Flow cytometric detection of micronuclei and cell cycle alterations in fish-derived cells after exposure to three model genotoxic agents: mitomycin C, vincristine sulfate and benzo(a)pyrene

The measurement of cytogenetic alterations in vitro is considered an initia l step in the risk assessment procedures for genotoxic agents, The concern about genotoxic pollutants in natural fish population makes the use of fish -derived cells an useful tool for these purposes. The technological improve ments in well-established cytogenetic endpoints, such as micronuclei (MN) e stimations by means of flow cytometry, have been proposed in the later year s using mammalian cells. In this work, we test the capability of flow cytom etry to evaluate MN induction and cell cycle alterations in an established fish cell line (RTG-2) using three agent-inductor models at different conce ntrations and exposure periods. For mitomycin C, an inverse relationship be tween length of exposure period and concentrations was observed. A dose-res ponse relationship was observed after exposing RTG-2 cells to vincristine s ulfate and benzo(a)pyrene. As this study shows, RTG-2 cells respond to clas togenic and aneugenic effects of the tested chemicals through the induction of MN at similar doses to mammalian cells and without the addition of exog enous metabolic activity. The possibility to check cell cycle alterations, in the same sample, gives the opportunity to evaluate early signals of cyto toxicity. The use of flow cytometry improves the assay by means of its spee d and objectivity, which makes the assay very useful for genotoxicity asses sment of aquatic chemicals. (C) 2000 Elsevier Science B.V. All rights reser ved.