Institute of Radiation Medicine, Fudan University, Shanghai, China.
Mutat Res. 2013 Jan-Feb;741-742:51-6. doi: 10.1016/j.mrfmmm.2012.12.007. Epub 2013 Jan 8.
Combination radiation is a real situation of both nuclear accident exposure and space radiation environment, but its biological dosimetry is still not established. This study investigated the dose-response of micronuclei (MN) induction in lymphocyte by irradiating HMy2.CIR lymphoblast cells with α-particles, γ-rays, and their combinations. Results showed that the dose-response of MN induced by γ-rays was well-fitted with the linear-quadratic model. But for α-particle irradiation, the MN induction had a biphasic phenomenon containing a low dose hypersensitivity characteristic and its dose response could be well-stimulated with a state vector model where radiation-induced bystander effect (RIBE) was involved. For the combination exposure, the dose response of MN was similar to that of α-irradiation. However, the yield of MN was closely related to the sequence of irradiations. When the cells were irradiated with α-particles at first and then γ-rays, a synergistic effect of MN induction was observed. But when the cells were irradiated with γ-rays followed by α-particles, an antagonistic effect of MN was observed in the low dose range although this combination radiation also yielded a synergistic effect at high doses. When the interval between two irradiations was extended to 4h, a cross-adaptive response against the other irradiation was induced by a low dose of γ-rays but not α-particles.
联合辐射是核事故照射和空间辐射环境的真实情况，但目前其生物剂量测定尚未建立。本研究通过用α-粒子、γ射线及其组合照射 HMy2.CIR 淋巴母细胞，研究了淋巴细胞微核（MN）诱导的剂量反应。结果表明，γ射线诱导的 MN 剂量反应与线性二次模型拟合良好。但对于α粒子照射，MN 诱导具有双相现象，包含低剂量超敏特征，其剂量反应可以通过涉及辐射诱导旁观者效应（RIBE）的状态向量模型很好地刺激。对于联合暴露，MN 的剂量反应与α-照射相似。然而，MN 的产量与照射的顺序密切相关。当细胞首先用α-粒子照射，然后用γ射线照射时，观察到 MN 诱导的协同效应。但是，当细胞先用γ射线照射，然后用α-粒子照射时，在低剂量范围内观察到 MN 的拮抗效应，尽管这种组合辐射在高剂量下也产生协同效应。当两次照射之间的间隔延长至 4 小时时，低剂量γ射线诱导对另一次照射的交叉适应性反应，但α-粒子则没有。
