蛛网膜下腔出血后脑血管痉挛模型制作的优化与观察

Evaluation and Optimization of Cerebral Vaospasm Model with Subarachnoid Hemorrhage

目的明确蛛网膜下腔出血(SAH)模型经改良后脑血管痉挛(CVS)双相变化时程发展及与缺血损伤的关系。方法新西兰大白兔随机分为对照组和注血后不同时间点模型组。用优化的经皮一次注血法制作SAH模型,取脑组织冠状切视交叉前后2～4mm和中段基底动脉制备组织病理切片,HE染色后测定动脉皱缩指数(CC)和海马CA1区正常神经元细胞。每日行神经行为学评分,观察血凝块并评分。结果动物苏醒时间短。血管皱缩从注血后12h开始出现至第4d均明显,第5d时有所缓解后再次加重(P<0.05);海马CA1区存活神经元密度在各组间比较差异无统计学意义(P>0.05);CC和海马CA1区存活神经元数量间无相关关系。结论本改良模型短时、平稳,注血后12h直至第4d属于急性脑血管痉挛,第5d后属于迟发性脑血管痉挛,暂不适宜用海马CA1区神经细胞作SAH后脑损伤的病理评价。

Objective To determine biphasic changes of cerebral vasospasm（CVS） after subarachnoid hemorrhage（SAH） and its association with ischemic neurological injuries.Methods 55 adult male New-Zealand rabbits weighing 2.0-2.5 kg were randomly divided into 2 groups： control and SAH groups（including 10 subgroups at different sacrificed time： 12 h,24 h,2 d,3 d,4 d,5 d,6 d,7 d.8 d,9 d）.The rabbits were induced into cisterna magna by withdraw of 0.5 mL cerebrospinal fluid followed with administration of 2 mL saline（control group） or fresh unheparinised autologous arterial blood（SAH group）.The neurobehavioral scores were measured every day.The middle basilar artery and hippocampus were examined by optical microscope with HE stain,measuring coefficient of corrugation（CC） and survival number of hippocampal CA1 neurons. The neurological injury was assessed by injured hippocampal CA1 neurons and neurobehavioral scores.Results Severe and moderate vasospasms were detected in basilar arteries of the rabbits in the SAH group.Compared with the control group,the CC of the rabbits of the SAH group decreased significantly at 12 h,24 h,2 d,3 d,and 4 d（P〈0.05）.The recovery on day 5 was temporary and the CC plunged again from day 6（P〈0.05）.No statistical significance was found in the numbers of survived hippocampal CA1 neurons between the two groups（P〉0.05）.There was no correlation between hippocampal CA1 survival neurons and cerebrovasospasm progression.Conclusion Acute vasospasm occur from 12 h to day 4,which is followed by delayed vasospasm from day 5 to day 9.The hippocampal CA1 histopathological measurement is not suitable for evaluating brain injury after SAH.