title: Changes in oxidative stress markers and biological markers of muscle injury with aging at rest and in response to an exhaustive exercise.
abstract: OBJECTIVE
  The aim of this study was to evaluate whether oxidative stress markers and biomarkers of muscle injury would be affected by aging at rest and in response to an incremental exhaustive exercise.
  
  
  METHODS
  Fifteen young (20.3 ± 2.8 years) and fifteen older adults (65.1 ± 3.5 years) performed an incremental cycle ergometer test to exhaustion. Before and after exercise, oxidative stress [superoxide dismutase (SOD), glutathione peroxidase (GPX), glutathione reductase (GR), ascorbic acid, α-Tocopherol, malondialdehyde (MDA)] and muscle injury [creatine kinase (CK), lactate deshydrogenase (LDH)] biomarkers were assessed.
  
  
  RESULTS
  At rest, there was no difference in oxidative stress markers and LDH level between the groups, however CK was significantly higher in the young group than the elderly group (p<0.05). During recovery, in comparison with resting values, a significant increase in SOD (1092 ± 145.9 vs. 1243 ± 98 U/g Hb), GPX (67.4 ± 12.7 vs. 79.2 ± 15.6 U/g Hb) and GR (6.5 ± 0.9 vs. 7.7 ± 0.5 U/g Hb) activities were observed only in the young group (p<0.05). MDA has increased only in the older group (0.54 ± 0.2 vs. 0.79 ± 0.2 µmol/l) (p<0.01). CK increased in both groups (young group: 122.5 ± 22.2 vs. 161.9 ± 18.7 UI/l; older group: 88.8 ± 34.1 vs. 111.1 ± 25.9 UI/l) (p<0.01), however LDH has increased only in the young group (400.5 ± 22.2 vs. 485 ± 18.7 UI/l) (p<0.01) without alteration in the older group (382.8 ± 34.1 vs. 418.5 ± 25.9 UI/l).
  
  
  CONCLUSIONS
  These findings indicate that aging is associated with a decrease in antioxidant efficiency and an increase in oxidative stress damage. Furthermore, older adults would not more susceptible to exercise-induced muscle injury than young people.
authors.affiliation: Université Lille Nord de France, EA 4488, Activité Physique Muscle Santé, Faculté des Sciences du Sport et de l'Education Physique, Ronchin, France.
authors.forename: Mohamed Amine
authors.initials: MA
authors.lastname: Bouzid
authors.affiliation: Research Laboratory «Sport Performance Optimisation», National Center of Medecine and Science in Sports, Tunis, Tunisia.
authors.forename: Omar
authors.initials: O
authors.lastname: Hammouda
authors.affiliation: Service EFR, CHRU de Lille, Lille, France.
authors.forename: Regis
authors.initials: R
authors.lastname: Matran
authors.affiliation: Service EFR, CHRU de Lille, Lille, France.
authors.forename: Sophie
authors.initials: S
authors.lastname: Robin
authors.affiliation: Université Lille Nord de France, EA 4488, Activité Physique Muscle Santé, Faculté des Sciences du Sport et de l'Education Physique, Ronchin, France.
authors.forename: Claudine
authors.initials: C
authors.lastname: Fabre
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000375:Aging; D000975:Antioxidants / Q000378:metabolism; D015415:Biomarkers / Q000097:blood / Q000378:metabolism; D003402:Creatine Kinase / Q000378:metabolism; D019587:Dietary Supplements; D015444:Exercise; D005260:Female; D005979:Glutathione Peroxidase / Q000378:metabolism; D005980:Glutathione Reductase / Q000378:metabolism; D006801:Humans; D008297:Male; D008315:Malondialdehyde / Q000378:metabolism; D008875:Middle Aged; D018763:Muscle Fatigue; D018482:Muscle, Skeletal / Q000293:injuries* / Q000378:metabolism*; D018384:Oxidative Stress; D012146:Rest; D013482:Superoxide Dismutase / Q000378:metabolism; D055815:Young Adult; D024502:alpha-Tocopherol / Q000378:metabolism
chemical_list: D000975:Antioxidants; D015415:Biomarkers; D008315:Malondialdehyde; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D005980:Glutathione Reductase; D003402:Creatine Kinase; D024502:alpha-Tocopherol