ORGANOTYPIC CULTURE OF HUMAN SKIN TO STUDY MELANOCYTE MIGRATION

An ex vivo model system was developed to investigate melanocyte migrat ion. Within this model system, melanocytes migrate among other epiderm al cells in the epibolic outgrowth of skin explants. This process is i nitiated by loss of contact inhibition of epidermal cells at the rim o f the explants and by locally produced chemotactic factors. Punch biop sies provided explants of reproducible diameter. Optimal culture condi tions include medium consisting of Dulbecco's Minimal Essential Medium containing 10% inactivated normal human serum and placement of explan ts epidermal side up at the air-liquid interphase. Within 7 days, epid ermal cells completely surround the explant. Approximately 3 days afte r the onset of keratinocyte migration, melanocytes distribute themselv es within the newly formed epidermis. Throughout the 7-day culture per iod, melanocytes and keratinocytes show maintenance of subcellular mor phology, and the dermo-epidermal junction remains intact. Melanocyte m igration was quantified using immunoperoxidase staining in combination with light microscopy and computer-aided image analysis. Preliminary results using the model system to compare migration in control and non lesional vitiligo skin indicate that no inherent migration defect is r esponsible for impaired repigmentation of vitiligo lesions. The organo typic culture model system allows for investigations on melanocytes wi thin their environment of autologous epidermal and dermal components, closely resembling in vivo circumstances in human skin.