急性低压低氧对小鼠学习记忆能力及海马组织一氧化氮和内皮素-1水平的影响

Effects of acute hypobaric hypoxia on abilities of learning and memory, the level of nitric oxide and endothelin-1 in hippocampus of mice

目的 探讨模拟高原急性低压低氧环境对小鼠学习记忆行为及脑组织含水量、海马组织一氧化氮（Nitric oxide,NO）和内皮素-1（Endothelin-1,ET-1）的影响.方法 将小鼠随机分为常压常氧组和低压低氧组（模拟海拔6000 m 8 h）,用Morrs水迷宫测定小鼠的空间学习记忆能力;用干湿质量法测定脑组织含水量的变化;用酶联免疫吸附法观察其海马组织NO和ET-1的变化.结果 与常压常氧组比较,低压低氧组小鼠寻找平台的潜伏期延长[常压常氧组：（26.39±8.44）s,低压低氧组：（44.60±7.80）s,P＜0.01],目标象限停留时间减少[常压常氧组：（22.98±6.14）s,低压低氧组：（19.78±2.74）s,P＜0.05],脑组织含水量增加（P＜0.05）,海马组织NO[常压常氧组：（2.37± 1.07） μmol/gProt,低压低氧组：（4.48±1.45）μmol/gProt,P＜0.01]和ET-1水平增高[常压常氧组：（38.87±6.17） ng/L,低压低氧组：（52.09±6.75） ng/L,P＜0.01].结论 急性低压低氧环境小鼠学习记忆能力下降,这可能与急性低压低氧所致的脑水肿、海马组织NO和ET-1水平增加有关.

Objective To examine the effects of acute hypobaric hypoxia on abilities of learning and memory,the water content in brain,the level of nitric oxide（NO） and endothelin-1 （ET-1） in hippocampus of mice.Methods The acute hypobaric hypoxia environment were made by putting the mice in a hypobaric chamber simulated at altitude of 6 000 meters for 8 hours.The capabilities of learning and memory of mice were detected by Morris water maze test.The content of water in hippocampus were examined by measuring the ratio of dry/wet weight,and the level of NO and ET-1 in brain was detected by colorimetric method.Results Morris water maze test showed that the mean escape latency of mice in the hypobaric hypoxia group were longer than that in the normobaric normoxia group（（44.60±7.80） s vs （26.39±8.44）s,P〈0.01）,and the target quadrant residence time were decreased（（19.78±2.74） s vs （22.98±6.14）s,P〈 0.05）.Compared with the normobaric normoxia group （NO：（2.37 ± 1.07） μmol/gProt,ET-1：（38.87 ± 6.17） ng/L）,the water content in brain of mice in the hypobaric hypoxia group was increased （P〈 0.05）,meanwhile,both the level of NO （（4.48 ± 1.45） μmol/gProt） and ET-1 （（52.09±6.75）ng/L） in brain were increased too（P〈0.01）.Conclusion Hypobaric hypoxia can decrease the abilities of learning and memory of mice,and these changes might be related with the increased water content and the increased level of NO and ET-1 in hippocampus of mice.