老年大鼠空间学习记忆能力下降与海马背侧胆固醇含量增加的关系

The correlation between spatial memory deficits and the increased cholesterol content of the dorsal hippocampus in aged rats

目的探讨正常老年大鼠空间学习记忆能力变化与海马背侧组织胆固醇代谢之间的关系。方法实验大鼠分老年实验组和青年对照组,利用Morris水迷宫方法评价空间学习记忆能力,然后测定海马背侧组织胆固醇含量及代谢相关酶羟甲基戊二酸单酰CoA还原酶(3-hydroxy-3-methylglutaryl coenzyme A reductase,HMG-CoAR)和胆固醇-24S-羟化酶(cholesterol24-hydroxylase,CYP46)mRNA表达的变化。结果与青年对照组相比,老年实验组逃避潜伏期明显延长(P<0.05),海马背侧组织总胆固醇的含量明显升高(P<0.05),HMG-CoAR mRNA相对表达量无明显变化,CYP46mRNA相对表达量明显降低(P<0.05)。结论正常老年大鼠空间学习记忆能力下降可能与海马背侧组织胆固醇含量增加有关。

Objective To investigate the relationship between the spatial memory and cholesterol content of the dorsal hippocampus in aged rats. Methods Spatial memory of 21 and 4 months old rats were evaluated by Morris water maze task. And the cholesterol content and the expression of 3-hydroxy-3-methylglutaryl coenzyme A reductase （HMG-CoAR） and cholesterol 24-hydroxylase （CYP46） in dorsal hippocampus were assayed respectively. Results The escape latencies were longer, the total cholesterol content of the dorsal hippocampus was higher, CYP46 mRNA expression in the dorsal hippocampus was decreased in aged rats than those in the young （ all P 〈 0. 05 ）. But there was no significant difference in HMG-CoAR mRNA expression between the two groups. Conclusions The spatial memory deficits of the aged might be correlated with the increased cholesterol content in the dorsal hippocampus.