Genotoxicity evaluation of fullerene C60 nanoparticles in a comet assay using lung cells of intratracheally instilled rats

The genotoxicity of fullerene C60 nanoparticles was evaluated in vivo with comet assays using the lung cells of rats given C60 nanoparticles. The C60 nanoparticles were intratracheally instilled as a single dose at 0.5 or 2.5 mg/kg or repeated dose at 0.1 or 0.5 mg/kg, once a week for 5 weeks, to male rats. The lungs were obtained 3 or 24 h after a single instillation and 3 h after repeated instillation. Inflammatory responses were observed in the lungs obtained 24 h after a single instillation at 2.5 mg/kg and repeated instillation at 0.5 mg/kg. Histopathological examinations revealed that C60 nanoparticles caused slight changes including hemorrhages in alveoli and the cellular infiltration of macrophages and neutrophils in alveoli. In comet assays using rat lung cells, no increase in % Tail DNA was found in any group given C60 nanoparticles. These findings indicate that C60 nanoparticles had no potential for DNA damage in comet assays using the lungs cells of rats given C60 even at doses causing inflammation.