GROWTH AND DIFFERENTIATION OF EPIDERMAL-CELLS FROM THE RAINBOW-TROUT ESTABLISHED AS EXPLANTS AND MAINTAINED IN VARIOUS MEDIA

Growth and a number of differentiated characteristics of cultured epid ermal cells from the rainbow trout Oncorhynchus mykiss were compared u sing two commercially available serum-free media, a dermal substrate/s erum free kit and a serum-containing medium which had been previously optimized for epidermal cell culture. Each medium supported short term growth over 15 days. Only the medium supplied for dermal substrate cu lture supported longer growth periods. This medium was supplied for us e with a collagen/stromal substrate but gave good cultures even withou t the substrate. Differentiation, measured by examining mucous cells, cytokeratins, epidermal growth factor receptor, gap junction status an d ultrastructure showed that serum-free media gave quantitatively and qualitatively superior expression and short term retention of differen tiation over serum-containing medium. Epithelial cell growth with expr ession of differentiated characteristics can be maintained in primary culture in serum-free medium for at least as long as in serum-containi ng medium. This provides a useful technique for use when serum presenc e in medium is undesirable or proves toxic to the specialized cell typ e under investigation.