Effect of platelet-activating factor on secretion of mucous glycoprotein from chinchilla middle ear epithelial cells in vitro.
Platelet-activating factor (PAF) is a naturally occurring phospholipid that acts as a pleiotropic mediator and mediates cell-cell reactions under physiological and pathological conditions. Recently, it has been shown that PAF is a strong secretagogue of mucous glycoprotein in the airways, suggesting its role in mucous glycoprotein secretion and the pathogenesis of otitis media with effusion. In the current study, we examined the effect of PAF on mucous glycoprotein secretion in cultured chinchilla middle ear epithelial cells. PAF at 1 microM significantly stimulated mucous glycoprotein secretion from cultured chinchilla middle ear epithelial cells. This action was concentration-dependent, with secretions reaching near maximum when the cells were incubated with PAF at 100 microM. In a time-dependent study, PAF demonstrated an initial rapid stimulation of mucous glycoprotein secretion, followed by a gradual increase thereafter. A six-fold increase was seen in the first 2 h compared with controls. Cycloheximide, a protein synthesis inhibitor, demonstrated an inhibitory effect on PAF-stimulated mucous glycoprotein secretion in this study. These findings suggest that PAF plays an important role in the pathogenesis of otitis media with effusion by stimulating mucous glycoprotein secretion in vitro.
Lin
J
J
Department of Otolaryngology, University of innesota Otitis Media Research Center, University of Minnesota Medical School, Minneapolis 55455, USA.
Kim
Y
Y
Lees
C
C
Juhn
S K
SK
D000818:Animals; D002470:Cell Survival; D002682:Chinchilla; D002725:Chloroform / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004337:Drug Carriers; D004432:Ear, Middle / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D004847:Epithelial Cells; D004848:Epithelium / Q000187:drug effects / Q000378:metabolism; D066298:In Vitro Techniques; D008562:Membrane Glycoproteins / Q000187:drug effects / Q000378:metabolism*; D009092:Mucous Membrane / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D010972:Platelet Activating Factor / Q000494:pharmacology*; D013997:Time Factors
D004337:Drug Carriers; D008562:Membrane Glycoproteins; D010972:Platelet Activating Factor; D002725:Chloroform