Aim: 

Obese Zucker rats are accepted as a good experimental animal model to study Metabolic Syndrome (MS). Obesity associated with MS is regarded as a "low grade inflammatory process" in which pro-inflammatory cytokines released by macrophages play an important role. Also, it is well known that exercise modulates the inflammatory response in healthy animals, and involved in this modulation is the 72 kDa extracellular heat shock protein (eHsp72) stimulating macrophages to release IL-1b. Taking this into account, the aim of the present investigation was to evaluate the effect of an exercise training protocol (running on a treadmill for 35 minutes at 35 cm/sec, 5 days per week, for 16 weeks) and the effect of a bout of acute exercise (running on a treadmill for 35 minutes at 35 cm/min), with and without previous training, on the Hsp72-induced release of IL-1b by macrophages from obese Zucker rats.

Methods: 

Macrophages were incubated (37°C, 5% CO₂, and 100 RH) with Hsp72 (10mg/ml) for 24 hours, and then IL-1b concentrations were determined (by ELISA) in the supernatant of the culture.

Results: 

Hsp72 increased the release of IL-1b in macrophages from non-obese rats (Zucker Lean), but decreased it in macrophages from obese Zucker rats. Nevertheless, the exercise training protocol increased the Hsp72-induced release of IL-1b by macrophages from obese rats (trained obese rats vs sedentary obese rats). In addition, a single bout of acute exercise also stimulated the Hsp72-induced release of IL-1b in both sedentary and trained obese rats.

Conclusion: 

It is concluded that exercise stimulates the Hsp72-induced release of IL-1b by macrophages from obese rats which is normally low in their sedentary status when compared with non-obese rats.

This work was partially supported by grants DEP2006-56187-C04-03 (M.E.C.) and GRU08039 (Junta de Extremadura), and by a studentship from the Fundación Valhondo de Extremadura, Spain.