Endurance training induces depot - specific changes in IL - 10 / TNF - α ratio in rat adipose tissue # 13

White adipose tissue (WAT) is the source of proand antiinflammatory cytokines and recently, it recognized as an important source of interleukin 10 production (IL-10). Acute physical exercise induce an anti-inflammatory cytokine profile. However, the effect of chronic physical exercise in the production of IL-10 by the WAT has never been examined. IL-10 and TNF-α were assessed in WAT of rats engaged in endurance training. Animals were randomly assigned to either a sedentary control group (S, n=7) or an endurance trained group (T, n=8). Trained rats ran on a treadmill for 5 days/wk for 8 wk at 55-65% of the VO2max. Detection of IL-10 and TNF-α protein (by ELISA) and mRNA expression (by semi-quantitative PCR), as well as the mRNA of PPARγ, and immunocytochemistry to detect mononuclear phagocytes were carried out. A reduction in absolute retroperitoneal adipose tissue (RPAT) weight in T (44%; p<0.01), when compared with S was observed. IL-10 and TNF-α concentration were increased (60% p<0.05; 40%, p<0.05, respectively), in the mesenteric adipose tissue (MEAT) from the trained group, while no change related to training was observed in RPAT. In MEAT, IL-10/TNF-α ratio was increased for T group when compared with S (30%; p<0.05). PPAR-γ mRNA was increased in T (1.1 fold; p<0.01) when compared with S in the same adipose depot. No monocyte infiltration was found. In conclusion, exercise training induced increased IL-10 expression in the mesenteric depot, resulting in a modified IL-10/ TNF-α ratio. We also conclude that WAT presents a depot-specific response to endurance training.