Kulkarni Aditi C, Kuppusamy Periannan, Parinandi Narasimham
Center for Biomedical EPR Spectroscopy and Imaging, Comprehensive Cancer Center, Davis Heart and Lung Research Institute, Department of Internal Medicine, The Ohio State University, Columbus, Ohio 43210, USA.
Antioxid Redox Signal. 2007 Oct;9(10):1717-30. doi: 10.1089/ars.2007.1724.
Aerobic life has evolved a dependence on molecular oxygen for its mere survival. Mitochondrial oxidative phosphorylation absolutely requires oxygen to generate the currency of energy in aerobes. The physiologic homeostasis of these organisms is strictly maintained by optimal cellular and tissue-oxygenation status through complex oxygen-sensing mechanisms, signaling cascades, and transport processes. In the event of fluctuating oxygen levels leading to either an increase (hyperoxia) or decrease (hypoxia) in cellular oxygen, the organism faces a crisis involving depletion of energy reserves, altered cell-signaling cascades, oxidative reactions/events, and cell death or tissue damage. Molecular oxygen is activated by both nonenzymatic and enzymatic mechanisms into highly reactive oxygen species (ROS). Aerobes have evolved effective antioxidant defenses to counteract the reactivity of ROS. Although the ROS are also required for many normal physiologic functions of the aerobes, overwhelming production of ROS coupled with their insufficient scavenging by endogenous antioxidants will lead to detrimental oxidative stress. Needless to say, molecular oxygen is at the center of oxygenation, oxidative phosphorylation, and oxidative stress. This review focuses on the biology and pathophysiology of oxygen, with an emphasis on transport, sensing, and activation of oxygen, oxidative phosphorylation, oxygenation, oxidative stress, and oxygen therapy.
有氧生命的进化使其仅仅为了生存就依赖于分子氧。线粒体氧化磷酸化绝对需要氧气来产生需氧生物的能量货币。这些生物的生理稳态通过复杂的氧传感机制、信号级联反应和转运过程，由最佳的细胞和组织氧合状态严格维持。如果氧水平波动导致细胞内氧增加（高氧）或减少（低氧），生物体将面临一场危机，包括能量储备耗尽、细胞信号级联反应改变、氧化反应/事件以及细胞死亡或组织损伤。分子氧通过非酶和酶机制被激活为高活性氧（ROS）。需氧生物已经进化出有效的抗氧化防御机制来对抗ROS的反应性。尽管ROS对于需氧生物的许多正常生理功能也是必需的，但ROS的过量产生以及内源性抗氧化剂对其清除不足会导致有害的氧化应激。不用说，分子氧处于氧合、氧化磷酸化和氧化应激的核心。本综述重点关注氧的生物学和病理生理学，重点是氧的转运、传感和激活、氧化磷酸化、氧合、氧化应激和氧疗。
