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Enhanced darkfield image of the transition region between terminal bronchiole and first alveolar duct bifurcation at 168 days after exposure to MWCNT. The large arrow in this micrograph indicates a cluster of MWCNTs (white fibers) in the ridge of the first alveolar duct bifurcation. Smaller arrows indicate some of the numerous singlet and small MWCNT structures distributed throughout the alveolar septa of this critical transition region between conducting airways and gas exchange regions of the lungs.
Mercer et al. Particle and Fibre Toxicology 2013 10:33 doi:10.1186/1743-8977-10-33
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On July 30, 2013, Particle and Fibre Toxicology published a study entitled “Distribution and fibrotic response following inhalation exposure to multi-walled carbon nanotubes.”
In the study, the authors tested the hypothesis that inhalation exposure to multi-walled carbon nanotubes (MWCNT) produces a fibrotic response and that the response is chronically persistent. Male C57BL/6 J mice were exposed in a whole-body inhalation system to a MWCNT aerosol, and the authors examined the fibrotic response in the alveolar region at up to 336 days after termination of exposure.
The conclusion states: “Despite the relatively low fraction of the lung burden being delivered to the alveolar tissue, the average thickness of connective tissue in the alveolar region increased by 70% in the 336 days after inhalation exposure. These results demonstrate that inhaled MWCNTs deposit and are retained within the alveolar tissue where they produce a progressive and persistent fibrotic response up to 336 days post-exposure.”
While a number of the authors are affiliated with the National Institute for Occupational Safety and Health (NIOSH), the study includes a disclaimer that the findings and conclusions are those of the authors and do not necessarily represent the views of NIOSH.
Fonte: Nanotech Law BC
