更年期抑郁症模型大鼠记忆和海马超微结构变化研究

［摘要］目的　观察更年期抑郁症模型大鼠空间学习记忆及海马形态结构的变化。方法　雌性SD大鼠36只，随机分为四组，正常组、应激组、去势组和模型组。正常组不给予任何处理，应激组给予孤养加21天慢性不可预见性温和应激(CUMS)，去势组除卵巢切除术外不给予任何应激，模型组在卵巢切除术的基础上，给予孤养加21天CUMS。采用Morris水迷宫测试大鼠的学习记忆力；光镜以及透射电镜观察大鼠海马组织结构。结果　21天应激后，模型组大鼠学习记忆力下降；HE染色显示模型组大鼠海马锥体细胞层变薄，细胞间隙增大，排列紊乱，疏松，细胞结构不完整，甚至有大量细胞缺失；透射电镜下，模型组海马神经元细胞核呈现皱缩改变，核膜凹凸不整模糊不清，并有局部断裂；胞质内线粒体肿胀变性，嵴消失。结论　更年期抑郁症大鼠模型存在学习记忆力下降，这可能与应激造成的海马形态结构改变有关。

［关键词］慢性不可预见性温和应激；更年期抑郁症；海马；透射电镜

Changes of spacial learning and memory abilities and ultrastructure of hippocampus in perimenopausal depression model rats

［Abstract］Objective To observe Changes of spacial learning and memory and the ultrastructure of hippocampus in depression model rats.Methods Thirty-six female SD rats were randomly divided into four groups(9 in each).Normal group wasn’t given any stress，stressed group was given isolation-housing in combination with chronic unexpected mild stress(CUMS)for 21 days，ovariectomized group was given ovary resecting，and model group was made by resecting the ovaries of female rats，then giving isolation-housing in combination with 21 days of CUMS.Morris water maze test were used to test rats’behaviors.Light microscope and trans-mission electron microscope were used to observe the tissular structure of hippocampus.Results After ovaries resecting and 21 days of CUMS，rats in model group showed decling learning and memory abilities.HE staining showed that hippocampal pyramidal cell layer became thiner in rat model of depression，the gap between cells increased，and the cells arrayed in disorder，or loosely，even a large number of cells were lost.Transmission electron microscope showed that in rats of model group，hippocampal neurons were less，the nuclei collapsed，the whole nuclear membrane was fuzzy and there were some local fractures in the nuclear membrane；mitochondria within the cytoplasm were swollen and their ridges disappeared.Conclusion The decline of spacial learning and memory abilities in perimenopausal depression model rats might result from pathological changes in hippocampus.(www.xing528.com)

［Key words］chronic unexpected mild stress；perimenopausal depression；hippocampus；transmission electron microscope

更年期抑郁症是抑郁症的一种类型，是特指初次发病于更年期(也称为围绝经期，是指从卵巢功能紊乱到绝经后1年)，以焦虑不安和情绪低落为主要症状的疾病，属于情感性精神障碍，同时伴有思维迟缓、意志活动减退等症状，即存在认知功能障碍［1］。然而其发病机制目前尚不完全清楚，推测边缘系统异常可能是主要原因，而海马是边缘系统的重要组成部分。众所周知，海马与情绪及认知功能关系十分密切。目前关于更年期抑郁症动物模型的空间学习记忆和海马形态学结构变化的文献报道还不多见，因此，本文在卵巢切除术的基础上，联合孤养和21天的慢性不可预见性温和应激(CUMS)制备模型，主要测试大鼠的空间学习记忆能力以及观察大鼠海马的形态学结构，为更年期抑郁症的深入研究提供实验基础。