Radiation effect on the middle ear of the guinea pig

Abstract

Otitis media with effusion was induced in guinea pigs by cobalt⁶⁰ irradiation. Vascular permeability of the middle ear mucosa was observed by Majno's vascular labelling technique. The pathological change of the middle ear was examined under light microscope. Vascular permeability was increased at three days after 4000 rad irradiation and small vessels were labelled with carbon particles. At seven days after irradiation, carbon labelling of small vessels was more extensive and extravascular blackening was present. Edematous change of the middle ear mucosa and metaplasia of the epithelial cells were also observed. New bone formation of the tympanic bulla was increased by repeated irradiations.