Abstract

Engineered nanomaterials (ENMs) are increasingly produced and used today, but health risks due to their occupational airborne exposure are incompletely understood. Traditionally, nanoparticle (NP) toxicity is tested by introducing NPs to cells through suspension in the growth media, but this does not mimic respiratory exposures. Different methods to introduce aerosolized NPs to cells cultured at the air-liquid-interface (ALI) have been developed, but require specialized equipment and are associated with higher cost and time. Therefore, it is important to determine whether aerosolized setups induce different cellular responses to NPs than traditional ones, which could provide new insights into toxicological responses of NP exposure. This study evaluates the response of human alveolar epithelial cells (A549) to zinc oxide (ZnO) NPs after dry aerosol exposure in the Nano Aerosol Chamber for In Vitro Toxicity (NACIVT) system as compared to conventional, suspension-based exposure: cells at ALI or submerged. Similar to other studies using nebulization of ZnO NPs, we found that dry aerosol exposure of ZnO NPs via the NACIVT system induced different cellular responses as compared to conventional methods. ZnO NPs delivered at 1.0 µg/cm² in the NACIVT system, mimicking occupational exposure, induced significant increases in metabolic activity and release of the cytokines IL-8 and MCP-1, but no differences were observed using traditional exposures. While factors associated with the method of exposure, such as differing NP aggregation, may contribute toward the different cellular responses observed, our results further encourage the use of more physiologically realistic exposure systems for evaluating airborne ENM toxicity.

摘要

如今，工程纳米材料 (ENM) 的生产和使用越来越多，但人们尚未完全了解其职业空气暴露导致的健康风险。传统上，纳米颗粒 (NP) 毒性是通过在生长培养基中悬浮将 NPs 引入细胞来测试的，但这并不能模拟呼吸暴露。已经开发了将雾化 NPs 引入在气液界面 (ALI) 培养的细胞中的不同方法，但需要专门的设备，并且成本和时间较高。因此，确定气雾化设置是否诱导对 NPs 的细胞反应与传统设置不同非常重要，这可以为 NP 暴露的毒理学反应提供新的见解。本研究评估了人类肺泡上皮细胞 (A549) 在体外毒性纳米气溶胶室 (NACIVT) 系统中干气溶胶暴露后对氧化锌 (ZnO) NP 的反应，与传统的基于悬浮液的暴露相比：ALI 的细胞或淹没。与使用 ZnO NPs 雾化的其他研究类似，我们发现与传统方法相比，通过 NACIVT 系统对 ZnO NPs 的干气溶胶暴露诱导了不同的细胞反应。ZnO NPs 以 1.0 µg/cm 的浓度交付NACIVT 系统中的²，模仿职业暴露，诱导代谢活性和细胞因子 IL-8 和 MCP-1 释放的显着增加，但使用传统暴露未观察到差异。虽然与暴露方法相关的因素，例如不同的 NP 聚集，可能导致观察到的不同细胞反应，但我们的结果进一步鼓励使用更符合生理学的暴露系统来评估空气中的 ENM 毒性。