不同剂量率γ射线照射诱发淋巴细胞早熟凝集染色体环产额的研究

Comparison of prematurely condensed chromosome-rings induced by different dose-rates of gamma irradiation

目的比较不同剂量率γ射线照射诱发的淋巴细胞早熟凝集染色体环（PCC—R）的产额，建立不同剂量率的人外周血早熟凝集染色体环与辐射剂量之间的剂量效应曲线。方法取健康成年人外周血，分别用吸收剂量率为0．5和1．0Gy／min的^60Coγ射线照射，吸收剂量为0、1、2、5、10、15、20和25Gy。培养48h，终止培养前1h加入冈田酸（okadaic acid）诱导早熟凝集染色体，观察人外周血淋巴细胞PCC—R产额与照射剂量的关系。结果在20Gy剂量范围内，人外周血淋巴细胞PCC—R产额随着剂量的增加而增加。在25Gy剂量范围内，在相同剂量情况下，吸收剂量率为1．0Gy／min的PCC-R产额都要高于0．5Gy／min的产额，且在20和25Gy剂量点的差异有统计学意义。结论PCC-R作为大剂量受照情况下的生物剂量指示剂，基于不同剂量率建立的剂量效应关系曲线所估算剂量的结果会有所不同。

Objective To compare the prematurely condensed chromosome-rings （PCC-R） induced by different dose-rate of gamma irradiation and establish an easy biological method for different dose-rate of dose-response curve of PCC-R. Methods Peripheral blood samples were taken from healthy adults and irradiated by ^60Co γ-rays toO, 1, 2, 5, 10, 15, 20 and25 Gy with dose rates of 0.5 Gy/min or 1.0 Gy/min,respoctively. Then the lymphocytes were cultured for 48 h. At 1 h before the end of culture, okadaic acid was added into culture medium to induce PCC-R. The yield of PCC-R was counted at each dose point. Results The PCC-R product increased with the irradiated dose up to 20 Gy. The production of PCC-R of 1.0 Gy/min gamma irradiation was higher than that of 0.5 Gy/min at each dose point and significantly higher at 20 and 25 Gy, Conclusions Dose estimation based on PCC-R is different when using dose-response curve established with different dose-rate.