Cytokinesis-block micronucleus assay with kinetochore detection in colchicine-treated human fibroblasts.

A modified micronucleus assay using antikinetochore antibody has been developed in cytokinesis-blocked human fibroblasts as a simple method to identify aneuploidy-inducing agents. Different protocols for inducing binucleated cells by cytochalasin B in colchicine-treated human fibroblasts were investigated. A dose-related increase in kinetochore-positive micronuclei was obtained when cytochalasin B was given subsequent to colchicine treatment. No induction of micronuclei was observed in combined treatments of the two substances. These results indicate that the detection of kinetochores in micronucleated cytokinesis-blocked human fibroblasts can be effectively applied to the identification of environmental agents with aneuploidy-inducing potential. However, in testing such compounds particular attention should be paid to the protocol used for inducing cytokinesis-blocked cells.