Acute exercise modulates the inflammatory response in adipose tissue in both lean and obese mice

Acute physical exercise acts as a metabolic stressor, promoting activation of the immune system, and this response could be relevant in the adipose tissue remodeling process. In addition, some cytokines have important functions in lipolysis. Because chronic exercise improves obesity-related metabolic and inflammatory dysfunction, herein we investigated the effect of acute exercise on the inflammatory responses in the adipose tissues of lean and obese mice.

Lean mice were fed a standard chow diet, whereas obese mice were fed a high-refined carbohydrate diet for 8 wk. Both groups were subjected to 60 min of moderate-intensity exercise.

In the epididymal adipose tissue of lean mice, exercise enhanced interleukin (IL)-6 and tumor necrosis factor-α levels, which correlated positively with increased serum free fatty acid concentrations. In vivo confocal imaging of epididymal adipose tissue vessels revealed higher recruitment of neutrophils after exercise. Also, the number of leukocytes expressing CD11b⁺F480^- was elevated 6 h after exercise. Similarly, the chemokine (C-X-C motif) ligand 1 level increased at 6 h and remained high until 24 h after exercise. Myeloperoxidase activity was increased at 6, 12, and 24 h after exercise. Surprisingly, however, no changes were observed in epididymal adipose tissue from obese mice, considering proinflammatory cytokines (IL-6 and tumor necrosis factor-α). On the other hand, IL-13, IL-4, and IL-10 levels were higher in obese mice after exercise.

These data suggest that acute exercise promotes an inflammatory response in the adipose tissue of lean mice that is observed as part of its role in adipose tissue remodeling. In contrast, acute exercise promotes an antiinflammatory response in adipose tissue from obese mice, likely as an important tool for restoring homeostasis.