中文摘要：

目的研究不同负荷运动对学习记忆障碍小鼠脑内自由基的影响。方法取昆明种小鼠60只，将其分为6组：空白对照组、模型对照组、尼莫地平组、高负荷运动组、中负荷运动组及低负荷运动组。采取被动跑转笼方式对高、中、低负荷运动组小鼠进行运动训练。实验进行第6周时各组小鼠均腹腔注射亚硝酸钠制作学习记忆障碍模型，空白对照组则同期腹腔注射等量生理盐水。尼莫地平组小鼠从实验第5周开始给予尼莫地平药物治疗，直至整个实验结束。于实验进行第8周时采用分光光度计检测各组小鼠脑组织中超氧化物歧化酶（SOD）活性及丙二醛（MDA）含量。结果与模型对照组比较，尼莫地平组小鼠SOD活性显著升高（P〈0．05），MDA含量有降低趋势，但组间差异无统计学意义（P〉0．05）。高、中、低负荷运动组小鼠SOD活性均较模型对照组显著增强（P〈0．01），MDA含量均较模型对照组显著降低（P〈0．05），且上述影响与运动负荷间无明显依赖关系。结论高、中、低负荷运动均能显著增强学习记忆障碍小鼠脑内SOD活性，降低MDA含量，提高脑内自由基清除能力。

英文摘要：

Objective To study the effects of different exercise loadings on free radicals in the brains of mice with memory disorders. Methods Sixty mice were, at random, divided into a control group, a model group, a nimodipine group, a group with a high load of exercise, a group with a moderate load of exercise and a group with a low load of exercise. The three exercise groups trained to run on a wheel. In the 6th week of the experiment, all the groups were injected with sodium nitrite in the abdominal cavity to model mice with memory disorders, except the control group which was injected with the same amount of sodium chloride. From the 5th week, the nimodipine group was treated with 30 mg · kg^-1 of nimodipine once daily until the end of the experiment. In the 8th week, the superoxide dismutase （SOD） activity and the malonic aldehyde （MDA） content in the brain tissue of mice in each group were measured with a spectrophotometer. Results Compared with the model contrast group, SOD activity in the nimodipine group was significantly elevated. MDA content had a tendency to decrease, but the differences among the groups were not statistically significant. SOD activity and MDA levels in the three exercise groups increased significantly. There was no significant dependence of any of these effects on the exercise load. Conclusions Any loading of exercise can significantly enhance SOD activity in the brains of mice with memory disorders, lower the level of MDA and elevate the ability to clean up free radicals.