中文摘要：

目的探讨慢性脑缺血大鼠海马区Numb表达的动态变化与认知功能之间的关系。方法 SD大鼠随机分为8周、10周、12周对照组和实验组;复制慢性脑缺血模型;Morris水迷宫试验检测行为学变化;免疫组织化学和Western blotting检测海马区Numb的表达变化。结果实验组逃避潜伏期比对照组明显延长（P〈0.05）,实验组Numb的阳性细胞百分数及相对光密度值比对照组显著减少（P〈0.05）。结论海马区Numb表达的持续下降可能是慢性缺血导致认知功能障碍的重要原因之一。

英文摘要：

【Objective】 To investigate the relationship of the expression of Numb in the hippocampus and the congnitive function after chronic cerebral ischemic in aged rats.【Methods】 The rats were divided into six groups at random： control groups of 8 weeks,10 weeks and 12 weeks,experimental groups of 8 weeks,10 weeks and 12 weeks.The chronic cerebral ischemia models were produced by pemlanent occlusion of bilateral common carotid arteries.The performance in Morris water maze was investigated.The expression of Numb was measured by immunohistochemical technique and Western blotting.【Results】 The escape latencies of experimental groups were longer than those of control groups（P 〈0.05）.As compared with the controls,the expressions of Numb were notably decreased.【Conclusion】 The decline expression of Numb after chronic cerebral ischemia may play an important role in cognitive impairment of aged rats.