Oxidative profiles of endurance horses racing different distances

Abstract

Increased oxidative stress during prolonged endurance exercises may result in muscle damage, fatigue and decreased performance. An adequate stress response during training is critical to obtain improved results and high animal welfare standards. The aim of this study was to evaluate the red blood cell haemolysate concentrations of superoxide dismutase (SOD), glutathione peroxidase (GPx), reduced glutathione (GSH) and catalase (CAT) and the plasma concentrations of malondialdehyde (MDA) from endurance horses in different distances at high speed in a tropical climate. Fifteen horses were tested; five at 160km (18.54 -17.16km/h race speed), five at 120km (21.53 -17km/h race speed) and five at 80km (20.06 -18.01km/h race speed). Blood samples were collected at rest, immediately after and three hours after the horses left the final vet check and three, seven and fourteen days after the race. No significant increases (P > 0.05) in the levels of SOD, GPx, GSH, CAT or MDA were observed for any of the times or distances examined. Based on these observations, we conclude that reactive oxygen species (ROS) formation during exercise evokes specific adaptations, such as increased antioxidant/oxidative damage-repairing enzyme activity, increased resistance to oxidative stress and lower levels of oxidative damage.Keywords: horse, oxidative stress, endurance RESUMO Aumento do estresse oxidativo durante o exercício prolongado pode resultar em fadiga muscular, lesões e diminuição do desempenho. Uma adequada resposta a esse estresse durante o treinamento é fundamental para a obtenção de melhores resultados e bem-estar dos animais. O objetivo deste estudo foi avaliar a concentração de superóxido dismutase (SOD), glutationa peroxidase (GPx), glutationa reduzida (GSH) e catalase (CAT) no

Polydatin prevents bleomycin‑induced pulmonary fibrosis by inhibiting the TGF‑β/Smad/ERK signaling pathway

“…Excessive MPO catalyzes the oxidation of protein tyrosine to produce oxidants such as 3-nitrotyrosine and 3-chlorotyrosine (50). When the oxidant production exceeds the local antioxidant defense reaction, it leads to oxidative stress and tissue oxidative damage (51). Meanwhile, in vitro studies confirmed that MPO oxidation products can trigger fibrocyte proliferation and promote fibrosis (52).…”

Effect of prolonged submaximal exercise on serum oxidative stress biomarkers (d-ROMs, MDA, BAP) and oxidative stress index in endurance horses

“…The discrepancy between the mentioned findings [ 24 ] and the present study could be attributed to OS biomarker selection, a small number of horses (four), and a relatively low average speed of 10.5 km/h in the former compared to the present study which had a larger sample size and horses competing with almost 30% faster average speed. A previous report [ 2 ] assessed the levels of SOD, GPx, reduced GSH, catalase, and the plasma MDA in endurance horses, performing at different distances. Interestingly, that study did not record any significant changes in values of OS biomarkers after the race, although higher values of SOD, GPx, GSH, and MDA were recorded after the 80 km race but not at 160 km.…”

“…During short-term maximal exercise in Thoroughbred racehorses, there is an increase in oxygen consumption that reaches levels 30 times above basal [ 1 ]. Even though endurance riding is classified as a prolonged aerobic exercise [ 2 ], the high oxygen demands over a longer period of time result in an increased reactive oxygen species (ROS) formed by 1 to 2% of the oxygen that is not completely reduced into carbon dioxide and water [ 3 ]. The consequence of increased oxidants is a disarranged equilibrium between oxidants and antioxidants resulting in oxidative stress (OS) [ 4 ].…”

Changes in biochemical parameters in horses during 40 km and 80 km endurance races

“…Exercise causes redistribution of fl uids and electrolytes within the body compartments, resulting in a rapid decline in plasma volume following the onset of exercise, proportional to the intensity and duration of effort [1]. Prolonged submaximal aerobic exercise, such as endurance racing [2], causes cardiorespiratory, endocrine and neuromuscular systems to operate at an elevated level for an unnatural length of time [3,4]. During long races, horses are exposed to thermolysis, electrolyte loss and emergence of large amounts of catabolism products as a consequence of hemolysis, partial rhabdomyolysis, energy metabolism, and liver and kidney metabolism [5,6].…”

“…Previous studies of hematological and biochemical blood parameters in endurance horses [2,4,13] have been performed on horses competing at distances from 80 to 160 km. These distances are considered to be high to very high levels of exercise for a trained horse.…”