Rapid method for improving slide quality in the bone marrow micronucleus assay; an adapted cellulose column procedure

Micronuclei are routinely scored in anucleate erythrocytes in bone marrow smears stained with acridine orange. Intense fluorescence from the many nucleated cells in the preparations can interfere with micronucleus detection and cause fatigue in the reader. A method for removing nucleated cells by filtering bone marrow through cellulose packed in syringes was developed by Romagna some ten years ago, but has not been used routinely because of the excessive time needed to prepare columns. We have modified the method very simply by filling chromatography columns by pipet with a cellulose suspension. We show here that column filtration of bone marrow does not affect the numbers of micronucleated polychromatic erythrocytes (MN-PCEs) scored from mice treated with the chromosome breaking agents mitomycin C and cyclophosphamide, or the aneuploidy-inducing spindle poisons, colchicine and vinblastine. The extra preparation time is only about half an hour for a full scale micronucleus assay, and results in better slides and faster scoring.