Differentiation of tracheal mucociliary epithelium in primary cell culture recapitulates normal fetal development and regeneration following injury in hamsters

Hamster tracheal epithelial cells were grown in primary culture for 8 days on a collagen gel substrate, in hormone-supplemented serum-free medium (Ham's F-12). On Days 1-3 in culture, the colonies were composed of a monolayer of poorly-differentiated flattened cells. Most of these were large cells which appeared to be altered secretory (mucous) cells. On Days 4 and 5, many of the epithelial cells were cuboidal. The rough endoplasmic reticulum was moderately developed, and mucous granules were seen at the cell apices. Preciliated and newly formed ciliated cells were observed on Day 6, and a differentiated mucociliary epithelium was established by Day 7 in culture. The study shows that in the hamster tracheal epithelium, the stages of normal fetal development and regeneration following injury, which have been characterized previously in vivo, are recapitulated in vitro. Formation of a mucociliary tracheal epithelium occurs within 7 days in vivo and in vitro.