Bourgeois Brian, Owens John Wesley
Department of Environmental Toxicology, Southern University & A&M College , Baton Rouge, LA , USA.
Toxicol Mech Methods. 2014 Mar;24(3):220-42. doi: 10.3109/15376516.2014.881945. Epub 2014 Jan 30.
Hurricanes Katrina and Rita hit the coast of Louisiana in 2005 and killed more than 2000 people. The two storms resulted in a significant spike in particulate matter (PM2.5) levels across the state of Louisiana. This report focuses on PM2.5 samples collected in 2005 from two monitoring sites in the neighboring cities of Baton Rouge and Port Allen, Louisiana. Inductively coupled plasma (ICP) revealed the presence of PM2.5-adsorbed representative and Fenton-active transition metals. Gas chromatography/mass spectrometry (GC-MS) analyses revealed the presence of 23 PAH compounds. Endotoxins were also detected. Metals and endotoxins were extracted with water. PAH were extracted with dichloromethane. In order to assess cytotoxicity, aqueous PM2.5 extracts were introduced to A549 Human Epithelial Lung Carcinoma Cells. Results indicated decreased cell viability in a dose-dependent manner, with an LC50 of 235 µg/ml and 250 µg/ml, respectively, for the two sites featured here. Endotoxins alone were not cytotoxic. The concentration of reactive oxygen species (ROS) and released LDH activity increased following exposure of A549 cells to aqueous PM2.5 extracts. Fluorescence microscopy revealed apoptotic and necrotic cell death mechanisms. ELISA revealed increased secretion of primary pro-inflammatory cytokines, IL-6, IL-8, and TNF-α. Global PCR gene expression revealed up-regulation of proteins associated with the cytokine storm; e.g. interleukins, chemokines, and TNF-α. Global antibody microarray was consistent with an inflammatory response, with up-regulation of cytokines involved in the down-field activation of the caspase cascade and kinase pathways. The up-regulation of metal-redox sensitive transcription factors, NF-κβ and AP-1, is consistent with a cell death mechanism initiated by Fenton-active transition metal redox catalysis.
2005年，卡特里娜飓风和丽塔飓风袭击了路易斯安那州海岸，造成2000多人死亡。这两场风暴导致路易斯安那州全州的细颗粒物（PM2.5）水平大幅飙升。本报告重点关注2005年从路易斯安那州巴吞鲁日和艾伦港这两个相邻城市的两个监测点采集的PM2.5样本。电感耦合等离子体（ICP）显示存在PM2.5吸附的代表性且具有芬顿活性的过渡金属。气相色谱/质谱（GC-MS）分析显示存在23种多环芳烃化合物。还检测到了内毒素。金属和内毒素用水提取。多环芳烃用二氯甲烷提取。为了评估细胞毒性，将PM2.5水提取物引入A549人上皮肺癌细胞。结果表明细胞活力呈剂量依赖性下降，此处所研究的两个监测点的半数致死浓度（LC50）分别为235微克/毫升和250微克/毫升。单独的内毒素没有细胞毒性。A549细胞暴露于PM2.5水提取物后，活性氧（ROS）浓度和释放的乳酸脱氢酶（LDH）活性增加。荧光显微镜检查揭示了凋亡和坏死性细胞死亡机制。酶联免疫吸附测定（ELISA）显示促炎细胞因子IL-6、IL-8和肿瘤坏死因子-α（TNF-α）的分泌增加。全基因组PCR基因表达显示与细胞因子风暴相关的蛋白质上调；例如白细胞介素、趋化因子和TNF-α。全基因组抗体微阵列与炎症反应一致，参与半胱天冬酶级联反应和激酶途径下游激活的细胞因子上调。金属氧化还原敏感转录因子NF-κβ和AP-1的上调与由芬顿活性过渡金属氧化还原催化引发的细胞死亡机制一致。
