FURTHER DEVELOPMENT OF THE EPIDERM 3D RECONSTRUCTED HUMAN SKIN MICRONUCLEUS (RSMN) ASSAY.
This study by scientists at Procter & Gamble Co., the Institute for In Vitro Sciences (IIVS), Advanced Testing Laboratory and MatTek Corp. demonstrated that an in vitro human reconstructed skin micronucleus assay (RSMN) based on MatTek’s EpiDerm in vitro human skin tissue equivalent has a higher predictive value than currently available in vitro genotoxicity tests. The upcoming ban on testing of cosmetics in animals by the European Union’s 7th Amendment to the Cosmetics Directive will require genotoxicity safety assessments of cosmetics ingredients and final formulations to be based primarily on in vitro genotoxicity tests. The current in vitro test battery produces an unacceptably high rate of false positives, and used by itself, would effectively prevent the use and development of many ingredients that are actually safe for human use. To address the need for an in vitro test that is more predictive of genotoxicity in vivo, we have developed an in vitro micronucleus assay using a three dimensional human reconstructed skin model (EpiDerm™) that more closely mimics the normal dermal exposure route of chemicals. We have refined this model and assessed its ability to predict genotoxicity of a battery of chemicals that have been previously classified as genotoxins or non-genotoxins based on in vivo rodent skin tests. Our reconstructed skin micronucleus assay correctly identified 7 genotoxins and 5 non-genotoxins, demonstrating its potential to have a higher predictive value than currently available in vitro genotoxicity tests, and its utility as part of a comprehensive in vitro genotoxicity testing strategy.
7th Amendment to the Cosmetics Directive, Cytokinesis, EPI-200-MNA, EpiDerm, Genotoxicity, Micronucleus assay, REACH, RSMN, Reconstructed skin micronucleus assay
1,2-epoxdodecane, 2-ethyl-1,3-hexanediol, 2-phenylphenol, 4-nitrophenol, Methyl methanesulfonate, Mitomycin C, N-ethyl-N’-nitro-N-nitrosoguanidine, N-methyl-N’-nitro-N-nitrosoguanidine, beta-butyrolactone, cytochalasin B (cytoB), dimethylcarbamyl chloride, n-ethyl-nitrosourea, n-methyl-nitrosourea, trypsin (0.25%)-EDTA
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