Chen Ying, Jin Cui-Zhen, Zhang Xue-Qing, Ge Shi-Li, Zhang Ze-Yun, Xu Hui, Liu Xiu-Lin, Wu De-Chang, Zhou Ping-Kun
Department of Radiation Toxicology and Oncology, Beijing Institute of Radiation Medicine, 27 Taiping Road, 100850, Beijing, People's Republic of China.
Radiat Environ Biophys. 2009 Feb;48(1):57-65. doi: 10.1007/s00411-008-0203-y. Epub 2008 Nov 13.
On 25 June 1990, a radiation accident occurred in a (60)Co source radiation unit in Shanghai, due to violations in operation regulations. This accident resulted in the exposure of seven individuals to acute high-dose and dose-rate whole-body external irradiation. Conventional chromosomal aberration analysis, G-banding automatic karyotype analysis and/or fluorescent in situ hybridization (FISH) painting methods were used to analyze chromosomal aberrations in peripheral blood lymphocytes from five of the victims 24 h to 17 years after accidental exposure to 1.9-5.1 Gy of (60)Co gamma-rays. The frequency of unstable chromosomal aberrations (dicentrics and rings) remained at constant levels 1 month after exposure. Three months after exposure, the frequency was reduced by 20-40% in three victims, while no reduction was seen in the other two victims. Twelve years after exposure, the number of dicentrics and rings decreased by more than 90%, and did not reveal a dose-dependent relationship. However, even at 12-17 years after exposure, stable chromosome aberrations, dominated by translocations, remained at a high level in a dose-dependent manner. The frequency of stable chromosomal aberrations detected by FISH showed a similar dose-dependent relationship as that detected by karyotype analysis of G-banding chromosomes. The G-banding analysis also suggested that the pattern of chromosome breakpoints is random. The FISH data showed a decreasing tendency with time for chromosome translocation frequency in the peripheral lymphocytes, and the rate of reduction varied among different individuals. It is likely that the higher dose the victim received, the lesser the translocation frequency decreased with time. The G-banding data also showed that the rate of reduction of translocations is different among individuals. From 5 to 17 years after accidental irradiation, a very small reduction (approximately 10%) of translocation frequency was observed in victims C and D, while there was about a 35% reduction (the highest among the victims) for victim G who received the smallest dose (1.9 Gy). These observations can be used to validate the existence of chromosomal aberrations in peripheral blood lymphocytes as a biological dosimeter for radiation exposures.
1990年6月25日，上海某（60）钴源辐射装置发生辐射事故，原因是违反操作规程。此次事故导致7人受到急性高剂量和高剂量率全身外照射。采用常规染色体畸变分析、G显带自动核型分析和/或荧光原位杂交（FISH）染色方法，对5名受害者在意外暴露于1.9 - 5.1 Gy的（60）钴γ射线后24小时至17年期间外周血淋巴细胞中的染色体畸变进行分析。不稳定染色体畸变（双着丝粒和环状染色体）的频率在暴露后1个月保持恒定水平。暴露后3个月，3名受害者的频率降低了20% - 40%，而另外2名受害者未见降低。暴露12年后，双着丝粒和环状染色体的数量减少了90%以上，且未显示出剂量依赖关系。然而，即使在暴露后12 - 17年，以易位为主的稳定染色体畸变仍以剂量依赖方式维持在较高水平。FISH检测到的稳定染色体畸变频率与G显带染色体核型分析检测到的频率呈现相似的剂量依赖关系。G显带分析还表明染色体断点模式是随机的。FISH数据显示外周淋巴细胞中染色体易位频率随时间呈下降趋势，且不同个体的下降速率不同。受害者接受的剂量越高，易位频率随时间下降得越少。G显带数据也表明不同个体间易位减少速率不同。在意外照射后5至17年，受害者C和D的易位频率仅有非常小的降低（约10%），而接受最小剂量（1.9 Gy）的受害者G的易位频率降低了约35%（在受害者中降幅最大）。这些观察结果可用于验证外周血淋巴细胞中染色体畸变作为辐射暴露生物剂量计的存在。
