Oxidative profiles of endurance horses racing different distances / Perfil oxidativo em cavalos de enduro competindo em diferentes distâncias

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...

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 hemolisado sanguíneo e malondialdeído (MDA) plasmático em cavalos de enduro correndo em diferentes distâncias, com alta média de velocidade, em clima tropical. Quinze cavalos foram testados, cinco em 160km (18.54-17.16km/h), cinco em 120km (21.53-17km/h) e cinco em 80km (20.06-18.01km/h). Amostras de sangue foram coletadas em repouso, imediatamente e três horas depois que os cavalos passaram pela inspeção veterinária final e três, sete e 14 dias após a corrida. Não houve aumentos significativos (P>0,05) dos níveis de SOD, GPx, GSH, CAT ou MDA em nenhum tempo nem distâncias analisadas. Com base nessas observações, pode-se concluir que as espécies reativas de oxigênio (ROS) formadas durante o exercício provocam adaptações específicas, tais como atividade antioxidante aumentada da enzima, maior resistência ao estresse oxidativo e menores níveis de danos oxidativos...

Purification and biochemical characterization of four iron superoxide dismutases in Trypanosoma cruzi

Four superoxide dismutase (SOD) activities (SOD I, II, III, and IV) have been characterized in the epimastigote form of Trypanosoma cruzi. The total extract was subjected to two successive ammonium sulphate additions between 35 and 85 percent, and the resulting fraction was purified using two continuous chromatography processes (ion exchange and filtration). Enzymes were insensitive to cyanide but sensitive to hydrogen peroxide, properties characteristic of iron-containing SODs. The molecular masses of the different SODs were 20 kDa (SOD I), 60 kDa (SOD II), 50 kDa (SOD III) and 25 kDa (SOD IV), whereas the isoelectric points were 6.9, 6.8, 5.2 and 3.8, respectively. Subcellular location and digitonin experiments have shown that these SODs are mainly cytosolic, with small amounts in the low-mass organelles (SOD II and SOD I) and the mitochondrion (SOD III), where these enzymes play an important role in minimizing oxidative damage.

Enzimas que participan como barreras fisiológicas para eliminar los radicales libres : I Superoxido dismutasas / Enzymes functioning as physiologic barriers to eliminate free radicals: I: Superoxide dismutase

La participación activa de los superóxido dismutasas (SODs), superóxido-superóxidorreductasa, 1.15.1.1) en su papel protagónico de primer nivel para eliminar la acción del radical superóxido (O2) cobra particular interés en la misma medida que se ha demostrado la activa participación de las formas radicálicas en un número cada día creciente de enfermedades de gran interés médico-social. En este trabajo abordamos el estudio de sus características fisico química y mecanismos de acción y a la vez discutimos alternativas en la estrategia de purificación