SECOND ANOXIA-REOXYGENATION DOES NOT CAUSE THE APOPTOTIC CELL DEATH OF NEONATAL CARDIOMYOCYTES: POSSIBLE ROLE OF CHANGES OF mRNA EXPRESSION OF CYTOPROTECTIVE GENES

Abstract

The cells death and genes expression in neonatal cardiomyocytes culture at two anoxia-reoxygenation modeling were investigated. The primary culture of neonatal cardiomyocytes was under­gone 30 min of anoxia followed by 24 h (A-R1) and the second anoxia-reoxygenation – 30 min and 60 min respectively (A-R2). The percentages of living, necrotic, apoptotic and autophagic cells were determined by staining with bis-benzimide, propidium iodide and monodansylcadaverine. Anoxia-reoxygenation sig­nificantly influenced the ratio of living, necrotic, apoptotic and autophagic cells both at its first A-R1 and second A-R2 epi­sodes. It was shown that the main mechanism of cell death after the both periods of anoxia-reoxygenation is necrosis. The changes of mRNA levels of genes of heat shock proteins HSP70 and HSP90, antiapoptotic protein Bcl2 and key regulator of au-tophagy FRAP in cardiomyocytes culture were established. The data obtained allow to make suggestion that in 24 h after the first episode of anoxia-reoxygenation A-R1 the overexpression of heat shock proteins starts the cascade of reactions that causes the necrotic cell death prevalent and the blocking of apoptotic program at second anoxia-reoxygenation A-R2.