title: Pulmonary and systemic responses of highly pure and well-dispersed single-wall carbon nanotubes after intratracheal instillation in rats.
abstract: The present study was conducted to assess the pulmonary and systemic responses in rats after intratracheal instillation of highly pure, well-dispersed, and well-characterized SWCNTs. Exposure to SWCNTs up to 2 mg/kg did not produce mortality, changes in clinical signs, or body weights during the observation period. Dose-dependent changes were observed in the lung weight, BALF inflammatory cells, and biochemical parameters such as LDH value, protein content, IL-1β and IL-6 activity, and histopathology. In the 0.04 mg/kg SWCNT-exposed group, almost no changes were observed during the observation period. In the 0.2 mg/kg SWCNT-exposed group, pulmonary inflammatory responses were observed after instillation. In the 1 mg/kg and 2 mg/kg SWCNT-exposed group, acute lung inflammation and subsequent granuloma accompanied by increased lung weights were observed. Furthermore, the histopathological findings in the lungs of rats exposed to SWCNTs showed inflammatory responses related with the vital reaction to the foreign substance that was instilled intratracheally, and there were no fibrosis, atypical lesion, or tumor-related findings even at the highest dose (2 mg/kg) of SWCNT-exposed groups up to 6 months after instillation. For all groups, histopathological changes due to the instillation exposure of SWCNTs were observed only in the lungs and lung-associated lymph nodes and not in the other tissues examined (i.e. the liver, kidney, spleen, and cerebrum).
authors: Research Institute of Science for Safety and Sustainability, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan.
authors: Norihiro
authors: N
authors: Kobayashi
authors: Masato
authors: M
authors: Naya
authors: Kohei
authors: K
authors: Mizuno
authors: Kazuhiro
authors: K
authors: Yamamoto
authors: Makoto
authors: M
authors: Ema
authors: Junko
authors: J
authors: Nakanishi
mesh_terms: D000280:Administration, Inhalation; D000818:Animals; D001992:Bronchoalveolar Lavage Fluid; D016207:Cytokines / Q000276:immunology; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D007958:Leukocyte Count; D008168:Lung / Q000187:drug effects* / Q000276:immunology / Q000473:pathology / Q000648:ultrastructure; D008198:Lymph Nodes / Q000187:drug effects / Q000473:pathology; D008297:Male; D046529:Microscopy, Electron, Transmission; D037742:Nanotubes, Carbon / Q000032:analysis / Q000633:toxicity* / Q000648:ultrastructure; D009929:Organ Size / Q000187:drug effects; D051381:Rats
chemical_list: D016207:Cytokines; D037742:Nanotubes, Carbon; D007770:L-Lactate Dehydrogenase