The redox state of the cell plays an important part in processes such as tumor progression, aging, atherosclerosis, chronic inflammatory processes, lung injuries and neurodegenerative diseases. Increased levels of intracellular reactive oxygen species (ROS) above normal basal levels are defined as cellular oxidative stress. ROS include superoxide anions (O2 .-), hydroxyl radicals and hydrogen peroxide (H2O2), which can be further changed into highly reactive hydroxyl radicals via iron-catalyzed Fenton reactions under pathological conditions. O2 .- can also rapidly react with nitric oxide (NO) to generate a stable free radical, peroxynitrite (OONO.-), which is a strong cytotoxic oxidant. Typically, oxidative stress is generated by increased production of ROS and/ or by damage to the antioxidant defense system during cellular processes (Sies, 1997; Hoidal, 2001; Sen and Packer, 1996). Oxidative stress can also be introduced by exogenous sources such as air pollutants and cigarette smoke. Since the lungs contain the largest surface area of epithelial and endothelial cells of any organ, they are at high risk for injury from inhalation of high concentrations of ROS.
ASJC Scopus subject areas
- Agricultural and Biological Sciences(all)