| Background and Objective:Learning and memory is one of the mainly nerve functions in the brain,which is the result of different neuronal cells associated closely.Therefore,maintaining brain cell health and plasticity throughout life are prerequisite to learning and memory capacity.In the brain function districts,the hippocampus is the classic region for cognitive and movement functions in humans and animals.Studies have been reported the rat cognitive dysfunction may be related to the neruons apoptosis in hippocampus. More and more,the results have been shown,Long-term regular physical exercise contributes to learning and memory capacity.Research also shows that apoptosis premature in the brain can trigger brain atrophy,Alzheimer's,Parkinson's etc,thus affecting learning and memory capacity.Bcl-2 and Bax is apair of important gene in the regulation of apoptosis,Bcl-2,also known as "survival gene",the level of expression is positively correlated to cell life.While the Bax is the pro-apoptotic gene, which expression can lead to cell release for certain elements,caused cysteine protease activation and antagonist Bcl-2 of the protective effect,inducing cell apoptosis,or by the start of mitochondrial permeability transition tending apoptosis. Other research have been shown that over the games caused apoptosis in rat hippocampus,but there were very few people who would be movement,the brain cell apoptosis and learning and memory linked to research.This study is analysis of the relationship to learning and memory capacity,apoptosis and Bcl-2 and Bax expression under the different long-term pattern of swimming exercise.Materials & methods:The elected 25 Spargue-Dawley rats were randomly divided into three groups:(1) The Control group,(C,n=7),conventional farming,adaptive swimming once a week,none other interventions.(2)The Moderate intensity swimming group(MS, n=8),moderate-intensity swimming training,the swimming pool is 100 cm×70cm×60cm rectangular,50 cm depth,water temperature 33±1℃.Rats training is five days a week,once a day;in the first day,swimming 10 min,after increasing daily,at the first weekend for 30 min,at the second weekend for 60 min,then maintenaning of the exercise until the weekend 8th.(3)The Overload group,(0,n=10),the first two weeks training arrangements are same as the MS group,but at 3th weekend,the swimming for 120 Min.While in the 4th week,beginning of high-intensity training: carrying the heavy weight of 1%for 120 min daily training.In the 5th week,negative the weight to body 3%,swimming 120 min a day.In the six week,keeping 3%of the load every day,morning and afternoon training,every time exercise 120 min.The rat were removed 10 min having a rest if he performanced exhaustance(Don't float under the water 10s),then continue the exercise for 120 min.In the 7thand 8thweeks, maintaining 2%load,the rats repeated exhaustive training 2 times daily,two spare is 30 min interval,training intensity program until the end of the test.Three groups of rats participate in the learning test of Y maze at the beginning of the 7thweek,and getting the standard,three days later,the rats of all groups participate in the memory test of Y maze.After the last training 24h,killing the samples,PI-staining test apoptosis in Flow cytometry,RT-PCR detection of Bcl-2,Bax mRNA expression level.The results:1.Compare with body weight in three groups of rats:After eight weeks of different modes of swimming training found that the MS group's wight changes modest(39.94±2.51)%,excessive exercise group O's weighe changes minimal (26.51±8.93)%and the control group C' is the greatest changes(59.05±17.68)%.2.Compare with learning ability:the number of the MS group institute for the standard is least(32.63±9.47),and the Group O's number is the highest(64.00±6.75).The group C's is between with the two groups(53.86±11.70).The number of mistakes institute standard in the frequency of the learning,the O group is the highest number of errors(34.29±5.71);the MS group is the least number of errors(17.50±7.01),the group C is between with the other two groups(28.29±4.68).3.20 times of memory capacity in the course of testing,MS group has the least number of errors(2.50±2.51),and the mistakes in the group O is the highest number(7.14±0.69),the group C is between with the other two groups(5.43±1.40). 4.Comparison of apoptosis in three groups of rats:the Group O has apoptosis significantly phenomenon(22.80±0.71)%,and in the group C(6.92±0.54)%and the MS group(6.73±0.53)%,apoptosis phenomenon occurre rarely.5.After eight weeks of the different modes of swimming training,in the suitable exercise group,the expression of Bcl-2 is significantly increased phenomenon(1.44±0.09),and in the group C(1.13±0.07)and the group O(0.77±0.02)have little increase.But the Bax expression level is the largest in the group O(2.06±0.02),in Group C(1.09±0.04)and the Group MS(1.07±0.02)expression have rarely.Conclusion:1.Excessive training could affect weight gain in rats.2.Long-term regular suitable for swimming exercise can promote rats spatial learning and memory capacity,and the excessive swimming training produce a certain obstacles on learning and memory ability in rats.3.Long-term over the swimming training cause the rat cells to apoptosis in the hippocampal neurons,and in appropriate training group and the control group don't find cell apoptosis.4.The long-term suitable swimming can leads to more the expression of Bcl-2 and conducive to the survival of nerve cells in the hippocampus,but excessive swimming training to increase the expression of Bax,caused the hippocampal cells to apoptosis. |
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