| Objective: To observe the effect of aerobic exercise on spatial learning memory and hippocampal GAP-43 gene expression of the SD rats depression model,and to explore the effect and mechanism of aerobic exercise on rats’ brains.Methods: There are 54 adult male SD rats in the age of 3 months.After the purchase,the rats were fed adaptively(1 week)and randomly divided into 6 groups(n=9): control group(group C),exercise pretreatment group(EC group),model 1group(M1 group),and depression-moderate group(ce group),post-depression exercise group(CE group)and model 2 group(M2 group).Except for group C,other groups used chronic mild unforeseeable stress depression(CUMS)animal models.EC group using CUMS depression building after 4 weeks of aerobic exercise intervention;In the ce group,4-week aerobic exercise intervention was performed during the CUMS depression model;In the CE group,aerobic exercise intervention was performed for 4 weeks after the 4-week CUMS model was established.M2 group did not exercise after CUMS depression and fed normally for 4 weeks;after 4 weeks of normal feeding,The M1 group was subjected to CUMS depression for 4 weeks.Morris water maze system was selected to train and detect the navigation and space exploration ability of rats.On the last day of the animal modeling experiment,rats were sacrificed by the decapitation method,and rats were quickly stripped of the hippocampus,which was stored in liquid nitrogen and paraffin.The general state of rats was recorded during animal modeling;the morphological and structural changes of hippocampal neurons in rats were observed by Nissl’s staining,and the success of the model was determined by ELISA.The expression of GAP-43 mRNA and protein in hippocampal was detected by immunofluorescence,Real time PCR and western-blotting.The data were processed and counted using SPSS19.0 statistical software.The expression of mRNA and protein in hippocampal GAP-43 gene was detected by immunofluorescence,Real time PCR and Western blotting.The data obtained from the experiment was processed and counted by SPSS19.0 statistical software.Results :(1)General state of rats: Group C rats showed normal state in the experiment;M1 group rats showed significant signs of depression in the experiment,which had large mental fluctuations,were easily stimulated,and the appetite was not good and could not be acted quickly.With less activity,the coat color became yellow,and at the same time there were mouse hair loss and other conditions;compared withgroup C,the state of ce group was similar to that of group C;compared with group M1,group M2 was higher than group M1.State;CE status,EC group status and ce group are similar;compared with CE,EC,and ce groups,ce group status is better.(2)The result of sugar consumption test showed that compared with C group,M1,EC,M2,and CE groups showed a significant decrease in sugar consumption and a significant increase in white water consumption(P < 0.05).The sugar water consumption and sugar water consumption ratio of the ce group were significantly higher than that of the M1 and M2 groups(P < 0.05)and the white water consumption was significantly lower than that of the M1 and M2 groups(P < 0.05).There was no significant difference compared with the C group.(P > 0.05);(3)Whole brain 5-HT results: There was no significant difference in the expression of whole brain 5-HT between M1,M2 and EC groups(P > 0.05),but significantly lower than that of C group(P < 0.01);CE and CE groups.The expression of 5-HT in whole brain was significantly higher than that in M1,M2,and EC groups(P < 0.05),and there was no significant difference from C group(P> 0.05).(4)Morris water maze results: When evasion latency was used,there was no significant difference between the 1st and the 2nd day in each group(P > 0.05).There was no significant difference in the use time between the M1 and M2 groups on the3 rd day(P> 0.05),but M1 and M2 were significantly higher than those in C,CE,and ce groups(P < 0.01).EC group was significantly more than C and CE groups(P<0.05).On the fourth day,the escape latency of M1 and M2 groups.The time of use was significantly more than that of rats in the C,CE,and ce groups(P < 0.05).The EC group was significantly more active than the CE group(P < 0.05).On the fifth day,the M1 and M2 groups had significantly more time spent in the evasion latency than the C group.CE and ce rats(P < 0.05)were significantly higher in the EC group than in the C group(P < 0.05).On the 6th day,the M1 and M2 groups had significantly more time spent in the evasion latency than the C,CE,and CE.In the group(P <0.05),the EC group was significantly more active than the C,CE,and ce groups(P <0.05).The number of crossing platform results: There was a significant difference in the number of rat navigation experiments on the 7th day(P < 0.05).The number of M1 and M2 groups crossing the platform was significantly lower than that of rats in the C,CE,and ce groups(P < 0.01),and the number of crossings in the EC group was significantly less than that of the C,CE,and ce groups(P < 0.01);After 4 weeks ofCUMS stimulation,the rats in the M1 and M2 groups exhibited a decrease in learning ability on the 3rd to the 6th day.In the space exploration experiment on the 7th day,the rats in the M1 and M2 groups showed decreased learning and memory abilities.The escaping latency in M1 and M2 groups was longer than that in ce and CE groups,and the number of platform crossings was lower than that in ce and CE groups.This suggests that exercise interventions during and after the onset of depression can improve the spatial learning ability of depressed model rats.(5)Nissl’s staining: The corresponding results of Nissl staining were as follows:Group C rats had normal neuronal morphological structure.However,the arrangement and morphological structure of hippocampal neurons in the EC group were changed.The arrangement of neurons was disordered and the number of neurons changed significantly.Compared with group C,the histological structure of rat hippocampal neurons in CE group was similar to that in group C,but the number of neurons was disorganized and the number of neurons was significantly reduced.At the same time,some cells were pyknosis;compared with group C,neurons in group ce The arrangement was tight,and the number of neurons was similar to that of the C group.Compared with the C group,the arrangement of the neurons and the morphological structure of the M1 group changed,showing that the arrangement of the neurons was more disorganized and the number of neurons was reduced,and some cells were observed.In the case of pyknosis,the number is small,there is a large distance between cells,some nuclei appear pyknosis,and it is vague.Nissl bodies in cell bodies and dendrites have lighter colors and show marked changes in depression characteristics.(6)Expression of GAP-43 protein and mRNA in rat hippocampus: Expression of GAP-43 protein and mRNA in rat hippocampus was highest in ce group,followed by M1 group,and lowest in M2 group,and lower than that in M1 and ce groups(P <0.05).Conclusion:(1)Depression can lead to structural damage of hippocampal tissue in rats and decreased spatial learning and memory ability.Exercise intervention is a way to improve the learning ability of depressive model rats.(2)Aerobic exercise promotes the formation and retention of learning and memory ability of depressed rats,which may be related to the increase of GAP-43 expression.(3)The intervention of aerobic exercise in the early stages,middle stages,later stages of depression can all slow down the development of depression,and the effect of aerobic exercise intervention in the middle and later stages is more obvious. |
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