Methods: Thirty male Wistar rats were used. Following a left thoracotomy, the heart was exposed and isolated in all the rats. Ten control rats remained untreated. In 10 rats (ischemia group), the left main coronary artery was occluded for 30 min and reperfused for 120 min. The remaining 10 rats (preconditioning group) underwent 5 min of occlusion and 5 min of reperfusion before 30 min occlusion and 120 min reperfusion. At the end of the experiments, the hearts were removed and assayed for immunohistochemical staining for bcl-2 expression.

Results: By immunohistochemical staining for bcl-2, the percentage of apoptotic cells was found as 40±4.27% in the preconditioning group, 65±4.11% in the ischemia group without preconditioning, and 2±0.66% in the control group. Compared to the ischemia group, the number of apoptotic cells was significantly lower in the preconditioning group (p<0.001). The lowest number of apoptotic cells was found in the control group (p<0.001).

Conclusion: Our results show that ischemic preconditioning reduces myocardial apoptosis.