title: Intraperitoneal administration of tangled multiwalled carbon nanotubes of 15 nm in diameter does not induce mesothelial carcinogenesis in rats.
abstract: Multiwalled carbon nanotubes (MWCNTs) have attracted public attention not only for their potential applications in engineering and materials science but also for possible environmental risks. MWCNTs share similar properties with asbestos, a definite human carcinogen causing malignant mesothelioma (MM), in that they are both biopersistent thin fibers with a high aspect ratio. Certain types of MWCNTs do induce MM in animal experiments. Though there are many different types of MWCNTs awaiting use in industry, there is little evidence about what types of MWCNTs present a high risk for MM in vivo. We have previously shown that the diameter of MWCNTs is one of the critical factors for mesothelial injury, which eventually leads to MM. Because of the extensive commercial use of MWCNTs, the properties of MWCNTs that determine carcinogenic activity should be clarified. Here we report that a high dose (10 mg) of a tangled form of pristine MWCNT (with a diameter of 15 nm) did not induce MM after intraperitoneal administration in rats, which were followed for up to 3 years after injection. This observation strengthens our previous finding that the rigidity, diameter, length and surface properties of MWCNTs are important factors in MM induction in vivo.
authors.affiliation: Department of Pathology and Biological Responses, Nagoya University Graduate School of Medicine.
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Nagai
authors.forename: Yasumasa
authors.initials: Y
authors.lastname: Okazaki
authors.forename: Shan Hwu
authors.initials: SH
authors.lastname: Chew
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Misawa
authors.forename: Yasumitsu
authors.initials: Y
authors.lastname: Miyata
authors.forename: Hisanori
authors.initials: H
authors.lastname: Shinohara
authors.forename: Shinya
authors.initials: S
authors.lastname: Toyokuni
mesh_terms: D000818:Animals; D001194:Asbestos / Q000009:adverse effects; D002471:Cell Transformation, Neoplastic / Q000737:chemistry; D004195:Disease Models, Animal; D004782:Environmental Health; D005260:Female; D007274:Injections, Intraperitoneal; D008297:Male; D008654:Mesothelioma / Q000139:chemically induced / Q000473:pathology*; D037742:Nanotubes, Carbon / Q000009:adverse effects; D051381:Rats; D011916:Rats, Inbred F344
chemical_list: D037742:Nanotubes, Carbon; D001194:Asbestos
keywords: environmental health; malignant mesothelioma; multiwalled carbon nanotube