Effects of late postconditioning on gene expression and cell death in neonatal rat cardiomyocyte cultures.

The cell death and gene expression in neonatal cardiomyocyte cultures were investigated in a late postconditioning model. The primary cultures were subjected to a 30min of anoxia followed by 60min or 24h of reoxygenation. Postconditioning was carried out in three cycles of 1min reoxygenations followed by 1min anoxia, respectively. After 24h of reperfusion the percentages of living, necrotic, and apoptotic cells were determined by staining with bis-benzimide and propidium iodide. Anoxia-reoxygenation significantly increased the necrotic and apoptotic cells both at its first and second episodes. Postconditioning in remote period did not protect the cells from the second anoxia. Postconditioning decreased the anoxia-reoxygenation-induced increase of HSP70 and HSP90 mRNA expression. We observed a decrease of HIF-3alpha gene expression in remote postconditioning. The FRAP gene expression was leveled to control value. Thus, the changes of mRNA gene expression did not show cytoprotection of cardiomyocytes in remote postconditioning model.