Several morphogenetic sequences occur during esophageal development and birth
defects occur due to defects in foregut morphogenesis. This work aimed to record
the cellular events in the morphogenesis of rabbits' esophageal epithelium. On the
16th day of gestation, the esophageal epithelium varied from stratified ciliated columnar
to stratified squamous type. The surface epithelium presented mucous cells with
mucigen granules of various sizes occupying their supranuclear cytoplasm. Cytoplasmic
vacuolation was evident in all layers of the esophageal epithelium at this age. On
the 18th gestational day, some light cells could be detected in the middle portion of
the epithelium, while others occupied the whole epithelial length. On the 21st day,
mucous cells are more frequently observed at the apical esophageal part as well as at
the surface epithelium. Numerous elongated dark cells could be distinguished embedded
between the basal cells. On the 24th gestational day the number of the mucous
cells reached its peak. Reaching the 30th gestational day, several lamellar bodies, a
keratinized layer and mitotic divisions could be demonstrated, and the number of
both mucous and dark cells was greatly decreased. Collectively, detection of surface
mucous and dark cells together with the non-cornified surface in some regions of the
rabbit esophageal epithelium at the end of gestation ensure a postnatal development
to reach the adult epithelium essential to sustain the passage of the harsh raw food.
Future immunohistochemical studies are recommended to investigate the components
of secretions in mucous cells and functional studies to highlight the dark cells
significance.