In vitro Mammalian Chromosomal Aberration Test

An increase in polyploidy may indicate that a chemical has the potential to induce numerical aberrations, including aneuploidy. However, the lack of polyploidy should not be considered adequate evidence that the test material does not have the potential to induce numerical aberrations.

Cells arrested in metaphase are examined microscopically for both numerical and structural chromosome aberrations. An alternate cytogenetic approach is the observation of micronuclei, which represent chromosomal-breakage fragments or lagging chromosomes in the cell cytoplasm. The cytogenetic assays may be performed either in vivo or in vitro. In vitro cytogenetic assays are performed in the presence and absence of exogenous metabolic activation systems (S9).