Department of Kinesiology, McMaster University, Ivor Wynn Centre, Room 215, Hamilton, Ontario L8S 4L8, Canada.
Muscle Nerve. 2011 Jan;43(1):58-64. doi: 10.1002/mus.21797.
Overproduction of reactive oxygen species (ROS) can damage cellular macromolecules and lead to cellular dysfunction or death. Exercise training induces beneficial adaptations in skeletal muscle that may reduce cellular damage from exposure to ROS. To determine the response of exercise-conditioned muscle to acute increases in ROS, four groups of mice were used: non-trained (NT, n = 12); NT + high-dose radiation (HDR, n = 3); exercise-trained (EX, n = 13, 3 days/week for 10 weeks, 10 m/min to 18 m/min); and EX + HDR (n = 3/group). Quadriceps muscle was harvested 3-5 days following the last exercise bout in the training program for measurement of antioxidant enzyme and metabolic enzyme activity. Total superoxide dismutase (41%), and manganese sodium oxide dismutase (51%) activities were significantly increased in radiation-challenged EX mice as compared with unchallenged EX mice (all P ≤ 0.05). No such increase was observed in NT mice. Citrate synthase (42%) and cytochrome c oxidase (38%) activities were both elevated in radiation-challenged EX mice as compared with unchallenged EX mice (both P < 0.05), and no such increase was observed in NT. We demonstrate that preconditioning skeletal muscle with EX enhances the response of antioxidant and mitochondrial enzymes to radiation.
活性氧（ROS）的过度产生会破坏细胞大分子，导致细胞功能障碍或死亡。运动训练会引起骨骼肌的有益适应，从而减少 ROS 暴露对细胞的损伤。为了确定运动适应的肌肉对 ROS 急性增加的反应，使用了四组小鼠：未训练（NT，n=12）；未训练+高剂量辐射（HDR，n=3）；运动训练（EX，n=13，每周 3 天，速度为 10 m/min 至 18 m/min；EX+HDR（n=3/组）。在训练计划的最后一次运动后 3-5 天，采集股四头肌肌肉，以测量抗氧化酶和代谢酶的活性。与未受挑战的 EX 小鼠相比，受辐射挑战的 EX 小鼠的总超氧化物歧化酶（41%）和锰钠氧化物歧化酶（51%）活性显著增加（均 P≤0.05）。在 NT 小鼠中未观察到这种增加。与未受挑战的 EX 小鼠相比，受辐射挑战的 EX 小鼠的柠檬酸合酶（42%）和细胞色素 c 氧化酶（38%）活性均升高（均 P<0.05），而在 NT 中未观察到这种增加。我们证明，用 EX 预处理骨骼肌可增强抗氧化酶和线粒体酶对辐射的反应。
