title: Exercise training enhances the skeletal muscle response to radiation-induced oxidative stress.
abstract: 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.
authors.affiliation: Department of Kinesiology, McMaster University, Ivor Wynn Centre, Room 215, Hamilton, Ontario L8S 4L8, Canada.
authors.forename: Michael
authors.initials: M
authors.lastname: De Lisio
authors.forename: Jan J
authors.initials: JJ
authors.lastname: Kaczor
authors.forename: Nghi
authors.initials: N
authors.lastname: Phan
authors.forename: Mark A
authors.initials: MA
authors.lastname: Tarnopolsky
authors.forename: Douglas R
authors.initials: DR
authors.lastname: Boreham
authors.forename: Gianni
authors.initials: G
authors.lastname: Parise
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D005081:Exercise Therapy / Q000379:methods*; D005720:Gamma Rays / Q000009:adverse effects; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018482:Muscle, Skeletal / Q000378:metabolism* / Q000503:physiopathology* / Q000528:radiation effects; D018384:Oxidative Stress / Q000502:physiology / Q000528:radiation effects*; D010805:Physical Conditioning, Animal / Q000502:physiology*; D017382:Reactive Oxygen Species / Q000378:metabolism* / Q000528:radiation effects; D013663:Teaching / Q000379:methods
chemical_list: D017382:Reactive Oxygen Species