Experimental studies on immunogenesis of otitis media with effusion

In order to investigate otitis media with effusion from the systemic perspective, we have studied histological reactions of the mucous membrane in the both middle ears in the sensitized animals. Guinea pigs were initially immunized by injection of BSA conjugated with alum (BSA-alum) into unilateral tympanic cavity. The second challenge of BSA-alum was performed on the seventh day after primary sensitization under an appropriate schedule. The guinea pigs were sacrificed for histological examination at 3 days after the second administration. Histological changes of the middle ear mucosa in the sensitized ear were characterized by hypertrophy of mucosa with fibrosis. Numerous mononuclear cells also existed. In non-sensitized ear (opposite side), the changes were edema of the mucosa showing mild proliferation of fibroblast and vasodilation. Mainly mononuclear cells were scattered. It was noted that these reactions were weaker than those of the sensitized ear.