Dramatic impacts on brain pathology, anxiety, and cognitive function in the knock-in APP mouse model of Alzheimer disease following long-term voluntary exercise.

Background: An active lifestyle is associated with improved cognitive functions in aged people and may prevent or slow down the progression of various neurodegenerative diseases including Alzheimer's disease (AD). To investigate these protective effects, male APP mice were exposed to long-term voluntary exercise.

Methods: Three-month-old AD mice were housed in a cage supplemented with a running wheel for 9 months for long-term exercise. At the age of 12 months, behavioral tests were completed for all groups. After completing behavioral testing, their brains were assessed for amyloid pathology, microgliosis, and cholinergic cells.

Results: The results showed that APP mice allowed to voluntarily exercise showed an improvement in cognitive functions. Furthermore, long-term exercise also improved anxiety in APP mice as assessed by measuring thigmotaxis in the Morris water task. We also found reductions in amyloid load and microgliosis, and a preservation of cholinergic cells in the brain of APP mice allowed to exercise in their home cages. These profound reductions in brain pathology associated with AD are likely responsible for the observed improvement of learning and memory functions following extensive and regular exercise.

Conclusion: These findings suggest the potential of physical exercise to mitigate the cognitive deficits in AD.