The present study addresses the hypothesis that the concentration of tetrahydroxylated Polycylic Aromatic Hydrocarbons (tetra-OH-PAHs) in hair might be a useful biomarker of human exposure to PAHs, providing quantitative assessment of the internal dose, as well as information on the associated toxicity in relation to individual's specific metabolism. By means of animal models, this work aimed at identifying new tetra-OH-PAHs which can be released from the hydrolysis of DNA-adducts and can also be directly detected in biological matrices usually used in the field of biomonitoring such as hair and urine. Results obtained from a targeted gas chromatography coupled with tandem mass spectrometry (GC-MS/MS) approach, demonstrated the presence of 8 tetrahydroxylated metabolites in DNA and 23 in hairs of rats exposed to mixtures of PAHs, which had never been analyzed before. Ten tetra-OH-PAHs were clearly characterized by using their analytical standards, corresponding to 4 parent PAHs (phenanthrene, chrysene, benz[a]anthracene and benzo[a]pyrene) whereas 13 tetra-OH-PAHs from 3 other parents (anthracene, fluoranthene and benz[k]fluoranthene) were detected but not yet characterized. No tetrahydroxylated metabolite has been clearly identified for naphthalene, fluorene, benzo[b]fluoranthene, benzo[g,h,i]perylene, or dibenzo[a,h]anthracene, which can all potentially form adducts. The relevance of tetra-OH-PAH analysis in hair as biomarkers of PAH exposure was evaluated in a dose-response study conducted on 64 rats (Long Evans females/n = 8 per groups) under repeated exposure (3 times per week) to a mixture of 16 PAHs at low doses (0.01-0.8 mg/kg) for 90 days. Most of the tetra-OH-PAHs targeted in the method were detected in the hairs of the rats, regardless of the dose of exposure. Significant linear relationships (R2 ranging from 0.558 to 0.964, p < 0.001) were observed between the administered dose and the tetra-OH-PAH concentrations in the hairs for 20 out of the 23 metabolites. By widening the range of PAH metabolites used as biomarkers of exposure so as to include the analysis of PAH tetrahydroxylated forms (especially those exhibiting more than 5 aromatic rings), the present methodology will enable multi-exposure assessments which are more accurately representative of actual situations of exposure to PAHs.

中文翻译：

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鉴定头发中多环芳烃的新四羟基化代谢物作为暴露的生物标志物和 DNA 加合物水平的特征

本研究提出假设，即头发中四羟基多环芳烃 (tetra-OH-PAHs) 的浓度可能是人类暴露于 PAHs 的有用生物标志物，提供内部剂量的定量评估以及相关毒性的信息与个体的特定代谢有关。通过动物模型，这项工作旨在鉴定新的四羟基多环芳烃，它们可以从 DNA 加合物的水解中释放出来，也可以在通常用于生物监测领域的生物基质中直接检测，如头发和尿液。从靶向气相色谱结合串联质谱 (GC-MS/MS) 方法获得的结果表明，暴露于多环芳烃混合物的大鼠的 DNA 中存在 8 种四羟基化代谢物，毛发中存在 23 种，这是以前从未分析过的。10 种四 OH-PAHs 使用他们的分析标准进行了明确表征，对应于 4 种母体 PAH（菲、屈、苯并 [a] 蒽和苯并 [a] 芘），而 13 种来自其他 3 种母体（蒽、荧蒽和苯并[k]荧蒽）被检测到但尚未表征。对于萘、芴、苯并 [b] 荧蒽、苯并 [g,h,i] 苝或二苯并 [a,h] 蒽，尚未明确鉴定出四羟基化代谢物，它们都可能形成加合物。在对 64 只大鼠（Long Evans 雌性/每组 8 只）重复暴露（每周 3 次）下进行的剂量反应研究中，评估了毛发中 tetra-OH-PAH 分析作为 PAH 暴露生物标志物的相关性。低剂量 (0.01-0.8 mg/kg) 的 16 种多环芳烃混合物，持续 90 天。无论暴露剂量如何，该方法中的大多数四羟基多环芳烃都在大鼠的毛发中检测到。对于 23 种代谢物中的 20 种，在给药剂量和毛发中的四羟基多环芳烃浓度之间观察到显着的线性关系（R2 范围从 0.558 到 0.964，p < 0.001）。通过扩大用作暴露生物标志物的多环芳烃代谢物的范围，以包括对多环芳烃四羟基化形式（尤其是那些表现出超过 5 个芳环的形式）的分析，本方法将能够进行更准确地代表实际情况的多重暴露评估暴露于多环芳烃。001) 在给药剂量和 23 种代谢物中的 20 种毛发中的四羟基多环芳烃浓度之间观察到。通过扩大用作暴露生物标志物的多环芳烃代谢物的范围，以包括对多环芳烃四羟基化形式（尤其是那些表现出超过 5 个芳环的形式）的分析，本方法将能够进行更准确地代表实际情况的多重暴露评估暴露于多环芳烃。001) 在给药剂量和 23 种代谢物中的 20 种毛发中的四羟基多环芳烃浓度之间观察到。通过扩大用作暴露生物标志物的多环芳烃代谢物的范围，以包括对多环芳烃四羟基化形式（尤其是那些表现出超过 5 个芳环的形式）的分析，本方法将能够进行更准确地代表实际情况的多重暴露评估暴露于多环芳烃。