中老年期CD-1小鼠海马突触蛋白Arc含量改变及其与认知功能下降的相关性研究

探究中老年CD-1小鼠海马突触蛋白Arc含量的改变及其与空间学习记忆能力下降的相关性。选取3月龄和15月龄CD-1小鼠各10只（雌雄各半），用Morris水迷宫和免疫组织化学法分别检测其空间学习记忆能力和海马Arc蛋白相对含量。与3月龄相比，15月龄鼠在Morris水迷宫学习期游泳路程延长（F_(1,16)= 5.338, P＜0.05），记忆期靶象限内游泳路程百分比下降（F_(1,16)=78.013, P＜0.01），海马CA1和CA3区Arc水平增加（P＜0.05）。相关分析显示15月龄鼠海马CA1、CA3和DG区Arc相对含量与学习期游泳路程正相关（P＜0.05），CA3、DG区Arc含量还与记忆期靶象限游泳路程百分比负相关（P＜0.05）。中老年CD-1小鼠海马Arc含量呈亚区特异性增高，可能涉及其空间学习记忆损害。

Change of synaptic protein Arc in hippocampus and its correlation with cognitive impairment in middle-aged CD-1 mice

This study explored the effect of Arc and its correlation with the impairment of spatial learning and memory in aged CD-1 mice. Ten CD-1 mice (5 males and 5 females) were selected from 3- and 15-month old respectively. The abilities of spatial learning and memory were accessed with Morris water maze (MWM), and the relative content of synaptic protein Arc in hippocampus were detected using immunohistochemical method. The results indicated that the swimming distance during the learning phase was significantly longer and the percentage of distance during the probe phase was significantly less in the 15-month mice than those in the 3-month old mice (F_(1,16)= 5.338, P < 0.05; F_(1,16)=78.013, P < 0.01). The 15-month old mice had significantly higher Arc in the CA1 and CA3 subregions of hippocampus than the 3-month mice (P < 0.05). In the mice aged at 15-month old, the Arc level in the CA1, CA3 and DG positively correlated with the learning swimming distance (P < 0.05), and the DG and CA3 negatively correlated with the probe percentage of distance within the target quadrant (P < 0.05). Our findings suggested that the Arc level of hippocampus increased in a subregion-specific manner, which might be involved in the impairment of spatial learning and memory in middle-aged CD-1 mice.