游泳运动对D-半乳糖致衰老小鼠学习记忆和胆碱能神经系统功能的影响

The Effects of Swimming Exercise on the Learning, Memory and Cholinergic System in Aging Mice

目的:探讨游泳运动对D-半乳糖所致衰老小鼠学习记忆和胆碱能系统功能的影响。方法:50只昆明种小鼠随机分成5组:对照组、模型组、15 min/天游泳组、30 min/天游泳组、45 min/天游泳组。除对照组外,所有小鼠连续8周皮下注射D-半乳糖复制衰老模型。运动组小鼠从第5周开始运动,连续4周。Morris水迷宫实验评价小鼠空间学习记忆能力。行为测试结束后,检测小鼠脑组织丙二醛(MDA)含量和超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-PX)活性及皮层和海马组织中乙酰胆碱酯酶(ACh E)和胆碱乙酰化转移酶(Ch AT)的活性。结果:水迷宫实验结果显示:15 min/天和30 min/天游泳组逃避潜伏期显著短于模型组,目标象限搜索时间百分比、通过目标区域次数均显著多于模型组。酶活性检测结果显示:15min/天游泳组小鼠脑组织SOD显著高于模型组,GSH-Px活性高于模型组但无显著性,MDA含量显著低于模型组;30 min/天游泳组小鼠脑组织SOD和GSH-Px活性均显著高于模型组、MDA含量显著低于模型组;15 min/天和30 min/天游泳组皮层和海马组织中ACh E、Ch AT活性均显著高于模型组。结论:15 min/天游泳运动和30 min/天游泳运动均能提高衰老模型小鼠的空间学习记忆能力,其中以30 min/天游泳运动的效果最好,其机制可能与其提高脑组织抗氧化和清除自由基能力,增强中枢胆碱能神经系统功能有关。

Objective To explore the effect of swimming exercise on the learning,memory and cholinergic system in aging mice. Methods 50 mice were randomly assigned to control group,aging control group and 3aging exercise groups. Except the control group,all mice were injected subcutaneously 150mg/kg of D-galactose once a day for 8 weeks. The mice in the three exercise groups respectively underwent swimming 15 minutes per day,30 minutes per day,and 45 minutes per day for 4 weeks. Morris water maze was used to evaluate the learning and memory ability of the mice. The activities of SOD,ACh E,Ch AT and GSH-Px,and the level of MDA were determined. Results The escaping latency was longer and the percentage of the time spending in target quadrant and the time going through target quadrant in 15-and 30-minute exercise groups were shorter than the aging control group significantly. The SOD activity was significantly higher and MDA concentration was significantly lower in 15-minute exercise group than in aging control group（P〈0.05）. The SOD and GSH-Px activities were significantly higher and MDA concentration was significantly lower in 30-minute exercise group than in aging control group. Comparing to the aging control group,the activities of ACh E and Ch AT in the cerebral cortex and hippocampus were significantly improved in exercise group,especially in 30-minute exercise group. Conclusion Exercise 30 minutes per day could significantly improve the learning and memory performances of aging mice induced by D-galactose,probably related to the enhanced ability of brain for against oxidation and for reducing free radicals,and to the improved function of cholinergic nerve system.