Steele Ernest C, Guo Qingmin, Namura Shobu
Department of Anatomy and Neurobiology, Morehouse School of Medicine, 720 Westview Dr SW, Atlanta, GA 30310, USA.
Stroke. 2008 Jul;39(7):2099-104. doi: 10.1161/STROKEAHA.107.504357. Epub 2008 Apr 24.
Filamentous middle cerebral artery occlusion (fMCAO) is the most frequently used focal cerebral ischemia model in rodents. The proximity of the ophthalmic artery to the middle cerebral artery suggests that fMCAO induces retinal ischemia. We therefore tested whether fMCAO induces ischemia/reperfusion damage in retina in mice.
SV129EV mice were subjected to transient (30 or 60 minutes) fMCAO followed by reperfusion under isoflurane anesthesia. Retinal perfusion was evaluated by intravenous injection of fluorescent microspheres combined with fluorescent microscopy using flat-mounted retinas. The fluorescent density of ipsilateral retina relative to contralateral retina was determined in each animal. Retinal injury was assessed by cresyl violet staining and in situ TUNEL.
Microsphere analysis demonstrated perfusion defect in the ipsilateral retina after 60 minutes fMCAO and effective restoration after reperfusion. Thirty minutes fMCAO did not produce evident histological changes, even after 2 days of reperfusion. Sixty minutes fMCAO followed by 2 hours reperfusion resulted in extensive cell damage in the inner nuclear (>30%) and ganglion cell (>50%) layers. TUNEL demonstrated very few positive cells, suggesting that damaged cells were mainly undergoing nonapoptotic cell death.
Sixty minutes fMCAO produces retinal injury in SV129EV mice. Potential visual dysfunction should be considered when a particular occlusion period is selected for studying neurological outcomes after fMCAO. Because visual disturbance is often associated with thrombotic/embolic stroke in humans, fMCAO represents an appropriate model for future studies aimed at understanding and ameliorating the changes that lead to retinal damage in these patients.
丝状大脑中动脉闭塞（fMCAO）是啮齿动物中最常用的局灶性脑缺血模型。眼动脉与大脑中动脉位置接近，提示fMCAO可诱发视网膜缺血。因此，我们测试了fMCAO是否会在小鼠视网膜中诱发缺血/再灌注损伤。
对SV129EV小鼠进行短暂（30或60分钟）的fMCAO，然后在异氟烷麻醉下进行再灌注。通过静脉注射荧光微球并结合使用平铺视网膜的荧光显微镜来评估视网膜灌注。在每只动物中测定同侧视网膜相对于对侧视网膜的荧光密度。通过甲酚紫染色和原位TUNEL评估视网膜损伤。
微球分析显示，60分钟fMCAO后同侧视网膜出现灌注缺陷，再灌注后有效恢复。即使再灌注2天，30分钟fMCAO也未产生明显的组织学变化。60分钟fMCAO后再灌注2小时导致内核层（>30%）和神经节细胞层（>50%）出现广泛的细胞损伤。TUNEL显示阳性细胞极少，表明受损细胞主要经历非凋亡性细胞死亡。
60分钟fMCAO会在SV129EV小鼠中导致视网膜损伤。在选择特定的闭塞时间来研究fMCAO后的神经学结果时，应考虑潜在的视觉功能障碍。由于视觉障碍在人类中常与血栓性/栓塞性中风相关，fMCAO是未来旨在理解和改善导致这些患者视网膜损伤变化的研究的合适模型。
