Tissue culture of human adult adenoids and of middle eear mucosa.

The increased number of mucus producing cells as well as the presence of stratified squamous epithelium in pathological and experimental middle ear conditions, point towards the possibility of metaplastic changes of the middle ear mucosa, similar to the metaplastic capabilities of respiratory mucosae in general, as observed clinically or provoked experimentally. The purpose of this study was to develop a model of postembryonic human respiratory mucosae, in vitro, for the study of triggering or inducing factors involved in its normal and metaplastic differentiation. Explants from adenoids and middle ear mucosa were cultured, both as organ cultures and monolayers, for periods of up to two weeks, and their developmental characteristics were studied and described. Over 50% of the explants showed mitosis, epithelial and monolayer growth, ciliary activity and differentiation into ciliated and into mucus-producing cells. Adenoid explants were grown in air without and with added 5% CO2. Under the latter conditions, the proportion of explants and monolayers showing ciliary activity was 50% greater. It is concluded that this model might be suitable for further studies of the factors which control cyto-differentiation in mucociliary epithelia. Maintaining its growth for a longer period would, however, be desirable.