Use of a serum-free reconstituted epidermis as a skin pharmacological model

This study is aimed at assessing some of the possibilities offered by a new kind of three-dimensional skin culture in the field of toxicity and skin inflammation. The Reconstituted Epidermis used is presently the only skin model on the market in which normal human keratinocytes are allowed to grow and to differentiate in a chemically defined culture medium. The response of this original tissue to chemical (anionic and cationic surfactants) and physical (UVB radiation) insults was compared with human keratinocytes in monolayer culture and assessed through histological analysis, cell viability quantification and interleukin-1 (IL-1) release measurement. For the surfactants and the UVB radiation a clear relationship was shown between the amount of IL-1 released and both the cell viability and the histological appearance of the skin. Sublethal doses of UV radiation induced exclusively an increase of intracellular amount of IL-1, the magnitude of which seemed to be time dependent. The irritating potential of various kinds of cosmetic creams was then assessed using this skin model and compared with human irritation data. The intensity of erythema and oedema induced by a 48-hr human patch test was consistent with the amount of IL-1 secreted in the medium, the histological appearance of the Reconstituted Epidermis and the cell viability.