Influences of cytochalasin-B on radiation-induced nucleoplasmic bridges in peripheral blood lymphocytes

Abstract

Objective To explore the influences of the final concentration and adding time of Cytochalasin-B (Cyt-B) on radiation-induced nucleoplasmic bridges (NPB) in cytokinesis-block assay. Methods Human peripheral blood samples were divided into 5 final concentration groups (group 2, 4, 6, 8, 10 μg/ml) according to different final concentrations of Cyt-B. Moreover, blood samples were divided into 4 adding time groups (group 0, 28, 40, 44 h) according to different adding times of Cyt-B. Blood samples were irradiated with 0 (sham irradiation) and 2 Gy 60Co -rays in vitro, at a dose rate of 1 Gy/min. A cytokinesis-block assay was carried out to prepare NPB samples. The percentages of mononucleated, binucleated and multinucleated cells, as well as the frequencies of NPB and micronucleus (MN) in binucleated cells were analyzed using an optical microscope. Results Nuclear division index (NDI) and the percentages of binucleated cells increased with increased concentration of Cyt-B, and decreased with delayed adding time of Cyt-B (except group 0 h) in both final concentration groups and adding time groups. After exposed to 2 Gy, NPB frequencies were no significant difference (except group 0 h). MN frequencies had the trend of decreased with the increased concentration of Cyt-B, but no significant difference with adding time of Cyt-B. Conclusions In cytokinesis-block assay, different final concentration and adding time of Cyt-B may induce to the variation of NPB frequencies, but there was no significant difference. Appropriate increased final concentration or ahead adding time of Cyt-B can increase the percentage of binucleated cells that help to improve the efficiency of analysis. Key words: Nucleoplasmic bridge; Cytochalasin B; Cytokinesis block assay; Micronucleus