Effects of Environmental Exposure to Iron Powder in Healthy and Elastase-Exposed Mice

Abstract

Background: Prolonged exposure to iron powder and other mineral dusts can harm affected populations, especially those with COPD. The goal of this study was to see how environmental exposure to metal dust affected lung mechanics, inflammation, remodeling, oxidative stress responses, and elastase in mice in two different mining centers in Vitória, ES, Brazil. Methods: This study utilized 72 male C57Bl/6 mice (36 summer and 36 winter), which were divided into six groups: control, non-exposed (SAL); non-exposed, given elastase (ELA); exposed to metal powder at a mining company (SAL-L1 and ELA-L1); and exposed to a location three miles away from the mining company (SAL-L2 and ELA-L2) for four weeks. On the 29th day of the protocol, the researchers assessed lung mechanics, bronchoalveolar lavage fluid (BALF), inflammation, remodeling, oxidative stress, and alveolar wall alterations (mean linear intercept – Lm). Results: ELA, ELA-L1 and ELA-L2 had an increase in Lm compared to the SAL groups (p<0.05). There was an increase in total cells and macrophages in ELA-L1 and ELA-L2 compared to the other groups (p<0.05). Exposed groups (ELA-L1, ELA-L2, SAL-L1, and SAL-L2) had an increase in cell expression of Inflammatory markers (IL-1β, IL-6, IL-10, IL-17, TNF-α, and neutrophils) (p<0.05); remodeling markers (TIMP-1, MMP-9, MMP-12, TGF-β, collagen fibers and MUC5AC); oxidative stress (iNOS); and mechanisms involved (NFkB) increased compared to ELA and SAL (p<0.05). Although we did not find differences in lung mechanics across all groups, there were low to moderate correlations between these parameters (elastance and resistance of lung tissue) (p0.05). Conclusions: Aside from lung mechanics, environmental exposure to iron and metal powder exacerbated inflammation, remodeling, and oxidative stress responses in exposed mice with and without emphysema. The mechanisms involved are dependent on iNOS and NFkB activation.