急、慢性高原缺氧对成年大鼠空间学习和记忆功能的影响

 目的： 探讨急性和慢性高原缺氧对成年大鼠空间学习和记忆功能的影响。方法： 研究分三部分。实验一：成年雄性SD大鼠分为平原组（A组）和急性高原缺氧组（B组）（n=15），B组于低压舱模拟海拔7 000 m高原连续暴露72 h后返回平原，24 h后两组同时进行Morris水迷宫定位巡航实验，连续训练3 d，每天4次，记录大鼠寻找平台的时间，第4天撤除平台，进行空间探索实验并记录大鼠穿越平台的次数和在目标象限停留的时间。实验二：成年雄性SD大鼠分为平原组（C组）和慢性高原缺氧组（D组）（n=13），D组置于低压舱模拟海拔6 000 m高原连续暴露35 d后返回平原，24 h后两组同时进行Morris水迷宫定位巡航实验，连续训练5 d，每天4次，第6天进行空间探索实验。实验三：成年雄性SD大鼠先进行Morris水迷宫定位巡航实验和空间探索实验(方法同实验二），于空间探索实验后随机分为平原组（E组）和急性高原缺氧组（F组）（n=15），F组于低压舱模拟海拔7 000 m高原连续暴露72 h后返回平原，2 h后两组再同时进行空间探索实验。结果： B组缺氧暴露后第1天寻找平台的时间较A组显著缩短（P<0.05），B组穿越平台次数和在目标象限停留时间百分比与A组比较差异无统计学意义。D组寻找平台潜伏期时间、穿越平台次数及在目标象限停留时间的百分比与C组相比，差异均无统计学意义。F组与E组缺氧前的各项指标均无显著差异，缺氧暴露后，F组穿越平台次数和在目标象限停留时间的百分比与E组相比差异无统计学意义。结论： 在本实验观察期内，急、慢性模拟高原缺氧对成年雄性大鼠对空间位置觉和方向觉（空间定位）的学习和记忆能力无显著影响（P>0.05）。急、慢性高原缺氧对工作记忆和空间参考记忆等功能的影响有待进一步研究。

Effects of acute and chronic hypobaric hypoxia on spatial learning and memory function of adult rats

[ABSTRACT] AIM: To explore the effects of acute and chronic hypobaric hypoxia on spatial learning and memory function of adult rats. METHODS: Three separate experiments were carried out. First, 30 adult male SD rats were divided into control (group A) and acute hypoxia (group B, 7000m, 72h), learning and memory function were tested by using Morris water maze. The spatial acquisition takes four trails per day, 3 days to reach asymptotic performance, remove the platform on the fourth day, use a novel start position during the probe trail. Record the data of latency, time in platform quadrant, times of passing platform. Second, 26 adult male SD rats were divided into control (group C) and chronic hypoxia (group D, 6000m, 35d). The spatial acquisition takes four trails per day, 5 days to reach asymptotic performance, remove the platform on the sixth day, use a novel start position during the probe trail. Record the data of latency, time in platform quadrant, times of passing platform. Third, after trained with Morris water maze (by using the method as the second one), 30 adult male SD rats were divided into control (group E) and acute hypoxia (group F, 7000m, 72h), 2 hours later, memory function were reevaluated. RESULTS: In the first day after acute hypoxia exposure, the latency of group B was significantly shorter than group A, however, the latency in the following days and the times of passing platform were not significantly different. There were no difference in the latency in the following days and the times of passing platform was found between group C and D. Memory tests didn’t show any difference between group E and F. CONCLUSION: Either acute or chronic hypobaric hypoxia do not affect the spatial learning and memory function of adult rats. [KEY WORDS] Acute hypoxia，chronic hypoxia，learning，memory，Morris water maze