PENUMBRAL TISSUES SALVAGED BY REPERFUSION FOLLOWING MIDDLE CEREBRAL-ARTERY OCCLUSION IN RATS
PENUMBRAL TISSUES SALVAGED BY REPERFUSION FOLLOWING MIDDLE CEREBRAL-ARTERY OCCLUSION IN RATS
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DOI：
10.1161/01.str.23.4.552
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发表时间：
1992-04-01
期刊：
影响因子：
8.3
通讯作者：
SIESJO, BK
中科院分区：
文献类型：
--
作者：
MEMEZAWA, H;SMITH, ML;SIESJO, BK
背景与目的：大鼠被广泛用于局灶性脑缺血的研究，并在大鼠大脑中动脉闭塞模型中建立了一些新的药理原理。本研究的目的是评估如何在暂时性局灶性缺血模型中通过再灌注挽救缺血组织，该模型会导致尾核和新皮层梗死。方法：麻醉大鼠的大脑中动脉分别用腔内细丝闭塞15、30、60、90、120、180分钟，再循环7天，利用组织病理学技术评估缺血性脑损伤的密度和定位。在不同的动物中测量局部脑血流量，以验证去除灯丝后是否有足够的再循环。结果：大脑中动脉闭塞15分钟后，8只大鼠中有7只出现尾核选择性神经元坏死，而新皮层正常。阻断30分钟后，8只动物中有7只发生了局限于外侧尾核的梗死，8只动物中有4只在新皮层发生了选择性神经元坏死。8只大鼠缺血时间延长至60分钟均可诱发脑皮层梗死。梗死面积随着闭塞时间的增加而逐渐增大，可达120-180分钟，此时梗死范围与永久性大脑中动脉闭塞24小时后所观察到的梗死范围一样广泛。结论：研究结果表明，通过再灌注挽救半影组织的时间窗比以往其他物种的数据所建议的时间窗短。结果可能反映了大鼠的侧支血流量低于其他物种。在对大鼠进行药理作用研究时，应考虑到这一点。
Background and Purpose: The rat is now extensively used for studies on focal cerebral ischemia, and several novel pharmacological principles have been worked out in rat models of middle cerebral artery occlusion. The objective of the present study was to assess how ischemic tissue can be salvaged by reperfusion in a model of transient focal ischemia that gives infarction of both the caudoputamen and the neocortex.Methods: The middle cerebral artery of anesthetized rats was occluded for 15, 30, 60, 90, 120, or 180 minutes by an intraluminal filament, and recirculation was instituted for 7 days to allow assessment of the density and localization of ischemic brain damage using histopathologic techniques. Local cerebral blood flow was measured in separate animals to verify that removal of the filament was followed by adequate recirculation.Results: Following 15 minutes of middle cerebral artery occlusion seven of eight rats showed selective neuronal necrosis in the caudoputamen, while the neocortex was normal. After 30 minutes of occlusion, seven of eight animals had infarcts localized to the lateral caudoputamen, and four of eight had selective neuronal necrosis in the neocortex. Prolongation of the ischemia to 60 minutes induced cortical infarction in all eight rats. The infarct size increased progressively with increasing occlusion time, up to 120-180 minutes, when the infarcts were as extensive as those observed following 24 hours of permanent middle cerebral artery occlusion.Conclusions: The results demonstrate a time window for salvage of penumbral tissues by reperfusion that is shorter than that suggested on the basis of previous data in other species. The results probably reflect a lower collateral blood flow in the rat than in other species. This should be taken into account when the effect of pharmacological agents is studied in rats.