Chronic exercise ameliorates the neuroinflammation in mice carrying NSE/htau23

The objective of the present study was to investigate whether chronic endurance exercise attenuates the neuroinflammation in the brain of mice with NSE/htau23. In this study, the tau-transgenic (Tg) mouse, Tg-NSE/htau23, which over expresses human Tau23 in its brain, was subjected to chronic exercise for 3 months, from 16 months of age. The brains of Tg mice exhibited increased immunoreactivity and active morphological changes in GFAP (astrocyte marker) and MAC-1 (microglia marker) expression in an age-dependent manner. To identify the effects of chronic exercise on gliosis, the exercised Tg mice groups were treadmill run at a speed of 12 m/min (intermediate exercise group) or 19 m/min (high exercise group) for 1h/day and 5 days/week during the 3 month period. The neuroinflammatory response characterized by activated astroglia and microglia was significantly repressed in the exercised Tg mice in an exercise intensity-dependent manner. In parallel, chronic exercise in Tg mice reduced the increased expression of TNF-α, IL-6, IL-1β, COX-2, and iNOS. Consistently with these changes, the levels of phospho-p38 and phospho-ERK were markedly downregulated in the brain of Tg mice after exercise. In addition, nuclear NF-κB activity was profoundly reduced after chronic exercise in an exercise intensity-dependent manner. These findings suggest that chronic endurance exercise may alleviate neuroinflammation in the Tau pathology of Alzheimer's disease.