Long-term maintenance of differentiated respiratory epithelium in organ culture I. Medium composition.

Six commerically prepared, chemically defined media were tested in the presence and absence of serum to assess their influence on the maintenance of viable hamster respiratory epithelium over extended periods of time in vitro. Unique proliferation of epithelial elements was observed in organ cultures maintained in "complex" media containing serum, whereas use of these media in the absence of serum produced disorganized epithelial changes resembling squamous metaplasia. Minimum essential media at low serum concentrations preserved the columnar structure of the normal tracheal epithelium for 8 wk and longer in vitro.