Stereological analysis of myocardium reorganization under the influence of extreme environmental conditions

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Abstract

The left ventricular myocardium of Wistar rats was studied by stereological methods after the following treatments: exposure to low temperature (-7°C), single overheating (at 43°C), adaptation to high altitudes (3200 m above sea level), and transfer to high latitudes (at 69° of the North). It was shown that the tissue spatial reorganization of the myocardium passes through two stages: at the first one the volume and surface-to-volume ratios of bulk tissue components (especially capillaries and cardiomyocytes) change considerably, at the second one a tendency toward the normalization of tissue architectonics is observed. This dynamics of tissue reorganization is likely to be conditioned by stress reaction and reveals some structural mechanisms of non-specific response to extreme impact. The changes observed were more pronounced in the rats exposed to low temperatures, as well as in rats transferred to high latitudes and did not depend on the character of changing the heart weight (increase or decrease). On the contrary, the ultrastructural spatial reorganization of cardiomyocytes was characterized by continuous disproportional changes of volume ratios of bulk organelles (especially mitochondria and myofibrils), which were evident during influence of environmental factors. These discrepancies in the dynamics of tissue and intracellular spatial reorganization of myocardium are supposed to reflect the fundamental peculiarities of spatial-temporal organization of regenerative processes in parenchymal cells and stromal components. Thus, the normalization of tissue spatial organization observed is not accompanied by the normalization of intracellular cardiomyocyte organization.

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A propos de : Lev M. Nepomnyashchikh

A propos de : Elena L. Lushnikova