Exposure to micro- and nanoplastic particles (MNPs) in humans is being identified in both the indoor and outdoor environment. Detection of these materials in the air has made inhalation exposure to MNPs a major cause for concern. One type of plastic polymer found in indoor and outdoor settings is polyamide, often referred to as nylon. Inhalation of combustion-derived, metallic, and carbonaceous aerosols generate pulmonary inflammation, cardiovascular dysfunction, and systemic inflammation. Additionally, due to the additives present in plastics, MNPs may act as endocrine disruptors. Currently there is limited knowledge on potential health effects caused by polyamide or general MNP inhalation. The purpose of this study is to assess the toxicological consequences of a single inhalation exposure of female rats to polyamide MNP during estrus by means of aerosolization of MNP. Bulk polyamide powder (i.e., nylon) served as a representative MNP. Polyamide aerosolization was characterized using particle sizers, cascade impactors, and aerosol samplers. Multiple-Path Particle Dosimetry (MPPD) modeling was used to evaluate pulmonary deposition of MNPs. Pulmonary inflammation was assessed by bronchoalveolar lavage (BAL) cell content and H&E-stained tissue sections. Mean arterial pressure (MAP), wire myography of the aorta and uterine artery, and pressure myography of the radial artery was used to assess cardiovascular function. Systemic inflammation and endocrine disruption were quantified by measurement of proinflammatory cytokines and reproductive hormones. Our aerosolization exposure platform was found to generate particles within the micro- and nano-size ranges (thereby constituting MNPs). Inhaled particles were predicted to deposit in all regions of the lung; no overt pulmonary inflammation was observed. Conversely, increased blood pressure and impaired dilation in the uterine vasculature was noted while aortic vascular reactivity was unaffected. Inhalation of MNPs resulted in systemic inflammation as measured by increased plasma levels of IL-6. Decreased levels of 17β-estradiol were also observed suggesting that MNPs have endocrine disrupting activity. These data demonstrate aerosolization of MNPs in our inhalation exposure platform. Inhaled MNP aerosols were found to alter inflammatory, cardiovascular, and endocrine activity. These novel findings will contribute to a better understanding of inhaled plastic particle toxicity.

中文翻译：

---

单次吸入聚酰胺微粒和纳米塑料颗粒会损害血管扩张，而不会在处女雌性 Sprague Dawley 大鼠中产生肺部炎症

在室内和室外环境中都可以确定人体暴露于微塑料颗粒和纳米塑料颗粒 (MNP) 的情况。在空气中检测到这些材料已使吸入 MNP 成为关注的主要原因。在室内和室外环境中发现的一种塑料聚合物是聚酰胺，通常称为尼龙。吸入燃烧产生的金属和碳质气溶胶会产生肺部炎症、心血管功能障碍和全身炎症。此外，由于塑料中存在添加剂，MNP 可能会干扰内分泌。目前，关于聚酰胺或一般 MNP 吸入引起的潜在健康影响的知识有限。本研究的目的是评估雌性大鼠在发情期间通过雾化 MNP 单次吸入聚酰胺 MNP 的毒理学后果。散装聚酰胺粉末（即尼龙）作为代表性的 MNP。使用粒度仪、级联冲击器和气溶胶取样器对聚酰胺雾化进行了表征。多路径粒子剂量测定 (MPPD) 模型用于评估 MNP 的肺沉积。通过支气管肺泡灌洗 (BAL) 细胞含量和 H&E 染色的组织切片评估肺部炎症。平均动脉压 (MAP)、主动脉和子宫动脉的金属丝肌动描记术以及桡动脉的压力肌动描记术用于评估心血管功能。通过测量促炎细胞因子和生殖激素来量化全身炎症和内分泌紊乱。我们的雾化暴露平台被发现会产生微米和纳米尺寸范围内的颗粒（从而构成 MNP）。预计吸入的颗粒会沉积在肺部的所有区域；没有观察到明显的肺部炎症。相反，注意到子宫血管系统的血压升高和扩张受损，而主动脉血管反应性未受影响。吸入 MNP 会导致全身性炎症，这可通过血浆 IL-6 水平升高来衡量。还观察到 17β-雌二醇水平降低，表明 MNP 具有内分泌干扰活性。这些数据证明了 MNP 在我们的吸入暴露平台中的雾化。发现吸入的 MNP 气溶胶会改变炎症、心血管和内分泌活动。这些新发现将有助于更好地了解吸入塑料颗粒的毒性。