Effects Of Different Hypoxic Exposure On Spatial Learning And Memory、Autonomous Exploration And Anxiety Emotions In Rats

ObjectiveThis paper aims to investigate the effect of different hypoxic exposure on spatiallearning and memory, autonomous exploration and anxiety emotions in rats, toprovide the theoretical basis for studying the influence of hypoxic exposure onautonomous exploration, cognitive and emotion of accelerated plateau crowd.Methods805-weeks old male Sprague-Dawley rats (weight is160-180g) were randomlydivided into two groups:11%oxygen concentration group and15%oxygenconcentration group, and each group included control group,4h group,8h group and12h group (n=10). Control group rats lived in normal oxygen concentration (21%O2).And4h group,8h group and12h group rats were placed in hypobaric camber for4h/d,8h/d,12h/d with different oxygen concentrition (11%and15%).And Morris watermaze test, open field test and zero maze test were processed after7days hypoxicexposure. Then detected these indicators as follows:1.Water maze test: The escapelatency, the number of rats crossing the platform and target quadrant time to assess therats’ spatial learning and memory ability.2.Open field test: The distance traveled,crossing, rearing, time spent in the central zone of the arena and grooming to assessthe rats’ ability of sports and autonomous exploration.3.Zero maze test: The numberof entering into the open sections and time spent in the open sections to assess therats’ anxiety emotions.Results(1)Water maze experiment testWith the increase of number of training, the escape latency of all rats graduallyreduced. In the15%oxygen concentration group, the escape latency on the first dayof8h group was significantly longer than that of control group and4h group（P<0.05),but there were no significant difference s in escape latency among groups on thesecond day and third day; at the same time, the target quadrant time of8h groupwassignificantly longer than that of12h group (P<0.010); there were no significantdifferences in the number of rats crossing the platform among groups of all indicatorsamong groups.No significant difference was observed in escape latency,the numberof rats crossing the platform and the target quadrant time in11%oxygenconcentration group.Then we compared the escape latency difference between3days,no significant difference was observed in11%oxygen concentration group, but8hgroup was significantly longer than that of control group in15%oxygenconcentration group.(2) Open field testNo significant differences were found in the distancetraveled,crossing,rearing,time spent in the central zone of the arena and groomingamong groups of11%oxygen concentration group. In15%oxygen concentration group, the distance traveled, crossing and rearing of4h group rats were significantless than control group(P<0.05), and the crossing of12h group rats were significantlyless than control group(P<0.05). In addition, crossing of4h group rats weresignificantly less than8h group (P<0.05). There were no significant differences intime spent in the central zone and grooming among groups of15%oxygenconcentration group.(3)Zero maze testIn11%oxygen concentration group, the number of rats entering into the opensections of8h group were less than control group(P<0.05). In15%oxygenconcentration group, the number of rats entering into the open sections of4h groupwere less than control group(P<0.05), and number of rats entering into the opensections and time spent in the open sections of12h group rats were significantlydecreased compared with control group(P<0.01for time spent in the open sectionsand P<0.05for the others).In addition, time spent in the open sections of12h grouprats were significantly less than8h group (P<0.01).Conclusion1. Intermittent hypoxic expoxure (11%/15%oxygen concentration,4/8/12h/d,7d)hasno effect on the spatial learning and memory in rat.2. Intermittent hypoxic expoxure (11%oxygen concentration,4/8/12h/d,7d)has noeffect on the autonomous exploration in rat;15%oxygen concentration,7d,4/12h/dintermittent hypoxic expoxure reduce rats’ autonomous exploration.3.11%oxygen concentration,7d,8h/d and15%oxygen concentration,7d,4/12h/dintermittent hypoxic expoxure increase anxiety.