Exercise training reduces inflammatory mediators in the intestinal tract of healthy older adult mice

Aging is associated with increased intestinal inflammation and elevated risk of chronic diseases including inflammatory bowel diseases and colon cancer; many epidemiologic studies show that regular exercise reduces risk. This study examined the effects of long-term voluntary exercise on inflammatory mediators expressed in the intestine of older (15-16 months), healthy C57BL/6 mice. Animals were assigned to four months of freewheel running (WR; n = 20) or to a "sedentary" no wheel running (NWR; n = 20) control group. Intestinal lymphocytes were harvested and analysed for expression of (1) pro-inflammatory (TNF-α, IL-1β) and pleiotropic (IL-6) cytokines, and (2) pro-(caspase-3/-7) and anti-(Bcl-2) apoptotic proteins. Training was confirmed by skeletal muscle enzyme activity; stress was assessed by plasma 8-iso-PGF(2α) and corticosterone. The WR mice had a lower expression of TNF-α, caspase-7, and 8-isoprostanes (p < .05) compared to sedentary controls, suggesting that long-term exercise may "protect" the bowel by reducing inflammatory cytokine and apoptotic protein expression.