机体在正常氧化还原反应中产生活性氧(reac-tive oxygen species,ROS),其性质活泼,除了部分是生理活动必需分子外,其余需及时清除;如机体一旦对过多ROS清除不力,就会发生氧化损伤。正常机体内有一些防御系统,在ROS的产生和清除间保持平衡,维持合适的比例。无论是机体内因还是外 The body produces reactive oxygen species (ROS) in the normal redox reaction, its nature is active, in addition to some of the essential molecules of physiological activity, the rest need to be promptly removed; such as the body once too much clearance of ROS ineffective, it will Oxidative damage occurs. There are defenses in the normal body that maintain the balance between production and clearance of ROS and maintain proper proportions. Whether the body is inside or outside