title: Role of exercise and ascorbate on plasma antioxidant capacity in thoroughbred race horses.
abstract: During exercise, the oxygen consumption and the production of free radicals increase and can lead to oxidative stress with a deleterious effect on cellular structures involved in physical activity. To evaluate the oxidative stress produced by exercise and the role of ascorbate as an antioxidant, venous blood samples were obtained from 44 thoroughbred racehorses, before and after a 1000+/-200-m race at maximum velocity. Fourteen of these horses were treated intravenously with 5 g of ascorbate before running. Antioxidant capacity (PAOC), endogenous and exogenous ascorbate concentration, total antioxidant reactivity (TAR), urate concentration, creatine kinase activity, protein concentration and thiobarbiturate reactive substances (TBAR) as oxidative stress indicators were measured in the plasma of some of these horses. PAOC, TAR and TBAR increased after the race, while plasma ascorbate and urate concentrations remained unchanged. Total plasma protein (TPP) concentrations increased in line with antioxidant capacity. As predicted, both the plasma ascorbate concentration and PAOC increased immediately after ascorbate administration, but was not modified after the race, such as TBAR. However, in both groups plasma creatine kinase activity increased after the race. These results would suggest that the administration of ascorbate could nullify the oxidative stress produced by exercise in thoroughbred racehorses, but could not prevent muscular damage.
authors.affiliation: Biomedical Sciences Institute, Faculty of Medicine, University of Chile, P.O. Box 70005, 7, Santiago, Chile. awhite@machi.med.uchile.cl
authors.forename: A
authors.initials: A
authors.lastname: White
authors.forename: M
authors.initials: M
authors.lastname: Estrada
authors.forename: K
authors.initials: K
authors.lastname: Walker
authors.forename: P
authors.initials: P
authors.lastname: Wisnia
authors.forename: G
authors.initials: G
authors.lastname: Filgueira
authors.forename: F
authors.initials: F
authors.lastname: Valdés
authors.forename: O
authors.initials: O
authors.lastname: Araneda
authors.forename: C
authors.initials: C
authors.lastname: Behn
authors.forename: R
authors.initials: R
authors.lastname: Martínez
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D001205:Ascorbic Acid / Q000097:blood / Q000494:pharmacology*; D001798:Blood Proteins / Q000378:metabolism; D003402:Creatine Kinase / Q000097:blood; D005260:Female; D005609:Free Radicals / Q000378:metabolism; D006736:Horses / Q000097:blood* / Q000502:physiology; D015227:Lipid Peroxidation / Q000187:drug effects; D008297:Male; D018384:Oxidative Stress; D010101:Oxygen Consumption; D005082:Physical Exertion / Q000502:physiology*; D012420:Running / Q000502:physiology; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism; D014527:Uric Acid / Q000097:blood
chemical_list: D000975:Antioxidants; D001798:Blood Proteins; D005609:Free Radicals; D017392:Thiobarbituric Acid Reactive Substances; D014527:Uric Acid; D003402:Creatine Kinase; D001205:Ascorbic Acid