ABSTRACT
The results of the extension of a collaborative study for the detection of chemical-induced DNA damage in rat hepatocytes in vitro are presented in this report. Three coded compounds, i.e. 1,4-butanediol dimethanesulphonate, hydrazine sulphate and sodium dichromate, were tested for DNA repair synthesis by seven different laboratories, either using autoradiographic procedures or the liquid scintillation counting technique. Inter-laboratory standardization was intentionally not requested in order to investigate the validity of each study design under routine conditions. 1,4-Butanediol dimethanesulphonate was clearly positive in most laboratories; sodium dichromate was generally positive, while the results on hydrazine sulphate were contradictory.
Subject(s)
DNA Damage , Mutagenicity Tests/standards , Animals , Autoradiography , Busulfan/toxicity , Cells, Cultured , Chromates/toxicity , DNA Repair , Hydrazines/toxicity , Laboratories/standards , Liver/cytology , Mutagenicity Tests/methods , Rats , Scintillation CountingABSTRACT
We report the results of a collaborative study for the detection of chemical-induced DNA damage in primary cultures of rat hepatocytes. The methods include the detection of unscheduled DNA synthesis (UDS) with either autoradiography (5 laboratories) or liquid scintillation counting (2 laboratories) and the assessment of DNA single-strand breaks with the alkaline elution assay (1 laboratory). Interlaboratory standardization was omitted in order to prove the agreement of the assays under routine conditions. Five coded chemicals were tested. For 4 chemicals (2-acetylaminofluorene, thiourea, glycerine and potassium chloride) the UDS data were consistent in all laboratories, thus indicating a high consensus of the test systems applied in the different laboratories. Those 3 chemicals that were not expected to elicit genotoxic activity (thiourea, glycerine, and potassium chloride) yielded negative results in all laboratories. 2-Acetylaminofluorene, a known DNA-damaging agent in hepatocytes, gave strongly positive responses in all laboratories. In contrast, N-nitrosodiphenylamine led to equivocal responses.
