Urban T, Hurbain I, Urban M, Clément A, Housset B
Service de Pneumologie et Laboratoire de Physiopathologie Pulmonaire, Hôpital Saint-Antoine et Faculté Saint-Antoine, Paris.
Ann Chir. 1995;49(5):427-34.
The main oxidizing free radicals (FR) are oxygen-derived metabolites (superoxide anion O2-, hydrogen peroxide H2O2, hydroxyl radical OH (zero)), hypochloric acid, chloramines, nitrogen dioxide, ozone and lipid peroxides. They are produced continually by living organisms, either in the intracellular compartment by the mitochondrial respiratory chain and mixed function oxidase system, or in the extracellular compartment, especially by phagocytes. The body possesses complex protective antioxidant systems against this potentially toxic production, such as dismutase superoxides, catalase, the glutathione enzyme system, metallic ion sequestration, enzymes degrading proteins injured by FR, metabolising hydroperoxides, and repairing DNA, and vitamins E, C, P, and betacarotene. A physiological steady-state is established under normal conditions between the production of oxidants and their neutralization by antioxidants. Oxidative lesions result from a disturbance of the oxidant-antioxidant balance. Oxygen-derived metabolites act on polyunsaturated cell membrane lipids, induce genetic alterations, and oxidize sulfhydryl groups of proteins, thereby modifying their functions. FR are involved in major physiological mechanisms such as phagocytosis, the inflammatory reaction, and the reperfusion ischaemia phenomenon observed during organ storage. The therapeutic use of enzymatic (SOD, catalase, GSH) and nonenzymatic antioxidants (vitamins E, N-acetylcysteine, allopurinol and oxypurinol) has yet to be evaluated. The current state of our knowledge indicates the extreme complexity of these systems and calls for caution in the therapeutic use of antioxidant substances.
主要的氧化自由基（FR）是氧衍生的代谢产物（超氧阴离子O2-、过氧化氢H2O2、羟基自由基OH（零））、次氯酸、氯胺、二氧化氮、臭氧和脂质过氧化物。它们由生物体持续产生，要么在细胞内由线粒体呼吸链和混合功能氧化酶系统产生，要么在细胞外，特别是由吞噬细胞产生。机体拥有复杂的保护性抗氧化系统来对抗这种潜在的毒性产生，如超氧化物歧化酶、过氧化氢酶、谷胱甘肽酶系统、金属离子螯合、降解被FR损伤的蛋白质的酶、代谢氢过氧化物以及修复DNA，还有维生素E、C、P和β-胡萝卜素。在正常情况下，氧化剂的产生与抗氧化剂对它们的中和之间建立了生理稳态。氧化损伤是由氧化剂-抗氧化剂平衡的紊乱引起的。氧衍生的代谢产物作用于多不饱和细胞膜脂质，诱导基因改变，并氧化蛋白质的巯基，从而改变其功能。FR参与主要的生理机制，如吞噬作用、炎症反应以及在器官储存期间观察到的再灌注缺血现象。酶促抗氧化剂（超氧化物歧化酶、过氧化氢酶、谷胱甘肽）和非酶促抗氧化剂（维生素E、N-乙酰半胱氨酸、别嘌呤醇和氧嘌呤醇）的治疗用途尚未得到评估。我们目前的知识状态表明这些系统极其复杂，因此在抗氧化物质的治疗应用中需要谨慎。
