The ligation of anterior descending coronary artery is the most widely used experimental model to induce myocardial infarction (MI) in rodents. The high mortality in the acute phase and the heterogeneity of the size of MI obtained are recognized drawbacks in this model. In an attempt to solve the problem, recently was developed a new experimental model of MI in rats based on the application of current myocardial ablation radio frequency. The new technique allowed one to obtain homogeneous and MI with sizes significantly reduce acute mortality. It should be noted also that the structural and functional cardiac changes evoked by ablation were similar to those observed in animals with MI induced by coronary ligation. In this project, it is proposed to evaluate the gene expression of 15 different signal transduction pathways (signals cell survival, cell cycle, stress, apoptosis, molecules related to calcium signaling, cell growth factors, transcription factors, angiogenesis, inflammation and hypoxia) in the left ventricle of rats with MI promoted by experimental models of coronary occlusion and ablation. The proposal is based on the fact that, with the identification of reprogramming of gene expression will be possible to consolidate that, besides the similarity in structural and functional remodeling of the myocardium, there is between the two models, similar modifications of the transcriptional response of genes that govern the ventricular remodeling after MI. Furthermore, the results of this design will make specific information about changes in signal transduction pathways of each experimental model which leads to unfavorable myocardial remodeling.
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