Use of the EpiDermTM 3D reconstructed skin micronucleus assay for fragrance materials

Abstract

In order to evaluate the utility of the 3D reconstructed skin micronucleus assay (3DRSMN) to assess clastogenic/aneugenic potential of the fragrance chemicals, a set of 22 fragrance materials were evaluated in 3DRSMN assay. These materials evaluated were also evaluated in an in vitro as well as in vivo micronucleus assay, conducted as per OECD guidelines. The results of the RSMN assay were in 100% agreement with the in vivo micronucleus assay results. From this dataset 18 materials were positive in an in vitro micronucleus assay but were negative in an in vivo micronucleus assay. All these 18 materials were also concluded to be negative in 3DRSMN assay, stressing the importance of the assay to help minimize misleading positive outcomes from the in vitro assay. Since the highest exposure for fragrances is through the dermal route, the RSMN assay fits the applicability domain for testing. Thus, RSMN assay is an important alternative to animal testing for characterization of the genotoxicity potential of fragrance materials.

Utility of ToxTracker in animal alternative testing strategy for fragrance materials

“…The focus of this study was to investigate the ability of the ToxTracker assay to address the potential mode of action of the tested materials. All of the materials had a positive results in the in vitro micronucleus assay, and negative results from the in vivo micronucleus assay (Thakkar et al, 2022). Based on the in vivo micronucleus assay, the results from the in vitro micronucleus assay results are “misleading” positives.…”

“…The first chemical in our current dataset, 2-octen-4-one, (an alpha, beta-unsaturated ketone class of fragrance material) was concluded to be positive in an in vitro micronucleus assay conducted using HPBL negative in the follow-up 3D skin study and standard in vivo micronucleus study. (Thakkar et al, 2022). The mutagenic activity of 2-oceten-4-one was also evaluated in an Ames bacterial reverse mutation study conducted mix.…”

“…The first chemical in our current dataset, 2‐octen‐4‐one, (an alpha, beta‐unsaturated ketone class of fragrance material) was concluded to be positive in an in vitro micronucleus assay conducted using HPBL negative in the follow‐up 3D skin study and standard in vivo micronucleus study. (Thakkar et al, 2022). The mutagenic activity of 2‐oceten‐4‐one was also evaluated in an Ames bacterial reverse mutation study conducted as per OECD 471, Salmonella typhimurium strains TA98, TA100, TA1535, TA1537, and Escherichia coli strain WP2uvrA were treated with 2‐octen‐4‐one in dimethyl sulfoxide (DMSO) at concentrations up to 5000 μg/plate.…”

“…Using this information, we can ideally use an appropriate animal alternative model with sufficient glucuronidation capacity to investigate the genotoxicity of the target material or its metabolite. Three‐dimensional skin tissue is considered to have sufficient glucuronyl transferase activity (Götz et al, 2012; Oesch et al, 2007) and also has demonstrated good concordance when compared with the results in the in vivo micronucleus study (Thakkar et al, 2022). Hence, 3D‐skin model‐based assay can help identify the accuracy of results observed in the in vitro micronucleus study and it also has the advantage of addressing this issue for products primarily applied by dermal route.…”

“…p‐Methoxy cinnamaldehyde was also concluded to be positive for its clastogenic potential in an in vitro MNT conducted using HPBL and negative in the follow‐up 3D skin and in vivo micronucleus studies (Thakkar et al, 2022). The mutagenic activity of p‐methoxycinnamaldehyde was also evaluated by an Ames bacterial reverse mutation study conducted as per OECD 471 for which S. typhimurium strains TA98, TA100, TA1535, TA1537 and E. coli strain WP2uvrA were treated at concentrations of up to 5000 μg/plate.…”