Vitro Tests for Chromosome Damage in Mammalian Cells

IN VITRO TESTS FOR CHROMOSOME DAMAGE IN MAMMALIAN CELLS  

An altmialive method to measming mutation induction within mammalian genes involves the examination of mammalian chromosomes microscopically for the presence of visible damage. Cultures of established cells (e.g., Chinese hamster fibroblasts) or primary cells (e.g., human periphraal l3rmphoc3rtes) can be used. 

In simplest terms, these tests generally involve exposme of cultured cells to the test material for short paiods (3-6 hoius) in the presence and absence of a metabolic activation system (e.g., S9 mix), and they also involve a prolonged treatment in the absence of S9. The cells are then harvested at an appropriate time (around 

A detailed discussion of the test procedures employed is contained within Galloway et al. (1994). Detectable levels of chromosome aberrations are often found only at doses that induce some evidence of cytotoxicity, and consequently most current recommended protocols require that the maximum test concentration should induce 50% reduction in cell number or culture confluency for cell lines, or an inhibition of mitotic index by 50% for lymphocytes. However, there are growing concerns as to the relevance of genotoxic effects that are found only at highly cytotoxic concentrations (Galloway 2000), and this may be reflected by the poor specificity of mammalian cells tests (Kirkland et al. 2005). 

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