内皮素转化酶抑制剂治疗脑血管痉挛的免疫组化研究

目的: 应用免疫组化方法探讨ET-1在蛛网膜下腔出血(SAH)引起的脑血管痉挛(CVS)中的作用,以及D-Val22]大ET-1(16-38)对基底动脉壁 ET-1表达的影响和不同用药方式和时机的作用是否相同.方法: 采用枕大池双注血法制备36只兔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,进行免疫组织化学染色,观察ET-1的免疫表达.结果: ET-1免疫阳性标记颗粒在生理盐水对照组散在不规则表达,而在SAH组血管壁各层都有重度表达.用药预防和治疗组免疫染色强度基本一致,血管壁各层的ET-1免疫反应强度介入SAH和对照组之间.结论: D-Val22]大ET-1(16-38)可明显抑制基底动脉壁ET-1的免疫表达,无论脑池还是静脉给药均能够达到有效地预防和治疗SAH后CVS.

Immunohistochemical study of endothelin converting enzyme inhibitor [D-Val22] big ET-1(16-38) for the prevention and treatment of cerebral vasospasm

AIM: To investigate the function of endothelin-1 (ET-1) in the cerebral vasospasm (CVS) following subarachnoid hemorrhage (SAH), the effects of D-Val 22] big ET-1 (16-38), an endothelin converting enzyme inhibitor, on the expression of ET-1 in the wall of basilar artery and the differences of these effects by different ways and timing of injection. 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 for perfusion-fixation on day 7. The basilar arteries and some brain tissue were removed for immunohistochemical studies. RESULTS: The immunohistochemical study on SAH day 7 found that in control group, the basilar arteries showed scattered irregular positive staining, and in SAH group, severe positive staining was found in EC, SMC and adventitia, especially in EC. In the other four groups, EC, SMC and adventitia showed slightly immunohistochemical staining. But there was no positive staining in brain cells adjacent to basilar artery. CONCLUSION: This study demonstrates that Big ET-1(16-38) markedly inhibits immunological expression of ET-1 in basilar arteries, which not only effectively prevents CVS, but also reverses CVS via the cisterna magna or intravenously. Our study indirectly proves that ET-1 is a major pathogenic factor of CVS.