急性一氧化碳中毒大鼠记忆功能改变与迟发性神经元损伤的相关性

背景:急性CO中毒大鼠可能发生迟发性健忘症,与人急性CO中毒导致的迟发性神经综合征相似,所以实验拟通过对急性CO中毒大鼠的研究来探讨迟发性神经综合征的发病机制。目的:观察急性CO中毒大鼠脑内迟发性神经元损伤和记忆功能的改变,并分析两者之间的关系。设计:随机对照动物实验。单位:解放军第四军医大学唐都医院急诊科;西安高新医院检验中心;解放军北京解放军空军总医院;解放军第四军医大学航空航天医学系高压氧治疗中心。材料:实验于2005-07/11在解放军第四军医大学航空航天医学系航空病理学和分子生物学实验室进行。取健康雄性Sprague-Dawley(SD)大鼠50只随机分为对照组和染毒组各25只。方法:将染毒组清醒大鼠放入自制染毒罐中,然后向罐内注入体积分数为0.999的CO气体。大鼠在罐内静式吸入CO与空气的混合气体,CO平均体积分数为3.451×10-3,60min后出罐。对照组不干预。主要观察指标:①记忆能力:染毒前和暴露后1,3,5,7d进行大鼠跳台实验,以跳台潜伏期为评价记忆保持巩固能力的指标,跳台潜伏期越短,记忆能力越差。②脑组织病理改变:暴露后1,3,5,7d跳台实验后,两组各处死6只大鼠,取脑,行苏木精-伊红染色以观察脑内病理损伤程度和海马CA1区锥体细胞数。③应用SPSS 10.0软件分析海马CA1区锥体细胞数与组大鼠跳台潜伏期间的关系。结果:48只大鼠进入结果分析。①跳台潜伏期:CO暴露后1,3d,两组相比没有差别,但在CO暴露后第5和7天,染毒组明显短于对照组(P<0.05,0.01)。②海马CA1区锥体细胞数:CO暴露后1d,染毒组与正常对照相比没有明显改变,但是在CO暴露后3,5和7d即明显减少,CO暴露后7d,可以观察到15%的锥体细胞发生死亡。③海马CA1区锥体细胞数减少与染毒组大鼠跳台潜伏期缩短之间有明显的相关性(r=0.270,P<0.01)。具体的主要数据,研究的主要发现(给出统计学显著性检验值)结论:主要结论及其潜在的应用价值。急性CO中毒导致迟发性神经元损伤,迟发性神经元损伤引起迟发性健忘症。

Correlation between memory deficit and delayed neuronal damage after carbon monoxide poisoning in rats

BACKGROUND:Acute carbon monoxide (CO) poisoning may lead to delayed amnesia in rats,and which is similar to delayed neurologic syndrome caused by acute CO in human.So,this experiment is to investigate the pathogenesis of delayed neurologic syndrome by studying acute CO poisoning in the rats.OBJECTIVE:To observe the changes in delayed neuronal damage and memory after acute CO poisoning in the rats,and analyze their correlation.DESIGN:Randomized controlled animal experiment.SETTING:Department of Emergency,Tangdu Hospital,Fourth Military Medical University of Chinese PLA;Department of Laboratory Medicine,Xi'an Gaoxin Hospital;The General Hospital of the Air Force of Chinese PLA,Center for Hyperbaric Oxygen Treatment,Department of Aerospace Medicine,Fourth Military Medical University of Chinese PLA.MATERIALS:This experiment was carried out in the Laboratory of Aviation Pathology and Molecular Biology,Department of Aerospace Medicine.Fourth Military Medical University of Chinese PLA from July to November 2005.Fiftyhealthy male Sprague-Dawley(SD)rats were randomized into control group and CO poisoning group,with 25 rats each.METHODS:The awake rats in the CO poisoning group were placed in self-made jar for poisoning,then which was pumped with 0.999 volume fraction of CO.Rats in the jar inhaled the mixture of CO and air for 60 minutes.The average volume fraction of CO in the jar was 3.451×10-3.Rats in the control group were untouched.MAIN OUTCOME MEASURES:①The step down test was carried out in the rats before and 1,3,5 and 7 days after Coexposure.Escape latency was used as an index for evaluating the ability of memory retention.Shorter escape latencyindicated poor memory ability.②Pathological changes of brain tissue:After step down test was carried out following 1,3,5 and 7 days of CO exposure,6 rats were separately sacrificed in each group,and their brains were harvested.The brain tissue sections were performed haematoxylin & eosin (HE) staining for observing pathological injury degree and the amount of pyramidal neurons in hippocampal CA1 region.③SPSS 10.0 software was used to analyze the relationship of the amount of pyramidal neurons in hippocampal CA1 region and escape latency.RESULTS:Forty-eight rats were involved in the final analysis.①There were no significant differences in escape latencyon the 1"and 3"days after CO exposure between two groups. but escape latency in the CO poisoning group was significantly shorter than that in the control group on the 5th and 7th days after CO exposure(P＜0.05,0.01).②There were no significant changes in the amount of pyramidal neurons in hippocampal CA1 region on the 1st day after CO exposure between CO poisoning group and control group,but pyramidal neurons in hippocampal CA1 region in the CO poisoning group were significantly reduced on the 3rd,5th and 7th days after CO exposure,and 1 5%dead pyramidal neurons were found on the 7th day after CO exposure.③Decrease of pyramidal neurons in hippocampal CA1 region was significantly correlated with shortening of escape latency of rats in the CO poisoning group(r=0.270,P＜0.01).CONCLUSION:Acute CO poisoning leads to delayed neuronal damage,which causes delayed amnesia.