JLE

European Cytokine Network

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Interleukin-6, TNF-alpha and interleukin-1 beta levels in blood and tissue in severely burned rats Volume 19, numéro 1, March 2008

Auteurs
Centre de recherches du service de santé des Armées, 24 Avenue des Maquis du Grésivaudan, BP87, 38702 La Tronche cedex, France, Unité Inserm U884, Laboratoire de bioénergétique fondamentale et appliquée, Université de Grenoble, France

Previous studies have demonstrated the early appearance of inflammatory cytokines in the systemic circulation after thermal injury both in humans and animals. The aim of this study was to evaluate the time course of several cytokines, IL-6, TNF-α and IL-1β in serum, lung, liver and brain of severely burned rats during the first week after thermal injury. Cytokine measurements were performed by enzyme-linked immunosorbent assay (ELISA). The comparison between the sham-burned animals and animals with third-degree burns on 20% or 40% of their total body surface area allowed for the study of the inflammatory process relative to the size of the injury. Serum IL-6 levels, which were undetectable in sham-treated animals, peaked during the first hours after injury and were proportionate to the size of the area burned. After a few days, IL-6 increased once more, but only in the most severely burned rats. In lung, liver and brain, low but measurable basal levels of TNF-α and IL-1 were detected in sham-burned animals. Strikingly, IL-1β levels remained significantly elevated in the lung after injury in animals having 20% and 40% burned skin area. Unexpectedly, both TNF-α and IL-1β production decreased gradually in liver and brain after burn injury. Also, the inflammatory response after a burn injury appeared to be biphasic. The first period corresponded to the early release of IL-6 into the circulation, proportional to the severity of the injury. After a few days, a second period was marked by the extension of the inflammatory processes from the injured area to the rest of the body, particularly to lung, which could be considered as at potential risk of involvement in severely burned patients.