长期中等负荷运动对大鼠空间学习记忆及海马神经黏附分子的影响

目的:研究长期中等负荷游泳运动对大鼠空间记忆及海马神经黏附分子(NCAM)的影响。方法:雄性SD大鼠40只,随机分为空白对照组(CN组)、水迷宫组(CM组)、运动组(EN组)和运动+水迷宫组(EM组)4组,每组10只。CN组和CM组常规饲养,不加干预;EN组和EM组进行7周中等负荷游泳训练,1次/天,6 d/周。第1次游10 min,此后每日增加5 min,至第2周末达60 min,第3周后每天游120 min,维持该运动量至第7周。每周末测大鼠体重。7周后,CN组和EN组大鼠断头取大脑海马组织,采用real-time PCR和Western blot检测NCAM mRNA和蛋白表达;CM组和EM组大鼠进行Morris水迷宫训练并检测定其定位航行和空间探索能力。结果:1、实验期间,EN组第5、7周末体重均显著低于CN组(P<0.05);EM组第4、5、6、7周末体重显著低于CM组(P<0.05,P<0.01)。2、Morris水迷宫训练后,EM组大鼠平均逃避潜伏期显著低于CM组(P<0.05),而在水迷宫空间探索实验中,EM组大鼠空间探索平均穿越次数较CM组显著增多(P<0.01)。3、EN组海马组织NCAM基因和蛋白表达均显著高于CN组(P<0.01)。结论:7周中等负荷运动缩短大鼠定位航行逃避潜伏期,提高大鼠空间探索穿越次数,长期适宜运动提高大鼠海马NCAM表达,有利于提高大鼠的空间学习记忆能力。

Long-Term Moderate Intensity Exercise Improves the Spatial Learning and Memorizing Abilities of Rats

Objective To discuss the effect of long-term moderate intensity exercise on the spatial learning and memorizing abilities and the expression of neural cell adhesion molecule(NCAM) in hippocampus of rats.Methods 40 male SD rats were divided into 4 groups at random:control group(CN,n = 10),Morris maze group(CM,n = 10),moderate intensity exercise group(EN,n = 10),and moderate intensity exercise plus Morris maze group(NM,n = 10).Rats in groups CN and CM were bred conventionally without any intervention;and in groups EN and NM underwent 7-week swimming with moderate intensity,once a day,6 days per week,started with 10 minutes,increased 5 minutes every day and eventually 120 minutes per day.At the end of the 7th week,rats in groups CN and EN were killed,then the expression of mRNA and protein of NCAM in the hippocampus were tested by real-time PCR and Western blot.Morris water maze experiment was carried out for rats in groups CN and MN to investigate the navigation and space exploration ability.Results 1.The body weight of rats in group EN was lighter than that in group CN after 5 and 7 weeks swimming(P < 0.05).The body weight of rats in group EM was lighter than that in group CM at the end of the 4th、6th and 7th week(P < 0.05).2.The escaping latency was shorter(P < 0.05)and average crossing frequency was increased(P < 0.01) in group EM than that in group CM.3.The expression of NCAM mRNA and NCAM protein in hippocampus increased in group EN as compared with that in group CN(P < 0.01).Conclusion Long-term moderate intensity exercise improves the spatial learning and memorizing abilities of rat through increasing the expression of NCAM.