诱导型一氧化氮合成酶在蛛网膜下腔出血后痉挛脑血管中的表达

目的 探讨iNOS在SAH后迟发性血管痉挛中的作用。方法 SAH模型采用大鼠枕大池二次注血法。HE染色测量SAH不同时期基底动脉腔的周长，比较痉挛程度；免疫组化和RT-PCR方法观察在痉挛最严重时基底动脉血管壁中iNOS的表达。结果 第7天时血管痉挛最为明显。免疫组化染色及RT—PCR分析均可见第7天时基底动脉血管壁中有iNOS的表达而在非SAH组为阴性。结论 iNOS在SAH后脑血管痉挛发生过程中起重要作用。

Expression of inducible nitric oxide synthase in the spastic cerebral artery after subarachnoid hemorrhage in rats

Objective To evaluate the role of inducible nitric oxide synthase (iNOS) at the severest stage of vasospasm after SAH. Methods The rat SAH model was induced by a 2-injection of blood into cisterna magna. HE staining was performed to estimate luminal perimeter of basilar artery at the different stage of SAH, and extents of vasospasm were compared; iNOS expressions on the day 7 after SAH were demonstrated by means of immunohistochemistry and RT-PCR respectively. Results (a) The development process of cerebral vasospasm in this rat model was similar to that after SAH happened clinically. Compared with the control, a narrow tend was found on day 3(P >0.05), and developed further on day 5(P <0.05). The dramatic differences were detectable on day 7 and day 9(P <0.01) and the constriction peaked on day 7.Vasospasm was relieved on day 14 (P >0.05). (b) iNOS immunoreactivity was mainly found in the vascular wall, especially in endothelial cells and adventitial layer on day 7 after SAH, and was undetectable in normal group. (c) iNOS mRNA expression was present in the vascular tissues on day 7 after SAH but absent in normal rats. Conclusion These results indicate a marked iNOS expression in the vascular tissue following SAH which may result in producing much greater amounts of NO. Furthermore, excessive production of NO may exert injurious effects on cells. The iNOS expression in vascular wall may play an important role in the development of cerebral vasospasm after SAH.