Different Exercise Load For A Long Time To Learning And Memory Ability And The Hippocampus Of Rats St8sia Ⅳ Expression

Objective:The experiment through establishing long-termdifferent exercise load of swimming model of SD rats, explores effects onlearning-memory of rats and on expressions of ST8SiaⅣ in rat’s hippocampal.Methods:The48SD rats are randomly divided into three groups including controlgroup （C,n=16）, moderate load exercise group （M, n=16）, over load exercisegroup （O, n=20）. Then the group C is randomly divided into group C₁and C₂,thatis quiet and biochemical group and quiet watermaze biochemical group. M group israndomly divided into group M₁and M₂, that is biochemical group of moderate loadand moderate load water maze biochemical group. O group is randomly dividedinto group O₁and O₂, that is biochemical group of overload and overload watermaze biochemical group. Group C do not exercise, the group M and O of rats start thedifferent load swimming training for7weeks. C₁, M₁, O₁groups of the rats with notbeing trained by the water maze,after the last training instantly are put to death. C₂, M₂,O₂groups of the rats with the water maze groups, after the10days’ water mazeare drawn.The mode is the same water maze group.We test the effects of swimmingtraining on learning and memory by Morris Water Maze, and inspect the ST8Sia IVexpression in hippocampus by the method of HE staining,immunohisto chemistry,real-time PCR and Western Blotting.Results:1. The water maze behavioral test results:The latency period of time is shortened with the extension of training time. There is nosignificant difference with the daily horizontal contrast. The first day of each group issignificantly higher than nine days （P <0.01）; C₂, M₂, O₂group in the first five days,four days, three days get into the stabilization period, the latency period of time is nolonger reduced. The first quadrant of the percentage of time each group graduallyincrease with the extension of training time. Each group of the first two days, thepercentage of time of the first quadrant is very significantly increased, the fifth day ofeach group to reach a steady state. The moderate load exercise group with the number ofcrossing the platform is higher than the other two groups, but the difference is notsignificant.2.HE staining results: The control group and moderate load exercise group ofrat hippocampal neurons arrang in neat rows, complete form, intercellular substancewith uniform and dense, and no abnormal change; Over load of hippocampal neuronsarrang in disorder, a part of the cells dyeing is deep and cells interstitial loose.3.Immunohistochemistry of results:In CA1and CA3of the hippocampus region neurons,ST8SiaIV positive expression of M₁group is significantly higher than C1and O1group （p<0.01）; ST8SiaIV positive expression of M₂and O₂group is significantlyhigher than C₂group （P <0.01）; ST8SiaIV positive expression of O₂group is higher than M₂group （P <0.05）.4Real-time PCR results: Compared with group C₁, geneexpression of M₁and O₁group are higher than C₁group, but the difference is notsignificant; Compared with the group M₁, gene expression of O1group lower than M₁group, but the difference is not significant. Compared with group C₂, gene expression ofM₂group is higher than C₂group （P <0.05）; Gene expression of O₂group is higher thanthe C₂group, but the difference is not significant; Compared with the M₂group, Geneexpression of O₂group lower than the M₂group, but the difference is notsignificant.5.Western blotting results:Compared with group C1, protein expression of O₁group is significantly higher than C1group （P <0.05）; Compared with the groupM₁,protein expression of O1group is significantly higher than M₁group （P <0.05）.Compared with C₂groups, protein expression of M₂group is significantly higherthan C₂group （P <0.05）; Protein expression of O₂group is significantly higher than C₂group （P <0.01）. Conclusion:1. The formation of spatial memory of Exercise groups isfaster than the control group.2.A long-term moderate exercise can protect of themicro-structureof the rat hippocampus and improve abilities of learning andmemory; Over loadexercise can cause hippocampal formation damage, which has anegative impact on learning.3. A long-term moderate exercise can increase expressionof ST8Sia Ⅳ. The possible mechanism is due to the increase of ST8SiaⅣ expression,and promote expression of PSA-NCAM and hippocampal neurons to establishsynaptic contacts, thus promoting learning and memory. Long-term over load exercisecan increase expression of ST8SiaⅣ.And the possible mechanism is due to theincrease of ST8SiaⅣ expression,and can promote expression of PSA-NCAM andhippocampal neurons to establish synaptic contacts to repair the neuronal damage of therat.