实验性蛛网膜下腔出血后兔脑血管内皮素受体A的表达及意义

Expression of endothelin receptor-A in brain vessel after experimental subarachnoid hemorrhage in rabbits and its significance

目的:探讨蛛网膜下腔出血(SAH)后脑血管内皮素受体A(ETRA)的表达与迟发性脑血管痉挛(DCVS)之间的关系.方法:将日本大耳白兔31只随机分为SAH模型组15只,盐水组10只,穿刺组3只,空白组3只.采用枕大池二次注血法制作SAH的动物模型,灌注处死后取基底动脉制成切片.进行ETRA免疫组化染色,图像分析法测量血管周长,用方差分析进行统计学检验.结果:在空白组、穿刺组和盐水组的基底动脉内ETRA有少量表达;SAH组基底动脉内ETRA的表达在3d组最强烈,其中血管内皮细胞表达最强烈,平滑肌也有表达,10d组的表达强度仍然较重.空白组动物的基底动脉内皮细胞完整,弹力膜无皱缩,管壁薄管腔大.SAH组和空白组的血管在图像上差异较大.通过对SAH组内各时间段标本的血管周长进行图像分析,对数据进行方差分析,SAH后血管周长的变化为:1h组稍有变化、3d组管径开始变小,弹力膜出现皱缩;5d组管腔变化最严重,弹力膜明显皱缩;7d,10d组血管表现出由痉挛到缓解的过程.脑血管痉挛最严重的时间晚于脑血管ETRA表达最强的时间.对盐水组血管周长统计数据进行方差分析,各时间段之间差异无显著性.结论:SAH后脑血管ETRA的高度表达可能是引起DCVS的重要因素之一.

AIM ： To study the expression of endothelin receptor A （ETRA） on the brain vessel after subarachnoid hemorrhage （SAH） and its relationship with the delayed cerebral vasospasm. METHODS： Thirty-one Japanese rabbits were randomized into SAH group （ n = 15 ）, normal saline group （ n = 10 ） , puncture group （ n = 3） and blank group （ n = 3 ）. The SAH animal model was made by in-fusing the blood into the cisterna magna twice. And then the basilar artery was harvested after the animals were sacrificed by perfusion. ETRA immunohistochemistry was used to stain the tissue, and the image analysis was employed to measure the circumference of the vessel. After that, the statistical analysis was performed by the analysis of variance. RESULTS： ETRA was expressed on the basilar artery in both blank group and punc- ture group. It was mainly located on the vascular endothelial cells. ETRA was also expressed on the basilar artery in the saline group. The expression was strong on the endothelial cells of basilar artery in the SAH group, especially at 3 d. Smooth muscle cells also expressed ETRA. Endothelial cells in the blank group were complete; elastic membrane didn＇t collapse. The circumference of the vessel in blank group and SAH group showed great difference by the statistical analysis （ P 〈 0.05 ）. In the SAH group, the vessel lumen changed severely in the 5 d subgroup; the vessel began to relieve from spasm in the 7 d and 10 d subgroup. The time when brain vessel spasm was most severe came later than the peak time of the ETRA expression on the brain vessel. Analysis of variance revealed that there wasn＇t any difference in the vessel circumference among different subgroups of the saline group （ P 〉 0. 05 ）. CONCLUSION： The high expression of ETRA on brain vessel after SAH may be one of main reasons for delayed cerebral vasospasm.