脑缺血再灌注后基质金属蛋白酶-9的早期表达及对血脑屏障的破坏

目的研究大鼠短暂性脑缺血再灌注对脑组织基质金属蛋白酶-9(MMPs)表达的影响及对血脑屏障的破坏程度，探讨两者之间的关系以及在脑缺血损伤中所起的作用。方法通过制作大鼠脑缺血／再灌注模型，观察脑缺血后不同再灌注时间对脑含水量、血脑屏障通透性及MMPs表达的影响。结果脑缺血再灌注6h时，大鼠脑组织即有含水量及血脑屏障通透性增加，并随着时间推移而呈上升趋势。MMPs主要表达在大鼠缺血侧脑半球内的缺血神经元、血管内皮细胞及嗜中性粒细胞等细胞胞浆中，其表达含量于缺血再灌注6h后开始增加，并于再灌注1～2d时达到峰值，而该组大鼠缺血对侧脑半球组织内未见MMPs表达；假手术组大鼠亦未发现MMPs表达。结论MMPs的早期表达与血脑屏障通透性的改变密切相关．提示MMPs可能参与脑梗死后血管源性水肿的早期形成，从而加重脑缺血再灌注损伤。

Early expression of matrix metalloproteinase 9 and blood-brain barrier disruption after transient cerebral ischemia-reperfusion in rats

Objective To study the effects of transient cerebral ischemia-reperfusion (CIR) on the expression of matrix metalloproteinase 9(MM9) in cerebral tissues and the disruption of blood-brain barrier(BBB), and to explore their relationship in addition to their roles in the cerebral ischemic injuries. MethodsThe effects of different reperfusion time after cerebral ischemia on the water content of brain, the permeability of BBB and the expression of MM9 were investigated after the CIR model was established in rats. ResultsAt 6h after CIR, the cerebral water content and the permeability of BBB were increased with time while MM9 was expressed mainly in the plasma of ischemic neurons and the vascular endothelial cells of the ischemic hemisphere. The expression of MM9 was increased at 6h after reperfusion in the ischemic hemisphere, and reached the peak at 1~2d after reperfusion. However, no expression of MM9 was observed in the hemisphere contralateral to the ischemic side in the CIR group and in the sham-operation group. ConclusionThe early expression of MM9 was closely related to changes of the BBB permeability, which indicated that MM9 might be involved in the cerebral edema of vascular origin in the early stage of cerebral infarction, leading to aggravation of the CIR injuries