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Pulmonary responses in rats after inhalation exposure to cerium oxide nanoparticles generated by the Harvard Versatile Engineered Nanomaterial Generating System (VENGES).

Castranova V; Barger M; Goldsmith W; Frazer D; Hines B; McKinney W; Pyrgiotakis G; Gass S; Demokritou P; Ma J
Toxicologist 2013 Mar; 132(1):174-175
Recently cerium compounds have been used in a variety of consumer products including semiconductors, UV shields and diesel fuel additives to increase fuel combustion efficiency and decrease diesel soot emissions. Our previous studies have shown that exposure of rats to CeO2 by intratracheal instillation not only induces sustained pulmonary inflammation, but also lung fibrosis. In the present study, the aerosols of CeO2 or CeO2 coated with a nanothin layer of amorphous SiO2 (aSiO2- CeO2) were generated by the Harvard VENGES. The aerosols were diluted with air and delivered to a whole body exposure chamber. Male Sprague Dawley rats were exposed to CeO2 or aSiO2-CeO2 at 2.7 mg/m3, 2h/day for 4 days along with air controls. Animals were sacrificed at 1or 84 days post exposure. Morphometric analysis of the CeO2 and aSiO2-CeO2 particle cores showed diameters of 12.8 and 19.2 nm, respectively. Mobility diameter modes of 82 and 96 nm were measured for the CeO2 and aSiO2-CeO2 aerosols aggregates in the breathing zone of the animals. Alveolar macrophages (AM) were obtained by bronchoalveolar lavage (BAL), and acellular BAL fluids (BALF) were saved for further analysis. At 1 day after CeO2 exposure, but not aSiO2-CeO2, significantly induced PMN infiltration and lactate dehydrogenase activity in the BALF. CeO2 significantly increased collagen degradation enzymes, matrix metalloproteinases (MMPs)-2 and tissue inhibitor of MMP-1 in the BALF, which may be involved in the modification of extracellular matrix. At 84 days post exposure, none of the particle treatment groups induced lung inflammation, cellular injury or alteration of hydroxyproline content in lung tissues. These results demonstrated that a thin coating of aSiO2 on CeO2 protected lungs from CeO2-induced acute lung toxicity, suggesting that a thin coating of aSiO2 may potentially be used to modify other nanoparticle-induced lung toxicity.
Nanotechnology; Microbiology; Microchemistry; Environmental-exposure; Exposure-levels; Physiological-function; Physiological-effects; Physiology; Chemical-properties; Aerosols; Risk-factors; Laboratory-animals; Animals; Neurological-system; Neurological-reactions; Molecular-biology; Molecular-structure; Metal-compounds; Metallic-compounds; Workers; Neurotoxicity; Neurotoxic-effects; Neurological-system; Neurological-reactions; Toxicology
1306-38-3; 7631-86-9
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The Toxicologist. Society of Toxicology 52nd Annual Meeting and ToxExpo, March 10-14, 2013, San Antonio, Texas
Page last reviewed: April 1, 2022
Content source: National Institute for Occupational Safety and Health Education and Information Division