A Preventive Effect of Exercise in a Mouse Model of Essential Tremor

Abstract

The effects of exercise have not been widely studied for potential benefits in essential tremor (ET), while this has been growing for other neurodegenerative disorders. This study examines the effects of two types of exercise [high-intensity interval training (HIIT) and resistance training (RT)] on mice that were subjected to harmaline injections to trigger tremor. We employed a repeated-measures design with three groups: a HIIT group, a RT group, and a sedentary (SED) control group. Each group received an injection before and after the intervention. Tremor kinetics (power within the 8-14 and 14-29 Hz bands) were assessed using accelerometry. Tremor kinematics were also assessed using high-speed video analysis, for validation. As potential signalling molecules from exercise, we also tested for blood lactate and BDNF in each group. Compared to pre-intervention measurements, we found a significant decrease in power within the 8-14 Hz band combined with an increase in the 14-29 Hz band, for the HIIT group, but not in the RT or SED groups. We also found a change in BDNF concentration for the HIIT group. These results suggest that the HIIT protocol may have helped the animal to shift tremor frequency to higher bands, thereby offering functional resistance to harmaline-induced tremor. This study supports high intensity aerobic physical exercise as a potential therapeutic/preventive intervention for ET, with translational implications for human studies.