Exercise speeds cutaneous wound healing in high-fat diet-induced obese mice

Obesity has been shown to impair cutaneous wound healing, which is associated with increased wound inflammation. Exercise is known to decrease obesity-associated inflammation and has been shown to speed cutaneous wound healing in aged mice. Therefore, we investigated whether treadmill exercise could speed cutaneous wound healing in obese, high-fat diet-fed mice.

We fed female C57Bl/6J mice a high-fat diet (45% calories from fat) for 16 wk to induce a state of obesity and insulin resistance. Mice then ran on a treadmill for 3 d before excisional wounding. On day 4, mice were wounded 1 h after exercise. Mice then exercised for 5 d after wounding, and healing was assessed by photoplanimetry for 10 d.

As described previously, obesity impaired wound healing, with significantly larger wound sizes measured from days 3 to day 10 after wounding (P < 0.05). Exercise did not improve healing in lean mice fed a normal chow diet. However, wound size was significantly smaller in exercised obese mice compared with their lean counterparts (P < 0.05 at day 1, day 4, and day 5 after wound). Surprisingly, we were unable to detect any differences in gene or protein expression of proinflammatory cytokines interleukin-1β and tumor necrosis factor-α or the anti-inflammatory cytokine interleukin-10 in the wounds. Likewise, there were no differences in gene expression of chemokines monocyte chemoattractant protein-1 and keratinocyte chemoattractant or of growth factor platelet-derived growth factor in wounds of exercise and sedentary mice.

This suggests an effect of exercise independent of alterations in inflammation. Future work should focus on early events after wounding, including exercise effects on hemostasis and myofibroblast function.