Development of a method to increase the proportion of polychromatic erythrocytes from mouse bone marrow for more rapid evaluation of the micronucleus assay. Comparison with the conventional method with respect to micronucleus frequency and time required for preparation and evaluation.

By treatment of bone marrow suspension in hypotonic (0.51%) saline, followed by purification on a cellulose column, the proportion of polychromatic erythrocytes in bone marrow smears can be increased 2.6-fold. Furthermore, practically all nucleated cells of erythropoietic or leukopoietic origin are removed. This kind of bone marrow preparation can lead to a considerable reduction in the time required for microscopical evaluation of the micronucleus assay without altering the rate of micronucleated polychromatic erythrocytes in a negative (isotonic saline) and a positive (mitomycin C) control group.