钙拮抗剂对大鼠脑缺血后血脑屏障通透性的影响

目的 研究钙离子拮抗剂对大鼠脑缺血再灌注后血脑屏障(BBB)通透性和脑梗死灶体积的影响. 方法 插线法制作大鼠脑缺血再灌注模型.缺血2 h后再灌注.将150只大鼠按随机数字表法分尼莫地平组和对照组,每组分再灌注6h、12h、24 h、48h、72 h五个时间段,再灌注后尼莫地平组和对照组立即分别腹腔注射尼莫地平和生理盐水2 mg/kg.每12小时注射一次,用甲酰胺荧光法及透射电镜观察不同时段BBB通透性破坏的情况,TTC染色后计算梗死灶体积百分比.结果 大鼠脑缺血再灌注后BBB通透性和梗死灶体积百分比随时间延长逐渐增加.且BBB通透性的增加呈现两个高峰,第一个高峰在再灌注后12 h,第二个高峰在再灌注后48 h.尼莫地平组BBB通透性及脑梗死灶体积百分比的增加均较对照组明显,差异有统计学意义(P<0.05). 结论 脑缺血再灌注增加BBB的通透性和脑梗死灶体积百分比.再灌注后给予尼莫地平可加重这些病理变化.

Nimodipine increases blood-brain barrier permeability after cerebral ischemia and reperfusion in rats

Objective To study the effect of nimodipine on the blood-brain barrier (BBB) permeability and cerebral infarct volume in mrs after cerebral ischemia and reperfusion. Methods Cerebral ischemia-reperfusion injury was induced by a 2-hour suture occlusion of the unilateral middle cerebral artery followed by reperfusion in 150 rats which were randomized into nimodipine and normal saline groups. Immediately after suture withdrawal to allow reperfusion, the two groups of rats were subjected to intraperitoneal injections of 2 mg/kg nimodipine (nimodipine group) or normal saline (saline group) at a 12-hour interval. At the time points of 6, 12, 24, 48 and 72 h after the reperfusion, the BBB permeability of the rats was evaluated with fluorophotometry and transmission electron microscopy, and the infect volume was estimated using TTC staining. Results The BBB permeability and the percentage of cerebral infarct volume increased gradually with prolonged reperfusion, and the BBB permeability presented with two peak increment occurring at 12 and 48 h of reperfusion, respectively. Nimodipine injection significantly increased the BBB permeability and the infarct volume in comparison with those in the saline group (P<0.05). Conclusion Cerebral ischemia and reperfusion destroys the integrity of the BBB and aggravates the ischemic cerebral infarction in rats, and the use of nimodipine after reperfusion further worsens these pathologies.