Identification of kinetochore-containing (CREST+) micronuclei in mouse bone marrow erythrocytes.

A methodology for the characterization of kinetochore-containing (CREST+) micronuclei (MN), based on the use of antikinetochore antibodies (derived from CREST patients) and indirect immunofluorescence, was applied to mouse bone marrow erythrocytes. The proposed protocol allows us to obtain fluorescent signals of good quality and highly reproducible data. The clastogenic agent mitomycin C (MMC; 1 mg/kg body wt) and the two aneugenic compounds chloral hydrate (CH; 200 mg/kg body wt) and colchicine (COL; 1 mg/kg body wt) were used to verify the sensitivity of this approach to chemicals with different mechanisms of action. These compounds were tested at a 20 h time interval from treatment and all of them were able to significantly increase (P less than 0.001) the frequency of MN in polychromatic erythrocytes. Of the MN observed in preparations from control animals, 45% were CREST+ and this percentage increased significantly (P less than 0.001) after treatment with CH or COL. On the contrary, only 22% CREST+ MN were found after treatment with MMC (statistical comparison with the control value: P less than 0.001). The CREST characterization of MN induced in vivo in mouse bone marrow allows us to infer the origin of MN formation, thus contributing to the identification of aneugenic agents.