高原低氧对雄性大鼠学习记忆及其额叶中的NR2A、P-NR2A、P-NR2B表达影响

Effects of high-altitude hypoxia on learning and memory in male rats and the expression of NR2A,P-NR2A and P-NR2B in their frontal lobe

目的探讨高原低氧对雄性大鼠学习记忆及其额叶中的NR2A、P-NR2A、P-NR2B表达影响。方法将48只SPF级的SD大鼠随机分为常氧组(分为1D组、5D组、12D组)和低氧组(分为1D组、5D组、12D组),共6组(8只/组)。通过水迷宫法评价雄性大鼠学习记忆能力,HE染色法观察额叶组织神经细胞形态,Western Blot法检测NR2A、P-NR2A、P-NR2B表达情况。结果水迷宫实验结果显示,随着训练次数的增加,大鼠发现平台的路程逐渐缩短;随着遗忘时间延长,大鼠穿越平台目标象限的次数减少。HE染色实验结果显示,各组额叶神经细胞结构形态完整,常氧组与低氧组神经细胞形态结构及数量无显著差异。在相同时间点与常氧组比,低氧组的NR2A在第一、五天的表达明显升高,在第十二天降低,差异有统计学意义(P<0.05);低氧组的P-NR2A、P-NR2B表达均明显升高(P<0.05)。结论低氧对雄性大鼠学习记忆能力均有一定程度的损害,可能机制是下调NR2A蛋白,上调P-NR2A蛋白,P-NR2B蛋白表达。

Objective To investigate the effects of high-altitude hypoxia on learning and memory in male rats,as well as the expression of NR2A,P-NR2A and P-NR2B in their frontal lobe.Methods A total of 48 SPF SD rats were randomly divided into normoxia group(1D,5D and 12D groups)and hypoxia group(1D,5D and 12D groups),totalling 6 groups(8 rats/group).The learning and memory ability of rats was evaluated by water maze method.The morphology of nerve cells in frontal lobe tissue was observed by HE staining.The expression of NR2A,P-NR2A and P-NR2B was detected by Western Blot.Results The results of water maze experiment showed that with the increase of training times,the distance of rats finding the platform was gradually shortened;with the prolongation of forgetting time,the number of rats crossing the target quadrant of the platform decreased.The results of HE staining showed that the morphological structure of frontal lobe neurons in each group was complete.There was no significant difference in the morphological structure and number of neurons between the normoxia group and the hypoxia group.Compared with the normoxia group at the same time point,the expression of NR2A in the hypoxia group was significantly increased on the first and fifth days,while decreased on the twelfth day.The difference was statistically significant(P<0.005).The expression of P-NR2A and P-NR2B in the hypoxia group was significantly increased(P<0.005).Conclusion Hypoxia has a certain damage to the learning and memory of male rats,possibly by downregulating the expression of NR2A and up-regulating the expression of P-NR2A and P-NR2B proteins.