Effects of Treadmill Exercise on the Behavior and NGF Expression in the CA1 and CA3 Zone of Hippocampus of Chronically Depressive Rats

Objetive:To explore the effects of the 4-week treadmill exercise on the behavior,the blood plasma ACTH and CORT content and NGF expression in the CA1 and CA3of hippocampus in the depressive rats induced by Chronic Unpredictable Stress(CUS).Methods:30male SD rats are randomly allocated to control group(C),stress model group(SM)and stress exercise group(SE).The model of chronic unpredictable stress for all rats is established and rats from control group are given 4-week treadmill exercise at the same time.The behavioral changes are conducted by open field test(OFT),tail suspension test(TST);then all rats are submitted to behavioral testing for spatial memory by the eight-radial arm maze test,blood plasma ACTH and CORT contents are tested by radioimmunoassay;applied immunohistochemical and image semi-quantitative methods to measure and analyze the number,area of NGF neurons of CA1 and CA3zone of Hippocampus are detected and analyzed by using immuneohistochemical method and semiquantitative.Results:1)as compared with the rats in the stress model group,the rats in the stress exercise group have a significantly increased number of squares crossed,number of times of standing up,number of times of decoration(P0.01,P0.05,P0.05),and a significantly decreased time in the central cell residence and immobility(P0.05,P0.05);2)as compared with the rats in the stress model group,a significantly shortened time to complete the 8-arm radial maze(P0.05),significantly reduced REM and TE(P0.05,P0.05);3)as compared with the rats in the stress model group,the rats in the stress exercise group have a significantly decreased level of the blood plasma ACTH and CORT content(P0.05,P0.01);and 4)as compared with the rats in the stress model group,the rats in the stress exercise group have a significantly increased number of NGF immune positive cells of CA1 and CA3zone of hippocampus(P0.05,P0.05,P0.05,P0.05).Conclusions:treadmill exercise can enhance the learning and memorizing ability of depressive rats;its mechanism may be related to that long-term voluntary wheeling exercise decreases the level of plasma ACTH and CORT content and overactive HPA axis antagonism,strengthen the brain antioxidant ability and enhance the NGF expression within hippocampus CA1 and CA3.