C70-Carboxyfullerenes as Efficient Antioxidants to Protect Cells against Oxidative-Induced Stress

Oxidative stress induced by excessive production of reactive oxygen species (ROS) has been implicated in the etiology of many human diseases. Acquiring a highly efficient antioxidant with good biocompatibility is of significance in eliminating the deleterious effect induced by the oxidative stress. Herein, we address our efforts on investigating the cytoprotective effect of carboxyfullerenes on H2O2-injured cells. Meanwhile, the uptake and intracellular location of carboxyfullerenes were studied. The results show, that C-70-carboxyfullerenes (dimalonic acid C-70 fullerene (DF70) and trimalonic acid C-70 fullerene (TF70)) exhibit an obviously protective effect against oxidative stress on C2C12 cells at concentrations as low as 2.5 mu mol L-1 whereas C-60-carboxyfullerenes (dimalonic acid C-60 fullerene (DF60) and quadrimalonic acid C60 fullerene (QF(60))) show a protective effect at relatively higher concentration (40 mu mol L-1)The molecular structure of carboxyfullerenes and the physiological state of cells play an important role in the different cytoprotective capability. Further study reveals that DF70 and TF70 could enter into cells and mainly localize into the lysosome, which possibly involves the protective mechanism by stabilizing lysosome. The use of a significantly low concentration of C-70-carboxyfullerene as the antioxidative agent will benefit the therapeutic approaches aiming at alleviating ROS-induced injuries such as muscle disorder and arthritis.