过刊浏览

大鼠缺血性脑损伤引起学习记忆障碍及心率变异性改变

李董, 杜春芸, 汤晓军, 金英雄, 雷霆, 姚扬, 杨卓, 张涛

南开大学生命科学学院,生物活性材料教育部重点实验室.天津 300071；南开大学医学院.天津 300071

摘要

该研究通过建立高脂缺血性脑损伤大鼠模型，进行水迷宫实验和心率变异性（heart rate variability，HRV）的功率谱分析，探讨脑损伤前后大鼠学习记忆的变化及缺血对自主神经的影响。23只成年雄性Wistar大鼠随机分为对照组（n=10）、高脂组（n=6）和高脂缺血组（n=7）。高脂组和高脂缺血组大鼠均饲以高脂饲料制成高血脂大鼠模型。各组大鼠进行水迷宫实验后，高脂缺血组用双侧颈总动脉结扎（2--VO）法制作缺血再灌注模型，同时记录心电图。7d后各组大鼠再次进行水迷宫实验和记录心电图，对HRV序列进行基于快速傅立叶转换（fast Fourier transformation，FFT）的功率谱分析。结果：（1）第一次水迷宫测试，3组大鼠空间探索实验和定位航行实验结果无统计学差异；第二次水迷宫实验，高脂缺血组与其它两组相比，空间探索实验中平台所在象限的记忆频度明显下降（{sl P}<0.01），定位航行实验中平台所在象限的记忆频度显著下降（{sl P}<0.01），10圆环记忆得分显著下降（{sl P}<0.001），但高脂组与对照组相比无明显差异。（2）高脂缺血组缺血后心率持续下降；缺血时HRV中频段功率（0.2---0.6Hz）呈现明显下降的趋势，高频段功率（0.6---2.5Hz）缓慢下降，中频／高频功率比值明显下降（{sl P}<0.05）。（3）缺血7d后高脂缺血组与高脂组相比，心率明显加快，HRV的中频段功率无显著变化，高频段功率明显下降，中频／高频功率比值显著增高（{sl P}<0.05）。结果表明，缺血过程中高脂缺血组大鼠的自主神经活动降低，交感神经活动相对于迷走神经活动减弱。缺血7d后，由于海马区神经元对缺血敏感易受损，造成高脂缺血组大鼠学习记忆障碍，同时引发迷走神经活动下降，大鼠交感．迷走神经系统平衡失调。

关键词： 脑缺血再灌注; 认知障碍; Morris水迷宫; 心率变异性

Changes of heart rate variability and impairment of learning and memory induced by cerebral ischemia/reperfusion in rats

Li Dong, Du Chunyun, Tang Xiaojun, Jin Yingxiong, Lei Ting, Yao Yang, Yang Zhuo, Zhang Tao

Key Laboratory of Bioactive Materials, Ministry of Education, College of Life Science,Nankai University.Tianjin 300071；China

Abstract

The present study was designed to observe the influence of cerebral ischemia/reperfusion injury on learning and memory in hyperlipidemic rats and estimate the changes of activity of autonomic nervous system. Twenty-three male Wistar rats were randomly divided into three groups, named control group （C group, n=10）, hyperlipidemia group （H group, n=6） and hyperlipidemia-ischemia group （HI group, n=7）, respectively. The rats in H and HI group were fed a high-fat diet for 2 weeks and the rats in all groups were examined through Morris water maze （MWM） task. The rats in HI group underwent ischemia/reperfusion by 2-vessel occlusion （2-VO） method, and had electrocardiogram （ECG） recording simultaneously. The MWM task and ECG recording were taken again after 7 d of recuperation. The following results were obtained： （1） In the second place navigation performance and probe trial performance, the frequency of memory in quadrant of hidden-platform and memory score decreased significantly in HI group compared to that in C and H groups. （2） The heart rate in HI group decreased slowly after ischemia; the power at high frequency band （HF） reduced gradually, meanwhile the power at middle frequency band （MF） and the ratio of power at MF and HF decreased clearly compared to baseline value.（3） After 7 d of ischemia/reperfusion, the heart rate in HI group was significantly higher than that in H group （P〈0.05）. While there was no statistical change in the power at MF, the power at HF decreased and the ratio of MF/HF increased significantly （P〈0.05）. The data demonstrated that ischemia/reperfusion decreased the activity of autonomic nervous system, and the reduction of sympathetic nerve activity was much more than that of vagus nerve activity. The results suggest that the hippocampus neuron injury caused by ischemia induces cognitive disorder and imbalance of vago-sympathetic nerve activity accompanied by vagus nerve suppression.

Key words: ischemia/reperfusion;cognition disorder;Morris water maze;Heart rate variability

收稿日期：　　录用日期：

通讯作者：　　E-mail:

引用本文：

李董, 杜春芸, 汤晓军, 金英雄, 雷霆, 姚扬, 杨卓, 张涛. 大鼠缺血性脑损伤引起学习记忆障碍及心率变异性改变[J]. 生理学报 2007; 59 (1): 35-41.

Li Dong, Du Chunyun, Tang Xiaojun, Jin Yingxiong, Lei Ting, Yao Yang, Yang Zhuo, Zhang Tao. Changes of heart rate variability and impairment of learning and memory induced by cerebral ischemia/reperfusion in rats. Acta Physiol Sin 2007; 59 (1): 35-41 (in Chinese with English abstract).