Arquivos Brasileiros de Cardiologia (Mar 2010)
Alterações na produção de IL-10 e TNF-α no músculo esquelético em ratos com insuficiência cardíaca secundária ao infarto do miocárdio Changes in the production of IL-10 and TNF-α in skeletal muscle of rats with heart failure secondary to acute myocardial infarction
Abstract
FUNDAMENTO: Estudos recentes demonstram que a expressão de mediadores inflamatórios, como as citocinas, é um importante fator de desenvolvimento e progressão da insuficiência cardíaca (IC), principalmente na presença de disfunção ventricular esquerda. Essas alterações têm sido demonstradas tanto no plasma como no músculo cardíaco e, mais recentemente, no músculo esquelético de ratos e pacientes com IC. OBJETIVO: Investigar a produção e expressão do fator de necrose tumoral-α (TNF-α) e interleucina-10 (IL-10) no músculo sóleo e extensor digital longo (EDL) em animais com disfunção ventricular pós-infarto do miocárdio (IM). MÉTODOS: Utilizaram-se ratos Wistar machos que foram submetidos à ligadura da artéria coronária esquerda sem posterior reperfusão. Quatro semanas após esse procedimento, os animais foram submetidos à análise ecocardiográfica e divididos nos seguintes grupos experimentais: falso operado (Sham) e IM. Mantiveram-se em observação por um período adicional de 8 semanas. RESULTADOS: O nível da citocina TNF-α aumentou 26,5% (p BACKGROUND: Recent studies show that the expression of inflammatory mediators, such as cytokines, is an important factor for the development and progression of heart failure (HF), especially in the presence of left ventricular dysfunction. These changes have been demonstrated both in the plasma and heart muscle and, more recently, in skeletal muscle of rats and in patients with HF. OBJECTIVE: To investigate the production and expression of tumor necrosis factor-α (TNF) and interleukin-10 (IL-10) in the soleus and the extensor digitorum longus (EDL) muscles of animals with left ventricular dysfunction after myocardial infarction (MI). METHODS: We used male Wistar rats that underwent ligation of the left coronary artery without reperfusion. Four weeks after this procedure, the animals underwent echocardiography and were divided into the following experimental groups: sham operated (sham) and IM. They remained under observation for a further period of 8 weeks. RESULTS: The level of the cytokine TNF-α increased by 26.5% (p <0.05), and its gene expression increased 3 times (p <0.01). The level of IL-10 decreased by 38.2% (p <0.05). Both changes occurred only in the soleus muscle, with no change in the EDL. The decrease (36.5%, p <0.05) in the IL-10/TNF-α ratio was due to both increased tissue levels of TNF-α and decreased tissue levels of IL-10. CONCLUSION: Our results showed significant changes in the IL-10/TNF-α ratio, which may have an additive role in the assessment of deterioration and progression of left ventricular dysfunction post-MI. Furthermore, our study suggests that these changes seem to be related to the muscle fiber type. (Arq Bras Cardiol 2010; 94(3):293-300)
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