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Toxicological evaluation of lung responses after intratracheal exposure to non-dispersed titanium dioxide nanorods.

Authors
Roberts-JR; Chapman-RS; Tirumala-VR; Karim-A; Chen-BT; Schwegler-Berry-D; Stefaniak-AB; Leonard-SS; Antonini-JM
Source
J Toxicol Environ Health, A 2011 May; 74(12):790-810
NIOSHTIC No.
20038716
Abstract
Fine- and coarse-sized titanium dioxide (TiO2) particles are considered to be relatively inert when inhaled. The goal of this study was to assess potential lung toxicity associated with well-characterized, non-dispersed rutile TiO2 nanorods (10 x 40 nm). In vitro bioreactivity of TiO2 nanorods was determined by electron spin resonance (ESR) to measure free radical production. To assess pulmonary effects in vivo, Sprague-Dawley rats were intratracheally instilled with saline, silica, or TiO2 nanorods (10 g, 100 g, or 1 mg/rat). On d 1, 3, and 6 posttreatment, left lungs were preserved for microscopy and histopathology, and lung lavage was performed on right lungs. Additional rats were treated with saline or TiO2 nanorods (100 g or 1 mg/rat) on d 0, intratracheally inoculated with 5 x 10(5) Listeria monocytogenes on d 3, and bacterial clearance was assessed. ESR showed a significant concentration-dependent generation of hydroxyl radicals by TiO2 nanorods in the presence and absence of macrophages; however, the hydroxyl radical signals from TiO2 samples were low compared to silica. Rats exposed to 1 mg of TiO2 nanorods had significantly elevated levels of lung injury, inflammation, and lavage fluid monocyte chemoattractant protein (MCP)-1 and macrophage inflammatory protein (MIP)-2 on d 1 and 3 that subsided by d 6, unlike the silica response that persisted. Immune cytokine secretion in the lung and bacterial clearance were not affected by preexposure to TiO(2) nanorods. To summarize, non-dispersed TiO(2) nanorods were found to induce radical formation and cellular oxidant production, and to generate transient and reversible pneumotoxic effects, and to not markedly alter pulmonary immune function.
Keywords
Alveolar-cells; Animal-studies; Biological-effects; Biological-systems; Immune-reaction; Laboratory-animals; Laboratory-testing; Lung-disorders; Lung-irritants; Microscopic-analysis; Nanotechnology; Particle-aerodynamics; Particulates; Physiological-effects; Physiological-response; Pulmonary-system; Pulmonary-system-disorders; Quantitative-analysis; Respiratory-hypersensitivity; Respiratory-irritants; Respiratory-system-disorders; Tissue-disorders; Toxic-effects; Toxicology
Contact
Jenny R. Roberts, PhD, Health Effects Laboratory Division, National Institute for Occupational Safety and Health (NIOSH), 1095 Willowdale Rd. (M/S 2015), Morgantown, WV 26505, USA
CODEN
JTEHD6
CAS No.
13463-67-7; 7631-86-9
Publication Date
20110501
Document Type
Journal Article
Email Address
jur6@cdc.gov
Fiscal Year
2011
NTIS Accession No.
NTIS Price
Issue of Publication
12
ISSN
1528-7394
NIOSH Division
HELD; DRDS
Priority Area
Manufacturing
Source Name
Journal of Toxicology and Environmental Health, Part A: Current Issues
State
WV; MD
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