缓激肽对大鼠缺血区血脑屏障的影响

目的研究缓激肽对局部脑缺血区超微结构、血脑屏障的通透性及继发性脑水肿的影响。方法制备大鼠大脑中动脉缺血模型,在大脑中动脉缺血2hr再灌注1hr末,颈内动脉灌注小剂量缓激肽(10μg/kg/min),应用电镜观察血脑屏障超微结构的改变;测定脑组织伊文思蓝含量来判断血脑屏障的通透性;应用干湿法测定脑含水量的变化。结果缓激肽灌注大鼠脑毛细血管紧密连接开放,对照组大鼠紧密连接完整;与对照组相比,缓激肽灌注组缺血侧脑组织伊文思蓝含量明显高于缺血对照组(P<0.01),但再灌注24hr后脑含水量并没有增加(P>0.05)。结论小剂量缓激肽通过开放紧密连接来增加缺血区血脑屏障的通透性,但并不会增加继发性脑水肿的程度。

Effect of Bradykinin on the Blood Brain Barrier in Ischemic Area of Rats

Objective To study the effect of bradykinin on ultrastructure and permeability of blood-brain barrier (BBB) and the secondary edema in cerebral ischemic rats. Methods The left middle cerebral artery was occluded 2hr followed by 1hr reperfusion. The ultrastructure of BBB was observed by electron microscope and the evans blue (EB) content was analyzed after the intracarotid infusion of low dose bradykinin (10μg/㎏/min). The water content of brain 24hr after reperfusion was assessed. Results The patency of the junctions between endothelial cells was seen clearly in the bradykinin infusion group, while it was not seen in the control group. EB content in ischemic side is increased significantly in the bradykinin infusion group than in control group (P<0.01), but without difference in the water content of brain between the control group and the bradykinin infusion group (P>0.05). Conclusion Low dose bradykinin selectively increased permeability of BBB in ischemic area by loosing the tight junction without affecting the extent of ischemia-induced vasogenic edema.