Orientador : Aguemi Kohayagawa / Banca: Alexandre Secorun Borges / Banca: Maria Adriana Machado Loba e Silva / Abstract: The objective of this study was to evaluate the oxidative erythrocyte metabolism in equines submitted to exercise on high-speed treadmill and the effect of vitamin E supplementation. Eight adults Arabian horses, males and females, were divided: control group (CG) and group supplemented with vitamin E (EG), (1000 UI/animal/day). All the equines were submitted to exercise with two incremental tests (T1 and T2). Exercise protocol for two tests started with 1.8m/s for 5 min, 4m/s for 3 min, 6m/s for 2 min and right after, periods of 1 min, challenging the equines with increasing speeds until the animals had no condition to keep the exercise on a treadmill inclined at 7%. Between the tests, a training protocol was performed for 20 days. Blood samples were taken before, during, and until 120 hours after exercise to determine erytrogram, erythrocyte reduced glutathione (GSH), superoxide dismutase (SOD), methemoglobin, erythrocyte osmotic fragility (EOF), total plasmatic protein (TPP), seric malondialdehyde (MDA) and vitamin E, seric enzymatic activity of aspartate aminotransferase (AST) and creatine kinase (CK), blood lactate and bloodgas. The results were compared by non-parametric Mann-Whitney and Friedman tests. Although differences were detected in only a few variables, it was possible to see increase in erytrogram and TPP by spleenic contraction and/or decrease of the plasma volume, and increase the erythrocyte volume by swelling. Sport anemia was observed between 24h and 120h after the exercise. The methemoglobin was compatible with the physiological levels and the EOF increased during the exercise in both groups. The MDA elevation confirm the liperoxidation by exercise effect, less intense EG by the supplementation with vitamin E. The exercise also induced increase of AST and CK enzymes, increase of blood lactate and metabolic acidosis. / Mestre

Orientador: Aguemi Kohayagawa. / Resumo: A produção de espécies reativas de oxigênio (ERO) é um evento presente em todas as células do organismo e pode estar aumentada em condições como hipóxia induzida pela anemia causando lesões em moléculas como DNA, lipídeos e proteínas. Com o objetivo de avaliar o estresse oxidativo na anemia induzida por perda aguda de sangue, foram utilizados 10 ovinos, mestiços da raça Texel, machos e fêmeas, com idade entre seis e oito meses, clinicamente sadios, mantidos em regime de confinamento. Os animais foram submetidos a duas flebotomias para a retirada de 30% e 20% do volume sangüíneo com intervalo de 12 horas. Amostras de sangue foram colhidas imediatamente antes da flebotomia, 6h e 12h após a primeira flebotomia, 6h, 12h, 24h, 48h, 72 horas, 4d, 5d, 6d, 10d, 14d, 21d e 28 dias após a segunda flebotomia. Foram avaliados o óxido nítrico, substâncias reativas ao ácido tiobarbitúrico, malondialdeído, cortisol e lactato séricos, hemograma e bioquímica sérica. A análise estatística dos dados foi realizada por meio do Teste de Análise de Variância de Medidas Repetidas (ANOVA) ao nível de 5% de significância. Os resultados demonstraram que o protocolo de indução de anemia foi capaz de induzir anemia 12 horas após a segunda flebotomia, estresse oxidativo e lipoperoxidação caracterizado pelo aumento das substâncias reativas ao ácido tiobarbitúrico. O cortisol elevou-se e alterou o leucograma aumentando o número de leucócitos, neutrófilos e a relação neutrófilo:linfócito. Todos os animais recuperaram-se dentro do período de 28 dias após a flebotomia. Conclui-se que a retirada de 30% e 20% do volume de sangue com intervalo de 12 horas provoca estresse oxidativo e lipoperoxidação em ovinos. / Abstract: Reactive oxygen species (ROS) are produced in all cells and an increase can be associated with hypoxia induced by anemia. This results in DNA, lipid and protein damage. The aim of this work was to evaluate the oxidative stress induced by experimental acute blood loss. Ten healthy cross Texel sheep underwent two phlebotomies with 12 hours interval. Blood samples were collected before the first phlebotomy (30% of blood volume) and 6 and 12 hours after. A second phlebotomy was performed 12 hours after the first one (20% of blood volume) and blood samples were collected, 6h, 12h, 24h, 48h, 72h, 4 days, 5 days, 6 days, 10 days, 14 days, 21 days and 28 days after. Thiobarbituric acid-reactive substances, malondialdehyde, nitric oxide, lipid peroxidation, serum cortisol, serum lactate, CBC and serum biochemistry were evaluated. Statistical analysis was reformed using repeated measures ANOVA. The experimental protocol used was able to induce anemia 12 hours after the second phlebotomy resulting in oxidative stress and lipoperoxiation characterized by the thiobarbituric acid-reactive substances increase. There was also a cortisol increase causing white blood cell changes: increased number of leukocytes, neutrophils and neutrophil and lymphocyte rate. All animals were normal 28 days after the phlebotomy. In conclusion, the protocol used showed that phlebotomy causing 30 and 20% at blood loss can induce oxidative stress and, lipid peroxidation in sheep. / Doutor