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.