Exercise training decreases DNA damage and increases DNA repair and resistance against oxidative stress of proteins in aged rat skeletal muscle.
Regular physical exercise retards a number of age-associated disorders, in spite of the paradox that free radical generation is significantly enhanced with exercise. Eight weeks of treadmill running resulted in nearly a 40% increase in maximal oxygen uptake in both middle-aged (20-month-old) and aged (30-month-old) rats. The age-associated increase in 8-hydroxy-2'-deoxyguanosine (8-OHdG) content was significantly attenuated in gastrocnemius muscle by exercise. The 8-OHdG repair, as measured by the excision of 32P-labeled damaged oligonucleotide, increased in muscle of exercising animals. The reactive carbonyl derivatives (RCD) of proteins did not increase with aging. However, when the muscle homogenate was exposed to a mixture of 1 mM iron sulfate and 50 mM ascorbic acid, the muscle of old control animals accumulated more RCD than that of the trained or adult groups. The chymotrypsin-like activity of proteasome complex increased in muscle of old trained rats. We suggest that regular exercise-induced adaptation attenuates the age-associated increase in 8-OHdG levels, and increases the activity of DNA repair and resistance against oxidative stress in proteins.
Radák
Zsolt
Z
Laboratory of Exercise Physiology, School of Sport Sciences, Semmelweis University, Alkotas u. 44, H-1123, Budapest, Hungary. radak@mail.hupe.hu
Naito
Hisashi
H
Kaneko
Takao
T
Tahara
Shunichi
S
Nakamoto
Hideko
H
Takahashi
Ryoya
R
Cardozo-Pelaez
Fernando
F
Goto
Sataro
S
D000080242:8-Hydroxy-2'-Deoxyguanosine; D000375:Aging / Q000502:physiology*; D000818:Animals; D001835:Body Weight; D004249:DNA Damage; D004260:DNA Repair; D003849:Deoxyguanosine / Q000031:analogs & derivatives* / Q000378:metabolism; D008297:Male; D009124:Muscle Proteins / Q000235:genetics / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D018384:Oxidative Stress / Q000502:physiology*; D010101:Oxygen Consumption; D010805:Physical Conditioning, Animal / Q000502:physiology*; D051381:Rats; D011916:Rats, Inbred F344
D009124:Muscle Proteins; D000080242:8-Hydroxy-2'-Deoxyguanosine; D003849:Deoxyguanosine