Effects of Past-Exercise Training on Mood-Related Behaviors and Epigenetic Modification in Mice

Abstract

Regular exercise is effective treatment for the improvement of mental illness. However, the duration of exercise effects and the impact on future mood-related behaviors, such as anxiety and depression, remain unclear. Therefore, we determined the long-term impacts of regular exercise on mood behaviors after cessation of exercise. Moreover, we focused on epigenetics, which is one of the mechanisms for the regulation of gene expression independent of DNA sequences, in hippocampal BDNF as its underlying mechanisms. Anxiety-like behaviors as a mood-related behaviors were measured by Elevated Plus Maze test. After 4 weeks of exercise training, the anxiolytic effects were lasting after 2 weeks of exercise cessation. Meanwhile, after 4 weeks of exercise cessation, anxiety-like behaviors were increased on the contrary. In contrast to our hypothesis, hippocampal Bdnf mRNA and DNA methylation levels were unchanged after 2 and 4 weeks of exercise cessation. These results suggest that the beneficial effects on mood-related behaviors after cessation of exercise are maintained in the short term. However, over a more extended withdrawal period, they can lead to an increase in anxiety.