Spontaneous and Forced Exercise Promotes Cognitive Function and Expression of GAP-43 and NT-3 in the Hippocampus of Aged Rats

[Purpose] The aim of this study was to investigate differences in cognitive function and expression of GAP-43 and NT-3 on the aged rat hippocampus in spontaneous (wheel running) and forced (treadmill) exercise groups. [Subjects and Methods] 45 male Sprague-Dawley rats (48-week-old aged rats) were randomly divided into 3 groups: namely, the controls (n = 15; CON), voluntary exercise group (n = 15; VE), and forced exercise group (n = 15; FE). Each exercise was applied for five days per week for 8 weeks, and the object recognition and object location tests were conducted in both the control and exercise groups after 8 weeks. In addition, Western blotting and immunohistochemistry were used to evaluate GAP-43 and NT-3 expression. [Results] There was significant improvement in the spontaneous exercise group and more improvement in the forced exercise group in the object location and object recognition tests for evaluation of cognitive function. Moreover, these results were similar to the results in GAP-43 and NT-3 immunohistochemistry in the hippocampus. [Conclusion] The present study suggests that forced exercise is a useful strategy for preventing the loss of cognitive function in the elderly.