Combined disorders in the brain and heart at the early stages of the stress response in arterial hypertension (experimental study)
Tatyana P. Romanova 1, Olga V. Zlobina 1, Ekaterina M. Kostromina 1, Tatyana V. Perevoznikova 1, Svetlana S. Pakhomy 1, Oleg O. Zlobin 2; 1Saratov State Medical University named after V. I. Razumovsky, Saratov, Russia; 2Saratov Medical University “Reaviz”, Saratov, Russia
Abstract
A high mortality rate is observed in patients who develop myocardial infarction combined with stroke in the context of arterial hypertension. The aim of the study is to investigate combined stress‑induced morphofunctional damage developing in the structures of the heart and brain against the background of arterial hypertension. Spontaneously hypertensive rats exposed to combined stress were used in the experiment. Before and after the experiments, the animals’ blood pressure levels and heart rate were measured. To identify disorders in neurons and cardiomyocytes, histological and histochemical methods, as well as polarizing and fluorescent microscopy, were used. The content of vasoactive prostaglandins of the E and F2a series in blood plasma was determined using the radioimmunoassay method. It was established that in response to stress in animals, with a sharp increase in blood pressure and heart rate, contractile changes, focal dystrophic and necrotic damage were detected in cardiomyocytes. In the myocardium, spasm of small arteries, dilation of veins, an increase in the number of functioning capillaries with signs of endothelial dysfunction, erythrostasis, perivascular edema, and hemorrhages were observed. In the brain, an increase in the density of open capillaries by 26.6% was detected. A violation of the permeability of the blood‑brain barrier was evidenced by the infiltration of the endothelium with a luminescent “marker,” with the release of plasma proteins into the perivascular space and the appearance of multiple diapedetic hemorrhagic foci. The intensification of metabolic processes in neurons was confirmed by an increase in the activity of ATPase and alkaline phosphatase. An increase in the number of hyperchromic neurons was observed in the cortex and subcortical nuclei. Local vascular dystonia was detected in the brain and heart. The content of pressor PG F2a in the plasma decreased by 2.3 times, which contributed to an increase in hyperemia. Consequently, already in the early stages of the post-stress reaction, pronounced disorders in the BBB occurred, which led to brain hypoxia and subsequently to cerebral hemorrhages, combined with significant damage to the muscular tissue of the heart.
Speaker
Svaetlana Sergeevna Pakhomy
Saratov State Medical University named after V. I. Razumovsky
Russia
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