Utility of ToxTracker in animal alternative testing strategy for fragrance materials

To determine the utility of the ToxTracker assay in animal alternative testing strategies, the genotoxic potential of four fragrance materials (2-octen-4-one, lauric aldehyde, veratraldehyde, and p-methoxy cinnamaldehyde) were tested in the ToxTracker assay. These materials have been previously evaluated in an in vitro as well as in vivo micronucleus assay, conducted as per OECD guidelines. In addition to these studies, reconstructed human skin micronucleus studies were conducted on all four materials. All four materials were positive in an in vitro micronucleus assay but were negative in both in vivo and 3D skin micronucleus assays. The ToxTracker assay, in combination with in silico methods to predict metabolism was used to identify mechanisms for the misleading positive outcomes observed in the in vitro micronucleus assays. The results show that the ToxTracker assay, in conjunction with in silico predictions, can provide the information needed to aid in the identification of an appropriate animal alternative follow-up assay, for substances with positive results in the standard in vitro test battery. Thus, the ToxTracker assay is a valuable tool to identify the genotoxic potential of fragrance materials and can aid with replacing animal-based follow-up testing with appropriate animal alternative assay(s).

Automated summary

The utility of the ToxTracker assay in animal alternative testing strategies was evaluated by testing the genotoxic potential of four fragrance materials. These materials had previously been evaluated using in vitro and in vivo micronucleus assays. In addition, reconstructed human skin micronucleus studies were conducted. While the in vitro micronucleus assays showed positive results, both in vivo and 3D skin micronucleus assays showed negative results. The ToxTracker assay, combined with in silico predictions, was able to identify mechanisms for the misleading positive outcomes observed in the in vitro micronucleus assays.