Effects Of Different Load Exercise On Senescence Of Brain And Memory In Rats

Background:The improvement of life quality means the keeping of good life quality when one comes to the agedness. And the healthy brain and good learning memory are the one of key factors for keeping the good life quality.When the brain grows into maturity, it would be aging and affect the memory ability.Although thoery about free radical injury had been mentioned in the research of exercises and senescence, we still need to make a further study for a proper conclusion about the effect of exercises on senescence.Objective: To promote the study of relationship between exercises and healthy brain,this thesis proposed the thoery and means about how to delay the brain senescence in morphology, biochemistry index, and behaviour function.Methods:Based on the subacute aging model , this experiment would demonstrate the effect on senescence in rats and memory caused by loaded exercises in different degree.The 32 3-month-old male rats of clean grade in this experiment were divided into 4 groups at random,8 in each group. Sedate group of adult rats(group C): no supply and exercise intervention, keeping routine activity. Sedate group of elderly rats(model,M): subcutaneous injection with D-galactose, no supply and exercise intervention, keeping routine activity. Group of elderly rats with small loaded exercises(model,S): subcutaneous injection with D-galactose, small loaded exercises on the treadmill.Group of elderly rats with big loaded exercises(model,B): subcutaneous injection with D-galactose, big loaded exercises on the treadmill.Load intensity is the percentage of the heaviest load, the big load refers to 70% of the heaviest and the small load 30% of the heaviest.The experiment would last 6 weeks, each week the biggest load of rats would be measured and load in the exercise would be adjusted accordingly.Motionon the treadmill scheme design based on Bedford's and Yanwanjun's experimental methods: that velocity15m/min, slope degree0,running 2min,rest 2min for 6groups, each of which exercises in successiononce a day for 6 weeks without weekends.After 4 weeks,learning memory of rats in eight-arm maze task would be measured. At the end of the sixth week, the contents of MDA and the activities of SOD and GSH-Px and LPO collected from cerebral cortex and hippocamps of rats would be measured with the biochemistry method.Ultrastructures of tissues were observed with electron microscope.Results:1.change in morphology :cristae on cerebral Mitochondria partly solvated with membrane;granules and degranulations on rough endoplasmic reticulum dissolved ; part of nuclear membrane became irregular in the shape. The amount of hippocampus organelles and chromatin lessened, cytoplasm and mitochondria edema.Cerebra nucleus of group S's rats are ellipse, and they have rich cytoplasm and less heterochromatin.2.In eight-arm maze task,the error times are increasing orderly from Group C ,Group S and Group M.The error times is greater for rats in Group M than those in Group C and rats in Group S and Group B can seek food correctly than those in Group M in unit time.3.Compared with rats in Group C, the amount of MDA and LPO in cerebral cortex and hippocampus of those in Group M is increasing but the activity of SOD and GSH-Px is decreasing.Compared with Group M, the activity of SOD and GSH-Px for rats in Group S is increasing, while the amount of MDA in cerebral cortex and hippocampus is decreasing.Conelusion:1.Within a certain time, cerebral cortex and hippocampus of rats appear senescence characteristics such as irregular nucleus, nuclear apoptosis and so on, which shows subacute aging model can become brain senescence model.2. Treadmill exercises in 6 weeks has a better effect on improving the learning ability of rats than small load exercises.3. Treadmill exercises in 6 weeks can stimulate the activity of SOD,GSH-Px and reduce the amount of MDA,LPO in rats' cerebral cortex and hippocampus effectively,delaying the procession of senescence of central nervous system and strengthening the learning memory ability, which shows proper exercises can improve antioxidant capacity of organism and restrain lipid peroxidation.