Validation of the In Vitro Reconstructed Skin Micronucleus Assay as a Potential Animal Alternative for Fragrance Materials

The in vitro reconstructed skin micronucleus assay is a skin-based assay which measures the clastogenicity and aneugenicity potential of chemical materials and mixtures. Reconstructed skin models are prepared from primary human cells and are expected to have DNA repair and cell cycle control mechanisms similar to in vivo systems. They are also expected to exhibit a human metabolic capability that is more biologically relevant than the exogenous rodent metabolizing enzymes currently used in standard in vitro genotoxicity assays. The skin is an effective barrier to chemicals and has enzymes actively involved in metabolism which may prohibit materials applied to the skin from entering systemic circulation, or allow detoxification to occur prior to systemic circulation. The major route of exposure to fragrances is via dermal exposure. Thus, making the in vitro skin test system of greater relevance as an animal alternative follow-up study to the regulatory approved in vitro micronucleus assay for fragrance materials. This study investigated this assay in seven fragrance materials. These
materials were selected because adverse results were obtained in the traditional in vitro micronucleus assay conducted according to OECD 487, however, no response was observed in the in vivo micronucleus assay conducted according to OECD 474. All seven chemicals resulted in negative results in the in vitro reconstructed skin micronucleus assay. There was 100% concordance when compared to the results in the in vivo micronucleus assay conducted according to OECD 474. These findings strengthen the use of the in vitro reconstructed skin micronucleus assay as an assay to evaluate the clastogenicity and aneugenicity and as a potential follow-up animal alternative tool to support the safety of fragrance materials.

EPI-200-MNA, micronucleus genotoxicity assay (MNSA), micronucleus skin assay, OECD 487, OECD 474

2-Octen-4-one, Lauric Aldehyde, 1,5-Dimethylbicyclo[3.2.1]octan-8-one-oxime, 3,3,5-Trimethylcyclohexaneacetic acid, Furfuryl thioacetate, 6-Methoxy-2,6-dimethylheptan-1-al, Veratraldehyde