中文摘要：

活性氧（reactive oxygen species，ROS）是生物体内一类活性含氧化合物的总称，主要包括超氧阴离子、羟自由基和过氧化氢等。细胞内有多种部位能生成ROS，主要包括线粒体、内质网、NADPH氧化酶复合体、脂氧合酶系、环氧合酶系等。静息条件下，细胞内ROS的水平被控制在很低的范围。而在细胞受到各种生理或病理因素作用时，当多种细胞外信号分子作用于其膜受体，ROS生成可以受到受体活化的诱导而“有目的”地快速增加，从而作为细胞内信号分子参与细胞增殖，分化和凋亡等各种细胞行为。

英文摘要：

Reactive oxygen species （ROS） are those oxygen-containing molecules in the forms of superoxide anion, hydroxyl radicals and hydrogen peroxide which appear more reactive than molecular oxygen. The sources of intracellular ROS are mitochondria, endoplasmic reticulum, NADPH oxidase, lipoxygenase, cycloxgenase, etc. Under a rest statue, the generation of ROS is restricted to a quite low level. However, affected by physiological or pathological conditions, a massive quantity of ROS can be produced ＂purposely＂ by the activation of the various cell membrane receptors, like tumor necrosis factor-α receptors, receptor tyrosine kinases, receptor serine/threonine kinases, G protein-coupled receptors, ion channel-linked receptors, etc. As a result, ROS are involved all aspects of cell behaviors, such as cell proliferation, differentiation and death, and other biochemical events.