Experimental model of acute myocardial infarction for evaluation of prevention and rehabilitation strategies in cardiovascular diseases – a pilot study

Introduction: Acute myocardial infarction (AMI) is an important acute disease of myocardial tissue, that occurs as a result of an imbalance between coronary blood supply and myocardial demand. Isoproterenol (ISO) is a synthetic catecholamine, a beta-adrenergic agonist that produces extensive biochemical, functional, and histological alterations in the heart, characteristic for AMI. The present study has been designed to identify the best dose of ISO that induces electrocardiogram (ECG) alterations, enzymatic reaction, and histopathological changes characteristic of AMI. Material and method: AMI was induced to Wistar-Bratislava white male rats, using three different subcutaneous doses of ISO (85 mg/kg bw, 100 mg/kg bw, and 150 mg/kg bw). ISO was administrated twice, with the second dose at 24h after the initial one. The ECGs were recorded at 24 hours after the last dose of ISO. Blood samples were collected for measurement of creatine kinase (CK), and CK-MB serum levels, and the hearts were excised and prepared for histopathologic examination. Results and discussions: All doses of ISO induced alterations in the ECG patterns such as increased heart rate and prolongation of QT and QTc intervals. Depression of the ST segment coupled with marked T wave inversion were observed at the doses of 100 mg/kg bw and 150 mg/kg bw of ISO. All doses of ISO induced an elevation of CK and CK-MB with highest levels observed for the dose of 150 mg/kg bw. Histopathologic examination revealed subendocardial AMI lesions for all doses tested. Conclusions: ISO in doses of 100 mg/kg and 150 mg/kg is useful for induction of infarct-like lesion on ECG, increased levels of myocardial necrosis enzymes and morphological changes characteristic for AMI.