Effects Of Hypoxic Training On Learning And Memory And The Number Of Newborn Cells In Hippocampal Dentate Gyrus Of Rats

Objective:The brain is highly sensitive to hypoxia, some degree of hypoxia would be the body of the system, organ, tissue and cell physiology, biochemistry and even a certain impact on the structure. Experiments have proved that hypoxic preconditioning on the brain with a compensatory protective effect. The experimental animal models to be adopted to male SD rats as experimental, the use of factors of hypoxia and exercise as an intervention, set different oxygen concentrations of hypoxic training on spatial learning and memory and hippocampal dentate gyrus The number of new cells, for the coaches to develop a reasonable, efficient, safe hypoxic training programs and provide experimental evidence for brain health.Methods:1. Subjects and Training:60 male Sprague-Dawley rats of 7 weeks, which average weight is (266.72±14.38) g. After three days adaptive feeding training, all the rats were divided randomlt into 6 large groups:control group(C), regular aerobic exercise group(E),15% oxygen concentration control group(15C),15% oxygen concentration exercise group(15E), 11% oxygen concentration control group(11C) and 11% oxygen concentration exercise group(11E)(n=10). Animal in exercise group daily exercised on treadmill for 30min once a day and the speed was 12m/min.15C and 11C were placed in the hypoxic room of 15% and 11% oxygen concentration 2h every day.15E and 11E were placed in the hypoxic room of 15%and 11% oxygen concentration 2h every day, the first 30min was treadmill exercise and placed in the hypoxic room 1.5h after exercise. After 7 days hypoxic training, Morris Water Maze test was processed.120 male Sprague-Dawley rats were used for cell morphology study, all the rats were divided randomlt into two groups(7 days group and 21 days group)(n=10).Then this two groups divided the same groups as before and the training is the same too. After 7 days hypoxic training, derived material from 7 days group animal. After 15 days, derived the same material from 21 days group animal. At the third day hypoxic training, all experimental animals should have had intraperitoneal injection of BrdU (50mg/kg). This injection should be performed ahead of 1h before the daily treadmill exercise and lasted for 5 days. When the sports programs were finished, all rats are anaesthetized, then perfused with normal saline and washed them with many POM for fixed them. At last, the followed task is taking brain tissue, making frozen sections for immunofluorescence staining, counting immunopositive dentate gyrus cells number by microscope.2.Behavioral study:The Morris water maze test was used to observe learning and memory behavior in rats of both groups.3.Morphological studies:The main chemical used immunofluorescence experiments, rat hippocampal dentate gyrus of the number of new cells for quantitative analysis.Results:1. Hypoxic exposure on spatial learning and memory ability1.1 hypoxic exposure on the impact of latency Place navigation test, the rats to find hidden underwater platform, the time reflects the ability of spatial learning in rats. Three groups of rats trained to find the latency with the increase in the number showed a decreasing trend, and the second,third day training of the incubation period compared with the first day of incubation there were significant differences (P<0.05). Training the next day, compared with C,11C and 15C groups were significantly lower than the latency group C group (P<0.05), in which the shortest latency of rats 15C.1.2 hypoxic exposure on the number of cross-platform Test conducting space exploration, it will remove the existing platform, the rats through the original platform location reflects the number of spatial memory in rats. Experiments in space exploration, compared with C,11C and 15C group rats were greater than the number of cross-platform C, in which the number of cross platform 15C group was significantly higher than C group (P<0.05).2. Hypoxic exercise on spatial learning and memory ability2.1 hypoxic exercise on the impact of latency In the second day of training,11E and 15E groups were higher than the latency group E group, the latency of them 11E group were significantly higher than E group (P <0.05).2.2 hypoxic exercise on the number of cross-platform Space exploration test, 11E and 15E groups rats were greater than the number of cross-platform E group, which cross-platform 15E group were significantly higher than the number of E group (P<0.05).3. Hypoxic exposure on the hippocampal dentate gyrus of newborn cells Immunofluorescence staining showed that 7 days 15C group and 7 days of 11C group dentate gyrus BrdU immunoreactive cells were more than 7 days C group, but not statistically significant (P> 0.05), of which 7 days 11C group, hippocampal dentate gyrus the largest number of BrdU positive cells. Interval of 15 days, the survival rate of newborn cells were:C group 61.47%,11C group 58.5%,15C group 67.65%.4. Hypoxic exercise on hippocampal dentate gyrus of newborn cells Immunofluorescence staining showed that 7 days 15E group and 7 days 11E group immune dentate gyrus BrdU-positive cells were less than 7 days E group, but not statistically significant (P> 0.05), of which 7 days 11E group, the hippocampal dentate gyrus the least number of BrdU positive cells. Interval of 15 days, the survival rate of newborn cells were:E Group 64.15%,11E group 70%,15E group 62.05%. Conclusions:1. Hypoxic stimulus can improve spatial learning and memory in rats, of which 15% of the oxygen concentration in the stimulus can be more significantly improved spatial learning and memory in rats capabilities.2. Hypoxic and exercise the dual stimulation, the spatial learning ability of rats to inhibit the role, while the lower oxygen concentration, the greater inhibition; However, for spatial memory in rats with a catalytic role, of which 15% oxygen concentration double stimulation and exercise to improve more obvious spatial memory in rats.3. Hypoxic stimulation of rat hippocampal dentate gyrus of the occurrence of new cells, of which 11% oxygen concentration in hypoxia, the effect is more obvious, but not conducive to the survival of new cells.4. Hypoxia and exercise stimulate the inhibition of the double dentate gyrus in rats the incidence of new cells, while the lower oxygen concentration, the greater the inhibition, but is conducive to the survival of newborn cells.