| Objective:Attack is a kind of biocompatible behavior that is important for the acquisition of resources and the establishment of hierarchical concepts in the territory.However,in animal and human clinical studies,it is shown that the attacking is a destructive act,which could harm others' mental or physical condition and destroy other goals.The neural loop that regulates the attack behavior is very complex and is similar to the loop that controls the mood of the animal,including the edge system,the temporal lobe,the frontal lobe,the thalamus,and so on.Any functional abnormality of these brain structures can lead to the generation of attacking behavior and the decline of learning and memory capacity.BDNF is an important factor in central nervous system development,neural plasticity and in vivo homeostasis,which protects hippocampal neurons and improves brain function.Some scholars confirmed brain BDNF levels can lead to depression and aggression,lower BDNF can increase the hippocampal neurons of harmful stress sensitivity,indirect cause nerve toxicity,lead to hippocampal neuronal atrophy or death,of learning and memory and cognitive function also caused certain negative influence,through drug means to enhance the level of brain BDNF may produce antidepressant effect,of learning and memory and cognitive function also is greatly improved.In recent years,as an intervention movement can alleviate the attacks caused by stress behavior,improve bad mood,improve learning and memory ability,and has become a respected way of intervention to improve learning.In this study,we investigated the effects of exercise on the improvement of learning and memory ability,the effects of BDNF,TrkB and CREB protein expression on the expression of BDNF/TrkB/CREB/BDNF this loop to control.Methods:A total of 24 male Sprague-Dawley(SD)male healthy rats weighing about 190 g-220 g were used as the experimental animals.The animals were given the Animal Experimental Center of Xi'an Jiaotong University School of Medicine.After one week of adaptive feeding,the rats were randomly divided into four groups:Group A is the contrast to the quiet group,Group B is the group to single cage feeding,Group C is the group to single cage feeding swimming,Group D is the group to the invading.The indicators and methods of detection include the following:1.The detection of rats'weight;2.The detection of rats' behaviors:(1)Open field experiment:the total distance,the central activity time,the number of standing,the number of urination;(2)Morris water maze experiment:total distance,latency,the percentage of the distance of the station's quadrant in the total distance,the percentage of the time of the station's quadrant in the total time;(3)The attacking test experiment:attack latency,the number of attacks.3.The detection of biochemical index:ELISA was used to detect the content of peripheral serum BDNF;Western Blot detected the expression of BDNF protein in rats' central hippocampus,the expression of TrkB protein and the expression of CREB protein.Result:1.The results of body weight showed that the change rate of body weight in rats showed a different degree of growth over time,but the attack behavior and swimming training will make the weight gain rate of rats decreased.2.The results of the open field showed that there were no significant differences in the total distance,the time of central activity,the number of standing and the number of urine urination in the rats after the end of the adaptive week.After modeling,compared with the quiet group,the total distance of the attacking model group reduced by 62.32%(P<0.01),the time of central activity reduced by 63.60%(P<0.01),and the number of standing reduced by 47.46%(P<0.01).The total distance of the exercising model group reduced by 56.16%(P<0.01),the time of central activity reduced by 58.16%(P<0.01),and the number of standing reduced by 42.43%(P<0.01).After four weeks' swimming training,compared with the quiet group,the total distance of thr attacking model group reduced by 47.79%(P<0.01),the time of central activity reduced by 56.85%(P<0.01),and the number of standing reduced by 61.57%(P<0.01).The total distance,the time of central activity,the number of stading of the exercising model group also relatively reduced,nevertheless the trend was obviously smaller,the total distance reduced by 38.08%(P<0.05),the time of central activity reduced by 18.49%(P<0.05),and the number of standing reduced by30.78%(P<0.05).Compare with the attacking model group,the exercising model group had an obvious increase in index after four weeks' swimming training.The time of central activity increased by 47.06%(P<0.05),the number of standing increased by 44.48%(P<0.05).In the whole period of the experiment,there were no significant differences in the number of urination.3.The results of the attack test showed that there were no significant differences in the attacking latency and the number of attacks in the attacking model group before and after the test,compared with that before the test,the attacking latency increased 33.57%(P<0.01)and the number of attacks reduced by 36.11%(P<0.01).Compared with the attacking model group,there were significant changes in the attacking latency and the number of attacks for the exercising model group.4.The results of Morris water maze experoment showed that in thepositioning experiment after modeling,the total distance and the latency of the rats in each group gradually decreased over the learning days.Compared with the quiet group,the latencies of the attacking model group and exercising model group pbviously lengthened(P<0.05).In the space exploration experiment after modeling,the number of crossings of the attacking model group reduced by 80.47%compared with the quiet group,and the number of crossings of the exercising model group reduced by72.47%.Apart from that,there were no differences in the other three indexes.In the positioning space experiment after exercise,since the first time there had been apparent differences in the total distance between the exercising model group and the quiet group(P<0.05),but in the period from the second day to the fourth day of the learning test,there had not been apparent differences between the exercising model group and quiet group.However,compared with the total distance of the attacking model group,that of the exercising model group had apparent differences(P<0.05).There were apparent differences(P<0.05)and extremely apparent differences(P<0.01)in the latency between the exercising model group and the quiet group.In the four days' learning test,the learning ability of the attacking model group was the worst.Its latency reduced by 18.74%compared with the quiet group,and reduced by 63.09%compared with the exercising model group,compared with exercising model group had extremely apparent differences(P<0.01).In the space exploration experiment after exercising,there were no apparent differences in the total distance among all the groups of rats.The number of crossings of the rats in the attacking model group reduced by 71.43%(P<0.01)compared with the quiet group,and reduced by 64.03%(P<0.05)compared with the exercising model group.For the attacking group,the percentage of the station's quadrant time in the total time reduced by 35.31%(P<0.05)compared with the quiet group and reduced by 42.57%(P<0.01)compared with the exercising model group.For the attacking group,the percentage of the atation's quadrant distance in the total distance reduced by 40.81%(P<0.05)compared with the quiet group,and reduced by 36.83%(P<0.05)compared with the exercising model group.5.The results of ELISA showed that for the attacking model group,the rats' content of peripheral serum BDNF reduced by 26.55%(P<0.05)compared with the quiet group.For the exercising model group,the rats' content of peripheral serum BDNF increased by 14.38%.For the exercising model group,the peripheral serum BDNF increased by 37.11%(P<0.01)compared with the attacking model group.6.The result of Western Blot's experiment showed that after four weeks'swimming training,for the exercising model group,The content of hippocampus BDNF,TrkB and CREB protein expression all improved compared with the quiet group.There were obvious differences in the content of BDNF and TrkB protein expression in the attacking model group(P<0.05)and there were extremely obvious differences in the cotent of CREB protein expression(P<0.01).Compared with the attacking model group,for the exercising model group there were extremely obvious differences in the content of BDNF,TrkB and CREB protein expression.7.According to the Pearson analyses betweenBDNF,TrkB,CREB and the number of the attacks showed that there were significant negative correlation(r=-0.697,p=0.012;r=-0.682,p=0.014;r=-0.638,p=0.026).There was a significant positive correlation between BDNF,CREB and learning and memory(r=0.605,p=0.037;r=0.601,p=0.039).There were significant positive correlations between BDNF and TrkB,TrkB and CREB(r=0.832,p=0.006;r=0.908,p=0.001),there was a significant positive correlati-on between BDNF and CREB(r=0.738,p=0.23).Conclusion:1.The swimming training can improve the attack model of rats'explorative excitement in the surrounding environment,eliminating the fear and depression caused by the attacking mood and behavior.2.The single cage feeding with the stimulus of invasion made rats' learning ability and memory ability decrease.The swimming training can improve the learning and memory abilities of the rats with attacking behaviors.3.The swimming training can significantly prolong the latency of attack model of rats'attacks behavior,reduce the number of rats' attacks,and ease rats'attacking mood and behavior.4.Rats' central hippocampus BDNF,TrkB and CREB protein expression were negatively corrlated with their attacking behaviors and were positively correlated with their learning ability.The swimming training can effectively improve rats' central hippocampus BDNF,TrkB and CREB protein expression level,that exercise ease attacking behaviors and improve learning ability and memory ability was achieved by the loop of BDNF/TrkB/CREB/BDNF. |
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