Evaluation of a new procedure for the flow cytometric analysis of in vitro, chemically induced micronuclei in V79 cells

Measurement of the frequency of micronuclei induced in cells by ionizing ra diation or by chemical treatment is widely used to analyze cytogenetic dama ge. The microscopic scoring of micronuclei is a tedious and time-consuming procedure. Therefore, attempts have been made to automate micronuclei scori ng by means of image analysis or flow cytometry. A new procedure for the fl ow cytometric analysis of chemically induced micronuclei in V79 Chinese ham ster cells has been established in our laboratory. Debris was separated fro m micronuclei by means of a new gating procedure using area and width fluor escence of the stained suspension of micronuclei and nuclei, in order to te st the sensitivity and specificity of this improved method of flow cytometr ic analysis, five well-known mutagenic compounds were tested. With the new technique, the frequency of micronuclei measured and analyzed corresponded well with results obtained by conventional microscopy. In addition, a large series of negative compounds, and weak, middle, and strong micronuclei ind ucers, were tested in order to establish criteria for discrimination betwee n genotoxic and nongenotoxic compounds by flow cytometry. This new procedur e for flow cytometric detection of micronuclei represents a quick, reliable , and relatively simple method for in vitro micronucleus testing. Environ. Mol. Mutagen. 32:387-396, 1998 (C) 1998 Wiley-Liss, Inc.