Laboratory of Environmental Toxicology, Chulabhorn Research Institute, Lak si, Bangkok, Thailand; Center of Excellence on Environmental Health and Toxicology, CHE, Ministry of Education, Thailand; Inter-University Program in Environmental Toxicology, Technology and Management (Chulabhorn Research Institute, Asian Institute of Technology, Mahidol University), Thailand.
Int J Hyg Environ Health. 2014 Jan;217(1):23-33. doi: 10.1016/j.ijheh.2013.03.002. Epub 2013 Mar 15.
Particulate pollution is a major public health concern because epidemiological studies have demonstrated that exposure to particles is associated with respiratory diseases and lung cancer. Diesel exhaust particles (DEP), which is classified as a human carcinogen (IARC, 2012), are considered a major contributor to traffic-related particulate matter (PM) in urban areas. DEP consists of various compounds, including PAHs and metals which are the principal components that contribute to the toxicity of PM. The present study aimed to investigate effects of PM on induction of oxidative DNA damage and inflammation by using lymphocytes in vitro and in human exposed to PM in the environment. Human lymphoblasts (RPMI 1788) were treated with DEP (SRM 2975) at various concentrations (25-100 μg/ml) to compare the extent of responses with alveolar epithelial cells (A549). ROS generation was determined in each cell cycle phase of DEP-treated cells in order to investigate the influence of the cell cycle stage on induction of oxidative stress. The oxidative DNA damage was determined by measurement of 8-hydroxy-deoxyguanosine (8-OHdG) whereas the inflammatory responses were determined by mRNA expression of interleukin-6 and -8 (IL-6 and IL-8), Clara cell protein (CC16), and lung surfactant protein-A (SP-A). The results showed that RPMI 1788 and A549 cells had a similar pattern of dose-dependent responses to DEP in terms of particle uptake, ROS generation with highest level found in G2/M phase, 8-OHdG formation, and induction of IL-6 and IL-8 expression. The human study was conducted in 51 healthy subjects residing in traffic-congested areas. The effects of exposure to PM2.5 and particle-bound PAHs and toxic metals on the levels of 8-OHdG in lymphocyte DNA, IL-8 expression in lymphocytes, and serum CC16 were evaluated. 8-OHdG levels correlated with the exposure levels of PM2.5 (P<0.01) and PAHs (P<0.05), but this was not the case with IL-8. Serum CC16 showed significantly negative correlations with B[a]P equivalent (P<0.05) levels, but positive correlation with Pb (P<0.05). In conclusion, a similar pattern of the dose-dependent responses to DEP in the lymphoblasts and lung cells suggests that circulating lymphocytes could be used as a surrogate for assessing PM-induced oxidative DNA damage and inflammatory responses in the lung. Human exposure to PM leads to oxidative DNA damage whereas PM-induced inflammation was not conclusive and should be further investigated.
颗粒物污染是一个主要的公共卫生关注点，因为流行病学研究表明，暴露于颗粒物与呼吸道疾病和肺癌有关。柴油尾气颗粒物（DEP）被归类为人类致癌物（IARC，2012 年），被认为是城市地区交通相关颗粒物（PM）的主要贡献者。DEP 由各种化合物组成，包括多环芳烃和金属，这些是导致 PM 毒性的主要成分。本研究旨在通过体外使用淋巴细胞和在环境中暴露于 PM 的人体来研究 PM 对氧化 DNA 损伤和炎症的诱导作用。用人淋巴母细胞（RPMI 1788）用不同浓度的 DEP（SRM 2975）处理（25-100μg/ml），以比较与肺泡上皮细胞（A549）相比，反应的程度。为了研究细胞周期阶段对氧化应激诱导的影响，在 DEP 处理的细胞的每个细胞周期阶段中确定 ROS 的产生。通过测量 8-羟基脱氧鸟苷（8-OHdG）来确定氧化 DNA 损伤，而通过白细胞介素-6 和-8（IL-6 和 IL-8）、克拉拉细胞蛋白（CC16）和肺表面活性蛋白-A（SP-A）的 mRNA 表达来确定炎症反应。结果表明，RPMI 1788 和 A549 细胞在颗粒摄取方面表现出类似的DEP 剂量依赖性反应模式，在 G2/M 期发现最高水平的 ROS 生成、8-OHdG 形成以及 IL-6 和 IL-8 表达诱导。人体研究在 51 名居住在交通拥挤地区的健康受试者中进行。评估了 PM2.5 和颗粒结合的多环芳烃和有毒金属对淋巴细胞 DNA 中 8-OHdG 水平、淋巴细胞中 IL-8 表达和血清 CC16 的影响。8-OHdG 水平与 PM2.5（P<0.01）和 PAHs（P<0.05）的暴露水平相关，但与 IL-8 无关。血清 CC16 与 BaP 当量（P<0.05）水平呈显著负相关，但与 Pb 呈正相关（P<0.05）。总之，淋巴母细胞和肺细胞对 DEP 的剂量依赖性反应模式相似，这表明循环淋巴细胞可用于评估 PM 诱导的氧化 DNA 损伤和肺部炎症反应。人体暴露于 PM 会导致氧化 DNA 损伤，而 PM 诱导的炎症反应尚无定论，需要进一步研究。
