Two-Photon Imaging during Prolonged Middle Cerebral Artery Occlusion in Mice Reveals Recovery of Dendritic Structure after Reperfusion
Two-Photon Imaging during Prolonged Middle Cerebral Artery Occlusion in Mice Reveals Recovery of Dendritic Structure after Reperfusion
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DOI：
10.1523/jneurosci.3724-08.2008
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发表时间：
2008-11-12
影响因子：
5.3
通讯作者：
Murphy, Timothy H.
中科院分区：
文献类型：
--
作者：
Li, Ping;Murphy, Timothy H.
大脑中动脉（MCA）丝闭塞是公认的局灶性缺血动物模型。该模型的优点是相对较长的遮挡时间和较大的半影区域，可以模拟人类中风的各个方面。在这里，我们使用双光子和共聚焦显微镜结合使用激光散斑的血流区域测量来评估 MCA 缺血区域边界和树突结构丧失之间的空间关系，以及再灌注对具有荧光（主要是第 5 层）神经元的成年 YFP（黄色荧光蛋白）和 GFP（绿色荧光蛋白）C57BL/6 转基因小鼠树突损伤的影响。通过检查树突损伤的空间范围，我们确定 60 分钟的 MCA 闭塞产生了一个具有严重结构损伤的核心，在再灌注后没有恢复（开始类似于中线外侧 3.8 毫米），再灌注后恢复的核心内侧 0.6 毫米的可逆性损伤区域（半影），以及一个结构相对完整的低灌注区域（类似于 1 毫米宽；内侧半影）。闭塞发生后 122.1 +/- 10.2 秒，结构丧失之前发生单次缺血性去极化。缺血 60 分钟后的动物再灌注与损伤加剧（再灌注损伤）无关，并导致带泡树突结构的显着恢复，但仅在树突损伤结构边界外侧约 0.6 mm 范围内。总之，我们发现即使在缺血 60 分钟后再灌注后也可以发生树突结构的恢复，但可能仅限于具有部分血流或氧合的相对较小的半暗带区域。
Filament occlusion of the middle cerebral artery (MCA) is a well accepted animal model of focal ischemia. Advantages of the model are relatively long occlusion times and a large penumbra region that simulates aspects of human stroke. Here, we use two-photon and confocal microscopy in combination with regional measurement of blood flow using laser speckle to assess the spatial relationship between the borders of the MCA ischemic territory and loss of dendrite structure, as well as the effect of reperfusion on dendritic damage in adult YFP (yellow fluorescent protein) and GFP (green fluorescent protein) C57BL/6 transgenic mice with fluorescent (predominantly layer 5) neurons. By examining the spatial extent of dendritic damage, we determined that 60 min of MCA occlusion produced a core with severe structural damage that did not recover after reperfusion (begins similar to 3.8 mm lateral to midline), a reversibly damaged area up to 0.6 mm medial to the core that recovered after reperfusion (penumbra), and a relatively structurally intact area (similar to 1 mm wide; medial penumbra) with hypoperfusion. Loss of structure was preceded by a single ischemic depolarization 122.1 +/- 10.2 s after occlusion onset. Reperfusion of animals after 60 min of ischemia was not associated with exacerbation of damage (reperfusion injury) and resulted in a significant restoration of blebbed dendritic structure, but only within similar to 0.6 mm lateral of the dendritic damage structural border. In summary, we find that recovery of dendritic structure can occur after reperfusion after even 60 min of ischemia, but is likely restricted to a relatively small penumbra region with partial blood flow or oxygenation.