有氧运动干预对不同衰老时期大鼠衰老后学习记忆能力的影响

关键词：学习记忆  衰老  运动  自由基  脑源性神经营养因子

Keywords:learning and memory  aging  exercise  free radicals  brain-derived neuro trophic factor

摘要：

      摘要 目的：采用有氧运动干预不同衰老时期的大鼠，探讨不同时期进行有氧运动干预对D-半乳糖致衰老模型大鼠学习记忆能力的影响。 方法：4月龄SPF级雄性大鼠75只，随机分为5组：生理盐水对照组（N1组，n=15）、衰老对照组（N2组，n=15）、衰老前有氧运动组（S1组，n=15）、衰老中有氧运动组（S2组，n=15）和衰老后有氧运动组（S3组，n=15）。N1组先进行生理盐水注射6周，然后进行4周的自然喂养；N2组先进行D-半乳糖注射6周，然后进行4周的自然喂养；S1组先进行有氧运动4周，然后进行6周的D-半乳糖注射；S2组先进行4周的自然喂养，然后进行6周的D-半乳糖注射，同时进行有氧运动干预；S3组先进行6周的D-半乳糖注射，然后再进行4周的有氧运动干预。大鼠造模结束后采用Morris实验检测大鼠的学习记忆能力，Morris水迷宫实验后进行断头取脑检测大鼠脑内的分子表达水平。 结果：Morris水迷宫定位航行实验结果：N1组和S2组大鼠经过前三天的学习后，潜伏期之间无显著性差异（P>0.05），N2组、S1组和S3组大鼠经过前四天的学习之后，潜伏期之间才无显著性差异（P>0.05）。Morris水迷宫空间探索实验结果：N1组穿越原站台位置次数显著性多于N2组（P<0.01）；S2组穿越原站台位置次数显著性多于N2组（P<0.01）。各组大鼠自由基检测结果如下：N1组大鼠脑内超氧化物歧化酶（superoxide dismutase，SOD）、谷胱甘肽过氧化物酶（glutathione peroxidase，GSH-Px）含量显著性高于N2组（P<0.01），N1组大鼠脑内丙二醛（malondialdehyde，MDA）含量显著性低于N2组（P<0.01）；S1组大鼠脑内SOD、GSH-Px含量显著性低于N2组（P<0.05），S1组大鼠脑内MDA含量显著性低于N2组（P<0.01）；S2组大鼠脑内SOD、GSH-Px含量显著性高于N2组（P<0.01），S2组大鼠脑内MDA含量显著性低于N2组（P<0.01）；S3组大鼠脑内SOD、GSH-Px和MDA含量与N2组无显著性差异（P>0.05）。各组大鼠海马内脑源性神经营养因子基因检测结果显示：N1与N2组之间存在显著性差异（P<0.05），N2与S1组之间无显著性差异（P>0.05）；N2与S2组之间无显著性差异（P>0.05）；N2与S3组之间无显著性差异（P>0.05）。各组大鼠海马体内脑源性神经营养因子（BDNF）免疫荧光实验结果显示：N1与N2组之间存在显著性差异（P<0.05）；N2与S1组之间不存在显著性差异（P>0.05）；N2与S2、S3组之间存在显著性差异（P<0.01）。 结论：在衰老过程中进行有氧运动干预可以有效清除体内的氧自由基，从而改善衰老大鼠的学习记忆能力。其作用机制可能与在衰老过程中进行有氧运动可以改善机体内的抗氧化能力有关。

Abstract:

      Abstract Objective： To explore the effects of aerobic exercise intervention at different stages on the learning and memory abilities of D-galactose-induced aging model rats. Method： Seventy-five male SPF rats aged 4 months were randomly divided into five groups： physiological saline control group （N1 group， n=15）、 aging control group （N2 group， n=15）、 pre-aging aerobic exercise group （S1 group， n=15）、 aerobic exercise group during aging （S2 group， n=15） and aerobic exercise group after aging （S3 group， n=15）. The N1 group was first injected with physiological saline for 6 weeks， followed by 4 weeks of natural feeding； The N2 group was first injected with D-galactose for 6 weeks， followed by 4 weeks of natural feeding； The S1 group first underwent aerobic exercise for 4 weeks， followed by 6 weeks of D-galactose injection； The S2 group underwent 4 weeks of natural feeding followed by 6 weeks of D-galactose injection and aerobic exercise intervention； The S3 group underwent 6-week D-galactose injection followed by 4-week aerobic exercise intervention. After the rat modeling was completed， the learning and memory abilities of the rats were tested using the Morris water maze test. After the Morris test， rats were decapitated to collect brain tissues for detecting molecular expression levels. Result： The results of Morris water maze navigation test showed that there was no significant difference in escape latency between N1 and S2 groups of rats after the first three days of learning （P>0.05）， and there was no significant difference in escape latency between N2， S1， and S3 groups of rats after the first four days of learning （P>0.05）. The results of the Morris water maze spatial probe test showed that the N1 group had significantly more crossings of the original platform position than the N2 group （P<0.01）； The number of times the S2 group crossed the original platform position was significantly higher than that of the N2 group （P<0.01）. The results of free radical detection in each group of rats were as follows： the levels of Superoxide Dismutase （SOD） and Glutathione peroxidase （GSH-Px） in the brain of N1 group rats were significantly higher than those of N2 group （P<0.01）， and the level of Malondialdehyde （MDA） in the brain of N1 group rats was significantly lower than that of N2 group （P<0.05）； The levels of SOD， GSH-Px in the brains of S1 rats were significantly lower than those of N2 group （P<0.05）， and the level of MDA in the brains of S1 group rats was significantly lower than that of N2 group （P<0.01）； The levels of SOD and GSH-Px in the brains of rats in group S2 were significantly higher than those in group N2 （P<0.01）， while the level of MDA in the brains of rats in group S2 was significantly lower than those in group N2 （P<0.01）； There was no significant difference in the levels of SOD， GSH-Px， and MDA in the brains of S3 group rats compared to N2 group （P>0.05）. The results of brain-derived neurotrophic factor （BDNF） gene detection in the hippocampus of each group of rats showed that there was a significant difference between N1 and N2 groups （P<0.05）， while there was no significant difference between N2 and S1 groups （P>0.05）； There was no significant difference between N2 and S2 groups （P>0.05）； There was no statistical difference between the N2 and S3 groups （P>0.05）. The results of the BDNF immunofluorescence assay in the hippocampus of each group of rats showed that there was a statistically significant difference （P<0.05） between the N1 and N2 groups； There was no significant difference between N2 and S1 groups （P>0.05）； There is a statistical difference （P<0.01） between N2 and S2/S3 groups. Conclusion： Aerobic exercise intervention during aging can effectively eliminate oxygen free radicals in the body， thereby improving the learning and memory abilities of aging rats. The underlying mechanism of action may be related to the fact that aerobic exercise during aging can improve the body's antioxidant capacity.