A comparison of two methods for evaluating drug-induced chromosome alterations

Evaluating the technique and procedure for mutagenicity testing in mammals is a prerequisite to the development of a broad spectrum mutagenic assessment program. Two techniques, chromosome examination and micronucleus scoring, show promise but their applicability for mass screening is uncertain. We determined the slide observation time for these two techniques in mice treated orally, subcutaneously, intravenously, and intraperitoneally with cyclophosphamide (CY). In each instance, we detected a dose-response in less observation time by counting micronuclei in polychromatophilic erythrocytes. The simplicity of the scoring method, the ease of micronucleus identification and the rapidity of scoring all suggest the micronucleus test may be favorably integrated into a mutagenicity screening program.