Effect of exercise on endotoxin shock with special reference to changes in concentration of cytokines

The effects of exercise on susceptibility to endotoxin shock and the serum levels of interleukin-1 (IL-1) and interleukin-6 (IL-6) were studied in mice primed with Propionibacterium acnes (P. acnes, 1.0 mg). Endotoxin shock was induced by injection of lipopolysaccharide (LPS, 0.2 mg) 7d after the priming injection of P. acnes. The exercise-loaded mice performed voluntary exercise for 120 min on a running-wheel and LPS was injected into the tail vein immediately after the end of exercise. Two of the nine animals in the exercised group survived, whereas all the mice in the control group died. The mean survival time after LPS injection in the exercised group (10.75 +/- 4.51 h) was significantly longer than that in the control group (3.3 +/- 1.34h). The serum concentrations of IL-1 (2,883 +/- 1,542 U/ml) and IL-6 (966 +/- 619 ng/ml) in the exercised group, sampled 2h after LPS challenge, were significantly lower than those in the control group (6,571 +/- 2,766 U/ml and 2,428 +/- 1,228 ng/ml, respectively). It is suggested that the exercise-induced inhibition of endotoxin shock may be caused, at least partly, by the decreased production of IL-1 and IL-6.