中文摘要：

目的观察大脑皮质梗死后β淀粉样肽（A／3）表达规律，明确Aβ在丘脑表达是否与直接缺血有关。方法电凝法制备大鼠大脑皮质梗死（MCAO）模型。动物按随机数字表法分为Sham组（18只）和MCAO组（30只）。2，3，5-氯化三苯基四氮唑（TTC）染色和免疫组化分别检测脑梗死灶和Aβ。结果TTC染色显示MCAO组梗死灶局限于大脑皮质。MCAO组梗死周边Aβ在MCAO后2d开始表达，7d达高峰，28d基本消失；其表达呈细小颗粒状，2d和28d时分别分布于神经元和胶质细胞内。同侧丘脑Ap在MCAO后3d开始表达，7d更明显，持续至28d；其Aβ表达一直分布于细胞外，形状随时间延长由细小颗粒状逐渐聚集成斑块状。结论大脑皮质梗死后梗死周边和同侧丘脑有Aβ动态表达，同侧丘脑Aβ表达与直接缺血无关。

英文摘要：

Objective To investigate the expression pattern of beta-amyloid （Aβ） in rats after focal cerebral cortex infarction, and to identify whether the Aβ expression in the ipsilateral thalamus was directly related to focal cerebral isehemia. Methods The distal middle cerebral artery occlusion （MCAO） was performed by electrocoagulation in rats. The rats were divided randomly into sham group （ n = 18 ） and MCAO group （ n = 30 ） . We used 2, 3, 5-triphenyhetrazolium chloride （ TTC ） staining and immunohistochemical staining to detect the location of cerebral infarction and Aβ expression, respectively. Results TTC staining showed that the cerebral infarction was consistently restricted to the frontal and temporoparietal cortex. In the peri-infarct area of the MCAO group, Aβ expression began at day 2, reached the maximum level at day 7, and disappeared almost completely at day 28 after MCAO. The Aβ appeared as diffuse small dots, and was located in neurons and astrocytes at day 2 and day 28, respectively. Meanwhile, in the ipsilateral thalamus, Aβ expression began at day 3, increased markedly at day 7, and remained until day 28 after MCAO. The Aβ was located constantly in the extracellular region of the ipsilateral thalamus, and aggregated gradually from small dots to dense plaque-like deposits with the time of ischemia. Conclusions There are dynamic changes of Aβ expression in both the peri-infarct area and the ipsilateral thalamus following MCAO. The Aβ expression in the ipsilateral thalamus is not directly related to focal cerebral isehemia~