<0.01)。而在经雌二醇处理的ERKO大鼠中则未发现这些变化。结论Ang-1是雌激素保护、脑血流恢复、脑毛细血管密度增加等脑缺血再灌注后损伤修复诸多环节中的关键一环,Ang-1是雌二醇介导的神经保护的重要分子。

Objective:Probing the effect of estradiol on angiopoietin-1 mRNA(Ang-1 mRNA) expression in a castrated rat with focal cerebral ischemia after reperfusion.Methods Experiments were performed by using 6-aged female and wild type(WT) health,castrated Wistar rats and a cerebral ischemia-reperfusion model in estrogen- receptor gene knockout(ERKO) castrated rats with cerebral ischemia(middle cerebral artery occlusion(MCAO)).The animals were divided into 4 groups,namely,WT castrated rat placebo group(A group),estradiol benzoate group(B group);ERKO castrated rat placebo group(C group) and estradiol benzoate group(D group).Plasma estradiol level,changes in cerebral blood flow,changes in brain capillary density after cerebral ischemia-reperfusion and Ang-1,Ang-2,Tie-2,VEGF,VEGFR-1,VEGFR-2 mRNA repressions were determined respectively by using radio-immunity analysis,Laser doppler flowmetry(LDF),immunohistochemical staining of CD34 epitopes and mRNA quantitative analysis.Results;The Plasma estradiol level in WT and ERKO castrated rats treated with estradiol was 198.13 ± 87.50pg/ml and 209.36 ± 92.73pg/ml respectively,which was higher than that for their respective control(p <0.01).In the meantime,the magnitude of changes in cerebral blood flow after cerebral ischemia-reperfusion in WT MCAO castrated rats treated with estradiol was 42.4±13.9%,the capillary density in the basal nuclei and parietal lobe cortex of their brain was 38.3 ±12.5 PU and 41.9 ± 14.1 PU respectively,and the Ang-1 mRNA expression in brain tissues was as high as 6.1 ± 1.8.All these results were higher than those for their respective control(p<0.01).No such changes were,however,identified in ERKO rats treated with estradiol.Conclusions Ang-1 is a critical factor for the repair of cerebral ischemia-reperfusion injury in many links such as estrogen protection,cerebral blood flow restorations,increases in brain capillary density,etc.It emerges as an important molecule for estradiol-mediated neuroprotection.