In the process of oxidative phosphorylation, protons are pumped into the intermembrane space to establish the mitochondrial membrane potential (MMP). Relying on the electrochemical gradient, protons can return to the matrix through the ATP synthase complex with ATP generation. MitoQ, a lipophilic cation drug, can be bsorbed to the inner mitochondrial membrane with the cationic moiety staying at the intermembrane space[1].