脑血管痉挛后基底动脉超微结构的变化及内皮素转化酶抑制剂的影响

目的: 研究SAH后基底动脉内膜和中层超微结构的变化,观察脑池和静脉应用内皮素转化酶(ECE)抑制剂预防和治疗CVS后基底动脉内膜和中层超微结构改变,探讨ECE抑制剂的脑血管保护作用.方法: 采用枕大池双注血法制备兔36只SAH后CVS模型.随机分成生理盐水对照组、SAH组、脑池给药预防组、静脉给药预防组、脑池给药治疗组和静脉给药治疗组.全部实验动物于首次注血后7 d进行灌注固定,留取基底动脉和脑组织标本,在电镜观察超微结构的改变. 结果: 电镜下,对照组血管壁超微结构无变化;SAH组电镜下血管内皮层结构以及内皮层细胞结构发生严重变性改变;用药治疗和预防组电镜下各组之间血管超微结构的改变无明显差异,组织变性程度明显轻于SAH组.结论: SAH后CVS可引起血管内膜和中层超微结构发生明显的变性,[D-Val22]大ET-1(16～38)可明显抑制基底动脉壁内膜和中层超微结构的损伤,有效地预防了SAH后CVS的发生.

Ultrastructural changes of artery after cerebral vasospasm with and without endothelin converting enzyme inhibitor

AIM: To investigate the ultrastructural changes of basiliar artery under transmission electron microscope (TEM) with and without [D-Val 22 ] big ET-1(16~38), an endothelin converting enzyme inhibitor, in the cerebral vasospasm (CVS) following subarachnoid hemorrhage (SAH). METHODS: CVS models were developed by injecting arterial blood twice through the citerna magna 48 hours apart. Thirty-six rabbits were equally assigned to six groups: Control group, SAH group, prevention group with citerna magna injection, prevention group with intravenous injection, treatment group with citerna magna injection and treatment group with intravenous injection group. All animals were killed using perfusion-fixation on day 7 and the basilar arteries and some brain tissue were removed for ultrastructural studies. RESULTS : TEM displayed normal morphology of EC, its conjunction, SMC and intimal elastic lamina (IEL) in control group, while in SAH group, marked pathological changes were observed, including desquamation and dystrophy of ECs, disruption of tight junction, vacuolated cytoplasm, condensation of chromatin in ECs, corrugation of IEL, and distortion of SMC. In other groups, TEM showed slight ultrastructural changes in EC, SMC and IEL. CONCLUSION: CVS following SAH causes marked ultrastructural changes of basiliar artery and [D-Val 22 ] big ET-1(16~38)can markedly inhibit the changes.