Oxygen free radicals or oxidants that arise from molecular oxygen by successive single-electron reduction reactions, include the superoxide anion (O2), the hydrogen peroxide (H2O2), and hydroxyl radicals (·OH) (Chan 1996). Physiological levels of free radicals are needed for redox sensitive signal pathways, cell development and cell apoptosis (Chan 2001). During brain ischemia/reperfusion (I/R)...

Reactive oxygen species (ROS)plays an important role in sperm motility. The physiological generation at low concentration induces beneficial effects on sperm functions and plays a significant role in sperm metabolism. Meanwhile, the excessive generation of reactive oxygen species can overwhelm protective mechanism and triggers changes in lipid and protein layers of sperm plasma membrane, which ...