Vascular events in experimental otitis media models: a comparative study

The vascular leakage and components of middle ear effusion (MEE) were determined and compared in various experimental otitis media models in the rat: purulent otitis media (POM); serous otitis media (SOM); mucoid-like otitis media (MOM); stimulating the external auditory canal with a 14 degrees C airstream and vagotomy. When the Evans blue technique was used, all otitis media models exhibited a significant increase in middle ear vessel permeability. The MEEs contained numerous PMNLs, except for animals stimulated with a 14 degrees C airstream, in which the MEE was free of cells. The IgG/SIgA ratio in MEEs indicated that the MEE components are derived from serum in the early phases of fluid accumulation, in these otitis media models. In POM, MEE components appeared to be derived from local synthesis by the middle ear mucosa as well.