IMPROVEMENT OF EPIDERMAL DIFFERENTIATION AND BARRIER FUNCTION IN RECONSTRUCTED HUMAN SKIN AFTER GRAFTING ONTO ATHYMIC NUDE-MICE

To determine whether epidermis reconstructed in vitro at the air-liqui d interface on de-epidermized dermis has the capacity to normalize the expression of differentiation-specific markers, its lipid composition and stratum corneum barrier properties, human skin equivalents were t ransplanted onto athymic nude mice and investigated at different stage s ranging from I to 4 months after grafting. Indirect immunofluorescen ce with species- or non-species-specific antibodies revealed that as e arly as 1 month after transplantation keratinization, and involucrin, loricrin and transglutaminase patterns were normalized. Human melanocy tes were observed in the basal layer of the pigmented graft. As reveal ed by high-performance thin-layer chromatography and transmission elec tron microscopy after ruthenium tetroxide fixation, the lipid profile and the intracellular lamellar organization were similar to those foun d in natural epidermis. Transepidermal water loss measurements and pen etration studies showed that the barrier properties of the reconstruct ed epidermis after transplantation were comparable to those of normal human skin.