This improved healing response in the old mice may be the result of an exercise-induced anti-inflammatory response in the wound.
EXERCISE ACCELERATES CUTANEOUS WOUND HEALING AND DECREASES WOUND INFLAMMATION IN AGED MICE.
This study purpose was to determine the effect of exercise on wound healing and inflammation in young (three months) and old (18 months) female Balb/cByJ mice. Mice were assigned to either exercise (EX) or sedentary control (CON) groups. EX mice were run on a motorized treadmill at a moderate intensity for 30 min per day for eight days. All mice were given four full thickness dermal wounds and the rate of wound closure was assessed daily for 10 days. Four months later, the aged mice were re-randomized to treatment, wounded again in different locations, and wounds were harvested at 1, 3, or 5 days post-wounding. Wound tissue was analyzed for interleukin-1 beta (IL-1beta), interleukin-6 (IL-6), keratinocyte chemoattractant (KC), monocyte chemoattractant protein-1 (MCP-1), and tumor necrosis factor alpha (TNF-alpha) protein. Myeloperoxidase (MPO) activity and F4/80 mRNA were assessed as an indirect measure of neutrophil and macrophage content, respectively. There was a trend (p = 0.10) for exercise to reduce wound size in young mice, and exercise significantly (p < 0.05) decreased wound size in old mice. TNF-alpha, KC, and MCP-1 were significantly (p < 0.05) lower in wounds from EX old mice when compared to CON. No group differences were found for wound IL-1beta or IL-6, MPO activity, or F4/80 mRNA. Our data suggest that exercise accelerates the wound healing process in old mice. This improved healing response in the old mice may be the result of an exercise-induced anti-inflammatory response in the wound. Key words: exercise, wound healing, aging, inflammation, cytokines.