Oxidative damage of mitochondria induced by Fe(II)citrate or t-butyl hydroperoxide in the presence of Ca2+: Effect of coenzyme Q redox state

The role of coenzyme Q on the process of mitochondrial membrane damage associated with oxidative stress was studied in a suspension of uncoupled mitochondria exposed to Ca2+ in the presence of Fe(II)citrate or t-butyl hydroperoxide. Reduction of coenzyme Q by succinate was shown to inhibit both inner membrane lipid peroxidation and permeabilization induced by Fe(II)citrate. In contrast, the inner membrane permeabilization induced by Ca2+ alone or Ca2+ plus t-butyl hydroperoxide was potentiated by the presence of succinate. These results support our previous proposition that the mitochondrial damage associated with oxidative stress generated by these prooxidants in the presence of Ca2+ is mediated by different mechanisms.