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 DNA damage in workers exposed to benzene at low concentrations. Methods Sixty-two workers exposed to low concentration in an electronics enterprise in Dongguan City were selected as benzene group, and 45 workers in a food processing enterprise were selected as the control group. The method of combining sampling and observation is used to classify the similar contact group (SEG). Lymphocyte DNA damage was detected by single cell gel electrophoresis (comet assay), using the comet cell rate and comet cell tail length as indicators. Results The percentage of comet cells (15.7%) in the benzene group was higher than that in the control group (8.1%), the difference was statistically significant. In the observation group, the proportion of tail length of comet cells that expressed DNA damage in lymphocytes was 42.0% and 12.9% in grade I and grade II, respectively (32.9% and 5.2% in grade I and grade II, respectively) Statistical significance. The percentage of comet cells increased with contact concentration (<0.1, 0.1-3.0,> 3.0) (14.5%, 15.6%, 17.8% 0.1 ~ 3.0,> 3.0) (grade Ⅰ and Ⅱ were 42.3%, 44.6% and 13.1%, 16.9% respectively), the difference was statistically significant. The rate of comet cell increased with the increase of cumulative contact concentration (<0.7,0.7 ~ 22.2,> 22.2) (14.5%, 15.6%, 17.8%), the difference was statistically significant. The proportions of tail length of comet cells increased with the increase of cumulative contact concentration (<0.7, 0.7-22.2,> 22.2) (Grade I and II were 39.6%, 41.3%, 45.7% and 9.9%, 13.0% 16.4%), the difference was statistically significant. Conclusions Exposure to occupational health standards below national standards can also cause significant DNA damage, indicating that current occupational hygiene limits are not safe enough, especially in terms of preventing hematologic and genotoxic effects.