Release of Cytokines by Blood Monocytes During Strenuous Exercise

Abstract

During strenuous exercise in endurance athletes, monocytes are activated and there is an acute inflammation and hypoxemia possibly due to lesional pulmonary edema. IL-6 and TNF-α released by monocytes may be implicated in the acute phase of lesional pulmonary edema. A study was carried out to determine whether TNF-α and IL-6 are released during strenuous exercise, and, if adrenalin released during exercise alters their generation. Ten young and six master athletes underwent an incremental exercise test. Arterial blood was drawn at rest, at the end of the exercise, and 20 minutes afterwards. Monocytes were isolated and incubated for 18 hours in the presence or absence of adrenalin. II-6 and TNF-α were measured in monocyte supernatants. The spontaneous release of IL-6 or TNF-α was increased in young athletes when compared to older subjects. The spontaneous release of TNF-α was increased, but not significantly, by exercise and there was no correlation between the release of IL-6 and TNF-α and lung function measured during hypoxemia. Adrenalin inhibited the release of IL-6 or TNF-α. Correlations were observed between the in vitro release of IL-6 or TNF-α and age, V̇O₂max, maximal ventilation and maximal power output of the subjects.

Key words

TNF-α - exercise - hypoxemia - monocytes - adrenalin