Assessment of reactive oxygen species production in cultured equine skeletal myoblasts in response to conditions of anoxia followed by reoxygenation with or without exposure to peroxidases.

Objective—To culture equine myoblasts from muscle microbiopsy specimens, examine myoblast production of reactive oxygen species (ROS) in conditions of anoxia followed by reoxygenation, and assess the effects of horseradish peroxidase (HRP) and myeloperoxidase (MPO) on ROS production. Animals—5 healthy horses (5 to 15 years old). Procedures—Equine skeletal myoblast cultures were derived from 1 or 2 microbiopsy specimens obtained from a triceps brachii muscle of each horse. Cultured myoblasts were exposed to conditions of anoxia followed by reoxygenation or to conditions of normoxia (control cells). Cell production of ROS in the presence or absence of HRP or MPO was assessed by use of a gas chromatography method, after which cells were treated with a 3,3′-diaminobenzidine chromogen solution to detect peroxidase binding. Results—Equine skeletal myoblasts were successfully cultured from microbiopsy specimens. In response to anoxia and reoxygenation, ROS production of myoblasts increased by 71%, compared with that of control cells. When experiments were performed in the presence of HRP or MPO, ROS production in myoblasts exposed to anoxia and reoxygenation was increased by 228% and 183%, respectively, compared with findings for control cells. Chromogen reaction revealed a close adherence of peroxidases to cells, even after several washes. Conclusions and Clinical Relevance—Results indicated that equine skeletal myoblast cultures can be generated from muscle microbiopsy specimens. Anoxia-reoxygenation– treated myoblasts produced ROS, and production was enhanced in the presence of peroxidases. This experimental model could be used to study the damaging effect of exercise on muscles in athletic horses

Efeitos de diferentes esforços de luta de judô na atividade enzimática, atividade elétrica muscular e parâmetros biomecânicos de atletas de elite Los efectos de diferentes esfuerzos de lucha del judo en la actividad enzimática, actividad eléctrica muscular y biomecánica de los parámetros de atletas de élite Effects of different strengths in the judo fights, muscular electrical activity and biomechanical parameters in elite athletes

O treinamento esportivo provoca adaptações neuromusculares e alterações metabólicas visando a performance durante a competição. Nas competições de judô, o número de lutas a que os atletas são submetidos e suas respectivas durações e intervalos são aleatórios, fatores que podem influenciar a performance objetivada no treinamento. O presente estudo investigou a hipótese de que diferentes durações de lutas, 90s, 180s e 300s, poderiam influenciar a atividade enzimática, elétrica muscular e a produção do pico de torque. Antes e após cada luta, foram coletadas amostras sanguíneas dos atletas; em seguida, os mesmos realizaram cinco contrações dinâmicas (90º/s) com a utilização de um dinamômetro isocinético (Biodex System 3). Simultaneamente registrou-se o sinal eletromiográfico dos músculos agonista, antagonista e sinergista do movimento avaliado. Não se verificou alteração no torque. As enzimas AST e ALT apresentaram aumento na atividade, nas lutas de 90s (p = 0,0033/p = 0,00059), 180s (p = 0,0044/p = 0,0033) e 300s (p = 0,0044/p = 0,0033). Aumento (p = 0,0180) da atividade da CK após a luta de 300s foi verificado. A LDH diminuiu após a luta de 90s (p = 0,0392). Na análise intermuscular observou-se após a luta de 90s aumento do sinal eletromiográfico do agonista (p = 0,005); na luta de 180s, aumento do antagonista (p = 0,0129) e na luta de 300s, diminuição (p = 0,0137) da atividade do músculo agonista. Observou-se que os esforços da luta de 300s podem ter induzido lesões no tecido muscular caracterizadas pela elevação da CK plasmática, embora a lesão não tenha sido suficiente para detectar fadiga através da dinamometria isocinética. Conclui-se que o protocolo proposto foi suficiente para alteração enzimática e eletromiográfica, sugerindo adaptações metabólicas e neurais a partir do estresse das lutas de judô.<br>El entrenamiento deportivo provoca adaptaciones neuromusculares y alteraciones metabólicas que buscan una actuación durante la competición. En las competencias de judo, el número de luchas a que los atletas se someten así como la duración respectiva y los intervalos son al azar, factores estos que influencian en la actuación y en el entrenamiento. El estudio presente investigó la hipótesis de que las duraciones diferentes de luchas, 90s 180s y 300s, podrían influir en la actividad enzimático, eléctrico muscular y la producción del pico del cambio. Antes y después de cada lucha, fueron obtenidas las muestras sanguíneas de los atletas, tan pronto después de que los mismos lograron cinco reducciones dinámicas (90º/s) con el uso de un dinamômetro isocinético (Biodex Sistema 3). Simultáneamente se consignaron la señal electromiográfica de los músculos agonistas, antagonistas y sinérgica de los movimientos estimados. El estudio no verificó si hubo una alteración en el torque. Las enzimas AST y ALT presentaran aumento en la actividad, en las luchas de 90s (p = 0,0033/p = 0,00059), 180s (p = 0,0044/p = 0,0033) y 300s (p = 0,0044/p = 0,0033). Un aumento (p = 0,0180) de la actividad de CK después de que la lucha de 300s fue verificada. LDH disminuyó después de la lucha de 90s (p = 0,0392). En el análisis intermuscular se observó después de la lucha 90s un aumento de la señal electromiográfica del agonista (p = 0,005), en la lucha 180s un aumento de la del antagonista (p = 0,0129) y en la lucha 300s una disminución (p = 0,0137) de la actividad del músculo agonista. Fue observado, además, que los esfuerzos de la lucha de 300s podrían haber inducido lesiones en el tejido muscular caracterizado por una elevación de CK plasmático, aunque la lesión no ha sido bastante para descubrir la fatiga a través de la dinamometría isocinética. Ha mostrado que el protocolo propuesto era bastante para determinar las alteraciones enzimáticas y eletromiográficas, mientras hace pensar en las adaptaciones metabólicas y neurológicas que ocurren por la tensión de las luchas del judo.<br>The sportive training causes neuromuscular adaptations and metabolic alterations aiming the competition performance. In judo competitions, the number of fights to what athletes are submitted, as well as their respective endurance and intervals are randomized, and these factors may influence the aimed training performance. This study investigated the hypothesis that different fight endurances, 90s, 180s, and 300s could influence the enzymatic and muscular electrical activity, as well as the torque peak production. Before and after each fighting, a blood sampling was collected from each athlete. After and before each fight, they performed five dynamic contractions (90º/s) using an isokinetic Dynamometer (Biodex System 3). Simultaneously, it was recorded the electromyographic signal of the agonist, antagonist and synergistic muscles of the movement assessed. It was observed no alterations in the torque. The AST and ALT enzymes presented an increasing activity in the 90 sec. (p = 0.0033/p = 0.00059), 180 sec. (p = 0.0044/p = 0.0033), and in the 300 sec. (p = 0.0044/p = 0.0033) fights. It was verified an increase (p = 0.0180) in the CK activity after the 300 sec. fight. LDH decreased after the 90 sec. fight (p = 0.0392). Upon the intermuscular analysis, it was observed an increase in the electromyographic signal of the agonist muscle after the 90 sec. fight (p = 0.005), an increase of the antagonist muscle in the 180 sec. fight (p = 0.0129), and a decrease (p = 0.0137) in the activity of the agonist muscle in the 300 sec. fight. It was observed that the strength in the 300 sec. fight might reduced the injuries in the muscular tissue characterized by a raise in the plasmatic CK, although the injury was not sufficient to detect the fatigue through the isokinetic dynamometry. It can be concluded that the proposed protocol was sufficient to the enzymatic and electromyographic alteration, suggesting metabolic and neural adaptations from stress caused by the judo fights