Abstract

Background:

Traffic-related air pollution (TRAP) is made up of complex mixtures of particulate matter, gases and volatile compounds. However, the effects of TRAP on the cardiopulmonary system in most animal studies have been tested using acute exposure to singular pollutants. The cardiopulmonary effects and molecular mechanisms in animals that are chronically exposed to unmodified air pollution as a whole have yet to be studied. Additionally, sex-dependent toxicity of TRAP exposure has rarely been evaluated.

Objectives:

This study sought to assess the cardiopulmonary effect of chronic exposure to unmodified, real-world TRAP in both female and male rats.

Methods:

Four-week-old male and female rats were exposed to TRAP or filtered air for 14 months in a novel facility drawing air from a major freeway tunnel system in Northern California. Inflammation and oxidative stress markers were examined in the lung, heart, spleen, and plasma, and TRAP deposits were quantified in the lungs of both male and female rats.

Results:

Elemental analysis showed higher levels of eight elements in the female lungs and one element in the male lungs. Expression of genes related to fibrosis, aging, oxidative stress, and inflammation were higher in the rat hearts exposed to TRAP, with female rats being more susceptible than males. Enhanced collagen accumulation was found only in the TRAP-exposed female hearts. Plasma cytokine secretion was higher in both female and male rats, but inflammatory macrophages were higher only in TRAP-exposed male spleens.

Discussion:

Our results in rats suggest pathological consequences from chronic TRAP exposure, including sex differences indicating females may be more susceptible to TRAP-induced cardiac fibrosis. https://doi.org/10.1289/EHP7045

中文翻译：

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长期暴露于交通相关空气污染大鼠的病理心肺评估

摘要

背景：

交通相关空气污染 (TRAP) 由颗粒物、气体和挥发性化合物的复杂混合物组成。然而，在大多数动物研究中，TRAP 对心肺系统的影响已经通过急性暴露于单一污染物进行了测试。长期暴露在未经修饰的空气污染中的动物的心肺效应和分子机制作为一个整体尚待研究。此外，很少评估 TRAP 暴露的性别依赖性毒性。

目标：

本研究旨在评估长期暴露于未经修饰的真实世界 TRAP 对雌性和雄性大鼠的心肺影响。

方法：

4 周大的雄性和雌性大鼠在从北加州的一个主要高速公路隧道系统吸入空气的新设施中暴露于 TRAP 或过滤空气中 14 个月。在肺、心脏、脾脏和血浆中检查炎症和氧化应激标志物，并量化雄性和雌性大鼠肺中的 TRAP 沉积物。

结果：

元素分析显示，女性肺中的八种元素含量较高，男性肺中的一种元素含量较高。在暴露于 TRAP 的大鼠心脏中，与纤维化、衰老、氧化应激和炎症相关的基因表达较高，雌性大鼠比雄性大鼠更易感。仅在暴露于 TRAP 的女性心脏中发现了增强的胶原蛋白积累。雌性和雄性大鼠的血浆细胞因子分泌较高，但炎症巨噬细胞仅在暴露于 TRAP 的雄性脾脏中较高。

讨论：

我们在大鼠中的结果表明慢性 TRAP 暴露的病理后果，包括性别差异，表明雌性可能更容易受到 TRAP 诱导的心脏纤维化的影响。https://doi.org/10.1289/EHP7045