游泳运动对衰老大鼠学习记忆及海马CA1、CA3、DG区nNOS表达的影响

Effects of the Swimming Exercise on Learning and Memory and nNOS Expression within Hippocampus CA1,CA3,DG in the Aging Rats

目的:探讨游泳运动对衰老大鼠学习记忆能力、脑自由基代谢及乙酰胆碱酯酶(AchE)活性和海马CA1、CA3、DG区nNOS表达的影响。方法:选择40只24月龄SD衰老大鼠,随机分为衰老对照组、衰老运动组,20只5月龄大鼠为成年对照组。对照组在笼内正常生活,衰老运动组采用递增负荷游泳训练,连续8周。8周后检测大鼠脑自由基SOD、GSH-px、MDA及大脑AchE的活性,利用八臂迷宫测试大鼠空间学习记忆能力,采用免疫组织化学结合图像半定量方法对海马CA1、CA3及DG区nNOS神经元的表达进行测量和分析。结果:(1)与衰老对照组比较,衰老运动组参考记忆错误次数及总记忆错误次数均显著减少,完成八臂迷宫的时间显著缩短;(2)与衰老对照组比较,衰老运动组大鼠SOD活性显著增强,MDA含量减少,AchE活性均显著减弱;(3)免疫组化结果:衰老对照组大鼠海马CA1、CA3、DG区nNOS免疫阳性细胞数量和面积均显著低于衰老运动组,衰老运动组DG区nNOS免疫阳性细胞灰度值显著增加。结论:长期游泳运动可提高衰老大鼠的学习记忆能力,机理可能与游泳运动提高衰老大鼠抗氧化能力、改善受损的中枢胆碱能系统及增强大鼠海马CA1、CA3、DG区nNOS的表达有关。

Objective： To explore the influence of the swimming exercise on learning and memory, free radicals metabolism, acetylcholinesteras （AchE） activities and expression of nNOS within Hippocampus CA1, CA3 and DG of brain in the aging rats. Methods： Forty SD aged rats（24 mouths） were chosen and randomly divided into 2 groups： the aging control group（AC ） and the aging exercise group（AE）, twenty SD adult rats served as an adult control group （C）. The C group kept normal activities and the AE group undertook an 8-week swimming exercise with progressively increasing load. Then an 8-arms ra- dial maze was used to assessed each animal＇s capability of learning and memory; SOD, GSH-px, MDA and Ache activities were tested and nNOS expres- sion within Hippocampus CA1, CA3 and DG was detected and analyzed by using ABC immunohistochemical technique and semi quantitative. Results：（ 1 ） Compared with the AC group, the time of completing 8-arms radial maze shortened, RME and TE significantly decreased in the AE group; （2） Compared with the AC group, SOD activity obviously reinforced; MDA and AchE activities significantly weakened;（3） The immunohistochemical results： the amount and area of nNOS within Hippocampus CA1, CA3 and DG of the AC group were far less than those of the AE group, the gray degree of Hippocampus DG significantly increased in the AE group. Conclusion ： The swimming exercise may enhance the learning and memory ability of the aging rats, its mechanism might be that swimming exercise enhanced resisting oxidation of the rats, improved the injured central nerve cholinergic system and reinforced expression of nNOS within Hippocampus CA1 ,CA3 and DG at the same time.