Exposure effects beyond the epithelial barrier: trans-epithelial induction of oxidative stress by diesel exhaust particulates in lung fibroblasts in an organotypic human airway model

In vitro bronchial epithelial monoculture models have been pivotal in defining the adverse effects of inhaled toxicant exposures; however, they are only representative of one cellular compartment and may not accurately reflect the effects of exposures on other cell types. Lung fibroblasts exist immediately beneath the bronchial epithelial barrier and play a central role in lung structure and function, as well as disease development and progression. We tested the hypothesis that in vitro exposure of a human bronchial epithelial cell barrier to the model oxidant diesel exhaust particulates caused trans-epithelial oxidative stress in the underlying lung fibroblasts using a human bronchial epithelial cell and lung fibroblast co-culture model. We observed that diesel exhaust particulates caused trans-epithelial oxidative stress in underlying lung fibroblasts as indicated by intracellular accumulation of the reactive oxygen species hydrogen peroxide, oxidation of the cellular antioxidant glut...体外（in vitro）支气管上皮单层培养模型（bronchial epithelial monoculture models），在阐明吸入性毒物暴露所致不良效应的研究中发挥了关键作用；然而此类模型仅能代表单一细胞区室，无法准确反映暴露对其他细胞类型的效应。肺成纤维细胞（lung fibroblasts）紧邻支气管上皮屏障下方分布，在肺组织结构与功能维持以及疾病发生发展过程中均发挥核心作用。本研究采用人支气管上皮细胞与肺成纤维细胞共培养模型，验证了如下假说：将人支气管上皮细胞屏障暴露于模式氧化性柴油机排气颗粒物时，可使下方的肺成纤维细胞产生跨上皮性氧化应激（trans-epithelial oxidative stress）。本研究观察到，柴油机排气颗粒物可诱导下方肺成纤维细胞产生跨上皮性氧化应激，该效应可通过活性氧物种（reactive oxygen species）过氧化氢的细胞内蓄积、细胞抗氧化剂谷胱甘肽的氧化等指标得以印证（原文后续内容未完整呈现）。