Effects of Treadmill Exercise on the Learning and Memory of Depressed Rats and Their BDNF Expression within Hippocampus CA1

Objetive: To explore the effects of a 4- week treadmill exercise on depressed rats' learning and memory and blood plasma cort content,and their BDNF expression within Hippocampus CA1. The depression was induced by Chronic Unpredictable Stress(CUMS). Methods:30 male SD rats were randomly allocated to 3 groups,control group(C), stress model group(SM) and stress exercise group(SE). All rats except those of Group C were exposed to a chronic unpredictable stress(CUMS). The learning and memory ability of the rats were tested with an eight-arm radial maze test,the cort content was tested by radioimmunoassay and BDNF expression within Hippocampus CA1 was detected and analysised by using ABC immunohistochemical technique and semiquan-titative. Results:Compared with Group C,the blood plasma cort content increased in the SM group,the time for completing 8- arms radial maze shortened and WME(working memory error),RME(reference memory error) and TE(total memory error) significantly increased in eight-arm radial maze test,BDNF expression within Hippocampus CA1 decreased in the SM group rats compared with Group C. The results showed that treadmill exercise significantly improved learning and memory of the depressed rats,that the blood plasma cort content decreased and that BDNF expression enhanced within Hippocampus CA1 in the SE group rats. Conclusion:The treadmill exercise may enhance the learning and memory ability of depressed rats,the mechanism of which might be that treadmill exercise decreases the blood plasma cort content,overactive HPA axis antagonism and reduces the BDNF expression within Hippocampus CA1.