Free radicals in perinatal and neonatal care, part 2: oxidative stress during the perinatal and neonatal period.

摘要

Oxidative stress occurs when the production of reactive oxygen species (ROS), including free radicals, exceeds the handling capability of intracellular antioxidant enzymes and extracellular antioxidant defenses. This may occur because of factors that result in excess formation of free radicals and other reactive species, or due to impairment of antioxidant capability. Factors that may increase oxidative stress include smoking, infections and inflammation, lower levels of antioxidant production, and toxic exposures. Excessive oxidative stress leads to per-oxidative damage to cells, altered cellular function, and pathologic effects. Not all free radicals are deleterious, however, as low levels are important for normal function. They act as intermediaries in many body processes, including cytotoxicity, prostaglandin metabolism, vascular tone control, neurotransmission, reproduction, and normal growth and development.This is the second of a 2-part column about free radicals and oxidative stress during the perinatal and neonatal periods. Part 1 discussed free radicals in general; this part focuses on some of the roles of oxidative stress during reproduction, pregnancy, and in the newborn.