Avaliação bioquímica, morfológica e funcional do músculo estriado esquelético de ratos na insuficiência cardíaca
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Data
2011-02-25
Autores
Bertaglia, Raquel Santilone [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A insuficiência cardíaca (IC) está associada à miopatia dos músculos esqueléticos dos membros, com perda da massa muscular, diminuição na proporção da cadeia pesada das miosinas do tipo I (MHCI), aumento na proporção da cadeia pesada das miosinas do tipo II (MHCII), decréscimo do metabolismo oxidativo e alterações nos fatores de regulação miogênica (MRFs). Na IC também ocorre aumento do estresse oxidativo na musculatura esquelética, o qual está relacionado às mudanças estruturais, morfológicas e funcionais. Nesse estudo, nós investigamos e comparamos as características morfofuncionais dos músculos Sóleo (SOL), lento e com predomínio de fibras oxidativas e Extensor Digitorum Longus (EDL), rápido e com predomínio de fibras glicolíticas em ratos com IC induzida pela monocrotalina. Foram utilizados ratos Wistar, machos (90 a 100 g), divididos em 2 grupos: controle (CT) e insuficiência cardíaca (IC), induzida pela injeção de dose única de monocrotalina (MCT, 30mg/Kg i.p.). Após 22 dias da injeção da MCT, quando os animais apresentaram sinais de IC, todos os animais foram sacrificados e pesados. Os músculos SOL e EDL foram retirados, pesados e processados para as análises morfológicas, moleculares, bioquímicas e funcionais. A expressão gênica da MyoD e miogenina foram determinadas usando qRT-PCR, as isoformas de MHC foram determinadas por eletroforese em gel de poliacrilamida, a freqüência e área de secção transversal dos tipos de fibra foram analisadas pela reação histoquímica de ATPase miofibrilar (mATPase). Foram realizados estudos bioquímicos para a determinação do hydroperóxido de lipídeo (HL), da glutationa peroxidase (GSH-Px) e da superóxido dismutase (SOD) e catalase (CAT); o estudo miográfico foi realizado para determinar a força máxima de contração, o tempo de contração e de relaxamento e a resistência à fadiga...
Heart failure (HF) is characterized by a limited exercise tolerance, skeletal muscle myopathy with atrophy, shift toward fast muscle fiber and myogenic regulatory factors (MRFs) changes. Reactive oxygen species (ROS) also contribute to target organ damage in the heart failure syndrome. In this study, we investigated and compared the morphofunctional characteristics in SOL, a slow oxidative muscle and EDL, a fast glycolytic muscle in a monocrotaline-induced heart failure. Two groups of rats were studied: control (CT) and Heart Failure (HF), induced by a single intraperitoneal injection of monocrotaline (MCT, 30mg/Kg). MyoD and myogenin expression were determined by using qRT-PCR, MHC isoforms were studied by using polyacrylamide gel electrophoresis, muscle fiber-type frequency and cross sectional area (CSA) were analyzed by myofibrillar adenosine triphosphatase (mATPase). Biochemical study were performed to determine: lipid hydroperoxide (LH), glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD); myographic study was performed to analyze: amplitude, rise time, fall time and fatigue resistance in SOL and EDL muscles. All monocrotaline treated rats showed signs of HF (atrium and right ventricular hypertrophies, pleural and pericardial effusions, and congested liver). HF group showed SOL and EDL muscles atrophy, confirmed by CSA decreased in muscle fiber types (types I, IC, IIC and IIA in SOL and I, IIC, IIA, IIA/D and IIDB in EDL muscles); the frequency of IIC fiber type and the fall time of muscle contraction increased only in SOL muscle; he myogenin mRNA expression was lower only in the SOL muscle and the MyoD mRNA expression decreased only in EDL muscle. HF group also presented the concentration of lipid hydroperoxide increased, superoxide-dismutase and glutathione peroxidase activity reduced only in SOL muscle; EDL muscle showed the contractile properties, concentration... (Complete abstract click electronic access below)
Heart failure (HF) is characterized by a limited exercise tolerance, skeletal muscle myopathy with atrophy, shift toward fast muscle fiber and myogenic regulatory factors (MRFs) changes. Reactive oxygen species (ROS) also contribute to target organ damage in the heart failure syndrome. In this study, we investigated and compared the morphofunctional characteristics in SOL, a slow oxidative muscle and EDL, a fast glycolytic muscle in a monocrotaline-induced heart failure. Two groups of rats were studied: control (CT) and Heart Failure (HF), induced by a single intraperitoneal injection of monocrotaline (MCT, 30mg/Kg). MyoD and myogenin expression were determined by using qRT-PCR, MHC isoforms were studied by using polyacrylamide gel electrophoresis, muscle fiber-type frequency and cross sectional area (CSA) were analyzed by myofibrillar adenosine triphosphatase (mATPase). Biochemical study were performed to determine: lipid hydroperoxide (LH), glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD); myographic study was performed to analyze: amplitude, rise time, fall time and fatigue resistance in SOL and EDL muscles. All monocrotaline treated rats showed signs of HF (atrium and right ventricular hypertrophies, pleural and pericardial effusions, and congested liver). HF group showed SOL and EDL muscles atrophy, confirmed by CSA decreased in muscle fiber types (types I, IC, IIC and IIA in SOL and I, IIC, IIA, IIA/D and IIDB in EDL muscles); the frequency of IIC fiber type and the fall time of muscle contraction increased only in SOL muscle; he myogenin mRNA expression was lower only in the SOL muscle and the MyoD mRNA expression decreased only in EDL muscle. HF group also presented the concentration of lipid hydroperoxide increased, superoxide-dismutase and glutathione peroxidase activity reduced only in SOL muscle; EDL muscle showed the contractile properties, concentration... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Insuficiencia cardiaca, Rato como animal de laboratorio, Musculos, Heart failure
Como citar
BERTAGLIA, Raquel Santilone. Avaliação bioquímica, morfológica e funcional do músculo estriado esquelético de ratos na insuficiência cardíaca. 2011. 63 f. Dissertação (mestrado) - Universidade Estadual Paulista, Instituto de Biociências de Botucatu, 2011.