Shevchenko K. Influence of prenatal hypoxia on embryonic formation of the histoarchitecture and ultrastructure of rat atrial miocardium.

It was revealed that acute prenatal hypoxia leads to increasing of the relative volume of connective tissue and blood vessels of microсirculatory bed of myocardium, but these changes gradually restore and reach control values on the postnatal development. Under the conditions of chronic perinatal hypoxia the proliferative activity of cardiomyocytes, endothelial cells and fibroblasts increase significantly, that damage tissue architecture of the rat atrial myocardium. Based on ultrastructural analysis it was explored that acute prenatal hypoxia leads to reduction of numerical density and relative volume of secretory granules, damage mitochondria and myofibrils. Under the conditions of chronic perinatal hypoxia shifting of interrelation between different types of specific granules toward to the newly formed granules, the prevalence of relative volume of the Golgi complex, damage of mitochondrial structure, suppression of myofibrils accumulation take place. Stable changes of secretory, mitochondrial and contractile apparatus of cardiomyocytes remain in 30 days after the influence of chronic perinatal hypoxia.