Detonation of an improvised nuclear device highlights the need to understand the risk of mixed radiation exposure as prompt radiation exposure could produce significant neutron and gamma exposures. Although the neutron component may be a relatively small percentage of the total absorbed dose, the large relative biological effectiveness (RBE) can induce larger biological DNA damage and cell killing. The objective of this study was to use a hematopoietically humanized mouse model to measure chromosomal DNA damage in human lymphocytes 24 h after in vivo exposure to neutrons (0.3 Gy) and X rays (1 Gy). The human dicentric and cytokinesis-block micronucleus assays were performed to measure chromosomal aberrations in human lymphocytes in vivo from the blood and spleen, respectively. The mBAND assay based on fluorescent in situ hybridization labeling was used to detect neutron-induced chromosome 1 inversions in the blood lymphocytes of the neutron-irradiated mice. Cytogenetics endpoints, dicentrics and micronuclei showed that there was no significant difference in yields between the 2 irradiation types at the doses tested, indicating that neutron-induced chromosomal DNA damage in vivo was more biologically effective (RBE ∼3.3) compared to X rays. The mBAND assay, which is considered a specific biomarker of high-LET neutron exposure, confirmed the presence of clustered DNA damage in the neutron-irradiated mice but not in the X-irradiated mice, 24 h after exposure.
Cytogenet Genome Res

中文翻译：

---

暴露于中子和 X 射线 24 小时后人源化小鼠淋巴细胞的细胞遗传学损伤

简易核装置的爆炸凸显了了解混合辐射暴露风险的必要性，因为即时辐射暴露可能会产生大量的中子和伽马辐射。尽管中子成分在总吸收剂量中所占的百分比可能相对较小，但较大的相对生物有效性 (RBE) 可以诱导较大的生物 DNA 损伤和细胞杀伤。本研究的目的是使用造血人源化小鼠模型在体内暴露于中子 (0.3 Gy) 和 X 射线 (1 Gy) 后 24 小时测量人淋巴细胞的染色体 DNA 损伤。进行人双着丝粒和胞质分裂阻断微核测定以分别测量来自血液和脾脏的体内人淋巴细胞的染色体畸变。基于荧光原位杂交标记的mBAND测定法用于检测中子辐照小鼠血液淋巴细胞中中子诱导的1号染色体倒位。细胞遗传学终点、双着丝粒和微核表明，在所测试的剂量下，两种辐照类型之间的产量没有显着差异，表明与 X 射线相比，体内中子诱导的染色体 DNA 损伤在生物学上更有效（RBE ∼3.3）。mBAND 测定被认为是高 LET 中子暴露的特定生物标志物，证实了暴露后 24 小时，中子辐照小鼠中存在聚集的 DNA 损伤，但 X 辐照小鼠中没有。双着丝粒和微核表明，在所测试的剂量下，两种辐照类型之间的产量没有显着差异，表明与 X 射线相比，体内中子诱导的染色体 DNA 损伤在生物学上更有效（RBE ∼3.3）。mBAND 测定被认为是高 LET 中子暴露的特定生物标志物，证实了暴露后 24 小时，中子辐照小鼠中存在聚集的 DNA 损伤，但 X 辐照小鼠中没有。双着丝粒和微核表明，在所测试的剂量下，两种辐照类型之间的产量没有显着差异，表明与 X 射线相比，体内中子诱导的染色体 DNA 损伤在生物学上更有效（RBE ∼3.3）。mBAND 测定被认为是高 LET 中子暴露的特定生物标志物，证实了暴露后 24 小时，中子辐照小鼠中存在聚集的 DNA 损伤，但 X 辐照小鼠中没有。
细胞基因组研究