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영어

Alzheimer's disease is a most common form of dementia, often beginning with short-term memory problems. It gradually progresses and can eventually impair all cognitive functions. In the present study, we investigated the effects of treadmill exercise on the Alzheimer's disease focusing on the microglial activation. Alzheimer's disease was made by bilateral intracerebroventricular injection of streptozotocin. The rats in the exercise groups were made to run on a treadmill once a day for 30 min during 4 weeks, starting 3 days after STZ injection. Latency in the step-down avoidance task and latency in the Morris water maze task were increased in the Alzheimer's disease rats, in contrast, treadmill exercise shortened these parameters. Numbers of terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL)-positive and caspase-3-positive cells in the hippocampal dentate gyrus were decreased in the Alzheimer's disease rats, in contrast, treadmill exercise suppressed these numbers. Bax expression in the hippocampus was increased and Bcl-2 expression in the hippocampus was decreased in the Alzheimer's disease rats, in contrast, treadmill exercise decreased Bax expression and increased Bcl-2 expression. Expressions of GFAP and CD11b in the hippocampal dentate gyrus were increased in the Alzheimer's disease rats, in contrast, treadmill exercise suppressed GFAP and CD11b expressions. The present results demonstrated that treadmill exercise ameliorated Alzheimer's disease-induced disturbance of short-term memory and spatial memory ability through suppressing apoptosis. This anti-apoptotic effect of treadmill exercise might be ascribed to the inhibitory effect of treadmill exercise on microglial activation.