THE INDUCTION OF CELL-DIFFERENTIATION AND POLARITY OF TRACHEAL EPITHELIUM CULTURED ON THE AMNIOTIC MEMBRANE

We have developed a culture system of guinea pig tracheal epithelial c ells using the epithelium-denuded human amnion as a source of basement membrane. Culture medium fluid over the epithelial cells was replaced by air after 7-day immersion culture and thereafter maintained for 2 weeks. Electron microscopical observations revealed that the height of epithelial cells and the ratio of ciliated epithelial cells looked li ke that of normal guinea pigs epithelium growth in 2 weeks after the a ir interface, but that no goblet cells could be found. In order to stu dy cell polarity, we measured endothelin-1 levels in the media of apic al and basal sides of the epithelial cell monolayer by means of the en zyme-linked immunosorbent assay. The endothelin-1 content of the submu cosal side was over 30 times higher than that of the apical side. Thes e findings suggest that ET-1 would be mainly released from airway epit helial cells toward the submucosal side. (C) 1995 Academic Press. Inc.