低剂量工业射线探伤工人职业暴露的遗传损伤效应

目的:探讨低剂量电离辐射对工业射线探伤工人的遗传损伤效应。方法:选取重庆市某国有企业探伤工人31人为探伤组,招募年龄、性别构成和吸烟率无显著差异的健康服务行业人员49人作为对照组。采用热释光剂量计(TLD)对探伤人员进行个体剂量监测。微量全血培养的胞质分裂阻滞微核试验检测染色体损伤。采用Real-Time PCR分析线粒体DNA(mtDNA)拷贝数和超螺旋构象,长链PCR分析mtDNA的完整性,qRT-PCR分析线粒体转录因子A(TFAM)和过氧化酶体增殖受体γ轴共活化因子1α(PGC-1α)的mRNA水平。结果:探伤工人的辐射年有效剂量为(0.15±0.03) mSv/a,范围为(0.12~0.21) mSv/a。探伤组的微核率和核芽率均显著增加(P<0.01)。探伤组mtDNA拷贝数(40.04±24.99)与对照组(24.86±19.14)比较显著增加(P<0.05),探伤工人的mtDNA超螺旋构象有显著改变(P<0.05),探伤组mtDNA完整性(95.10±9.54)与对照组(313.51±14.58)相比明显降低(P<0.01),探伤组的TFAM和PGC-1α的mRNA水平均显著升高(P<0.01)。结论:探伤工人的辐射年有效剂量均值符合国家规定的放射职业接触标准。电离辐射职业暴露可引起探伤工人明显的染色体损伤和mtDNA损伤,需采取更安全有效的防护措施。

Genotoxic effects of low dose ionizing radiation occupationally exposed in industrial flaw detection workers

OBJECTIVE:To assess the genetic damage of low dose ionizing radiation(LDIR) occupationally exposed in flaw detection workers. METHODS:We used the Thermo-luminescent Dosimeter(TLD) to measure the individual exposure dose. Thirty-one flaw detection workers and forty-nine people without such exposure were enrolled. The cytokinesis-block micronucleus (CBMN) assay was performed to detect the chromosome damage in peripheral blood lymphocytes. Real-time PCR was used to analyze the mtDNA copy number and supercoiling formation change. Long-PCR was applied to analyze mtDNA integrity. qRT-PCR was applied to analyze mRNA levels of TFAM and PGC-1α. RESULTS:The mean annual effect dose in flaw detection workers was (0.15±0.03) mSv/a, range in (0.12-0.21) mSv/a. The MN and NBUDs rate in flaw detection worker group were obviously elevated compared with controls (P<0.01). In our study, the mtDNA copy number of flaw detection workers(40.04±24.99) was higher than controls (24.86±19.14) (P<0.01), and the supercoiling formation was also evidently changed (P<0.05). The mtDNA integrity of flaw detection workers (95.10±9.54) was decreased compared to controls (313.51±14.58)(P<0.01). The mRNA levels of TFAM and PGC-1α was found to be higher than controls (P<0.01). CONCLUSION:We found all of the annual effect dose of flaw detection workers are conforming the state radiological protection standards. However, the induction of chromosome damage and mtDNA damage caused by LDIR were evident, the health of flaw detection workers are at risk.