唐氏综合征细胞黏附分子在APP转基因小鼠海马中的表达变化及其意义

Expression of Down syndrome cell adhesion molecule in hippocampus of APP transgenic mice and its significance

目的观察唐氏综合征细胞黏附分子(DSCAM)在淀粉样前蛋白(APP)转基因小鼠海马中的表达变化规律,探讨其意义。方法选择月龄分别为1、3、6和12个月的APP转基因和野生型小鼠,应用免疫组织化学法对脑切片进行染色,观察DSCAM在APP转基因小鼠脑中的表达,应用蛋白免疫印迹法(Western blot)检测该蛋白在海马中表达量的变化规律,野生型小鼠做对照。结果 DSCAM主要在APP转基因小鼠大脑皮层、海马的锥体细胞中表达。在两组小鼠中,DSCAM在海马中的表达水平随年龄增长而下降(P<0.05)。DSCAM在APP转基因小鼠海马中的表达量明显高于同龄野生型小鼠(P<0.05)。结论 DSCAM在APP转基因小鼠海马内的过度表达可能在APP小鼠的学习和记忆能力下降中扮演重要角色。

Objective To investigate the changing regularity of the Down syndrome cell adhesion molecule （DSCAM） expression in the brain of amyloid precursor protein （APP） transgenic mice and explore the significance of DSCAM expression. Methods With immunohistochemistry and Western blot, the expression of DSCAM in the brains of APP transgenie mice （aged 1 m, 3 m, 6 m and 12 m）, especially the expression pattern and location in hippocampus were detected. The control group included age-matched wide type mice. Results DSCAM was widely expressed in the cerebral cortex and hippocampal pyramidal cell layer in the APP transgenic mice. The expression of DSCAM decreased with age in the hippoeampus of APP transgenic and wild-type mice （P 〈 0.05）. The hippocampus expression level of DSCAM in the APP transgenic mice was higher than that in the wild-type mice （P 〈 0.05）. There was no significant difference in DSCAM expression between 1-inonth old and 3-month old mice （P 〉 0.05）. Conclusions We propose that overexpression of DSCAM in the hippocampus might play an important role in the learning and memory defects of APP transgenic mice.