Cytotoxic Effects of Hydroxylated Fullerenes in Three Types of Liver Cells

Fullerenes C 60 have attracted considerable attention in the biomedical field due to their interesting properties. Although there has been a concern that C 60 could be metabolized to hydroxylated fullerenes (C 60(OH) x) in vivo, there is little information on the effect of hydroxylated C 60 on liver cells. In the present study, we evaluated the cytotoxic effects of fullerene C 60 and various hydroxylated C 60 derivatives, C 60(OH) 2, C 60(OH) 6–12, C 60(OH) 12 and C 60(OH) 36, with three different types of liver cells, dRLh-84, HepG2 and primary cultured rat hepatocytes. C 60, C 60(OH) 2 and C 60(OH) 36 exhibited little or no cytotoxicity in all of the cell types, while C 60(OH) 6–12 and C 60(OH) 12 induced cytotoxic effects in dRLh-84 cells, accompanied by the appearance of numerous vacuoles around the nucleus. Moreover, mitochondrial activity in liver cells was significantly inhibited by C 60(OH) 6–12 and C 60(OH) 12. These results indicate that the number of hydroxyl groups on C 60(OH) x contribute to the difference of their cytotoxic potential and mitochondrial damage in liver cells.