Facebook
Twitter
LinkedIn
Email
 |
Checking for direct PDF access through Ovid | |
Excerpt
Reactive oxygen species (ROS) are implicated in the mechanism of biological aging and oxidative damage inflicted by strenuous aerobic exercise; however, there is little direct evidence that ROS production is increased during exercise. The present study used dichlorofluorescence (DCF) as a novel intracellular probe to measure ROS production in the skeletal muscle of young adult (8 mo, N=24) and old (24 mo, N=24) male Fisher 344 rats at rest and after an acute bout of exercise. Young rats ran on treadmill at 25 m/min, 5% grade until exhaustion (55.4±2.7 min), whereas old rats ran at 15 m/min, 5% until exhaustion (58.0±2.7 min). ROS production rate in the deep vastus lateralis (DVL), measured by formation of oxidized DCF/min x mg protein, was increased by 77% (P<0.01) with aging, and was elevated by 39 and 50% (P<0.01) after exercise in young and old rats, respectively. ROS production in isolated DVL mitochondria was increased by 57% (P<0.01) with aging, but unaffected by exercise. Addition of ADP, NADPH and Fe3+ to the assay media enhanced ROS production in the mitochondria, but not homogenate, from exercised young rats (P<0.01), suggesting a potential role of NADPH oxidase during exercise. Lipid peroxidation measured by malondialdehyde content showed no age effect but increased 20% (P<0.05) with exercise in both young and old rats. Exercise also increased muscle protein carbonyl formation in both age groups. Mitochondrial glutathione content was not altered with either aging or exercise. These data indicate that ROS production is increased in skeletal muscle with aging and during prolonged exercise, which may explain the observed oxidative damage to lipids and proteins.
