Development of an in-house reconstructed human epidermis model as an alternative method in skin corrosion assessment.

Defining the corrosive properties of chemical products generally involves the use of animal models for human health safety assessment. However, a few alternatives to animal experimentation are currently internationally accepted in order to reduce animal suffering. One of these alternatives makes use of in vitro reconstructed human epidermis (RhE) models and predicts corrosive potential based on the evaluation of cell viability after topical exposure. These models rely on its similarity to human skin, both functional and histological, and are currently worldwide marketed by a few private companies. In this manuscript, we describe the fundamentals of the production of a Do It Yourself (DIY) RhE model, and the operating procedures for the assessment of skin corrosion based on the guidelines proposed for the development of new alternative methods for skin corrosion. Our results indicate that the DIY-RhE model resembles the anatomy of the normal human epidermis as seen by immunohistochemical analysis. Moreover, barrier properties of DIY-RhE were assessed by the measure of Transepithelial Electrical Resistance. Applicability of DIY-RhE for the assessment of skin corrosion was evaluated by measuring cell viability after topical exposure of twelve reference chemicals for 3 and 60 min. Predictive performance resulted in 100% sensitivity, 100% specificity and 100% accuracy matching current requirements for new RhE models proposed for the discrimination of corrosives and non-corrosives.