Effect of platelet activating factor and its antagonist on the mucociliaryclearance of the eustachian tube in guinea pigs

The purpose of this study was to test whether platelet activating factor (P AF) impairs the mucociliary clearance function of the eustachian tube (ET) in a dose-dependent manner and whether PAF antagonist can prevent the impai rment of mucociliary function of the ET induced by PAF Coomassie brilliant blue dye transport time (DTT) in normal guinea pigs was 69 seconds. The DTT s after the application of normal saline and PAF at 1 and 2 mu g/mL into bu llae were 66, 74, and 157 seconds. The time was over 15 minutes when 4, 8, and 16 mu g/mL of PAF were applied. The DTT was 62 seconds when the animals were pretreated with PAF antagonist (WEB 2170). There were significant del ays of the DTTs after treatment with 2, 4, 8, and 16 mu g/mL of PAF Histopa thologic examination of ETs from groups with a significant delay in DTTs sh owed intact cilia, mucous plugs, increased inflammatory cells, and exfoliat ion of cells. This study demonstrated that PAF impaired the mucociliary cle arance function of the ET in a dose-dependent manner. This impairment of mu cociliary clearance function was prevented by pretreatment with PAF antagon ist. The findings of the study suggest that PAF plays an important role in the pathogenesis of otitis media with effusion by impairing the ET clearanc e function.