Effects of isoflurane postconditioning on chronic phase of ischemia-reperfusion heart injury in rats.

INTRODUCTION: The application of isoflurane in a postconditioning manner, during early reperfusion of ischemic myocardium, reduces the infarct size. Its favorable effect on highly vascularized granulation tissue formation is very important considering the fact that increased genesis of blood vessels in peri-infarct zone reduces the infarct size and improves cardiac function. Taking into consideration the influence of isoflurane on the subacute phase of infarct healing, by using different immunohistochemical markers, we wanted to explore whether isoflurane postconditioning influences the chronic phase of healing. METHODS: The size of infarcted region was measured, and comparisons between isoflurane-treated and control animals were made. Quality of infarcted area was assessed by detecting vascular endothelial growth factor (VEGF), platelet/endothelial cell adhesion molecule-1 (PECAM-1/CD31) as a marker of angiogenesis, and nestin as a marker of immature progenitor cells, and de novo formed blood vessels (vasculogenesis). RESULTS: There was no difference between the control and isoflurane-treated groups in VEGF and PECAM-1/CD31 expression. However, a large reduction in infarct size was found (68.1% of control). Also, a marked decrease of nestin expression in immature progenitor cells, along with a marked increase of the same marker in cardiomyocytes, (signs of myocardium regeneration), was found in experimental animals when compared to control animals that did not receive isoflurane treatment. CONCLUSIONS: Based on our results, we can emphasize two morphologically detectable benefits of isoflurane postconditioning: a marked reduction in infarct size along with a more mature-looking infarct area in the chronic phase of infarct healing.