Decreased mitochondrial oxygen consumption and antioxidant enzyme activities in skeletal muscle of dystrophic mice after low-intensity exercise.
To evaluate low-intensity exercise training induced changes of mitochondrial metabolism in dystrophic skeletal muscle, oxygen consumption, reactive oxygen species (ROS) scavengers and antioxidant enzymes were measured in control (C57BL/10) and dystrophic (mdx) mice at 10 (young) and 22 (adult) weeks of age. Dystrophic and control mice were either kept sedentary or daily exercised on a treadmill (480 m/day, exercise training was initiated at 4 and 16 weeks of age for 6 weeks' duration). Mitochondrial oxygen consumption was significantly lower in skeletal muscle from exercised young compared to sedentary young dystrophics. Whereas oxygen consumption was unchanged in exercised adult dystrophics, exercised adult controls exhibit a significant increase vs. sedentary adult controls. Contents of TBARS and lipofuscin were increased (+48%, +24%), while alpha-tocopherol concentration tended to decrease (p > 0.05) in exercised vs. sedentary young dystrophics. Compared to sedentary groups, glutathione peroxidase activity was decreased in exercised young dystrophic muscle (-12%), but increased in exercised controls (young controls +60%, adult controls +47%). In conclusion, adaptation to exercise-induced formation of ROS was limited in young dystrophic skeletal muscle but regained in that of adults.
Faist
V
V
Institut für Ernährungswissenschaften, Universität Wien, Osterreich. vfaist@nutrfoodsc.uni-kiel.de
König
J
J
Höger
H
H
Elmadfa
I
I
D000220:Adaptation, Biological; D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D003402:Creatine Kinase / Q000097:blood; D005979:Glutathione Peroxidase / Q000378:metabolism; D008062:Lipofuscin; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008931:Mitochondria, Muscle / Q000201:enzymology / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000378:metabolism*; D009137:Muscular Dystrophy, Animal / Q000378:metabolism*; D010101:Oxygen Consumption; D010805:Physical Conditioning, Animal / Q000502:physiology*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D017392:Thiobarbituric Acid Reactive Substances; D014810:Vitamin E / Q000378:metabolism
D000975:Antioxidants; D008062:Lipofuscin; D017382:Reactive Oxygen Species; D017392:Thiobarbituric Acid Reactive Substances; D014810:Vitamin E; D005979:Glutathione Peroxidase; D003402:Creatine Kinase