Platelet-activating factor (PAF) induced cytokine production and otitis media with effusion (OME) in the rat middle ear.

Objectives: We examined the effect of platelet-activating factor (PAF) on IL-8 production in cultured rat middle ear epithelial cells (RMECs), and the concentrations of cytokine, PAF, and PAF-acetylhydrolase (PAF-AH) were also examined in the PAF-induced experimental OME (otitis media with effusion) of rats.

Methods: Using an enzyme-linked immunospecific assay, we measured the levels of cytokines in the cultured RMECs and the PAF-induced OME of rats. The PAF was quantitated by the platelet-aggregating activity and the PAF-AH was measured by radioimmunoassay.

Results: Both PAF and C-PAF, which is a stable analogue of PAF, significantly induced production of IL-8 in the RMECs in a dose-dependent manner. The PAF-induced IL-8 production was abolished by co-incubation with WEB2170, a specific PAF receptor antagonist. The concentrations of the cytokines and PAF in the PAF-induced OME of rats were higher on day 1 and the PAF and cytokine levels seemed to correspond well with the persistence of OME.

Conclusion: PAF may stimulate the local production of cytokines and may induce OME in the middle ear.