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Pulmonary toxicity study in rats with three forms of ultrafine-TiO2 particles: Differential responses related to surface properties

Warheit, David B. and Webb, Thomas R. and Reed, Kenneth L. and Frerichs, Scott and Sayes, Christie M. (2007) Pulmonary toxicity study in rats with three forms of ultrafine-TiO2 particles: Differential responses related to surface properties. TOXICOLOGY, 230 (1). pp. 90-104.

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Abstract

Surface properties are critical to assess effects of ultrafine-TiO2 particles. The aim of this study was to assess lung toxicity in rats of newly developed, well characterized, ultrafine-TiO2 particles and compare them to Ti02 samples in two different size ranges and surface modifications. Groups of rats were intratracheally instilled with doses of 1 or 5 mglkg of either two ultrafine rutile Ti02 particles (uf-1 or uf-2); rutile R-100 fine-TiO2 (F-1); 80/20 anatase/rutile P25 ultrafine-TiO2 (uf-3); or alpha-quartz particles. Phosphate-buffered saline (PBS) solution instilled rats served as vehicle controls. Following exposures, the lungs of PBS and particle-exposed rats were evaluated for bronchoalveolar lavage (BAL) fluid inflammatory markers, cell proliferation, and by histopathology at post-instillation time points of 24 h, 1 week, 1 and 3 months. The ranking of lung inflammation/cytotoxicity/cell proliferation and histopathological responses was quartz > uf-3 > F-1 = uf-1 = uf-2. Exposures to quartz and to a lesser degree, uf-3 anatase/rutile TiO2 particles produced pulmonary inflammation, cytotoxicity and adverse lung tissue effects. In contrast, exposures to F- 1 fine-TiO2 particles or to uf- 1/uf-2 ultrafine-TiO2 particle--types produced transient inflammation. We conclude that differences in responses to anatase/rutile uf-3 TiO2 particles versus the rutile uf-1 and uf-2 TiO2 particles could be related to crystal structure, inherent pH of the particles, or surface chemical reactivity. Thus, based on these results, inhaled rutile ultrafine-TiO2 particles are expected to have a low risk potential for producing adverse pulmonary health effects. Finally, the results demonstrate that exposures to ultrafine-TiO2 particle-types can produce differential pulmonary effects, based upon their composition, and crystal structure. Thus, the lung toxicity of anatase/rutile uf-3 should not be viewed as representative for all ultrafine-TiO2 particle-types. (c) 2006 Elsevier Ireland Ltd. All rights reserved.

Item Type:Article
Uncontrolled Keywords:titanium dioxide particles; ultrafine particles; titanium dioxide nanocrystals; pulmonary toxicity; rutile crystal structure; particle surface treatments; nanomaterials
Subjects:Risk > Environment, health and safety aspects of nanotechnology
ID Code:748
Deposited By:Farnush Anwar
Deposited On:15 Dec 2008 10:48
Last Modified:13 Jan 2009 14:16

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