游泳运动对APP/PS1转基因小鼠脑内MCT2表达及学习记忆的影响

The Effects of Swimming on the Expression of MCT 2 and Learning Memory in the Brain of APP/PS1 Transgenic Mice

目的探讨游泳运动对APP/PS1转基因小鼠学习记忆及大脑皮层和海马部位单羧酸转运蛋白(monocarboxylate transporter,MCTs)-2(MCT2)表达的影响。方法选取5月龄阿尔茨海默病(Alzheimer’s disease,AD)模型小鼠,分别标记未训练AD模型小鼠(AD-NT组)和训练的AD模型小鼠(AD-T组),同时选取5月龄野生型(WT)小鼠(C57BL/6)标记未训练WT小鼠(WT-NT组)。其中AD-T从5月龄开始给予4周游泳训练,其他2组正常饲养至6月龄,不给予任何处理。采用Morris水迷宫检测小鼠认知功能,Western Blot检测小鼠脑组织中MCT2蛋白表达,免疫组织化学染色观察大脑皮层和海马部位MCT2表达水平。结果Morris水迷宫结果显示,AD模型小鼠在经过4周耐力训练后,寻找平台的潜伏期和逃避路程均低于AD-NT,差异有统计学意义(P<0.05)。而在空间探索实验中,AD-T在目标象限停留的时间比例要高于未训练小鼠,差异有统计学意义(P<0.05)。Western Blot结果显示,经过4周游泳训练AD-T组小鼠脑组织中MCT2的蛋白表达量高于AD-NT组,差异有统计学意义(P<0.05)。皮层和海马区MCT2表达量在训练前后无明显差异。结论长期游泳运动相对改善了AD模型小鼠学习、记忆等认知功能,提高了中枢神经系统的能量代谢水平,但是脑内MCT2表达量增加并不明显。

Objective To explore the effects of swimming on the ability of learning and memory,and monocarboxylate transporter-2(MCT2)expression in cerebral cortex and hippocampus of APP/PS1 transgenic mice.Methods The 5-month old AD model mice were randomly separated into AD-NT and AD-T groups.Meanwhile,the 5-month old wild type mice(C57BL/6)were labelled as WT-NT.AD-T group model mice were made swimming training for 4 weeks from 5-month old.AD-NT and WT groups mice were raised normally until 6-month old and no treatment was given.Morris water maze was used to detect the cognitive function of mice in three groups.MCT2 protein expression in the brain was detected by Western-Blot.Immunohistochemistry was made to measure MCT2 expression in the cortex and hippocampus.Results Morriswater maze tests results showed that,after 4 weeks of endurance training,the average escape latency and escape distance of the AD-T group were significantly lower than that of the AD-NT group in the hidden platform experiment,the differences were statistically significant(P<0.05).In the space exploration experiments,the proportion of the AD-T model mice staying in the target quadrant was higher than that in the AD-NT group,the difference was statistically significant(P<0.05).Western blot analysis showed that the expression of MCT2 protein in brain tissue homogenate of AD-T mice increased after the training,the difference was statistically significant(P<0.05).Immunohistochemical staining showed that there was no significant difference of MCT2 expression in the cortex and hippocampus between before and after the training.Conclusion Long-term swimming exercise relatively improved the cognitive function of learning and memory in AD model mice,and increased the energy metabolism level of the central nervous system,but the increase of MCT2 expression in the brain was not obvious.