Effects of voluntary wheeling exercise on the learning and memory and c-fos expression of basolateral amygdaloid nucleus of depression model rats

In order to probe into the effects of 4-week voluntary wheeling exercise on the open field behavior,space learning and memorizing ability,blood serum cortisol and c-fos expression of basolateral amygdaloid nucleus of rats having depression caused by chronic and unpredictable stress,the authors divided 40 rats randomly into 4 groups;a control group,an exercise group,a stress model group and a stress exercise group,each of which included 10 rats,put the rats in the stress model group and stress exercise group under chronic and unpredictable stress once a day for consecutive 28 d,let the rats in the exercise group and stress exercise group do a voluntary wheeling exercise for 4 weeks,measured the level of blood serum cortisol of the rats after the voluntary wheeling exercise was completed,applied the open field experiment to test the automatic movement ability and explorative behavior of the rats,applied the 8-arm radial maze experiment to measure the space learning and memorizing ability of the rats,applied immunohistochemical and image semi-quantitative methods to measure and analyze the number,area and grey level of c-fos neurons of basolateral amygdaloid nucleus,and revealed the following findings;1) as compared with the rats in the stress model group,the rats in the stress exercise group had a significantly increased number of squares crossed,number of times of standing up,number of times of decoration(P0.01,P0.05),and a significantly decreased number of fecal granules(P0.05);2) as compared with the rats in the stress model group,the rats in the stress exercise group had a significantly decreased level of blood serum cortisol(P0.05),a significantly shortened time to complete the 8-arm radial maze(P0.01),significantly reduced WME and RME(P0.05),and a much smaller number of total errors(P0.01);3) as compared with the rats in the stress model group,the rats in the stress exercise group had an increased number of c-fos immune positive cells of basolateral amygdaloid nucleus and an increased level of expression of positive product area(P0.05),and a not significantly different grey level of positive cells(P0.05) although it decreased.The said findings indicated the followings;voluntary wheeling 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 blood serum cortisol of depressive rats and enhances the c-fos expression of basolateral amygdaloid nucleus of their brains.