可溶性铬盐职业接触者DNA链断裂的研究

Study on DNA strand breaks in workers exposed to soluble chromate

目的通过对职业接触可溶性铬盐人群外周血淋巴细胞DNA链断裂水平的研究,了解该生物指标在职业人群中分布的水平、特点及其影响因素,探讨其作为职业接触铬盐人群生物标志物的可行性,为职业接触铬盐劳动者生物监测及健康危险性评价提供理论依据。方法本研究利用横断面现场研究,对山东省济南市某铬盐生产企业进行了流行病学调查。接触组选择重铬酸钾制造业铬盐作业健康劳动者114名(男74名、女40名),对照组为无毒物接触史的健康农民30名(男22名、女8名),两组人群在年龄、性别和吸烟状况等方面相匹配。通过问卷调查了解研究对象的一般情况、职业暴露情况、饮酒吸烟情况、既往疾病史(用药史)、急性感染情况、个人防护情况等。利用单细胞凝胶电泳法,检测外周血淋巴细胞DNA链断裂水平,并通过计算加权分评价损伤程度;作业环境铬盐浓度的测定采用双滤膜个体采样器8 h工作日连续采样,滤膜铬盐含量采用火焰原子吸收分光光度法测定;红细胞中铬浓度测定采用石墨炉原子吸收分光光度法。用SPSS10.0统计软件进行多元回归分析。结果(1)职业接触可溶性铬盐劳动者外周血淋巴细胞DNA链断裂水平得分为54.52±23.51,高于对照组的24.70±11.84,有统计学意义(P<0.01)。(2)当空气中个体铬盐暴露浓度小于106.00μg/m3时,职业接触可溶性铬盐劳动者DNA链断裂水平,随个体铬盐暴露水平的增加而增加,并呈明显的剂量-反应关系。(3)相关分析结果表明:外周血淋巴细胞DNA链断裂水平与空气中个体铬盐暴露水平、红细胞中铬浓度水平均呈显著的正相关性(P<0.01)。(4)多元回归证实:在α=0.10水平上,吸烟剂量、空气中铬盐浓度、接触铬盐的年限对淋巴细胞DNA链断裂水平影响显著。结论DNA链断裂可以作为职业接触可溶性铬盐劳动者遗传损伤效应性生物标志物,可望用于职业接触可溶性铬盐劳动者生物监测及健康危险性的评价。

Objective To explore the biological effective markers, we investigated DNA strand breaks in peripheral lymphocytes from occupational population with broad ranges of soluble chromate exposure. Methods We conducted a cross-sectional study in the chromate exposed workers employed at a chromate factory in a district of Jinan, Shandong Province. The studied population contained 114 workers from different processes of the chromate plants, in addition, 30 farmers in the countryside about one hundred kilometers away from the factory, without exposure to chromate were matched with the exposed subjects by age, gender and smoking status being identified as a control group. Personal information on age, chromate exposure, medical history （including acute infection and medicine usage）, smoking habit and alcohol consumption was obtained by questionnaire. DNA strand breaks in lymphocytes were detected by single-cell gel electrophoresis assay （comet assay） and the DNA damaged degree was evaluated by the score weighted by comet type. The air concentration of chromate was determined by individual sampling for 8 hours per clay as shift work and chromium was assayed by atomic absorption spectrometry. The chromium content in the erythrocytes from peripheral blood was determined by graphite furnace atomic absorption spectrometry. The data were analyzed by SPSS10.0 software for statistical significance. Results （1） The results showed that the score for DNA strand breaks in lymphocytes were 54.52±23.51 in the exposed group, which was significantly higher than those in the control group （24.70±11.84） （P 〈 0.01）. （2） The degree of DNA strand breaks in lymphocytes was increased in a dose-dependent manner ranging from 0 μg/m^3 to 106.00 μg/m^3. （3）Correlation analysis showed that there was a significant positive correlation between airborne chromate concentration and the degree of DNA strand break in lymphocytes （P 〈 0.01）. （4） By multiple regression analysis, it was found that the airborne concentrations, chromium contents in red blood cells and smoking habits were factors which might affect the degree of DNA breaks. Conclusion Our findings suggest that DNA strand break in lymphocytes should be an effective biomarker for occupational chromate-exposed population and be applied in biological monitoring and health risk assessment for occupational chromate-exposed population.