Neutrophil infiltration into pleural cavity of rats by intrapleural injection of inflammatory cytokines and effect of dexamethasone

Abstract

In order to assess a role of inflammatory cytokines for infiltration of leukocytes, we injected 4 cytokines into the pleural cavity of rats. Intrapleural injection of recombinant human interleukin-8 (rhIL-8) and cytokine-induced neutrophil chemoattractant (CINC) caused neutrophil infiltration in the pleural cavity dose dependently, and both, showed a peak at 3hr. Recombinant human tumor necrosis factor (rhTNF) and rhIL-1α also caused neutrophil infiltration in the cavity but lower extent than those by rhIL-8 and CINC. Neutrophil infiltration by rhTNF and rhIL-1α was suppressed significantly by the pretreatment with dexamethasone at a dose of 0.5 mg/kg.
These results suggest that IL-8 and CINC may act directly in the recruitment of neutrophils at local inflammatory sites, whereas TNF and IL-1 may express their activities for neutrophil infiltration through the induction of CINC in rats.