Mucociliary dysfunction in experimental otitis media with effusion.

To investigate the morphologic changes of the eustachian tube mucociliary transport systems, experimental otitis media with effusion was induced by immune complex injection into the bullae of experimental animals. Horseradish peroxidase was chosen as an antigen because of its high antigenicity and traceability under light and electron microscopy. Seventy-three guinea pigs and 41 chinchillas were divided into three groups: active Arthus group, passive Arthus group, and control group. Animals were killed under general anesthesia from the first to 30th day after the injection. Within 5 days after injection, effusions were observed consistently in all animals, but in only 80 per cent on the 7th day and in only 50 per cent after the 10th day after injection. The most conspicuous findings were that the interciliary space of the mucociliary system was diffusely occupied by an electron-dense mucus, and the upper part of the ciliary shafts were tightly glued together. These features seem to indicate rheologic alterations of the mucus and a disorder of its coupling to the cilia. This study strongly suggests that the mucociliary coupling disorder caused by altered rheologic properties of the mucus causes clearance dysfunction of the eustachian tube, resulting in middle ear effusion. The various inflammatory products contained in the middle ear effusions elicit a persistent vicious cycle of inflammatory reactions in the tubotympanum.