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- Bendtsen, Katja Maria, et al.
(författare)
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Particle characterization and toxicity in C57BL/6 mice following instillation of five different diesel exhaust particles designed to differ in physicochemical properties
- 2020
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Ingår i: Particle and Fibre Toxicology. - : Springer Science and Business Media LLC. - 1743-8977. ; 17:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Diesel exhaust is carcinogenic and exposure to diesel particles cause health effects. We investigated the toxicity of diesel exhaust particles designed to have varying physicochemical properties in order to attribute health effects to specific particle characteristics. Particles from three fuel types were compared at 13% engine intake O2 concentration: MK1 ultra low sulfur diesel (DEP13) and the two renewable diesel fuels hydrotreated vegetable oil (HVO13) and rapeseed methyl ester (RME13). Additionally, diesel particles from MK1 ultra low sulfur diesel were generated at 9.7% (DEP9.7) and 17% (DEP17) intake O2 concentration. We evaluated physicochemical properties and histopathological, inflammatory and genotoxic responses on day 1, 28, and 90 after single intratracheal instillation in mice compared to reference diesel particles and carbon black. RESULTS: Moderate variations were seen in physical properties for the five particles: primary particle diameter: 15-22 nm, specific surface area: 152-222 m2/g, and count median mobility diameter: 55-103 nm. Larger differences were found in chemical composition: organic carbon/total carbon ratio (0.12-0.60), polycyclic aromatic hydrocarbon content (1-27 μg/mg) and acid-extractable metal content (0.9-16 μg/mg). Intratracheal exposure to all five particles induced similar toxicological responses, with different potency. Lung particle retention was observed in DEP13 and HVO13 exposed mice on day 28 post-exposure, with less retention for the other fuel types. RME exposure induced limited response whereas the remaining particles induced dose-dependent inflammation and acute phase response on day 1. DEP13 induced acute phase response on day 28 and inflammation on day 90. DNA strand break levels were not increased as compared to vehicle, but were increased in lung and liver compared to blank filter extraction control. Neutrophil influx on day 1 correlated best with estimated deposited surface area, but also with elemental carbon, organic carbon and PAHs. DNA strand break levels in lung on day 28 and in liver on day 90 correlated with acellular particle-induced ROS. CONCLUSIONS: We studied diesel exhaust particles designed to differ in physicochemical properties. Our study highlights specific surface area, elemental carbon content, PAHs and ROS-generating potential as physicochemical predictors of diesel particle toxicity.
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| 2. |
- Wierzbicka, Aneta, et al.
(författare)
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Indoor PM2.5 from occupied residences in Sweden caused higher inflammation in mice compared to outdoor PM2.5
- 2022
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Ingår i: Indoor Air. - : Hindawi Limited. - 0905-6947 .- 1600-0668. ; 32:12
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Tidskriftsartikel (refereegranskat)abstract
- We spend most of our time indoors; however, little is known about the effects of exposure to aerosol particles indoors. We aimed to determine differences in relative toxicity and physicochemical properties of PM 2.5 collected simultaneously indoors (PM 2.5 INDOOR ) and outdoors (PM 2.5 OUTDOOR ) in 15 occupied homes in southern Sweden. Collected particles were extracted from filters, pooled (indoor and outdoor separately), and characterized for chemical composition and endotoxins before being tested for toxicity in mice via intratracheal instillation. Various endpoints including lung inflammation, genotoxicity, and acute-phase response in lung and liver were assessed 1, 3, and 28 days post-exposure. Chemical composition of particles used in toxicological assessment was compared to particles analyzed without extraction. Time-resolved particle mass and number concentrations were monitored. PM 2.5 INDOOR showed higher relative concentrations (μg mg -1 ) of metals, PAHs, and endotoxins compared to PM 2.5 OUTDOOR . These differences may be linked to PM 2.5 INDOOR causing significantly higher lung inflammation and lung acute-phase response 1 day post-exposure compared to PM 2.5 OUTDOOR and vehicle controls, respectively. None of the tested materials caused genotoxicity. PM 2.5 INDOOR displayed higher relative toxicity than PM 2.5 OUTDOOR under the studied conditions, that is, wintertime with reduced air exchange rates, high influence of indoor sources, and relatively low outdoor concentrations of PM. Reducing PM 2.5 INDOOR exposure requires reduction of both infiltration from outdoors and indoor-generated particles.
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