CYTOKINESIS-BLOCK MICRONUCLEUS (CBMN) ASSAY/CBMN CYTOME ASSAY IN HUMAN LYMPHOCYTES AFTER IN VITRO IRRADIATION AND ITS USE IN BIODOSIMETRY

Abstract

Aim: Cytokinesis-block micronucleus (CBMN) assay and its comprehensive variant CBMN cytome assa are cytogenetic methods. CBMN is based on assessment of micronuclei in nucleated cells that hav completed only one nuclear division. Besides micronuclei, CBMN cytome assay analyzes additiona genotoxic (nucleoplasmic bridges and nuclear buds), cytostatic (nuclear division index), and cytotoxi (amount of necrotic and apoptotic cells) parameters. The aim of this study is to evaluate these parameter in human blood lymphocytes after in vitro irradiation and to assess its contribution to biodosimetry. Materia and methods: Human blood from 6 donors was irradiated by 0, 1, 2, 3, 4, or 5 Gy and cultivated fo in vitro 72 hours. Blood lymphocytes were stimulated with phytohemagglutinin and their cytokinesis was blocke by cytochalasin B. After cultivation, cultures were hypotonically treated, dropped onto glass slides an stained with Giemsa. Slides were evaluated by microscope. Results: We observed significantly increase amount of micronuclei, nucleoplasmic bridges, and nuclear buds measured in binucleated cells, significantl increased amount of micronuclei measured in mononucleated cells and significantly decreased nuclea division index after irradiation by 1, 2, 3, 4, and 5 Gy. Amount of death cells (apoptotic and necrotic significantly increased after irradiation by 4 and 5 Gy. Conclusion: Although all parameters assessed b CBMN cytome assay have biodosimetric potential, practically feasible is only evaluation of micronuclei i binucleated cells. This parameter was used to construct in vitro linear-quadratic dose-response calibratio curve which could be used as a biodosimetric tool for triage of radiation casualties.