中文摘要：

目的 以核质桥（NPB）为主要指标,探索低剂量60Co γ射线是否能诱导人外周血淋巴细胞的适应性反应及诱导剂量范围。方法 用60Co γ射线照射健康成年男子离体外周血,照射剂量分别为0、20、50、75、100、150和200 mGy（吸收剂量率为25 mGy/min）,照射后间隔6 h后再给予2 Gy照射（吸收剂量率为1 Gy/min）。采用胞质分裂阻滞法（CBMN）进行细胞培养,观察NPB及微核（MN）的发生情况。结果 0~200 mGy剂量范围内,NPB和MN数目随吸收剂量的增加而增多,并拟合出NPB的线性平方模型y=（1.5×10-4）x2-（5.67×10-3）x＋0.598 （R2=0.893 8）。提前给予75~100 mGy照射比直接受到2 Gy照射产生的NPB及MN数目均有所减少（U=2.66、2.97、3.96、5.89,P〈0.05）,在100 mGy照射后NPB减少最多（43.2%）。结论 低剂量60Co γ射线可以诱导人外周血淋巴细胞的适应性反应,诱导剂量范围为75~100 mGy。

英文摘要：

Objective To explore whether a low dose of 60Co γ-rays could induce the adaptive response in the formation of nucleoplasmic bridges （NPB） in human peripheral blood lymphocytes, and if so, the range of the priming dose. Methods Human peripheral blood samples from healthy males were collected and irradiated with 0, 20, 50, 75, 100, 150 and 200 mGy （dose-rate was 25 mGy/min） of 60Co γ-rays. After 6 h, the samples were irradiated with a challenge dose of 2 Gy （dose-rate was 1 Gy/min）. The cytokinesis-block micronucleus（CBMN）assay was carried out to analyze the NPB and micronuclei （MN） formation in binucleated cells. Results Within the dose range of 0-200 mGy,the yields of NPB and MN increased with irradiation dose of γ-rays and the dose response of NPB followed with a linear-quadratic equation of y=（1.5×10-4）x2-（5.67×10-3）x＋0.598 （R2=0.893 8）. Compared with the samples irradiated with 2 Gy alone, the yields of NPB and MN were significantly reduced when the samples were irradiated with a priming dose of 75-100 mGy before 2 Gy irradiation （U=2.66, 2.97, 3.96, 5.89,P〈0.05）. The biggest decrease ratio of NPB yields approached to 43.2% at the priming dose of 100 mGy. Conclusions Low doses in the range of 75-100 mGy of 60Co γ-rays could induce the adaptive response of NPB formation in human peripheral blood lymphocytes.