Abstract

Air liquid interface (ALI) exposure systems are gaining interest, and studies suggest enhanced response of lung cells exposed to particles at ALI as compared to submerged exposure, although the results have been somewhat inconsistent. Previous studies have used monocultures and measured particle deposition using assumptions including consistent particle deposition, particle density, and shape. This study exposed co-cultures of A549 and differentiated THP-1 cells to flame-generated particles using three exposure methods: ALI, pseudo-ALI, and submerged. The dose at ALI was measured directly, reducing the need for assumptions about particle properties and deposition. For all exposure methods an enhanced pro-inflammatory response (TNFα) and Cytochrome P450 (CYP1A1) gene expression, compared to their corresponding negative controls, was observed. ALI exposure induced a significantly greater TNFα response compared to submerged exposure. The submerged exposures exhibited greater induction of CYP1A1 than other exposure methods, although not statistically significant. Some of the factors behind the observed difference in responses for the three exposure methods include differences in physicochemical properties of particles in suspending media, delivered dose, and potential contribution of gas-phase species to cellular response in ALI exposure. However, given the difficulty and expense of ALI exposures, submerged exposure may still provide relevant information for particulate exposures.

摘要

气液界面 (ALI) 暴露系统越来越受到人们的关注，研究表明，与浸没暴露相比，在 ALI 下暴露于颗粒的肺细胞的反应增强，尽管结果有些不一致。先前的研究使用单一培养物并使用一致的颗粒沉积、颗粒密度和形状等假设来测量颗粒沉积。本研究使用三种暴露方法：ALI、伪 ALI 和浸没，将 A549 和分化的 THP-1 细胞的共培养物暴露于火焰产生的颗粒。ALI 处的剂量是直接测量的，减少了对粒子特性和沉积的假设的需要。与相应的阴性对照相比，所有暴露方法均观察到促炎反应 (TNFα) 和细胞色素 P450 (CYP1A1) 基因表达增强。与水下暴露相比，ALI 暴露引起的 TNFα 反应明显增强。与其他暴露方法相比，水下暴露对 CYP1A1 的诱导作用更强，但没有统计学意义。观察到的三种暴露方法的反应差异背后的一些因素包括悬浮介质中颗粒的物理化学性质、输送剂量的差异以及气相物质对 ALI 暴露中细胞反应的潜在贡献。然而，考虑到 ALI 暴露的难度和费用，水下暴露仍然可以提供颗粒物暴露的相关信息。