OXIDATIVE STRESS AND MITOCHONDRIAL DYSFUNCTION

Abstract

The process of cell damage resulting from the action of free radicals – reactive oxygen species (ROS) – is called oxidative stress. Most ROS are constantly formed in the cell – about 5 % of the oxygen consumed by tissues is converted into free radicals, but their level is normally so small that the cell inactivates them with the help of an antioxidant system. Different organs and tissues are exposed to different degrees of ROS and demonstrate different stability during the implementation of oxidative stress. The mechanisms of ROS formation by mitochondria under oxidative stress are still unclear. At the same time, it was found that mitochondrial dysfunction and the accumulation of mitochondrial mutations in tissues make a significant contribution to the aging process, as well as to the pathogenesis of a number of diseases characterized by neurodegeneration. Mutations lead to increased generation of free radicals, reduced ATP levels, and energy failure of cells. Coenzyme Q10 is a component of the mitochondrial respiratory chain. Violation of the biosynthesis of coenzyme Q10 can lead to a number of mitochondrial diseases. When coenzyme Q10 is deficient, sulfide metabolism plays a critical role. Sulfide metabolism in mammalian cells includes trans-sulfuration (biosynthetic) and hydrogen sulfide oxidation (H2S) (catabolic). Violation of H2S oxidation may contribute to oxidative stress in coenzyme Q deficiency or may play a synergistic role with oxidative stress in the pathogenesis of tissue specificity in coenzyme Q deficiency.