CORESTA Congress 2024 -- Within the standard genotoxicity test battery, the in vitro micronucleus (IVMN) test is an option for detecting chromosomal damage. As standard this is performed through slide preparations and manual scoring. Improving timelines and increasing cell numbers analysed is achieved through flow cytometry and staining methods. This method was utilised with V79 cells cultured in 24-well plates. These were treated with the OECD 487 test chemicals including nicotine and Total Particulate Matter (TPM) (ISO 20778:2018) generated from 3R4F Kentucky Reference, eluted in DMSO. Endpoints were measured using the Litron™ MicroFlow kit. Cytotoxicity was measured by relative population doubling (RPD), supported by the use of Cell Sorting Set-up Beads (Invitrogen™) during flow cytometry assessment. The Litron™ MicroFlow kit was used to stain and lyse the cells, then micronucleus (MN) induction was assessed on a flow cytometer. Results showed dose related increases in MN induction for all expected positive OECD test chemicals. 3R4F TPM at 3+21 -S9 showed a slight increase, prior to cytotoxicity. 3+21 +S9 showed dose-related induction. 24+0 -S9 showed increases to MN induction. This validation study confirmed the correct functioning of a high throughput IVMN assay by flow cytometry, with treatment in 24-well plates

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