常压高氧处理对APP／PS1转基因小鼠空间学习记忆能力的影响

The effect of normobaric hyperoxia on the spatial learning and memory of APP/PS1 double transgenic mice

目的探讨常压高氧（NH）处理是否改善APP／PS1双重转基因AD模型小鼠的空间学习和记忆能力。方法对APP／PS1双重转基因AD模型种鼠交配后产下的子代小鼠进行基因分型，待子代达10周时，取双重转基因小鼠20只，随机分成A、B2组（每组10只）。A组小鼠给予常压高氧（40％O2，60％空气）处理，8h／d，持续8周；B组常规喂养，作为对照。高氧处理后进行Morris水迷宫实验，分别检测各组小鼠在可视平台、隐蔽平台及空间探索实验中找到平台的时间及搜索的平均路程；行为学实验结束后，采用ELISA定量检测小鼠脑内Aβ水平。结果行为学实验结果：（1）可视平台下，2组小鼠找到平台的时间及搜索的平均路程差异无显著性（P〉0．05）；（2）隐蔽平台下，高氧处理组小鼠找到平台的时间及搜索的平均路程较对照组明显缩短（P〈0．01）；（3）空间探索实验中，高氧处理组小鼠经过平台的次数[（6．31±2．55）次]显著高于对照组[（3．13±1．59）次]（P〈0．01）。ELISA结果显示，高氧处理组小鼠大脑皮质及海马内Aβ40[（783．64±97．21）pg／ml和Aβ42（175．30±17．09）pg／ml]水平显著低于对照组[Aβ40（1251．59±42．29）pg／ml、Aβ42（286．83±12．96）pg／ml]（P〈0．01）。结论常压高氧处理能显著改善AD模型小鼠空间学习记忆障碍；常压高氧可能通过减少Aβ生成或／和促进血管内皮细胞清除Aβ而发挥作用。

Objective To investigate whether normobaric hyperoxia exert neuroprotective effect on APP/ PS1 double transgenic AD mouse model. Methods 20 APP/PS1 transgenic mice were randomly divided into 2 groups（A,B）. Mice in group A were treated with 40% oxygen for 8h per day,and lasted 8 weeks. Mice in group B were treated with normal air,as control. ELISA assay as well as behavioral test were used in the present study. Results Compared with normoxia-treated control, hyperoxia-treated mice had a significant lesser （P 〈 0.01 ） to reach the platform in hidden platform test ; furthermore, hyperoxia-treated mice （ 6.31 ± 2.55 ） had significantly much more platform-passing times in the probe trial （P 〈 0.01 ） than control （ 3. 13 ± 1.59 ）, while mice in both groups had similar latency and pathlength to reach platform in visible platform （P 〉 0.05 ）. ELISA showed that Aβ40（ 783.64 ± 97.21 ）pg/ml and Aβ42 （ 175.30 ± 17.09 ） pg/ml were significantly decreased in hyperoxia-treated mice ,compared with control[ Aβ40 （ 1251.59 ± 42.29 ） pg/ml and Aβ42 （ 286.83 ± 12.96 ） pg/ml ] （P 〈 0.01 ）. Conclusion Treatment with hyperoxia significantly decreases Aβ deposition, and remarkably improves the capability of spatial learning and memory of APP/PS1 transgenic mice. Hyperoxia may exert its neuroproteetive effect through decreasing Aβ generation or enhancing clearance of Aβ by endothelial cells.