Effects of human middle ear effusions on the mucociliary system of the tubotympanum in the guinea pig.

Effusion fluid resulting from otitis media contains a variety of inflammatory substances. This middle ear effusion (MEE) may be itself affect the mucosa of the tubotympanum and contribute to chronicity of the condition. The present study was designed to elucidate in vitro and in vivo effects of MEEs on the mucosa of the guinea pig tubotympanum. The results obtained demonstrated that the ciliary activity of the eustachian tube was reduced in the presence of human MEEs. This activity decreased to approximately 80% in the presence of serous MEE at 48 h and was 60% after exposure to mucoid MEE. Intratympanic inoculation of human MEEs resulted in accumulation of a serous effusion in the tympanic cavity. Histologic study of the tubotympanum in inoculated animals demonstrated mucociliary dysfunction as well as a general inflammatory process and increased vascular permeability. This damage was more prominent following inoculation with the mucoid MEEs. The ciliary depression and inflammation found in the tubotympanum suggest that the pathologic nature of MEEs may be, at least partially, responsible for the chronicity of otitis media.