Effect of high-intensity interval or continuous moderate exercise on cognition in a mouse model of mild cognitive impairment

Mild cognitive impairment (MCI) is a common prodromal condition of Alzheimer’s disease (AD), and exercise is a promising non-drug intervention. This study compared the effects of moderate-intensity continuous training (MICT) and high-intensity interval training (HIIT) on cognitive function in senescence-accelerated mouse prone 8 (SAMP8) mice with MCI, examining hippocampal synaptic plasticity mechanisms. Thirty 4-month-old male SAMP8 mice were randomly assigned to control, MICT, and HIIT groups (n=10).

Ten age-matched senescence-accelerated mouse resistant 1 (SAMR1) mice served as normal controls. The MICT and HIIT groups completed 8 weeks of treadmill exercise, while controls received only adaptive training. Novel object recognition (NOR) and Morris water maze (MWM) tests evaluated recognition and spatial memory.

Immunohistochemistry (IHC) and Western blotting were used to measure hippocampal synaptic markers (Postsynaptic density protein-95 (PSD95) and synaptophysin (SYN)). Results showed the control group had decreased discrimination indices and longer MWM escape latency, along with reduced hippocampal PSD95 and SYN expression. Both exercise groups demonstrated significant cognitive improvements and increased expression of synaptic markers, with HIIT outperforming MICT.

These findings suggest that both exercise protocols enhance cognitive function in MCI mice, with HIIT being more effective, associated with upregulation of hippocampal PSD95 and SYN, suggesting a potential role of enhanced synaptic plasticity. This supports exercise as a non-pharmacological strategy for MCI. This work was funded by Tianjin Key Medical Discipline Construction Project (Grant No.

Department of Neurology, Tianjin Huanhu Hospital, Tianjin Key Laboratory of Cerebral Vascular and Neurodegenerative Diseases, Tianjin, 300350, P.R. China Tianjin Huanhu Hospital Affiliated to Tianjin Medical University, Tianjin, P.R. China The authors declare that there are no competing interests associated with this work.

Animal experiments were conducted following a protocol approved by the Animal Ethics Committee of Tianjin Huanhu Hospital. All experiments were performed in accordance with relevant guidelines and regulations. Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.