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Citation
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HERO ID
157523
Reference Type
Journal Article
Title
Development of a short-term inhalation test in the rat using nano-titanium dioxide as a model substance
Author(s)
Ma-Hock, L; Burkhardt, S; Strauss, V; Gamer, AO; Wiench, K; van Ravenzwaay, B; Landsiedel, R
Year
2008
Is Peer Reviewed?
Yes
Journal
Inhalation Toxicology
ISSN:
0895-8378
EISSN:
1091-7691
Volume
21
Issue
2
Page Numbers
102-118
Language
English
PMID
18800274
DOI
10.1080/08958370802361057
Web of Science Id
WOS:000262472400003
Abstract
Evidence suggests that short-term inhalation studies may provide comparable prediction of respiratory tract toxicity to 90-day studies, presenting the opportunity to save time and resources in screening inhalation toxicity of test substances. The aim of this study was to develop a short-term inhalation test that could be employed to provide early evidence on respiratory tract effects which might occur from long-term exposure to aerosols of nano-materials. Male Wistar rats were exposed to aerosols of 0 (control), 2, 10 and 50 mg/m(3) nano-titanium dioxide (TiO2) by inhalation for 6 h/day for 5 days. Necropsies were performed either immediately after the last exposure or after 3 and 16 days post exposure (study days 5, 8 and 21, respectively). Treatment with nano-TiO2 resulted in morphological changes in the lung, with 50 mg/m(3) nano-TiO2 producing an increase in lung weight. Lung inflammation was associated with dose-dependent increases in bronchoalveolar lavage fluid (BALF) total cell and neutrophil counts, total protein content, enzyme activities and levels of a number of cell mediators. No indications of systemic effects could be found by measurement of appropriate clinical pathology parameters. Cell replication (determined by incorporation of 5-bromo-2'-deoxyuridine) was increased at all nano-TiO2 dose levels in large/medium bronchi and terminal bronchioles. The effects on the parameters measured were most prominent either on study day 5 or 8, with some endpoints returning to control levels by day 21. Overall, the pulmonary effects of nano-TiO2 observed in this short-term study were comparable to those previously reported in subchronic inhalation studies.
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