Radicaux libres et vieillissement

The complete reduction of oxygen to water is a complex process that can produce incompletely reduced intermediaries, named Reactive Oxygen Species (ROS). To complete their reduction, these compounds oxidize a lot of molecules, which may affect the function of the latter. The ROS have been therefore implicated in several acute or chronic diseases, as well as in aging. In his short review, we briefly describe how ROS are physiologically produced and eliminated. We then discuss evidence that suggests a possible link between ROS and aging. Comparatives studies of animals with different aging rates indicate that oxidative damages, as well as mitochondrial ROS production inversely correlate with longevity. Caloric restriction, which decreases the rate of aging of laboratory animals, decreases mitochondrial ROS production. The degree of unsaturation of tissue fatty acids (i.e., their sensitivity to lipid peroxidation) also correlates inversely with maximum longevity, suggesting that one of the main target for ROS are more resistant in long-lived animals. On the other hand, although antioxidants may prevent various age-related diseases, they do not seem to control the rate of aging.