鼠脑缺血性损伤程度与缺血时间的关系研究

Study on the relationship between ischemic time and extent of cerebral ischemic injury in rats

目的 探讨大脑中动脉 (MCA)闭塞时缺血侧不同部位的病理演变特征 ,研究缺血性损伤程度与缺血时间的关系。方法 利用线栓法 MCA闭塞模型 ,采取 HE染色 ,光镜电镜观察 MCA闭塞不同时相点缺血侧基底节区、皮质和海马的损伤特征 ,并直接对坏死和暗神经元计数 ,运用对数方程作出脑损伤程度 -缺血时间关系曲线 ,运算 ET5 0 值。结果 缺血 30分钟 ,坏死神经元首先出现在缺血侧基底节区 ,以后逐渐扩展到皮质 ,至缺血 2 4小时后 ,缺血中心逐步出现盘状坏死。缺血时间依赖性病理变化完全符合剂量反应曲线的S-形分布。结论 MCA闭塞后 ,MCA分布区的病理变化可分为组织水肿期、神经元急剧损伤期和盘状坏死期三个阶段。治疗窗因阻塞血管和缺血部位及组织可逆的期望值不同而异。主张治疗窗应“个体化”

Objective To explore the pathologic feature on different parts of ischemia during the middle cerebral artery occlusion (MCAO),and study the relationship between ischemic time and extent of cerebral injury.Methods A model of MCAO with the suture mothod was set up in rats,using HE staining, light and electronic microscope, the injury feature of ischemic basal ganglion area,cortex and hippocampus were observed in different time,and counted necrotic and dark neruons.Using a logistic equation to calculate the relationship between the duration of ischemia and the extent of injury.Results 30 min after cerebral ischemia onset,necrosis neurons appeared in ischemic basal ganglion area, and then progressively developed to cortex. Pannecrosis was observed after 24 h. Ischemia dependenced pathologic change completely fitted S shape distribution of dose response curves.Conclusions The pathologic changes induced by MCA occlusion had three periods: tissue edema period,neuron rapid injury period and pannecrosis period. Different vessels occlusion, different ischemic position and different expectation had different therapeutic window.This paper emphasized “individuation” of therapeutic window.