Exercise slows development of Alzheimer's-like brain changes in mice, new s...( eels were classified as sedentary....),Health

On 6 consecutive days after the exercise phase, the researchers placed each mouse in a Morris water maze to examine how fast it could learn the location of a hidden platform and how long it retained this information. (This water maze task involves a small pool of water with a submerged platform that the mouse must learn how to find.) The animals that exercised learned the task faster. Thus, the mice that used the running wheels for 5 months took less time than the sedentary animals to find the escape platform. The exercised mice acquired maximal performance after only 2 days on the task, while it took more than 4 days for the sedentary mice to reach that same level of performance. This suggests that exercise may help to offset learning/cognitive deficits present in AD patients.

Next, the investigators examined tissues from the brains of mice that had exercised for 5 months. They compared the levels of plaques, beta-amyloid fragments, and amyloid precursor protein, a protein found throughout the body and from which the beta-amyloid peptide is derived. In AD, beta-amyloid fragments clump together to form plaques in the hippocampus and cerebral cortex, the brain regions used in memory, thinking, and decision making.

Compared to the sedentary animals, mice that had exercised for 5 months on the running wheels had significantly fewer plaques and fewer beta-amyloid fragments (peptides) in the cerebral cortex and hippocampus, approximately by 50 percent. Additional studies, of exercised animals at 10 weeks old, showed that the mechanism underlying this difference began within the first month of exercise.

"These results suggest that exercise--a simple behavioral strategy--in these mice may bring about a change in the way that amyloid precursor protein is metabolized," says D. Stephen Snyder, Ph.D., director of the etiology of Alzheimer's program in the NIA's Neuroscience and Neuropsychology of Aging Progra
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Contact: Susan Farrer
301-496-1752
NIH/National Institute on Aging
26-Apr-2005