Influência da inibição da NADPH oxidase sobre o redemodelamento cardíaco de ratos com diabetes mellitus
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Data
2013-02-28
Autores
Gimenes, Rodrigo [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
O diabetes mellitus (DM) está associado a diversas doenças vasculares e cardíacas. Nos últimos anos, aumentaram as evidências de que pacientes diabéticos são acometidos por uma forma de doença miocárdica denominada miocardiopatia diabética. O aumento na produção de espécies reativas de oxigênio (EROs), causado por alterações metabólicas induzidas pelo DM, é um dos principais mecanismos desencadeadores de alterações miocárdicas. A maior fonte de EROs no sistema cardiovascular está relacionada a atividade da família de enzimas da NADPH oxidase. Em relação ao DM, há evidências de que a elevação da glicose sérica, induzida por estreptozotocina em camundongos ou em pacientes diabéticos, causa aumento na atividade da NADPH oxidase nos vasos. Sendo o sistema NADPH oxidase o principal responsável por desequilíbrio no sistema de produção e eliminação de EROs, e também por estar envolvido em muitas patologias cardíacas, estudos à respeito de seu bloqueio têm aumentado nos últimos anos. O objetivo do presente trabalho foi analisar a influência da inibição da NADPH oxidase por apocinina sobre o remodelamento cardíaco de ratos com DM. Foram utilizados ratos Wistar machos com 6 meses de idade, divididos em 4 grupos: controle (CTL, n=15), controle+apocinina (CTL+APO, n=20), diabético (DM, n=20) e diabético+apocinina (DM+APO, n=20). O diabetes foi induzido por estreptozotocina. Após 7 dias, foi iniciado tratamento com apocinina e mantido por 8 semanas. A avaliação estrutural e funcional in vivo do coração foi realizada por ecocardiograma. O estudo funcional in vitro foi realizado em músculo papilar isolado do ventrículo esquerdo (VE) em condições basal e após estimulação com manobras inotrópicas (contração pós-pausa, aumento da concentração extracelular de cálcio e adição de isoproterenol à solução nutriente). Para análise de variáveis anatômicas foram medidos os pesos úmidos...
Diabetes mellitus (DM) is associated with cardiac and vascular diseases. In recent years, there has been increased evidence that diabetic patients are affected by a form of myocardial disease known as diabetic cardiomyopathy. High production of reactive oxygen species (ROS), caused by diabetes-induced metabolic changes, is one of the main mechanisms leading to myocardial damage. A major source of ROS in the cardiovascular system is related to the activity of NADPH oxidase enzymes family. In streptozotocin-induced diabetic mice or in diabetic patients, serum glucose elevation increases NADPH oxidase activity in vessels. As NADPH oxidase is involved in imbalance of ROS production and elimination systems, and in pathophysiology of cardiac diseases, research on its blockade has increased in recent years. The purpose of this study was to analyze the influence of NADPH oxidase inhibition by apocynin on cardiac remodeling in rats with DM. Six month old male Wistar rats were assigned into 4 groups: control (CTL, n=15), control+apocynin (CTL+APO, n=20), diabetic (DM, n=20) and diabetic+apocynin (DM+APO, n=20). Diabetes was induced by streptozotocin. Seven days later, apocynin was initiated and maintained for 8 weeks. In vivo cardiac structures and functions were assessed by echocardiography. In vitro left ventricular (LV) functional study was performed in isolated papillary muscle preparation at basal condition and after inotropic stimulation with post-rest contraction, increase of extracellular calcium concentration, and addition of isoproterenol to the nutrient solution. Wet and dry weights of LV, right ventricle (RV), atria, lung, and liver sample were measured. LV histological sections were used to analyze interstitial collagen fraction. Antioxidant enzymes glutathione peroxidase (GSH-Px), catalase, and superoxide dismutase (SOD) were measured in serum. LV tissue samples were obtained for determination of ...
Diabetes mellitus (DM) is associated with cardiac and vascular diseases. In recent years, there has been increased evidence that diabetic patients are affected by a form of myocardial disease known as diabetic cardiomyopathy. High production of reactive oxygen species (ROS), caused by diabetes-induced metabolic changes, is one of the main mechanisms leading to myocardial damage. A major source of ROS in the cardiovascular system is related to the activity of NADPH oxidase enzymes family. In streptozotocin-induced diabetic mice or in diabetic patients, serum glucose elevation increases NADPH oxidase activity in vessels. As NADPH oxidase is involved in imbalance of ROS production and elimination systems, and in pathophysiology of cardiac diseases, research on its blockade has increased in recent years. The purpose of this study was to analyze the influence of NADPH oxidase inhibition by apocynin on cardiac remodeling in rats with DM. Six month old male Wistar rats were assigned into 4 groups: control (CTL, n=15), control+apocynin (CTL+APO, n=20), diabetic (DM, n=20) and diabetic+apocynin (DM+APO, n=20). Diabetes was induced by streptozotocin. Seven days later, apocynin was initiated and maintained for 8 weeks. In vivo cardiac structures and functions were assessed by echocardiography. In vitro left ventricular (LV) functional study was performed in isolated papillary muscle preparation at basal condition and after inotropic stimulation with post-rest contraction, increase of extracellular calcium concentration, and addition of isoproterenol to the nutrient solution. Wet and dry weights of LV, right ventricle (RV), atria, lung, and liver sample were measured. LV histological sections were used to analyze interstitial collagen fraction. Antioxidant enzymes glutathione peroxidase (GSH-Px), catalase, and superoxide dismutase (SOD) were measured in serum. LV tissue samples were obtained for determination of ...
Descrição
Palavras-chave
Stress oxidativo, Miocardio - Doenças, Diabetes, Rato como animal de laboratorio, Enzimas, Oxidative stress
Como citar
GIMENES, Rodrigo. Influência da inibição da NADPH oxidase sobre o redemodelamento cardíaco de ratos com diabetes mellitus. 2013. 66 f. Dissertação (mestrado) - Universidade Estadual Paulista Júlio de Mesquita Filho, Faculdade de Medicina de Botucatu, 2013.