Effect of low-intensity motor balance and coordination exercise on cognitive functions, hippocampal Aβ deposition, neuronal loss, neuroinflammation, and oxidative stress in a mouse model of Alzheimer's disease

Abstract

It is well known that physical exercise reduces the risk of Alzheimer's disease (AD) and age-related cognitive decline. However, its mechanisms are still not fully understood. This study aimed to investigate the effect of aging and rotarod exercise (Ex) on cognitive function and AD pathogenesis in the hippocampus using senescence-accelerated mice prone 8 (SAMP8). Cognitive functions clearly declined at 9-months of age. Amyloid-beta (Aβ) deposition, neuronal loss, and glia activation-induced neuroinflammation increased with aging. The rotarod Ex prevented the decline of cognitive functions corresponding to the suppression of Aβ deposition, neuroinflammation, neuronal loss, inducible nitric oxide synthase (NOS) activities, and neuronal NOS activities. In addition, the rotarod Ex suppressed proinflammatory M1 phenotype microglia and A1 phenotype astrocytes. Our findings suggest that low-intensity motor balance and coordination exercise prevented age-related cognitive decline in the early stage of AD progression, possibly through the suppression of hippocampal Aβ deposition, neuronal loss, oxidative stress, and neuroinflammation, including reduced M1 and A1 phenotypes microglia and astrocytes.

Keywords: A1 phenotype astrocyte; M1 phenotype microglia; Neuroinflammation; Nitric oxide synthase activity; Rotarod exercise; SAMP8.