中文摘要：

目的探讨氡及其子体对职业人群致肺癌的早期生物效应标志物。方法91名氡职业暴露工人按氡子体累积暴露剂量分为高[〉120WLM（工作水平月）]、中（60-120WLM）、低（30-59WLM）和最低（2-29WLM）4个剂量组,用聚合酶链反应-甲基化特异性（MSP）检测4组人群痰细胞中的6-氧-甲基嘌呤-DNA甲基转移酶（MGMT）基因的异常甲基化状态,用黄嘌呤氧化酶法测定血浆超氧化物歧化酶（SOD）活力。结果随着氡子体累积暴露剂量增加,MGMT基因甲基化率呈上升趋势（0.00%-28.00%）,且差异有统计学意义（P〈0.01）;在最低、低、中和高剂量职业氡暴露人群外周血中,SOD活力分别为（116.5±12.3）、（89.6±8.3）、（63.6±8.9）和（40.9±7.6）kU/L,组间差异有统计学意义（P〈0.05）,SOD活力呈逐渐下降趋势,线性回归方程y=138.78-16.32x（r=-0.96,P〈0.05）。结论MGMT基因甲基化和SOD活力与氡子体累积暴露剂量有关。

英文摘要：

Objective To study the methylation of O^6-methylguanine-DNA methyltransferase （MGMT） and activity of superoxide dismutase（SOD） in the target ceils of radon-exposed population. To provide the experimental base for finding the effect biomarker in the high risk population of radon-induced lung cancer. Methods 91 radon-exposed workers were divided into 4 groups, high dosage group [ 〉 120 WLM（working level month） ], medium dosage group （between 60 and 120WLM） ,low dosage group （ between 30 and 59 WLM） and the lowest dosage group （ between 2 and 29 WLM） according to the accumulated exposure dosage of the radon daughters. The aberrant promoter methylation of MGMT gene in the sputum ceils of the population in the four groups was detected with methylation specific PCR （MSP）. The activity of SOD was determined by xanthinoxidase indices. Results There was significantly upward trend for the MGMT gene methylation rate （0.00 % -28.00% ） with the increase of the accumulated exposure dosage of the radon daughters （ P 〈 0. 01 ） . The activities of SOD in human peripheral blood from the lowest to the high groups were （ 116. 5 ± 12.3 ）, （ 89.6 ± 8.3 ）, （ 63.6 ± 8.9 ） and （ 40.9 ± 7.6 ） kU/L respectively. There were significant differences among groups（ P 〈 0.05 ）. The activities of SOD decreased significantly with the cumulative dose increased（ y = 138.78 - 16.32x, r = - 0. 96, P 〈 0. 05 ）. Conclusion The methylation of MGMT gene and activity of SOD are related to the accumulate exposure dosage of the radon daughters.