眼晶状体被认为是体内最具辐射敏感性的组织之一.0.5 Gy及更高的辐射剂量会诱发放射性白内障,但研究表明长期低剂量的辐射暴露也会增加眼晶状体混浊风险.目前关于低剂量电离辐射诱导眼晶状体混浊发生的具体生物学机制仍不明确,许多相互竞争的机制链可能独立或共同导致混浊的发生,如眼晶状体上皮细胞基因组损伤、氧化应激、细胞间通讯破坏和炎性反应等,遗传和表观遗传因素也可在其中发挥作用.本文旨在对低剂量电离辐射诱发眼晶状体混浊发生机制,及个体易感性在其发生和发展中的作用进行综述,以期对该病的预防和控制提供科学参考.

Parental exposure to ionizing radiation (IR) can induce mutation in germline that may lead to genome instability, chromosomal aberrations, sex ratio variations, increased cancer susceptibility, and even increased probability of birth defects among their offspring, which substantially increase the burden of hereditary diseases. Up to now, the hereditary effect of IR has been observed in a number of species, but there is lack of evidence in humans. With reference to related studies in China and globally, this article reviews the human epidemiological studies of the hereditary effect of IR and briefly discusses why the hereditary effect of IR is not obvious in humans, so as to provide a reference for future assessment of the hereditary effect of radiation in China.

目的 探讨长期低剂量电离辐射对中国阳江市天然辐射高本底地区居民眼晶状体混浊情况的影响.方法 采用整群随机抽样法,分别选择阳江市辐射高本底地区(483例)和恩平市对照地区(517例)汉族常驻居民为研究对象,对其进行问卷调查和眼晶状体检查,采用Logistic回归分析分析眼晶状体混浊及其严重程度的危险因素.结果 高本底地区居民眼晶状体混浊、皮质性混浊和后囊下混浊的患病率均高于对照地区居民(60.7％vs 51.6％,53.4％vs 46.8％,21.9％vs9.3％,P值均＜0.05);高本底地区和对照地区居民核型混浊比较,差异无统计学意义(52.4％vs 47.6％,P＞0.05).调整年龄、性别、心血管/代谢性疾病、吸烟、饮酒、饮茶等混杂因素后,非条件Logistic回归分析结果显示,高本底地区居民罹患眼晶状体混浊、皮质性混浊和后囊下混浊的风险均高于对照地区居民(P值均＜0.05);多因素无序Logistic回归分析结果显示,高本底地区居民罹患2级核型混浊的风险高于1级核型混浊(P＜0.01);有序Logistic回归分析结果显示,高本底地区居民罹患更严重的皮质性混浊的风险升高(P＜0.01).结论 长期低剂量电离辐射接触可能会增加眼晶状体混浊风险,尤其是皮质性混浊和后囊下混浊的发生风险,并影响其严重程度.

The severe health risks of radiation workers occupationally exposed to low-dose ionizing radiation cannot be ignored. According to domestic and foreign investigations and studies on the health effects caused by low-dose ionizing radiation, this review discusses the main types and mechanisms of the health effects currently being studied in the field of radiobiology, and provides a reference for occupational safety protection and health surveillance of radiation workers.

Objective:To explore the influence factors of chromosomal aberration levels in radiation workers in hospitals.Methods:Two hundred and fourteen age- and sex- matched hospital radiation workers were recruited by stratified random sampling method. According to the job title, the individuals were divided into four groups including diagnostic radiology group ( n=57), radiotherapy group ( n=49), nuclear medicine group ( n=52) and interventional radiology group ( n=56). Chromosomal aberrations in peripheral blood lymphocytes from the subjects were measured using conventional cytogenetic analysis method, and the influence factors of chromosomal aberrations were analyzed. Results:There was significant difference in the frequencies of acentric fragment, translocation and total chromosome-type aberrations among the four groups ( χ2=9.906, 19.965, 32.824, P<0.05), and the rates of aberrations were significantly higher in the interventional radiology group and the nuclear medicine groups than those in the diagnostic radiology (interventional group: χ2=4.711, 10.798, 10.845, P<0.05; nuclear medicine group: χ2=3.853, 7.674, 7.708, P<0.05) and the radiotherapy groups (interventional group: χ2=9.209, 9.772, 21.330, P<0.05; nuclear medicine group: χ2=8.010, 6.969, 10.812, P<0.05). The rates of translocation and total aberrations ( χ2=7.706, 6.667, P<0.05) and the frequencies of acentric fragment, translocation and total aberrations ( χ2=12.263, 15.360, 21.478, P<0.01) were dependent on the length of service and the dose among different groups. The rates of translocation and total aberrations significantly increased along with exposure doses ( r=0.347, 0.263, P<0.01). Poisson regression analysis indicated that the job titles and annual effective dose partly affected the levels of chromosomal aberrations[ IRR=1.797 (nuclear medicine group), 2.136 (interventional group) and 1.422 (0.5-1 mSv group); P<0.05]. Conclusions:The frequencies of chromosomal aberrations in the radiation workers of interventional and nuclear medicine groups remain higher levels in hospital, thus it is necessary to strengthen the radiation protection on these radiation workers.

In this study, the effect of ionizing radiation on 8-hydroxy-2'-deoxyguanosine (8-OHdG) in human peripheral blood was investigated. Blood samples were collected from 230 radiation workers and 8 patients who underwent radiotherapy for population study. Blood samples from 2 healthy individuals were irradiated with different X-ray doses for in vitro experiment, and levels of 8-OHdG in serum and cell culture supernatants were assessed by enzyme-linked immunosorbent assay. Observations demonstrated the positive relationships between serum 8-OHdG level and radiation dose and working period were observed, and serum 8-OHdG levels were higher among interventional radiation workers than among other hospital radiation workers. In addition, 8-OHdG yields in supernatants increased, peaked at 3 Gy of radiation dose, and then decreased with further increases in radiation; the dose-response curve obtained fitted a polynomial function. By contrast, a similar trend was not found in radiotherapy patients. The present study suggests that 8-OHdG may be a useful biomarker reflecting oxidative damage among workers occupationally exposed to low-dose radiation.

Objective To understand effects of the interventional operation on thyroid,peripheral blood indexes and chromosomal aberrations (CA) of peripheral lymphocyte of children with congenital heart disease (CHD).Methods Follow-up studies were conducted in 70 child patients undergoing cardiac catheterization and 23 with open heart surgery as control from 2010 to 2013.Postoperative follow-up examinations included thyroid ultrasound,blood routine indexes and analyses of CAs.Results Difference in thyroid ultrasound abnormality rate was not statistically significant between children with cardiac catheterization and control group (40.0％ vs.43.5％,P ＞ 0.05).There was no significant difference in white blood cell (WBC) count between interventional group and control group (P ＞ 0.05).The effects of disease type and operation time on thyroid ultrasound and WBC count were not observed (P ＞ 0.05).The frequency of chromosome aberrations,including acentric fragment,dicentrics and translocation in interventional group [(0.76 ± 0.07) ％],was higher than in control group [(0.25 ± 0.07) ％,(Z =-3.631,P ＜ 0.05],and the rates of acentric fragment and translocation were also higher in interventional group (Z =-2.531,-2.397,P ＜ 0.05).Conclusions Effect of intervention therapy on thyroid structure and WBC count in children with CHD was not observed,but the genotoxic effects remain in children with cardiac catheterization.

Objective To explore the influence of long-term low-dose ionizing radiation on 8-hydroxy-2-deoxyguanosine(8-OHdG) level in the serum of radiation workers in hospitals.Methods 307 age-and sex-matched hospital radiation workers were recruited by stratified random sampling method.After deleting the subjects without dosage information,230 individuals were divided into four groups according to their job title [including diagnostic radiology (n =75),radiotherapy (n =60),nuclear medicine (n =41) and interventional radiology (n =54)].Serum 8-OHdG level was measured by ELISA assay.Results According to the statistical analysis,there was significant difference in the serum 8-OHdG level among four groups (F =9.071,P ＜ 0.05),and the content of serum 8-OHdG was significantly higher in the interventional radiology group than that in the groups of diagnostic radiology,radiotherapy and nuclear medicine (t =-4.473,-3.011,-2.189,P ＜ 0.05).There were significant differences in serum 8-OHdG level among different dose groups and working period groups(F =7.659,3.058,P ＜ 0.05).The serum 8-OHdG levels significantly increased along with exposure dose and working period (r =0.300,0.142,P ＜ 0.05).Conclusions Serum 8-OHdG may be a potential biomarker of oxidative DNA damage in radiation workers exposed to low-dose ionizing radiation.

Long-term exposure to low dose ionizing radiation contributes to the damage of radiosensitive tissue and organ in radiation workers.The main cytogenetic index used to evaluate radiation damage induced by chronic low dose ionizing radiation is the chromosome aberrations of peripheral blood lymphocytes.In this paper,the cytogenetic evaluation indicators of radiation workers exposed to low dose ionizing radiation were reviewed basing on the research achievements of domestic and foreign scholars.The goals of this review were to supply the present situation and limitation of chromosomal aberration analysis in peripheral blood lymphocytes of radiation workers and to provide a reference for the chromosomal aberration test and assessment of radiation workers in China.