Journal Article

Lung carcinogenicity of inhaled multi-walled carbon nanotube in rats

Ohnishi, Makoto, Kondo, Hitomi, Matsumoto, Michiharu, Takeuchi, Tetsuya, Mine, Takashi, Kasai, Tatsuya, Umeda, Yumi, Fukushima, Shoji

2016

Overview

Background Multi-walled carbon nanotubes (MWCNTs) constitute one of the most promising types of nanomaterials in industry today. With their increasing use, the potential toxicity and carcinogenicity of MWCNT needs to be evaluated in bioassay studies using rodents. Since humans are mainly exposed to MWCNT by inhalation, we performed a 104-week carcinogenicity study using whole-body inhalation exposure chambers with a fibrous straight type of MWCNT at concentrations of 0, 0.02, 0.2, and 2 mg/m 3 using male and female F344 rats. Results Lung carcinomas, mainly bronchiolo-alveolar carcinoma, and combined carcinomas and adenomas were significantly increased in males exposed to 0.2 and 2 mg/m 3 MWNT-7 and in females exposed to 2 mg/m 3 MWNT-7 compared to the clean air control group. However, no development of pleural mesothelioma was observed. Concentration-dependent toxic effects in the lung such as epithelial hyperplasia, granulomatous change, localized fibrosis, and alteration in BALF parameters were found in MWNT-7 treatment groups of both sexes. There were no MWNT-7-specific macroscopic findings in the other organs, including the pleura and peritoneum. Absolute and relative lung weights were significantly elevated in male rats exposed to 0.2 and 2 mg/m 3 MWNT-7 and in all exposed female groups. The lung burdens of MWNT-7 were clearly increased in a concentration-dependent as well as a duration-dependent manner. Conclusion There is clear evidence that MWNT-7 is carcinogenic to the lungs of male and female F344 rats, however no plural mesothelioma was observed.

• Publisher: BioMed Central,BioMed Central Ltd,Springer Nature B.V
• Subject: Aerosols / Animals / Asbestos / Bioassays / Biomedical and Life Sciences / Biomedicine / Body Weight - drug effects / Bronchoalveolar Lavage Fluid / Carbon / Carcinogenicity / Carcinogens / Development and progression / Environmental Health / Female / Genetic aspects / Humidity / Hypotheses / Inhalation / Inhalation Exposure / Lung cancer / Lung Neoplasms - chemically induced / Lung Neoplasms - pathology / Male / Mesothelioma / Nanotechnology / Nanotubes / Nanotubes, Carbon - toxicity / Organ Size - drug effects / Pharmacology/Toxicology / Physiological aspects / Pneumology/Respiratory System / Properties / Public Health / Rats / Rats, Inbred F344 / Risk factors / Toxicity