迁延性低剂量192铱受照人员染色体畸变及端粒酶活性变化

目的观察受192铱（192Ir）照射人员临床症状、染色体畸变情况及骨髓单个核细胞（bone marrow mononu-clear cells,BMNCs）端粒酶活性变化,积累迁延性、小剂量受照者远后效应的临床资料。方法以2002-07月发生在作者单位受迁延性、低剂量192Ir意外照射的54人为研究对象,随访受照人员在照射后1个月,1、5、10年的临床症状,微量全血培养法制备受检标本,检测非稳定性畸变和稳定性畸变情况,采用端粒重复序列扩增技术（telomerase repeat amplifi-cation protocol,TRAP）-酶联免疫吸附测定法（enzyme-linked immunosorbent assay,ELISA）检测对应时间点的BMNCs端粒酶活性。结果①受192Ir迁延性、低剂量照射后1个月,90.7%受照人员出现不同程度临床症状,多数在1年内消失或改善。②受照人员于照射后1个月非稳定性畸变检出率较高,其中＂双＋环＂畸变率（4.82±0.65）%,稳定性畸变率（1.06±0.07）%,总畸变率（9.62±0.81）%;1年后＂双＋环＂畸变及总畸变率均显著下降至1个月水平的20%;5到10年后非稳定性畸变、稳定性畸变已基本消失。③照射后1月,受照人员BMNCs端粒酶活性为（0.47±0.06）,较同龄健康对照组显著升高（P〈0.01）,1年、5年后受照人员BMNCs端粒酶活性分别为（0.42±0.06）,（0.34±0.05）,但仍高于对照组（P〈0.01）,10年后BMNCs端粒酶活性为（0.18±0.06）,回落至接近正常水平（P〉0.05）。结论 192Ir低剂量、迁延性受照人员早期可出现以＂双＋环＂为主的非稳定性畸变,相对应其BMNCs端粒酶活性增高;5～10年后两者均逐渐回落至正常水平,随访10年未发生骨髓衰竭综合征及白血病等恶性克隆性疾病。

Changes of Chromosome Aberration and Telomerase Activity in Staff Exposed to Persisting Low Dose 192Ir Radiation

Objective To observe the clinical symptoms, chromosome aberration and telomerase activity of the bone marrow mononuclear cells （BMNCs） in humans exposed to low dose 192 Ir radiation and collect clinical materials of the late effects on persisting low dose radiation. Methods A total of 54 persons exposed to low dose 192 Ir radiation were selected and received 10 years follow-up. Chromosome aberrations were analysed using micro-whole blood culture method. Telomerase activity of the BMNCs was detected by telomerie repeat amplification protocol-enzyme-linked immunosorbent assay （TRAP-ELISA）. Results ①One month after exposure to low dose 192Ir radiation,90. 7% subjects exhibited different de- grees of clinical symptoms, among which most were improved or disappeared within 1 year. ②Detection rate of unstable aberrations was high of the subjects one month after exposure. The cumulative incidence of ＂dic ＋ r＂ aberrations was （4. 82＋ 0. 65） ~, stable aberrations （1.06 ±0. 07） %, and total aberration （9. 62 ±0. 81） %. After 1 year, the incidence of ＂dic ＋ r＂ aberrations and total distortions decreased significantly to 20% of those at 1 month. After 5 to 10 years, unstable aberrations and stable aberrations almost disappeared. ③BMNCs telomerase activity was （0. 47 ± 0. 06） 1 month after exposure, significantly higher than the healthy controls （P〈0. 01）. It was （0. 42 ± 0. 06） and （0. 34 ± 0.05） 1 year and 5 years later respectively, significantly higher than the healthy controls （P 〈 0. 01）. BMNCs telomerase activity was （0. 18 ± 0. 06） 10 years later and dropped to nearly normal level （P〉0. 05）. Conclusion In the early stage after exposure to low dose 192Ir radiation, mainly ＂dic ＋ r＂ unstable aberrations can appear in the subjects, and the corresponding BMNCs telomerase activity are increased. After 5 to 10 years, both indexes gradually decrease to the normal level. Bone marrow failure disease and malignant clone disorder happen were not observed in 10 years follow-up.