间断性闭塞双侧颈动脉后永久性闭塞双侧颈内动脉：一种新的大鼠血管性痴呆模型

Penmnent occlusion of bilateral internal carotid arteries after intemittent occlusion of bilateral carotid arteries： a new rat model for vascular dementia

目的对经典二血管闭塞（two-vessel occlusion，2-VO）建模方法进行改良，以降低在Morris水迷宫等行为学实验中出现的系统误差。方法32只成年雄性Wistar大鼠随机分为经典2-VO模型组、改良模型组、假手术组和假结扎组，每组8只。经典2-VO模型组仅结扎双侧颈总动脉；改良模型组间断性夹闭颈总动脉，高选择性结扎翼颚动脉发出后的颈内动脉；假结扎组仅间断性夹闭颈总动脉；而假手术组仅分离颈总动脉和翼颚动脉分支上段。采用瞳孔对光反射、Morris水迷宫以及八臂迷宫等评价大鼠行为学。HE染色观察组织学变化。结果改良模型组和经典2-VO模型组Morris水迷宫逃避潜伏期（F=72．169～163．102，P均〈0．001）和八臂迷宫参考记忆错误次数（F=33．515～74．726，P均〈0．001）均较假手术组显著性延长和增加。经典2-VO模型组大鼠对光反射消失，其他组大鼠对光反射均正常。经典2-VO模型组到达平台时间较改良模型组和假手术组显著延长（P〈0．001），目标象限停留时间百分比也显著下降（术后7d时：F=13．770，P〈0．001；术后90d时：F=14．780，P〈0．001）。HE染色显示，改良模型组和经典2-VO模型组均出现海马CAI区细胞减少、白质稀疏等病理学变化；此外，经典2-VO模型组大鼠视神经区出现较多空泡样改变，而改良模型组则无此改变。结论间断性闭塞双侧颈动脉后永久性闭塞双侧颈内动脉法建立血管性痴呆模型可避免大鼠出现严重的视力损害。改良模型大鼠在Morris水迷宫和八臂迷宫实验中表现出明显的学习记忆功能下降，并存在海马损伤。

Objective To modify a classic two-vessel occlusion （2VO） modeling method in order to decrease the systematic errors in the behavioral experiments such as Morris water maze： Methods Thirty-two adult male Wistar rats were randomly allocated into classic 2VO model, modified model, sham operation and sham ligation groups （n =8 in each group）. Only the bilateral common carotid arteries were ligated in the classic 2VO model group; the common carotid arteries were clipped intermittently, and the origins of pterygopalatine arteries of the internal carotid arteries were high selectively ligated in the modified model group; the common carotid arteries were only ligated intermittently in the sham ligation group; and only the common carotid arteries and the upper segrnent of pterygopalatine artery branches were separated in the sham operation group. The rat behavior was evaluated using the pupillary light reflex, Morris water maze and eight-arm radial maze. HE staining was used to observe the histological changes. Results The Morris water maze escape latency （F = 72. 169 - 163. 102, all P 〈 0. 001） and the number of reference memory errors of eight-arm radial maze （F =33. 515 -74. 726, all P〈0. 001） in the modified model and the classic 2VO model groups were longer and higher than those in the sham operation group. The pupillary light reflex of the rats was lost in the classic 2VO model group and the pupillary light reflex of the rats was normal in other groups. The reaching platform time in the classic 2VO model group was significantly longer than that in the modified model and sham operation groups （P 〈0. 001 ）. The percentage of target quadrant dwell time was also decreased significantly （at day 7 after procedure： F = 13. 770, P 〈0. 001; at day 90 after procedure： F = 14. 780, P 〈0. 001）. HE staining showed pathological changes such as the cells decrease in hippocampal CA1 region and leukoaraiosis in the modified model and the classic 2VO model groups. In addition, there were more vacuole-like changes in the rat optic nerve region in the classic 2VO model group, while there were no such changes in the modified model group.Conclusions Estab- fishing vascular dementia model with permanent occlusion of bilateral internal carotid arteries after intermittent occlusion of bilateral carotid arteries could avoid severe visual impairment in rats. In the Morris water maze and eight-arm maze test, the modified model rats showed significant decrease in learning and memory abilities and had hippocampal damage.