Laboratory of Muscle Biology and Sarcopenia, Division of Exercise Physiology, West Virginia University School of Medicine, Morgantown, WV 26506, USA.
Exp Gerontol. 2010 Nov;45(11):882-95. doi: 10.1016/j.exger.2010.08.002. Epub 2010 Aug 10.
Aging is associated with increased oxidative stress. Muscle levels of oxidative stress are further elevated with exercise. The purpose of this study was to determine if dietary antioxidant supplementation would improve muscle function and cellular markers of oxidative stress in response to chronic repetitive loading in aging. The dorsiflexors of the left limb of aged and young adult Fischer 344 Brown×Norway rats were loaded 3 times weekly for 4.5 weeks using 80 maximal stretch-shortening contractions per session. The contra-lateral limb served as the intra-animal control. The rats were randomly assigned to a diet supplemented with Vitamin E and Vitamin C or normal non-supplemented rat chow. Biomarkers of oxidative stress were measured in the tibialis anterior muscle. Repetitive loading exercise increased maximal isometric force, negative work and positive work in the dorsiflexors of young adult rats. Only positive work increased in the aged animals that were supplemented with Vitamin E and C. Markers of oxidative stress (H(2)O(2), total GSH, GSH/GSSG ratio, malondialdehyde and 8-OHdG) increased in the tibialis anterior muscles from aged and young adult animals with repetitive loading, but Vitamin E and C supplements attenuated this increase. MnSOD activity increased with supplementation in the young adult animals. CuZnSOD and catalase activity increased with supplementation in young adult and aged animals and GPx activity increased with exercise in the non-supplemented young adult and aged animals. The increased levels of endogenous antioxidant enzymes after Vitamin E and C supplementation appear to be regulated by post-transcriptional modifications that are affected differently by age, exercise, and supplementation. These data suggest that antioxidant supplementation improves indices of oxidative stress associated with repetitive loading exercise and aging and improves the positive work output of muscles in aged rodents.
衰老是与氧化应激增加有关。运动进一步提高了肌肉的氧化应激水平。本研究的目的是确定抗氧化剂补充饮食是否会改善衰老过程中慢性重复加载对肌肉功能和氧化应激的细胞标志物的影响。使用 80 次最大拉伸-缩短收缩/次，每周 3 次对老年和年轻成年 Fischer 344 棕色×挪威大鼠左侧背屈肌进行 4.5 周的加载。对侧肢体作为体内对照。大鼠被随机分配到补充维生素 E 和维生素 C 的饮食或正常的非补充大鼠饲料。在前胫骨肌肉中测量氧化应激的生物标志物。重复加载运动增加了年轻成年大鼠背屈肌的最大等长力、负功和正功。只有补充了维生素 E 和 C 的老年动物的正功增加。重复加载后，老年和年轻成年动物的前胫骨肌肉中的氧化应激标志物（H2O2、总 GSH、GSH/GSSG 比、丙二醛和 8-OHdG）增加，但维生素 E 和 C 补充剂减轻了这种增加。MnSOD 活性在年轻成年动物中随补充而增加。CuZnSOD 和过氧化氢酶活性在年轻成年和老年动物中随补充而增加，而 GPx 活性在未补充的年轻成年和老年动物中随运动而增加。维生素 E 和 C 补充后内源性抗氧化酶水平的增加似乎受到转录后修饰的调节，而这种调节受年龄、运动和补充的影响不同。这些数据表明，抗氧化剂补充可改善与重复加载运动和衰老相关的氧化应激指标，并改善老年啮齿动物肌肉的正功输出。
