Effects Of Exercise On Spatial Learning And Memory Ability And Hippocampal Functional Protein Expression In Rats

Objective:By observing the changes of spatial learning and memory ability of rats after long-term moderate and overload exercise training,the expression of hippocampal functional protein was detected,and the relationship between the changes of hippocampal functional protein expression and the effects of long-term different load exercise on spatial learning and memory ability of rats was explored.It provides more experimental basis for how to arrange sports training to promote learning and memory ability.Methods: Forty adult male SD rats were randomly divided into three groups after 3 days of adaptive feeding.Considering that excessive swimming training may cause drowning of rats,the number of rats in the excessive exercise group was increased.The specific groups were as follows: control group(C,n =12),moderate load exercise group(M,n = 12),overload exercise group(O,n =16).Group C was fed routinely without swimming,group M was given moderate load swimming for 7 weeks,and group O was given excessive load swimming for 7 weeks.Morris water maze test was used to test spatial learning and memory ability at the same time as exercise training at the 7th week.24 hours after the end of the test,rats in each group were executed and blood and hippocampus samples were taken.Serum testosterone was detected by ELISA,hippocampal tissue was observed by HE staining,and the expression of BDNF,TrkB,NCAM and NR2 B in hippocampus was detected by Western Blot method.Results:1.Weight: At week 2-7,the weight of rats in group M and group O was significantly lower than that in group C(P < 0.05);at week 6 and 7,the weight of rats in group O was significantly lower than that in group M(P < 0.05).2.Serum testosterone: The serum testosterone content in group O was significantly lower than that in group C and group M(P < 0.05);there was no significant difference in serum testosterone content between group C and group M(P > 0.05).3.Morris water maze behavioral test.Location navigation experiment: The latency of Morris water maze walking in rats was affected by time point(time)factors and different load exercise(P < 0.05).Space exploration experiment: The number of times of traversing platform in group M was significantly higher than that in group C and group O(P < 0.05).4.Histological structure of hippocampus: The pyramidal cells of hippocampus in group C and M were numerous,dense,well arranged,with intact membrane structure,clear outline and full cytoplasm;the pyramidal cells of hippocampus in group O were fewer,less dense,irregularly arranged,with blurred membrane outline and less cytoplasm than those in group C and M.5.The expression of BDNF in hippocampus of rats in group M and group O was significantly higher than that in group C(P < 0.05);The expression of BDNF in hippocampus of rats in group O was higher than that in group M,but there was no significant difference(P > 0.05).6.The expression of TrkB in hippocampus of rats in group M was significantly higher than that in group C(P < 0.05);the relative expression ofTrkB in hippocampus of rats in group O was lower than that in group M and higher than that in group C,but there was no significant difference(P > 0.05).7.The expression of NCAM in hippocampus: The relative expression of NCAM in M group was significantly higher than that in O group and C group(P< 0.05);the relative expression of NCAM in O group was significantly higher than that in C group(P < 0.05).8.The relative expression of NR2 B in hippocampus of rats in group M and group O was significantly higher than that in group C(P < 0.05);the relative expression of NR2 B in hippocampus of rats in group O was higher than that in group M,but there was no significant difference(P > 0.05).Conclusions:1.Long-term medium-load training can improve spatial learning and memory ability,which may be due to the simultaneous enhancement of BDNF and TrkB pathways,the improvement of synaptic plasticity,the acceleration of signal transduction by NR2 B and the promotion of adaptive changes by NCAM,and the improvement of synaptic plasticity.2.Long-term overload training can slow down the ability of spatial learning and memory.This inhibition may be due to the damage of hippocampal morphology caused by the overexpression of NR2 B.BDNF and TrkB pathways can not be enhanced and repaired in time accordingly,and the effect of NCAM on synaptic adaptation is much less than that of moderate load training,which ultimately reduces synaptic plasticity.