School of Medicine, Xizang Minzu University, Wenhui East Road, Xianyang, 712082, China; Tibetan Medicine Screening Laboratory, Xizang Minzu University, Wenhui East Road, Xianyang, 712082, China.
Second Department of Surgery, Xingping People's Hospital, Jincheng Road, Xingping 713100, China.
Behav Brain Res. 2019 Jul 23;367:82-90. doi: 10.1016/j.bbr.2019.03.047. Epub 2019 Mar 27.
The present study aimed to observe the effects of acute exposure to hypobaric hypoxia on learning and memory in adult Sprague-Dawley (SD) rats as well as the changes in N-methyl-D-aspartate receptor (NMDAR) subunits. Learning and memory abilities were evaluated with Morris water maze following simulated hypoxia at 5000 m or 7000 m for 2, 4 or 6 days. The number of red blood cells, the level of hemoglobin, oxidative stress markers, the extent of neuronal damage in the hippocampal CA1, and the expression of NMDAR subunits were all measured. In place navigation test, the escape latency significantly increased only in the 5000 M 6Day (P < 0.05) group than the latency in the plain group on the fourth day. In the spatial probe test, the times of platform passing showed no significant difference between the hypoxia and plain groups. Polycythemia, an increased ratio of superoxide dismutase/malondialdehyde and degeneration of neurons appeared in an elevation-dependent and duration-dependent manner in those hypoxia groups. Furthermore, the protein expression of NR1 increased and the protein expression levels of NR2A, NR2B, and NR3A were all decreased in the 5000M 6Day and 7000M 6Day groups. In summary, the feeble effect of acute exposure to simulated hypobaric hypoxia on learning and memory in adult SD rats may be attributed to increased antioxidative capacities and decreased expression of NR3A. And moreover, differences in the expressions of NMDAR subunits were closely related to the altitude and duration.
本研究旨在观察急性低压缺氧暴露对成年 Sprague-Dawley（SD）大鼠学习记忆能力的影响，以及 N-甲基-D-天冬氨酸受体（NMDAR）亚基的变化。在模拟海拔 5000 米或 7000 米的缺氧条件下，分别暴露 2、4 或 6 天后，使用 Morris 水迷宫评估学习和记忆能力。测量红细胞数量、血红蛋白水平、氧化应激标志物、海马 CA1 神经元损伤程度以及 NMDAR 亚基的表达。在位置导航测试中，只有在 5000M 6Day 组（P<0.05）与第四天平原组相比，逃避潜伏期显著增加。在空间探测测试中，缺氧组和平原组之间的平台通过次数没有显著差异。在那些缺氧组中，以海拔和时间依赖的方式出现了红细胞增多、超氧化物歧化酶/丙二醛比值升高和神经元变性。此外，在 5000M 6Day 和 7000M 6Day 组中，NR1 蛋白表达增加，NR2A、NR2B 和 NR3A 蛋白表达水平均降低。总之，急性模拟低压缺氧暴露对成年 SD 大鼠学习记忆能力的微弱影响可能归因于抗氧化能力的增强和 NR3A 表达的降低。此外，NMDAR 亚基表达的差异与海拔和时间密切相关。
