Tonkonogi M, Walsh B, Svensson M, Sahlin K
Department of Physiology and Pharmacology, Karolinska Institutet and Department of Sport and Health Sciences, Stockholm University College of Physical Education and Sports, S-11486 Stockholm, Sweden.
J Physiol. 2000 Oct 15;528 Pt 2(Pt 2):379-88. doi: 10.1111/j.1469-7793.2000.00379.x.
The influence of endurance training on oxidative phosphorylation and the susceptibility of mitochondrial oxidative function to reactive oxygen species (ROS) was investigated in skeletal muscle of four men and four women. Mitochondria were isolated from muscle biopsies taken before and after 6 weeks of endurance training. Mitochondrial respiration was measured before and after exposure of mitochondria to exogenous ROS (H2O2 + FeCl2). Endurance training increased peak pulmonary O2 uptake (VO2,peak) by 24 % and maximal ADP-stimulated mitochondrial oxygen consumption (state 3) by 40% (P<0.05). Respiration in the absence of ADP (state 4), the respiratory control ratio (RCR = state 3/state 4) and the ratio between added ADP and consumed oxygen (P/O) remained unchanged by the training programme. Exposure to ROS reduced state 3 respiration but the effect was not significantly different between pre- and post-training samples. State 4 oxygen consumption increased after exposure to ROS both before (+189 %, P< 0.05) and after training (+243 %, P<0.05) and the effect was significantly higher after training (P<0.05, pre- vs. post-training). The augmented state 4 respiration could in part be attenuated by atractyloside, which indicates that ADP/ATP translocase was affected by ROS. The P/O ratio in ROS-treated mitochondria was significantly lower (P<0.05) compared to control conditions, both before (-18.6+/-2.2 %) and after training (-18.5+/-1.1%). Muscle activities of superoxide dismutase (mitochondrial and cytosolic), glutathione peroxidase and muscle glutathione status were unaffected by training. There was a positive correlation between muscle superoxide dismutase activity and age (r = 0.75; P<0.05; range of age 20-37 years), which may reflect an adaptation to increased generation of ROS in senescent muscle. The muscle glutathione pool was more reduced in subjects with high activity of glutathione peroxidase (r = 0.81; P<0.05). The influence of short-term training on mitochondrial oxygen consumption has for the first time been investigated in human skeletal muscle. The results showed that maximal mitochondrial oxidative power is increased after endurance training but that the efficiency of energy transfer (P/O ratio) remained unchanged. Antioxidative defence was unchanged after training when expressed relative to muscle weight. Although this corresponds to a reduced antioxidant protection per individual mitochondrion, the sensitivity of aerobic energy transfer to ROS was unchanged. However, the augmented ROS-induced non-coupled respiration after training indicates an increased susceptibility of mitochondrial membrane proton conductance to oxidative stress.
研究了耐力训练对4名男性和4名女性骨骼肌中氧化磷酸化以及线粒体氧化功能对活性氧（ROS）敏感性的影响。从耐力训练6周前后采集的肌肉活检样本中分离出线粒体。在将线粒体暴露于外源性ROS（H2O2 + FeCl2）之前和之后测量线粒体呼吸。耐力训练使峰值肺氧摄取量（VO2,peak）增加了24%，使最大ADP刺激的线粒体氧消耗量（状态3）增加了40%（P<0.05）。在无ADP状态下的呼吸（状态4）、呼吸控制率（RCR = 状态3/状态4）以及添加的ADP与消耗的氧气之比（P/O）在训练方案后保持不变。暴露于ROS会降低状态3呼吸，但训练前后样本之间的影响无显著差异。暴露于ROS后，状态4氧消耗量在训练前（增加189%，P<0.05）和训练后（增加243%，P<0.05）均增加，且训练后的影响显著更高（P<0.05，训练前与训练后比较）。增加的状态4呼吸部分可被苍术苷减弱，这表明ADP/ATP转位酶受ROS影响。与对照条件相比，ROS处理的线粒体中的P/O比值在训练前（降低18.6±2.2%）和训练后（降低18.5±1.1%）均显著降低（P<0.05）。超氧化物歧化酶（线粒体和胞质）、谷胱甘肽过氧化物酶的肌肉活性以及肌肉谷胱甘肽状态不受训练影响。肌肉超氧化物歧化酶活性与年龄之间存在正相关（r = 0.75；P<0.05；年龄范围20 - 37岁），这可能反映了对衰老肌肉中ROS生成增加的一种适应。谷胱甘肽过氧化物酶活性高的受试者中肌肉谷胱甘肽池的还原程度更高（r = 0.81；P<0.05）。首次在人类骨骼肌中研究了短期训练对线粒体氧消耗的影响。结果表明，耐力训练后最大线粒体氧化能力增加，但能量转移效率（P/O比值）保持不变。相对于肌肉重量，训练后抗氧化防御不变。尽管这对应于每个线粒体抗氧化保护的降低，但有氧能量转移对ROS的敏感性不变。然而，训练后ROS诱导的非偶联呼吸增加表明线粒体膜质子传导对氧化应激的敏感性增加。
