急性低压低氧暴露不同时间对大鼠空间记忆能力的影响

目的探讨急性低压低氧暴露不同时间对大鼠大脑空间记忆能力的影响,为进一步研究急进高原大脑认知功能损害机制及防护药物提供理论依据。方法 56只SD大鼠随机分为平原组(对照组)和模拟海拔6000 m暴露2 d组、4 d组、6 d组、8 d组、10 d组、12 d组。急性低压低氧暴露不同时间后,立即进行Morris水迷宫定位导航训练和空间探索测试7 d,记录各组大鼠逃避潜伏期、游泳总路程、60 s内穿越平台次数和目标象限滞留时间。结果急性低压低氧暴露不同时间组大鼠测试第7天平均逃避潜伏期〔(29.2±2.6)、(23.8±2.0)、(26.7±2.4)、(27.2±2.1)、(26.1±2.4)、(26.0±2.3)s〕均较对照组〔(19.3±1.7)s〕显著延长(P0.01);测试第7天平均游泳总路程也均较对照组显著增长(P0.01);而60s内穿越平台次数则均较对照组显著减少(P0.05,P0.01);目标象限滞留时间均较对照组显著缩短(P0.05,P0.01)。暴露不同时间各组大鼠7 d测试期逃避潜伏期变化趋势是:暴露2 d组较对照组延长最多,暴露4 d组较暴露2 d组回落,暴露6 d以上组较暴露4 d组再次延长,但仍较暴露2 d组短;其他3个指标在7 d测试期也显示出与之一致的变化趋势。结论急性低压低氧暴露可致大鼠空间记忆能力下降,短时间低压低氧暴露对空间记忆的影响比长时间低压低氧更为明显。

EFFECT OF DIFFERENT EXPOSURE TIME OF ACUTE HYPOBARIC HYPOXIA ON RAT SPATIAL MEMORY

Objective To investigate the effects of different exposure time of acute hypobaric hypoxia on the formation of spatial memory in rat brain,so as to provide a theoretical basis for further study of the mechanism and protective drugs for cognitive impairment induced by rapid ascent to high altitude. Methods A total of 56 Sprague-Dawley rats were randomly divided into normal control group and 6 simulated 6000 m above sea- level altitude groups of different exposure time（2 d,4 d,6 d,8 d,10 d,and 12 d）. After exposure to hypobaric hypoxia,the Morris water maze navigation test and space exploration experiment were immediately conducted. Results On the 7th day of the Morris water maze test,the escape latency in different exposure time groups〔（29. 2 ±2. 6）,（23. 8 ±2. 0）,（26. 7 ±2.4）,（27. 2 ±2. 1）,（26. 1 ±2. 4）,（26. 0 ±2. 3）s〕was significantly longer than in control group（19. 3 ±1. 7）s（P〈0. 01）;the path-length to find the platform in exposure groups was also significantly longer than in control group（P〈0. 01）;while the number of times of crossing the former platform location,and swimming time in the target quadrant within 60 s in exposure groups were significantly less than in control group（P〈0. 01 or P〈0. 05）. The trend of change of the escape latency during 7 day test in different exposure time groups was that the escape latency in 2 d exposure group was the longest; that turned up in 4 d exposure group（shorter than 2 d exposure）; then the rest groups became longer again than the 4 d exposure group,but still shorter than 2 d exposure group. Moreover,the other 3 indicators during 7 day test also showed a similar trend of change. Conclusion Acute hypobaric hypoxia can cause spatial memory impairment in rat brain.The effect of short-term hypobaric hypoxia on spatial memory was more significant than that of long-term hypobaric hypoxia.