Differentiated properties of rabbit tracheal epithelial cells in primary culture

The purpose of this study was to establish whether rabbit tracheal epithelial cells, grown in primary cell culture, retain neurohormonal receptor and mediator activity. Epithelial cells were isolated by enzymatic treatment and cultured on a collagen matrix. The culture medium consisted of a 1:1 mixture of Dulbecco's modified Eagle medium and Ham's F12 supplemented with 5% fetal calf serum, epidermal growth factor, insulin, transferrin, fibronectin, hydrocortisone, and trace elements. Cultures had a population doubling time of 48 h. Mucus-containing cells and cilia were not observed after 7 days of incubation. Positive immunofluorescent staining with monoclonal antibodies to keratins established the epithelial nature of the cell cultures. Primary cell cultures responded to beta-adrenergic agonists with a dose- and time-dependent increase in intracellular adenosine 3',5'-cyclic monophosphate (cAMP) levels. Propranolol, a beta-adrenergic antagonist, blocked the effects of the beta-adrenergic agonist. Adrenergic agonists also mediated a dose-dependent increase in the generation and release of prostaglandin E2 (PGE2). PGE2 caused an increase in cAMP levels. The results demonstrate that primary cultures of rabbit tracheal epithelial cells retain hormonal responses of the isolated epithelium and tracheal mucosa-submucosa.