6周游泳训练对注射D-半乳糖致衰老大鼠学习记忆能力及海马区NGF及其下游信号分子表达的影响

The Effect of 6-Week Swimming on the Learning and Memory Function,the Expression of Nerve Growth Factor and Its Expression of Downstream Molecular Signal in Hippocampus of Aging Rats Induced by Injecting D-galactose

目的:探讨6周游泳训练对注射D-半乳糖致衰老大鼠空间学习记忆能力和海马神经生长因子及下游信号分子的影响。方法:30只雄性SD大鼠随机分为正常对照(NC)组、衰老模型对照(AC)组和衰老模型训练(AE)组,每组10只。AC组与AE组每日皮下注射1次D-半乳糖(125 mg/kg),共6周。同时AE组进行连续6周、每周5天、每天1次的中等强度(90分钟)游泳训练。6周后,采用Morris水迷宫测试大鼠学习记忆能力,TUNEL染色检测海马CA3区凋亡神经元数目,Western blot检测海马组织NGF、P-Akt、Akt、Bcl-2和Bax表达。结果:与衰老模型对照组相比,衰老模型训练组大鼠在Morris水迷宫实验中的逃避潜伏期明显缩短,穿越平台区域次数明显增多(P<0.01);其海马凋亡细胞数显著减少(P<0.01),NGF、P-Akt和Bcl-2表达显著增加(P<0.01),Bax表达显著降低(P<0.01),Akt表达无明显差异(P>0.05)。结论:6周游泳训练可以改善衰老大鼠学习记忆能力,减少海马神经元凋亡,其机制可能是上调NGF、P-Akt和Bcl-2表达,同时下调Bax表达,进而促进神经元存活。

Objective To study the effect of 6-week swimming on the spatial learning and memory function,the expression of nerve growth factor and its expression of downstream molecular signal in hippocampus of aging rats.Methods Thirty male SD rats were randomly divided into normal control group（NC,n = 10）,aging control group（AC,n = 10）and aging exercise group（AE,n = 10）.Rats in groups AC and AE were injected with D-galactose（125 mg/kg/d） subcutaneously for 42 days,and the rats in group AE were forced to swim at moderate intensity（5 days/week,90min/day） for 6 weeks.After 6 weeks,the spatial learning and memory ability of rats was detected by the Morris water maze,and the apoptosis of neurons in hippocampus CA3 region were detected with terminal-deoxynucleotidyl transferase mediated nick end labeling（TUNEL）,and the protein expressions of NGF,P-Akt,Akt,Bcl-2 and Bax in hippocampus tissues were analyzed using Western blot.Results As compared with the group AC,the escape latency shortened obviously,the number that rats crossed the plateau region increased obviously（P 0.01）,the apoptosis of neurons in hippocampus CA3 region significantly decreased（P 0.01）,the protein expressions of NGF,P-Akt and Bcl-2 increased more significantly（P 0.01）,and the expressions of Bax decreased in the group AE.Meanwhile,there was no significance difference in the protein expression of Akt in all groups（P 0.05）.Conclusion The 6-week swimming improves the spatial learning-memory of aging rats and reduces the apoptosis of neurons in hippocampus.