title: A review of toxicity studies of single-walled carbon nanotubes in laboratory animals.
abstract: We summarized the findings of in vivo toxicity studies of single-walled carbon nanotubes (SWCNTs) in laboratory animals. The large majority addressed the pulmonary toxicity of SWCNTs in rodents. Inhalation, pharyngeal aspiration, and intratracheal instillation studies revealed that SWCNTs caused acute and chronic inflammation, granuloma formation, collagen deposition, fibrosis, and genotoxic effects in the lungs. Pulmonary toxicity of well-dispersed SWCNTs was more potent than less dispersed ones. Airway exposure to SWCNTs also induced cardiovascular diseases in mice. Oxidative stress was caused by the administration of SWCNTs. Injected SWCNTs were distributed throughout most of the organs including the brain, mainly retained in the lungs, liver, and spleen, and eliminated through the kidney and bile duct. Orally administered SWCNTs are suggested to be absorbed from the gastrointestinal tract to the blood circulation in mice and rats. Although no definitive study on the carcinogenicity of SWCNTs is available at present, evidence of carcinogenicity has not been reported in toxicity studies cited in this review. Overall, the available data provides initial information on SWCNT toxicity. To further clarify their toxicity and risk assessment, studies should be conducted using well-characterized SWCNTs, standard protocols, and the relevant route and doses of human exposure.
authors.affiliation: Research Institute of Science for Safety and Sustainability, National Institute of Advanced Industrial Science and Technology (AIST), 16-1 Onogawa, Tsukuba, Ibaraki 305-8569, Japan. Electronic address: ema-makoto@aist.go.jp.
authors.forename: Makoto
authors.initials: M
authors.lastname: Ema
authors.affiliation: Research Institute of Science for Safety and Sustainability, National Institute of Advanced Industrial Science and Technology (AIST), 16-1 Onogawa, Tsukuba, Ibaraki 305-8569, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Gamo
authors.affiliation: Research Institute of Science for Safety and Sustainability, National Institute of Advanced Industrial Science and Technology (AIST), 16-1 Onogawa, Tsukuba, Ibaraki 305-8569, Japan.
authors.forename: Kazumasa
authors.initials: K
authors.lastname: Honda
mesh_terms: D000818:Animals; D001822:Body Burden; D005260:Female; D006801:Humans; D008168:Lung / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D008171:Lung Diseases / Q000139:chemically induced* / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D008297:Male; D051379:Mice; D023421:Models, Animal; D037742:Nanotubes, Carbon / Q000633:toxicity*; D051381:Rats; D018570:Risk Assessment; D013045:Species Specificity; D013997:Time Factors; D014018:Tissue Distribution; D018675:Toxicity Tests / Q000379:methods*
chemical_list: D037742:Nanotubes, Carbon
keywords: Carbon nanotubes; Inflammation; Inhalation; Intratracheal instillation; Nanomaterials; Nanotoxicology; Oxidative stress; Pharyngeal aspiration; Pulmonary toxicology; Single-walled carbon nanotubes