Information on particle deposition, retention, and clearance is important when evaluating the risk of inhaled nanomaterials to human health. The revised Organization Economic Cooperation and Development (OECD) inhalation toxicity test guidelines now require lung burden measurements of nanomaterials after rodent subacute and sub-chronic inhalation exposure (OECD 412, OECD 413) to inform on lung clearance behavior and translocation after exposure and during post-exposure observation (PEO). Lung burden measurements are particularly relevant when the testing chemical is a solid poorly soluble nanomaterial. Previously, the current authors showed that total retained lung burden of inhaled soluble silver nanoparticles (AgNPs) could be effectively measured using any individual lung lobe. Accordingly, the current study investigated the evenness of deposition/retention of poorly soluble gold nanoparticles (AuNPs) after 1 and 5 days of inhalation exposure. Rats were exposed nose-only for 1 or 5 days (6 h/day) to an aerosol of 11 nm well-dispersed AuNPs. Thereafter, the five lung lobes were separated and the gold concentrations measured using an inductively coupled plasma-mass spectrophotometer (ICP-MS). The results showed no statistically significant difference in the AuNP deposition/retention among the different lung lobes in terms of the gold mass per gram of lung tissue. Thus, it would seem that any rat lung lobe can be used for the lung burden analysis after short or long-term NP inhalation, while the other lobes can be used for collecting and analyzing the bronchoalveolar lavage fluid (BALF) and for the histopathological analysis. Therefore, combining the lung burden measurement, histopathological tissue preparation, and BALF assay from one rat can minimize the number of animals used and maximize the number of endpoints measured.

中文翻译：

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难溶性金纳米粒子 (AuNPs) 的叶状沉积甚至与可溶性银纳米粒子 (AgNPs) 相似


在评估吸入纳米材料对人类健康的风险时，有关颗粒沉积、保留和清除的信息非常重要。修订后的经济合作与发展组织 (OECD) 吸入毒性测试指南现在要求在啮齿动物亚急性和亚慢性吸入暴露后对纳米材料进行肺负荷测量（OECD 412、OECD 413），以了解暴露后和暴露后期间的肺清除行为和易位-暴露观察（PEO）。当测试化学品是固体难溶性纳米材料时，肺负荷测量尤其重要。此前，当前作者表明，可以使用任何单个肺叶有效测量吸入可溶性银纳米粒子（AgNP）的总保留肺负荷。因此，当前的研究调查了吸入暴露 1 天和 5 天后难溶性金纳米颗粒 (AuNP) 沉积/保留的均匀性。将大鼠仅用鼻子暴露于 11 nm 分散良好的 AuNP 气溶胶中 1 或 5 天（6 小时/天）。此后，分离五个肺叶并使用电感耦合等离子体质谱仪（ICP-MS）测量金浓度。结果显示，就每克肺组织的金质量而言，不同肺叶中的金纳米粒子沉积/保留没有统计学上的显着差异。因此，似乎任何大鼠肺叶都可用于短期或长期吸入 NP 后的肺负荷分析，而其他肺叶可用于收集和分析支气管肺泡灌洗液 (BALF) 和组织病理学分析。 因此，将一只大鼠的肺负荷测量、组织病理学组织制备和 BALF 测定结合起来可以最大限度地减少使用的动物数量并最大限度地增加测量的终点数量。