Protective effects of carboxyfullerene in irradiated cells and BALB/c mice

It has been reported that carboxyfullerene (C3) exhibits a strong free radical scavenging capacity, which plays a critical role in radiation damage. We hypothesized that C3 is an effective radioprotective agent. In this study, we demonstrated that C3 effectively scavenged hydroxyl radical in a cell-free Fenton system and that C3 showed no obvious toxicity for cultured cells. Different concentrations (100-400 mg/L) of C3 pretreatment effectively protected AHH-1 cells from radiation-induced apoptosis, by about 2-folds, while only 100 mg/L of C3 reduced the apoptosis rate of human intestinal crypt epithelial cells (HIECs). C3 also alleviated DNA damage detected using comet assay at 0, 4, and 8 h after irradiation. It was found that 75% of mice were protected from 7.2 Gy γ-irradiation-induced death when 100 mg/kg of C3 was administered prior to irradiation, but no change was observed for the survival time of mice which died. We also found that C3 attenuated radiation-mediated decreases in endogenous antioxidants such as SOD and GSH and reduced the level of MDA. In conclusion, these data showed that C3 effectively protected cells and mice from radiation injury, thus indicating the potential of C3 as a safe and effective radioprotectant.