Journal
TOXICOLOGY LETTERS
Volume 192, Issue 3, Pages 286-293Publisher
ELSEVIER IRELAND LTD
DOI: 10.1016/j.toxlet.2009.11.006
Keywords
Nanoparticles; Nanoclays; Lung; Pulmonary; Lung toxicity; Multinucleate giant cells
Categories
Ask authors/readers for more resources
Sepiolite is a magnesium silicate-containing nanoclay mineral and is utilized as a nanofiller for nanocomposite applications We postulated that lung exposures to Sepiolite clay samples could produce sustained effects Accordingly, the pulmonary and extrapulmonary systemic impacts in rats of intratracheally instilled Sepiolite nanoclay samples were compared with quartz or ultrafine (uf) titanium dioxide particle-types at doses of 1 mg/kg or 5 mg/kg All particulates were well characterized, and dedicated groups were evaluated by bronchoalveolar lavage, lung cell proliferation, macrophage functional assays and full body histopathology at selected times postexposure (pe) Bronchoalveolar lavage results demonstrated that quartz particles produced persistent, dose-dependent lung inflammatory responses measured from 24 h through 3 months pe Exposures to uf TiO(2) particles or Sepiolite samples produced transient neutrophilic responses at 24-h pe, however, unlike the other particle-types, Sepiolite exposures produced macrophage-agglomerates or multinucleate giant cells at 1 week, 5 weeks and 3 months pe In vitro alveolar macrophage functional studies demonstrated that mononuclear cells recovered from quartz but not Sepiolite or uf TiO(2)-exposed rats were deficient in their chemotactic capacities. Moreover, lung parenchymal cell proliferation rates were increased in rats exposed to quartz but not Sepiolite or uf TiO(2) particles Histopathological evaluation of lung tissues revealed that pulmonary exposures to Sepiolite nanoclay or quartz samples produced inflammation in centriacinar regions at 24-h pe but the effects decreased in severity over time for Sepiolite and increased for quartz-exposed rats The quartz-induced lesions were progressive and were characterized at 3 months by acinar foamy alveolar macrophage accumulation and septal thickening due to inflammation, alveolar Type II cell hyperplasia and collagen deposition. In the Sepiolite nanoclay group, the finding of multinucleated giant cell accumulation associated with minor collagen deposition in acinar regions was rarely observed Exposures to ultrafine TiO(2) produced minimal effects characterized by the occurrence of phagocytic macrophages in alveolar ducts Full body histopathology studies were conducted at 24 h and 3 months post particle exposures. Histopathological evaluations revealed minor particle accumulations in some mediastinal or thoracic lymph nodes. However, it is noteworthy that no extrapulmonary target organ effects were observed in any of the particle-ex posed groups at 3 months postexposure. (C) 2009 Elsevier Ireland Ltd All rights reserved
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available