Toxicology Unit, Department of Psychobiology, University of A Coruña, Edificio de Servicios Centrales de Investigación, Campus Elviña, 15071-A Coruña, Spain.
Mutat Res. 2011 Mar 18;721(1):81-8. doi: 10.1016/j.mrgentox.2011.01.001. Epub 2011 Jan 15.
Lead is a heavy metal that has been used for many centuries and it is still used for various industrial purposes thanks to its physical and chemical characteristics. Human exposure to lead can result in a wide range of biological effects depending upon the level and duration of exposure. Despite the fact that lead has been found capable of eliciting genotoxic responses in a wide range of tests, not all studies have been conclusive. Although several experimental studies have shown that lead may modulate immune responses, data in exposed humans are still preliminary. The purpose of our study was to evaluate the genotoxic and immunotoxic effects of lead exposure in a group of 70 male workers from two Portuguese factories. The control group comprised 38 healthy males. The exposed individuals showed significantly higher levels of lead in blood and zinc protoporphyrin, and significantly lower δ-aminolevulinic acid dehydratase activity than the controls, suggesting a relatively high lead exposure. Nevertheless, the limit of 70 μg/dl for lead in blood established by the Portuguese regulation was never reached. Results of the comet assay were not modified by the exposure, but a significant increase in the mutation frequency in the exposed workers was obtained in the T-cell receptor mutation assay. Furthermore, data obtained in the analysis of the different lymphocyte subsets showed a significant decrease in %CD8+ cells and a significant increase in the %CD4+/%CD8+ ratio in exposed individuals with regard to the controls. No clear effect was observed for vitamin D receptor genetic polymorphism on the parameters evaluated. In view of our results showing mutagenic and immunotoxic effects related to lead exposure in occupational settings, it seems that the Portuguese biological exposure limit for lead needs to be revised in order to increase the safety of exposed workers.
铅是一种重金属，已经使用了几个世纪，由于其物理和化学特性，它仍然被用于各种工业用途。人类接触铅会导致一系列生物效应，这取决于接触的水平和时间。尽管已经发现铅在广泛的测试中能够引起遗传毒性反应，但并非所有研究都具有结论性。尽管几项实验研究表明铅可能调节免疫反应，但暴露于铅的人类的数据仍然是初步的。我们的研究目的是评估两组来自葡萄牙两家工厂的 70 名男性工人的铅暴露的遗传毒性和免疫毒性效应。对照组由 38 名健康男性组成。暴露组的血液和锌原卟啉中的铅水平明显高于对照组，δ-氨基-γ-酮戊酸脱水酶活性明显低于对照组，这表明铅暴露程度相对较高。然而，葡萄牙法规规定的血液中铅的 70μg/dl 限值从未达到过。彗星试验的结果不受暴露的影响，但在 T 细胞受体突变试验中，暴露工人的突变频率显著增加。此外，在对不同淋巴细胞亚群的分析中获得的数据显示，与对照组相比，暴露个体的 %CD8+细胞显著减少，而 %CD4+/%CD8+比值显著增加。维生素 D 受体遗传多态性对所评估的参数没有明显影响。鉴于我们的结果显示与职业环境中铅暴露相关的致突变和免疫毒性效应，似乎需要修订葡萄牙的生物暴露限值，以提高暴露工人的安全性。
