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Effect of exenatide on myocardial conduction in periinfarct areas post myocardial infarction and its mechanism |
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Abstract ObjectiveTo investigate the effect of exenatide on myocardial conduction in peri-infarct area postmyocardial infarction(MI) and its possible mechanism. MethodsEighty male SpragueDawley(SD) rats were randomly divided into sham operation group, MI group, MI plus Ex-4 group and MI plus Ex-4 plus Ex9-39 group according to random number table, with 20 rats in each group. MI modeling was established by the ligation of left anterior descending coronary artery. The paraffined section of myocardial tissue in each group was stained with hematoxylin and Masson four weeks after surgery. In Langerdorffperfused heart, the conduction velocity, total activation time and its dispersion were recorded by microelectrode array. And the expression of connexin43(Cx43) in periinfarct areas was also detected in the method of Western blotting. ResultsThe area of MI, crosssectional area of cardiomyocyte and the percentage of interstitial fibrosis in the MI plus Ex-4 group decreased, as compared to those in the MI group(P<0.05 ). Since exenatide can improve postMI conduction in peri-infarct areas, the patients in the MI plus Ex-4 group presented with acceleration of conduction, increased conduction homogeneity, shortened total activation time and reduced dispersion of total activation time(P<0.05). The expression of Cx43 was strengthened in the MI plus Ex-4 group as compared to that in the MI group(P<0.05). The effect of exenatide was partly antagonized by using Ex9-39(P<0.05). ConclusionExenatide as a GLP-1 agonist may improve the conduction in peri-infarct areas through ameliorating the interstitial fibrosis postMI and strengthening the expression of Cx43.
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