低浓度接触苯的工人淋巴细胞DNA损伤的剂量-反应关系

A dose-response relationship study of lymphocyte DNA damage for workers exposed to low concentrations of benzene

目的研究低浓度接触苯的工人淋巴细胞DNA损伤的剂量-反应关系。方法选取东莞市某电子企业低浓度接触工人62人为接苯组,另选择某食品加工企业工人45人为对照组。采用采样法和观察法相结合的方法划分相似接触组(SEG)。用单细胞凝胶电泳试验(彗星试验)检测淋巴细胞DNA损伤,以彗星细胞率和彗星细胞尾长作为指标。结果接苯组彗星细胞率(15.7%)高于对照组(8.1%),差异有统计学意义。观察组代表淋巴细胞DNA损伤的彗星细胞尾长不同分级的比例(Ⅰ和Ⅱ级分别为42.0%和12.9%)均高于对照组(Ⅰ和Ⅱ级分别为32.9%和5.2%),差异有统计学意义。彗星细胞率随接触浓度升高(<0.1、0.1~3.0、>3.0)而升高(14.5%、15.6%、17.8%),彗星细胞尾长不同分级的比例随接触浓度升高(<0.1、0.1~3.0、>3.0)而升高(Ⅰ和Ⅱ级分别为42.3%、44.6%和13.1%、16.9%),差异有统计学意义。彗星细胞率随累积接触浓度增大(<0.7、0.7~22.2、>22.2)而升高(14.5%、15.6%、17.8%),差异有统计学意义。彗星细胞尾长不同分级的比例随累积接触浓度增大(<0.7、0.7~22.2、>22.2)而升高(Ⅰ和Ⅱ级分别为39.6%、41.3%、45.7%和9.9%、13.0%、16.4%),差异有统计学意义。结论低于国家职业卫生标准的接触亦可引起明显的DNA损伤,说明目前的职业卫生限值不够安全,尤其在预防血液毒性和遗传毒性作用方面。

Objective To study the dose-response relationship of lymphocyte DNA damage for workers exposed to low concentrations of benzene.Methods Sixty-two workers exposed to low concentrations of benzene from an electronics company in Dongguan were selected as an observation group,and forty-five workers from a food processing enterprise as a control group.Similar exposure groups（SEG）were defined through using both the sampling method and observation method.Lymphocyte DNA damage was detected by a experiment of a single cell gel electrophoresis（comet assay）.The observation index was the comet cell rate and comet cell tail length.Results Comet cell rate of the exposed benzene group（15.7%）was higher than the control group（8.1%）,and statistically significant difference was found（P 0.001）.The proportion of highgrade comet cell tail length in the observational group（42.0%/12.9%for Class I/II respectively）was higher than that in the control group（32.9%/5.2% for Class I/II）with statistical significance.With increased concentration of exposure（0.1、0.1～3.0、3.0）,statistical higher comet cell rate（14.5%、15.6%、17.8%）and proportion of high-grade comet cell tail length（42.3%/44.6% and13.1%/16.9% for Class I/II respectively）.Similar results were found with cumulative exposure.The more exposure（0.7、0.7～22.2、22.2）,the higher rate of comet cell（14.5%、15.6%、17.8%）and proportion of high-grade comet cell tail length（39.6%/41.3%,45.7%/9.9%,and 13.0%/16.4% for Class I/II respectively,P〈0.01）.Conclusions Obvious DNA damage could happen even with exposure lower than the national health standard,which suggests the insufficiency of current occupational health limits,especially in aspects of hematologic and genetic toxicity.The limit value of a new occupational health should be developed.