Individuals with higher metabolic rates have lower levels of reactive oxygen species hydrogen peroxide in vivo

There is increasing interest in the effect of energy metabolism on oxidative stress, but much ambiguity over the relationship between the rate of oxygen consumption and the generation of reactive oxygen species (ROS). Production of ROS (such as hydrogen peroxide, H2O2) in the mitochondria is primarily inferred indirectly from measurements in vitro, which may not reflect actual ROS production in living animals. Here, we measured in vivo H2O2 content using the recently developed MitoB probe that becomes concentrated in the mitochondria of living organisms, where it is converted by H2O2 into an alternative form termed MitoP; the ratio of MitoP/MitoB indicates the level of mitochondrial H2O2 in vivo. Using the brown trout Salmo trutta, we tested whether this measurement of in vivo H2O2 content over a 24 h-period was related to interindividual variation in standard metabolic rate (SMR). We showed that the H2O2 content varied up to 26-fold among fish of the same age and under identical enviro...能量代谢对氧化应激的影响日益受到学界关注，但关于耗氧速率与活性氧（reactive oxygen species, ROS）生成之间的关系仍存在诸多模糊之处。目前线粒体中活性氧（如过氧化氢H₂O₂）的生成主要通过体外实验（in vitro）间接推断，而该结果或许无法反映活体动物体内真实的ROS生成情况。本研究利用新近开发的MitoB探针，对活体H₂O₂含量进行测定：该探针可在活体生物的线粒体中富集，并被H₂O₂转化为名为MitoP的变体形式；MitoP与MitoB的比值可反映活体线粒体H₂O₂的水平。本研究以褐鳟（Salmo trutta）为实验对象，探究了24小时内的活体H₂O₂含量测定结果，与个体间标准代谢率（standard metabolic rate, SMR）的差异是否存在关联。研究结果显示，在相同年龄且处于相同环境[原文此处存在截断]的褐鳟个体中，H₂O₂含量的差异最高可达26倍。