Use of in vitro skin recombinants to evaluate cutaneous toxicity: A preliminary study

The cytotoxicity of surfactants (N cetyl-trimethylammonium bromide, sodium dodecyl sulfate, and sorbitan monooleate), formalin, and two non-water-soluble formulations was tested using a skin recombinant made of human keratinocytes cultured on dead deepidermized dermis. Histologic observations and biochemical parameters of cytotoxicity (LDH release and MTT activity) are closely related. Moreover, as in the in vivo situation, cationic surfactant is more toxic than anionic and nonionic. Relative cytotoxicity of surfactants and formalin was markedly reduced on reconstructed epidermis in comparison with monolayer culture of human keratinocytes, emphasizing the toxicologic importance of the stratum corneum barrier. Histologic observations show that salicyclic acid, a well-known keratolytic agent in vivo, induced a reduction of the horny layer thickness of the skin recombinant. These preliminary results suggest that the skin recombinant on de-epidermized dermis may prove to be a useful in vitro model for the evaluation of cutaneous toxicity of topically applied substances.