卒中后抑郁大鼠认知功能及海马脑源性神经营养因子的变化

目的评价卒中后抑郁大鼠学习记忆功能,观察海马CA3区脑源性神经营养因子（brain-derived neurotrophicfactor,BDNF）的表达变化。方法 60只成年雄性SD大鼠平均分为四组：对照组、抑郁组、卒中组与卒中后抑郁组,卒中后抑郁模型大鼠在大脑中动脉栓塞后接受连续3周的慢性不可预见性温和应激程序,用Morris水迷宫试验评价学习记忆功能,用免疫组织化学方法计数BDNF阳性细胞数。结果抑郁组、卒中组及卒中后抑郁组大鼠认知功能明显低于对照组,差异具有统计学意义（P〈0.05）,其中卒中后抑郁组最为严重。海马BDNF阳性细胞数由高到低排列,对照组〉卒中组〉抑郁组〉卒中后抑郁组。结论卒中后抑郁大鼠学习记忆功能下降,与脑缺血损伤及慢性应激均有关,认知功能缺陷与海马CA3区脑源性神经营养因子的表达减低程度相一致。

The changes in hippocampal brain-derived neurotrophic factor expression and cognitive function of rats under post-stroke depression

Objective The study attempted to evaluate the cognitive deficit of learning and memory in rats undergoing poststroke depression （PSD） and investigate the correlation between the changes in cognitive function and the expression of brain-derived neurotrophic factor（BDNF） in the CA3 area of hippocampus. Method Sixty adult male SD rats were evenly divided into four groups, namely, control group, depression group, stroke group and PSD group. The rats in the PSD group received a three-week chronic unpredictable mild stress procedure after stroke treatment of the right middle cerebral artery embolization. Morris water maze test was performed to assess the spatial learning and memory functions and immunohistochemistry staining method was used to analyze the expression of BDNF. Findings The cognitive impairments of rats in the PSD group were worse than those in the stroke group or the depression group（P 〈 0.05）. It was found that the number of BDNF positive neurons decreased more significantly in the PSD proup than in the depression or stroke group as compared with the control group. Conclusion The combined effects of cerebral, ischemic injury and chronic stressors are responsible for the decline of learning and memory functions in rats under post-stroke depression. The decrease of cognitive faculty is coincidental with the down-regulation of BDNF expression in CA3 area of hippocampus.