Development of a highly sensitive in vitro phototoxicity assay using the SkinEthic (TM) reconstructed human epidermis

The reconstituted human epidermis model SkinEthic(TM) was used to evaluate the phototoxicity of topically applied chemicals. For comparison with publi shed data, we first tested a library of 13 nonphototoxic (NPT) and phototox ic (PT) compounds, applied onto SkinEthic(TM) reconstituted human epidermal tissues, in a protocol as close as possible to the one described by Liebsc h using another skin tissue model. The results showed that, under these non optimized conditions, the SkinEthic(TM) model was already able to fully dis criminate between known NPT and PT compounds. Furthermore, these epidermal tissues being highly resistant to UVA irradiation, it was possible to incre ase irradiation by (at least) 3-fold without decrease in tissue viability. In such conditions, the phototoxicity assay is much more sensitive, so that the model is expected to be of great interest for the detection not only o f strong but also of weak phototoxic compounds.