Rosdy, M. M. Fartasch, and M. Darmon. Normal Permeability Barrier to Tritiated Water in Reconstituted Human Epidermis. Poster Presentation at the PPP-meeting (Prediction of Percutaneous Penetration) on April 2-5, 1997. La Grande Motte, France.

A fully differentiated epidermis is produced routinely in vitro by culturing normal human foreskin keratinocytes (NHK) on inert polycarbonate filter substrates at the air-liquid interface in chemically defined medium MCDB 153 containing insulin and EGF. Histological sections show proper stratification and terminal differentiation after 2 weeks of air-exposure. Electron microscopy (using ruthenium tetroxide-post fixation) shows that the structural organization and distribution of the stratum corneum lipids in 16 days cultures is similar to that seen in native epidermis. Permeability to water was assessed by measuring the passage of tritiated water through the reconstituted epidermis compared to ex vivo foreskin epidermis samples: equivalent Kp (permeability coefficient) values were obtained when the cultures reached maturity at day 16 of air-exposure.