Effects Of Swimming Training On The Ability Of Learning And Memory And The Gen Of Expression Of APP And NR1 In Hippocampus For Ovariotomy Rats

Learning and memory are the advanced activities of brain.Hippocampus plays an important role in spatial learning and memorizing.The injury of hippocampus will influence the ability of spatial learning and memorizing.Studies show that core subunit NR1 is the necessary part of NR1/NR2 complex which is the basic unit for NMDA function.NR1 plays an important role in the novel object recognition task and the spatial learning and memorizing.Lack of estrogen weakens the ability of spatial learning and memorizing and decreased NR1 expression.Lack of estrogen is the important reason causes degenerative disease in menopause women.Clinical observation and restrospective study find lack of estrogen causeβ-amyloid denaturation which is the main reason of AD disease.Recently,studies about developing body show moderate voluntary activity may promote the ability of spatial learning and memorizing and are helpful for brain neuron proliferation,survival and differentiation as well as related protein expression which are associated with the decreased risk of degenerative diseases.Studies show that there is cross talk between exercise and estrogen in brain domain.The current study designed to probe the effects of 8 weeks weightless swimming training on the ability in novel object recognition task and Y maze learning as well as the gene expression of APP and NR1 in Hippocampus for bilateral ovariotomy rats.38 female rats were included in this study and were divided into 4 groups,which included sham-operation group(SH-CT,n=9),sham-operation and exercise group (SH-EX,n=9),ovariotomy group(OVX-CT,n=10)and ovaritomy and exercise group (OVX-EX,n=10).SH-EX and OVX-EX groups did 8 weeks weightless swimming while SH-CT and OVX-CT were exposed to water stimulations the same times.In the sixth week,all the rats did the novel object recognition task and in the seventh and eighth week Y maze learning test and memory test respectively.24 hours after the last time exercise,all rats were killed and hippocampus were saved for testing APP and NR1 mRNA expression through RT-PCR method. Results:1.Neither swimming training nor lack of estrogen leaded to significant change in the novel object recognition task(p＞0.05).Lack of estrogen weakened the ability to learn and memorize and swimming training prevent the cognitive disorder to some extent.2.Lack of estrogen decreased the mRNA expression of APP and NR1,but swimming training increased them.Conclusion:Normal level of estrogen was very important for spatial learning and memorizing which were associated with NR1 and APP mRNA expression decrease.However, exercise,as a kind of exogenous stimulation to the body,can prevent the cognitive disorder caused by lack of estrogen.