An in vitro model for detecting skin irritants: methyl green-pyronine staining of human skin explant cultures

• Published in: Toxicology in vitro 2002-10, Vol.16 (5), p.581-588
• Main Authors: Jacobs, J.J.L, Lehé, C, Cammans, K.D.A, Das, P.K, Elliott, G.R
• Format: Article
• Language: English
• Subjects: Alternative method; Animal Testing Alternatives; Animals; Biological and medical sciences; Cells, Cultured; Coloring Agents - chemistry; Dose-Response Relationship, Drug; General aspects. Methods; Human skin; Humans; Irritant testing; Irritants - classification; Irritants - toxicity; Medical sciences; Methyl Green - chemistry; Methyl-green pyronine; Pig skin; Pyronine - chemistry; Rabbits; Reproducibility of Results; RNA - analysis; Skin - chemistry; Skin - drug effects; Skin - pathology; Staining and Labeling - methods; Swine; Toxicity Tests; Toxicology
• ISSN: 0887-2333; 1879-3177
• DOI: 10.1016/S0887-2333(02)00039-5

We evaluated the potential of human organotypic skin explant cultures (hOSECs) for screening skin irritants. Test chemicals were applied to the epidermis of the skin explants which were incubated for 4, 24 or 48 h in tissue culture medium. A decrease in epidermal RNA staining, visualised in frozen sections using a modified methyl-green pyronine (MGP) staining procedure, was used as a marker of irritancy. A decrease in epidermal RNA after a 4-, 24- or 48-h exposure to a certain concentration of a test chemical equated to a MGP score of 3, 2 or 1, respectively. The MGP score was 0 if there was no keratinocyte cytotoxicity after a 48-h exposure. A minimum of three donors were used per chemical and the average MGP score was used to classify the chemical as irritant or not. Chemicals with an average MGP score ⩾1.5 were classified as irritants (R38), at that concentration. Chemicals with a MGP score