Validation of an in vitro micronucleus assay in 24-well plates using MicroFlow® flow cytometry

UKEMS 2025 -- Micronuclei are produced from whole chromosomes or acentric fragments that are unable to attach to the spindle at mitosis and appear during the next interphase as small similarly staining bodies adjacent to the main daughter nucleus. These are more easily counted than structural aberrations at mitosis and analysis can be performed rapidly on large numbers of cells using MicroFlow® flow cytometry methodology (Litron Laboratories, New York, USA). In this study, cells were exposed to a range of known positive controls. Total particulate matter (TPM) was generated from 3R4F cigarettes and nicotine for 3 hours in the absence or presence of S9 and for 24 hours in the absence of S9. Flow cytometry methodology enables higher throughput analysis versus conventional microscope slide scoring. Validation data was generated in accordance with OECD 487 using a 24-well platform that ensures sufficient sample volume and cell number can be achieved using adherent cells.