INHIBITORY-ACTION OF INDOMETHACIN ON NEUTROPHIL INFILTRATION IN MONOSODIUM URATE-INDUCED PLEURISY IN RATS

The effects of indomethacin on the production of cytokines at inflammatory sites were investigated in the monosodium urate (MSU) pleurisy model characterized by both cellular influx and edema. Indomethacin (10 mg/kg) orally administered 0.5 hr prior to MSU injection into the pleural cavity significantly inhibited MSU-induced neutrophil accumulation in the cavity. In addition, the drug slightly enhanced the level of MSU-induced tumor necrosis factor production without affecting interleukin-l production. Furthermore, indomethacin inhibited both the levels of MSU-induced rat cytokine-induced neutrophil chemoattractant (CINC/gro) and interleukin-6 (IL-6) production by 78.3% at 3 hr and 45.8% at 4 hr post-injection, respectively. Although intrapleural injection of CINC/gro induced neutrophil infiltration in a dose-dependent manner, IL-6 did not affect the action of CINC/gro on neutrophil influx. These findings suggest that the inhibitory action of indomethacin on neutrophil infiltration is, at least, partly mediated by a decrease in the MSU-induced CINC/gro content in this model.