中文摘要：

目的 探索胞质分裂阻滞分析中，松胞素B终浓度和加入时间对辐射诱导淋巴细胞核质桥水平的影响。方法 本研究按照不同松胞素B终浓度分为2、4、6、8、10 μg/ml 5个终浓度组，此外，按照不同松胞素B加入时间分为0、28、40、44 h组4个加入时间组。用2 Gy（吸收剂量率为1 Gy/min）60Co γ射线照射正常人离体外周血（设0 Gy对照组），采用胞质分裂阻滞分析法，进行细胞培养、收获、制片、染色。在光学显微镜下分析单核细胞、双核细胞、多核细胞的比例，以及双核细胞中核质桥率及微核率。结果 各终浓度组和加入时间组（0 h组除外）的核分裂指数、双核细胞比例均随松胞素B终浓度的升高而升高，随松胞素B加入时间的推迟而降低。2 Gy射线照射后，各终浓度组和加入时间组（0 h组除外）核质桥率差异无统计学意义（P〉0.05）；5个终浓度组间微核率具有随松胞素B终浓度的增加而下降的趋势，4个加入时间组间微核率差异无统计学意义（P〉0.05）。结论 不同松胞素B终浓度和加入时间可使辐射诱导的核质桥率在一定范围内变化，但差异无统计学意义。适当增加松胞素B终浓度、提前加入时间可使双核细胞比例升高，有助于提高分析效率。

英文摘要：

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.