The study aims to investigate the influence of exposure to low concentrations of benzene on urinary biomarkers of nucleic acid oxidative damage and methylation. Benzene exposure was characterized for 93 coke production workers by measuring both airborne benzene and S-phenylmercapturic acid (SPMA) and unmodified benzene (U-B) in urine samples, collected at the end of the shift (ES) and at the next morning before shift (next BS). In the same urinary samples, biomarkers of oxidative damage and nucleic acid were determined. Urinary concentrations of cotinine and creatinine were also determined to evaluate the smoking effect and to normalize urinary concentrations of analytes, respectively. The biomarkers of benzene internal dose, of oxidative damage (8-hydroxyy-7,8-dihydroguanine, 8-hydroxy-7,8-dihydroguanosine and 8-hydroxy-7,8-2'deoxyguanosine) and some of the biomarkers of nucleic acid methylation (5-Methyl-Cytosine, 1-Methyl-Guanine and 7-Methyl-Guanine) were higher in the ES than the next BS samples. Positive associations between ES 5-Methyl-Cytosine and both SPMA and U-B were found. In conclusion, occupational exposure to low levels of benzene seems to be related to urinary ES 5-Methyl-Cytosine that could be a possible biomarker to evaluate the changes of the nucleic acid methylation status.

中文翻译：

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暴露于低浓度苯的工人的尿液中核酸氧化和甲基化生物标志物

该研究旨在调查暴露于低浓度苯对核酸氧化损伤和甲基化的尿液生物标志物的影响。通过测量在轮班结束 (ES) 和轮班前的第二天早上收集的尿液样本中的空气中苯和 S-苯基巯基酸 (SPMA) 和未改性苯 (UB)，对 93 名焦炭生产工人的苯暴露进行了表征。下一个 BS）。在相同的尿样中，确定了氧化损伤和核酸的生物标志物。还测定了可替宁和肌酐的尿浓度，以分别评估吸烟效果和使分析物的尿浓度正常化。苯内剂量、氧化损伤（8-羟基-7,8-二氢鸟嘌呤、8-羟基-7,8-二氢鸟苷和8-羟基-7,8-2'）的生物标志物 脱氧鸟苷）和一些核酸甲基化的生物标志物（5-甲基-胞嘧啶、1-甲基-鸟嘌呤和 7-甲基-鸟嘌呤）在 ES 中高于下一个 BS 样品。发现 ES 5-甲基胞嘧啶与 SPMA 和 UB 之间呈正相关。总之，职业暴露于低水平的苯似乎与尿 ES 5-甲基-胞嘧啶有关，这可能是评估核酸甲基化状态变化的生物标志物。