Effects Of Aerobic Exercise On ERK Gene Expression And DNA Methylation Level In Hippocampus Of Aging Rats

Objective: Research on aerobic exercise intervention in different periods of aging rats hippocampal ERK gene expression and its effect of DNA methylation,to explore the effect of aerobic exercise on hippocampus ERK and mechanism,explore the best intervention movement slow brain aging period,It can also provide theoretical foundation and experimental data.Methods: Adult male 3-month-old SPF SD rats(n=75).Divided rats into 5 groups after a week’s feeding(n=15): NS control group(group C),Aging model group(group A),Exercising before aging(group S1),Exercising while aging group(group S2),Exerting after aging group(group S3).In addition to the group C,the rest of the group adopts the abdominal cavity injection of D-GA lactose way to establish sub acute aging animal models.Group S1,S2,S3 carried out the intervention of moderate load swimming exercise becoming aging,while aging and after aging.Animal model experiment method to be put to death in the rat,the last day of the breakfast stripping in the rat hippocampus,liquid nitrogen preservation,paraffin embedding for use respectively.During modeling process observed and recorded condition of rats,including heights,hair,eating and water consumption,mental condition and activity;Missal staining;Western Blotting and Real-time PCR were applied to detect ERK;Data was analyzed by SPSS19.0.Results:(1)general state: The state of the normal group C rat;A group of rats appeared obvious signs of aging,characterized by lethargy,loss of appetite,slow and decreased activity,and the color yellow falls off phenomenon such as;Compared with group C,S2 group rats state close to C;And then group A,S2 group of state is A good group of rats;S1 and S3 group Similar to group A;S1,S2,S3 group than,S2 best group status.(2)Nissl staining: In group C,Group C rats hippocampal neurons morphology is normal;Group A neuron cell structure is incomplete,the number decreased significantly,some ambiguous nucleus neurons,austenite color becomes shallow;And then group C,S2 close to C group;And then group A,S2 arrange relatively orderly set of hippocampal neurons,the number and spacing relatively normal cells;Similar to group A S1 and S3 team;Than S1,S2,S3 group,best S2 group rats,the arrangement of hippocampal neurons,quantity,color is best.(3)Rat hippocampal ERK protein and mRNA expression: hippocampal ERK protein and mRNA expression trend,the highest expression of group C,S2 group,group A minimum,and significantly lower than other groups(P < 0.01);Than with the C group,close to the group C,S2 group were significantly higher than that of other groups;And then group A,Group and the rats than in group A,S2 is significantly improved(P< 0.01),S1 and S3 group there was no significant difference between groups(P> 0.05);S1,S2,S3 group than,S2 group significantly higher than the other two groups.(4)Rat hippocampal ERK gene methylation detection: the lowest methylation level in rats of group C,Group A,S3 supreme;S1 group take second place;Compared with group C,S2 group and group C are similar,methylation levels are relatively low,no difference between groups(P> 0.05);And rats than in group A,S2 group rats is significantly lower than that of group A(P < 0.01),S1 and S3 all have different degrees of group A is reduced,no difference between groups(P>0.05);Than to the S1,S2,S3 group,S2 group significantly higher than the other two groups(P < 0.01).(5)Correlation analysis between ERK methylation levels and ERK protein: There was negative correlation between ERK methylation levels and ERK protein(P>0.05).Hint: the higher methylation levels are,the lower ERK protein and mRNA levels are.Conclusions:(1)make aging rats hippocampal neurons of degenerative change in morphological structure,make the ERK high gene methylation,cause the ERK protein and mRNA expression in hippocampus,affect the function of the ERK signaling pathways,and decreased brain function.(2)aerobic exercise as one of exogenous stimulus effect on gene expression of modification.Can make the ERK gene methylation,thus makes the gene protein and mRNA expression level,repair of hippocampal neuron morphological structure,maintain the function of the brain.The ERK aerobic exercise gene methylation,is one of the movement to delay the possible mechanism of brain aging.(3)In different period of aging rats of aerobic exercise intervention,the effect is different.Among them,in the process of aging is the most significant effect of aerobic exercise intervention,suggests that aerobic exercise intervention should be in the process of aging brain aging.