LOW MITOCHONDRIAL FREE-RADICAL PRODUCTION PER UNIT O-2 CONSUMPTION CAN EXPLAIN THE SIMULTANEOUS PRESENCE OF HIGH LONGEVITY AND HIGH AEROBIC METABOLIC-RATE IN BIRDS
LOW MITOCHONDRIAL FREE-RADICAL PRODUCTION PER UNIT O-2 CONSUMPTION CAN EXPLAIN THE SIMULTANEOUS PRESENCE OF HIGH LONGEVITY AND HIGH AEROBIC METABOLIC-RATE IN BIRDS
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DOI：
10.3109/10715769409056584
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发表时间：
1994-01-01
影响因子：
3.3
通讯作者：
LOPEZTORRES, M
中科院分区：
文献类型：
--
作者：
BARJA, G;CADENAS, S;LOPEZTORRES, M
鸟类是独一无二的，因为它们可以结合高耗氧率和高最大寿命(MLSP)。造成这种能力的原因尚不清楚。在包括人类在内的灵长类动物中也存在类似的情况，它们的MLSP比从它们的O2消耗率预测的要高。本工作比较了成年雄性大鼠(MLSP=4岁)和成年鸽子(MLSP=35岁)的线粒体氧自由基产生和耗氧速率。全动物安静时的氧耗量和脑、肺、肝线粒体的氧耗量鸽子均高于大鼠。然而，鸽子的线粒体自由基生成量是大鼠组织的2-4倍。这是可能的，因为鸽子线粒体显示出每单位O-2消耗的自由基速率比大鼠线粒体低一个数量级：鸟类线粒体显示呼吸链上的自由基泄漏较低。这一结果首次在这里描述，可能解释了鸟类同时增加最大寿命和基础代谢率的能力。这也表明，氧化应激与衰老和长寿相关的主要因素不是氧气消耗的速度，而是氧自由基的产生速度。以前关于衰老的存活率理论的不一致可以用自由基衰老理论来解释，该理论侧重于氧自由基的产生速度和位于不断产生自由基的地方附近的与衰老相关的靶点的局部损害。
Birds are unique since they can combine a high rate of oxygen consumption at rest with a high maximum life span (MLSP). The reasons for this capacity are unknown. A similar situation is present in primates including humans which show MLSPs higher than predicted from their rates of O-2 consumption. In this work rates of oxygen radical production and O-2 consumption by mitochondria were compared between adult male rats (MLSP = 4 years) and adult pigeons (MLSP = 35 years), animals of similar body size. Both the O-2 consumption of the whole animal at rest and the O-2 consumption of brain, lung and liver mitochondria were higher in the pigeon than in the rat. Nevertheless, mitochondrial free radical production was 2-4 times lower in pigeon than in rat tissues. This is possible because pigeon mitochondria show a rate of free radical production per unit O-2 consumed one order of magnitude lower than rat mitochondria: bird mitochondria show a lower free radical leak at the respiratory chain. This result, described here for the first time, can possibly explain the capacity of birds to simultaneously increase maximum longevity and basal metabolic rate. It also suggests that the main factor relating oxidative stress to aging and longevity is not the rate of oxygen consumption but the rate of oxygen radical production. Previous inconsistencies of the rate of living theory of aging can be explained by a free radical theory of aging which focuses on the rate of oxygen radical production and on local damage to targets relevant for aging situated near the places where free radicals are continuously generated.