Bejma J, Ji L L
Department of Kinesiology, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
J Appl Physiol (1985). 1999 Jul;87(1):465-70. doi: 10.1152/jappl.1999.87.1.465.
Reactive oxygen species (ROS) are implicated in the mechanism of biological aging and exercise-induced oxidative damage. The present study examined the effect of an acute bout of exercise on intracellular ROS production, lipid and protein peroxidation, and GSH status in the skeletal muscle of young adult (8 mo, n = 24) and old (24 mo, n = 24) female Fischer 344 rats. Young rats ran on a treadmill at 25 m/min and 5% grade until exhaustion (55.4 +/- 2.7 min), whereas old rats ran at 15 m/min and 5% grade until exhaustion (58.0 +/- 2.7 min). Rate of dichlorofluorescin (DCFH) oxidation, an indication of ROS and other intracellular oxidants production in the homogenate of deep vastus lateralis, was 77% (P < 0.01) higher in rested old vs. young rats. Exercise increased DCFH oxidation by 38% (P < 0.09) and 50% (P < 0.01) in the young and old rats, respectively. DCFH oxidation in isolated deep vastus lateralis mitochondria with site 1 substrates was elevated by 57% (P < 0.01) in old vs. young rats but was unaltered with exercise. Significantly higher DCFH oxidation rate was also found in aged-muscle mitochondria (P < 0.01), but not in homogenates, when ADP, NADPH, and Fe(3+) were included in the assay medium without substrates. Lipid peroxidation in muscle measured by malondialdehyde content showed no age effect, but was increased by 20% (P < 0.05) with exercise in both young and old rats. Muscle protein carbonyl formation was unaffected by either age or exercise. Mitochondrial GSH/ GSSG ratio was significantly higher in aged vs. young rats (P < 0.05), whereas exercise increased GSSG content and decreased GSH/GSSG in both age groups (P < 0.05). These data provided direct evidence that oxidant production in skeletal muscle is increased in old age and during prolonged exercise, with both mitochondrial respiratory chain and NADPH oxidase as potential sources. The alterations of muscle lipid peroxidation and mitochondrial GSH status were consistent with these conclusions.
活性氧（ROS）与生物衰老机制及运动诱导的氧化损伤有关。本研究检测了一次急性运动对年轻成年（8月龄，n = 24）和老年（24月龄，n = 24）雌性Fischer 344大鼠骨骼肌细胞内ROS产生、脂质和蛋白质过氧化以及谷胱甘肽（GSH）状态的影响。年轻大鼠在跑步机上以25米/分钟的速度和5%的坡度跑步直至力竭（55.4±2.7分钟），而老年大鼠以15米/分钟的速度和5%的坡度跑步直至力竭（58.0±2.7分钟）。在休息状态下，老年大鼠股外侧肌深部匀浆中二氯荧光素（DCFH）氧化速率，即ROS和其他细胞内氧化剂产生的指标，比年轻大鼠高77%（P < 0.01）。运动使年轻和老年大鼠的DCFH氧化分别增加38%（P < 0.09）和50%（P < 0.01）。在以位点1底物培养的分离的股外侧肌深部线粒体中，老年大鼠的DCFH氧化比年轻大鼠升高了57%（P < 0.01），但运动对其无影响。当在测定培养基中不添加底物而加入ADP、NADPH和Fe(3+)时，在老年肌肉线粒体中也发现DCFH氧化速率显著更高（P < 0.01），但在匀浆中未发现。通过丙二醛含量测定的肌肉脂质过氧化未显示出年龄效应，但年轻和老年大鼠运动后均增加了20%（P < 0.05）。肌肉蛋白质羰基形成不受年龄或运动的影响。老年大鼠线粒体GSH/GSSG比值显著高于年轻大鼠（P < 0.05），而运动增加了两个年龄组的GSSG含量并降低了GSH/GSSG比值（P < 0.05）。这些数据提供了直接证据，表明老年和长时间运动期间骨骼肌中的氧化剂产生增加，线粒体呼吸链和NADPH氧化酶均为潜在来源。肌肉脂质过氧化和线粒体GSH状态的改变与这些结论一致。
