Treadmill exercise slows cognitive deficits in aging rats by antioxidation and inhibition of amyloid production

Chronic administration of D-galactose simulates the changes in natural senescence and accelerates aging in animal models and has been used in aging research. The present study was undertaken to investigate the molecular mechanisms underlying the effects of exercise on learning and memory in rats with D-galactose-induced aging. The learning and memory performance in aging rats, either after exercise or without exercise, was assessed with the Morris water maze test. The effect of treadmill exercise on the expression of amyloid-β 42 and two key enzymes involved in processing of the β-amyloid precursor protein, a disintegrase and metalloprotease domain 17 and β-site amyloid precursor protein-cleaving enzyme 1, in the hippocampi of rats were monitored using real-time quantitative PCR. Moreover, oxidative stress-associated changes, including changes in superoxide dismutase activity and malondialdehyde content, in the hippocampi were assessed after exercise. Our results showed that treadmill exercise significantly improved learning and memory performance in aging rats. The behavioral changes were likely induced by repression of amyloid-β 42 protein levels, through the upregulation of a disintegrase and metalloprotease domain 17 mRNA and downregulation of β-site amyloid precursor protein-cleaving enzyme 1 mRNA, and a concomitant increase in superoxide dismutase activity and decrease in malondialdehyde content, in rat hippocampi. Our data suggest that exercise may be an effective therapy for alleviating learning and memory decline due to aging or the onset of neurodegenerative diseases.