Effects of different exercise modes and intensities on cognitive performance, adult hippocampal neurogenesis, and synaptic plasticity in mice.

ABSTRACT

Exercise can induce beneficial improvements in cognition. However, the effects of different modes and intensities of exercise have yet to be explored in detail. This study aimed to identify the effects of different exercise modes (aerobic and resistance) and intensities (low and high) on cognitive performance, adult hippocampal neurogenesis and synaptic plasticity in mice. A total of 40 C57BL/6J mice were randomised into 5 groups (n = 8 mice per group) control, low-intensity aerobic exercise, high-intensity aerobic exercise, low-intensity resistance exercise, and high-intensity resistance exercise. The aerobic exercise groups underwent treadmill training, while the resistance exercise groups underwent ladder climbing training. At the end of the exercise period, cognitive performance was assessed by the Y-maze and Barnes maze. In addition, adult hippocampal neurogenesis was evaluated immunohistochemically by 5-bromo-2'-deoxyuridine (BrdU)/ neuronal nuclei (NeuN) co-labeling. The levels of synaptic plasticity-related proteins in the hippocampus, including synaptophysin (SYP) and postsynaptic density protein 95 (PSD-95), were analyzed by western blotting. Our results showed no significant differences in cognitive performance among the groups. However, high-intensity aerobic exercise significantly increased hippocampal adult neurogenesis relative to the control. A trend towards increased adult neurogenesis was observed in the low-intensity aerobic group compared to the control group. No significant changes in synaptic plasticity were observed among all groups. Our results indicate that high-intensity aerobic exercise may be the most potent stimulator of adult hippocampal neurogenesis.