Oxidative stress induced by intermittent exposure at a simulated altitude of 4000 m decreases mitochondrial superoxide dismutase content in soleus muscle of rats.
The effects were examined of 6-month intermittent hypobaric (4000 m) exposure on the antioxidant enzyme systems in soleus and tibialis muscles of rats. At the end of the 6-month experimental exposure, the six rats in both the exposed group and the control group were sacrificed. Immunoreactive mitochondrial superoxide dismutase (Mn-SOD) contents were measured as well as the activities of antioxidant enzymes [Mn-SOD, cytosolic SOD (Cu,Zn-SOD), catalase (CAT), and glutathione peroxidase (GPX)]. Thiobarbituric acid-reactive substances (TBARS) were also determined as an indicator of lipid peroxidation. The high altitude exposure resulted in a marked increase in TBARS content in soleus muscle, suggesting increased levels of oxygen free radicals. Conversely, significant decreases in both Mn-SOD content and activity in soleus muscle were noted after exposure. Such trends were not noticed in tibialis muscle. On the other hand, no significant changes in Cu,Zn-SOD, CAT, or GPX were observed in either muscle. These results suggested that the increases in lipid peroxidation were most probably a result of decreased Mn-SOD function which was more depressed in oxidative than in glycolytic muscle.
Radák
Z
Z
Laboratory for Exercise Physiology, University of Tsukuba, Ibaraki, Japan.
Lee
K
K
Choi
W
W
Sunoo
S
S
Kizaki
T
T
Oh-ishi
S
S
Suzuki
K
K
Taniguchi
N
N
Ohno
H
H
Asano
K
K
D000531:Altitude; D000818:Animals; D002374:Catalase / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000378:metabolism; D006614:Hindlimb; D008297:Male; D008931:Mitochondria, Muscle / Q000201:enzymology*; D018384:Oxidative Stress; D051381:Rats; D017208:Rats, Wistar; D013312:Stress, Physiological / Q000378:metabolism*; D013482:Superoxide Dismutase / Q000378:metabolism*; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism
D017392:Thiobarbituric Acid Reactive Substances; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase