Myocardium and microvessel endothelium apoptosis at day 7 following reperfused acute myocardial infarction

Objectives: This study was to investigate the salvaged myocardial and microvascular endothelial cells apoptosis at the first week of reperfused acute myocardial infarction (AMI). Methods: Sixteen mini swines (20-30 kg) were randomly assigned to the sham-operated group and the AMI group. The acute myocardial infarction and reperfusion model was created, and pathologic myocardial tissue was collected at day 7 following left anterior descending coronary artery reperfusion, and detected by transmission electron microscope, in situ cell apoptosis detection (TUNEL method), Real-time Quantitative Polymerase Chain Reaction and Western blot. Results: In the AMI group, the infarcted area showed the myolysis, fibroblast and injuried endothelial cells under transmission electron microscope. The infarcted area had higher apoptotic index of microvascular endothelial cells than the marginal area, the normal area, and the sham-operated area (all P<0.05). Fas and Bax mRNA expressions in the infarcted area were higher than those in the marginal area, the normal area, and the sham-operated area (all P<0.05), and both protein overexpressions and Bcl-2 low expression in the infarcted and marginal areas compared with the normal area and the sham-operated area. Conclusions: The overexpressions of Fas and Bax or the low expression of Bcl-2 in the infarcted and marginal heart tissue may play an important role in the acceleration of myocardial and endothelial apoptosis at 7th day following reperfused acute myocardial infarction. (C) 2009 Elsevier Inc. All rights reserved.