earticle

영어

Diabetes is a metabolic disorder, and it is considered as a major risk factor for Alzheimer’s disease (AD). In the present study, we evaluated whether treadmill exercise ameliorates progression of AD in relation with glycogen synthase kinase-3β (GSK-3β) activity using streptozoto-cin (STZ)-induced diabetic rats. For this study, step-down avoidance task, immunohistochemistry for glycogen synthase kinase-3β (GSK-3β) and tau, and western blot for phosphor-phosphoinositide 3 kinase (p-PI3K)/PI3K and phosphor-Akt (p-Akt)/Akt were performed. Diabetes mellitus was induced by intraperitoneal injection of STZ. The rats in the exercise groups were made to run on the treadmill for 30 min per one day, five times a week, during 12 weeks. The present results showed that short-term and long-term latencies in the step-down avoidance task were decreased by induction of diabetes, and treadmill exercise inhibited these latencies in the diabetic rats. Induction of diabetes sup-pressed the ratio of p-PI3K to PI3K and the ratio of p-Akt to Akt, and treadmill exercise increased these ratios in the diabetic rats. The num-bers of GSK-3β-positive and tau-positive cells in the hippocampal den-tate gyrus was higher in the diabetes-induction group than that in the control group, and treadmill exercise inhibited these numbers in the di-abetic rats. In the present study, treadmill exercise suppressed hyper-phosphorylation of tau in the hippocampus by decreased GSK-3β activ-ity through PI3K/Akt pathway activation in the diabetic rats. Based on the present results, treadmill exercise may helpful to prevent diabe-tes-associated AD occurrence.