Cultivation of keratinocytes derived from epidermal explants of sheep skin and the roles of growth factors in the regulation of proliferation.

Procedures to promote the growth of primary cultures of keratinocytes derived from sheep epidermis through several passages are described. Rapid epithelial outgrowth was obtained from explants of epidermis isolated from trypsinized inguinal skin biopsy specimens. Following initiation and attachment, cells displayed the polygonal morphology typical of keratinocytes in culture and survived a number of passages before terminally differentiating and sloughing from the surface of the culture vessel. Proliferation occurred in the absence of a feeder layer and was attained in a medium supplemented with foetal bovine serum and hydrocortisone or cholera toxin. Growth was stimulated by the addition of epidermal growth factor or fibroblast growth factor (FGF) to the culture medium. The detection of basic-FGF immunoreactivity in Western immunoblots of extracts of fresh tissues suggests a role for this factor in autocrine or paracrine growth regulation of skin cell populations in vivo.