FEATURES OF REMODELING OF BLOOD VESSELS OF RAT LUNGS IN APPLYING DIFFERENT METHODS OF FLUID RESUSCITATION AFTER GENERAL DEHYDRATION

Abstract

Dehydration of the body is the result of the variety of physiological and pathological conditions. At the same time, the number of factors should be taken into account in fluid resuscitation, because inadequate correction can lead to undesirable consequences – water intoxication. In this case, abnormal accumulation of water in the bloodstream can lead to hyponatremia with the transfer of fluid into cells and intercellular space and edematization. On the other hand, uncontrolled use of solutions with high sodium content may cause the development of hypernatremia with a converse effect. The purpose of the study: to establish the peculiarities of remodeling of blood vessels of rat lungs with general dehydration in applying various methods of fluid resuscitation and give them quantitative characteristics. Object and methods of research. White laboratory viripotent male rats, that had general dehydration, went through the fluid resuscitation with pre-dosed water consumption, water consumption without restrictions and unlimited consumption of physiological solution. Morphometric research included measurement identification of capacity of the artery walls – the Vohenvort index, as the relations area of vessel to area of its aperture. Research results and their discussion. In the group of animals with a 10-day dehydration, blood flow capacity of the smaller and bigger artery curcuits decreased. Histological examination of the lung tissues showed an increase in the thickness of the walls with narrowing of the lumen of the small branches of the pulmonary arteries and arterioles. Sometimes there were arteries with uneven thickness and deformation of the walls. Unlike small, medium-sized branches, the branches of large-caliber pulmonary arteries looked expanded and full-blooded. In most cases, the veins contained small concentrations of erythrocytes in their lumen. Their perivascular spaces looked expanded. During fluid resuscitation without limiting its amount in the first day after application, there was a development of swelling of the parenchyma (thickening of interalveolar septum, enlargement of dystelectasis zones), also the expansion of peribronchial and perivascular spaces. Often, peripheral hemorrhages were discovered in the lumen of the alveoli, as well as the accumulation of erythrocytes in the lumen of small bronchi and bronchioles, which appeared as a result of deepening of circulatory disorders recorded after 10 days of dehydration. A similar dynamics was observed in the application of unlimited consumption of physiological solution for fluid resuscitation, although the amplitude of change in the level of indices was comparatively lower. In the method of dose correction with drinking water, results showed more physiological nature of restoration of the blood vessels in lung structure. In this group of animals there was a gradual and almost complete restoration of the morphofunctional state of the arterial walls, starting from the first day of experimentation. Moreover, since the 6th day of the restoration period, all the results were significantly different from the animals with dehydration, and on the 10th day of the experiment almost completely matched the results obtained from the control group of animals. Depending on the type of fluid resuscitation, the reactions of the bronchial arteries were similar. Conclusions 1. Prolonged general dehydration leads to significant changes in the blood vessels of the rat lungs, which decrease in the level of their morphometric parameters (reducing the blood flow of the arteries of both small (pulmonary) and large (bronchial) circuits to increased tone and hypertrophy with thickening of their walls and the corresponding narrowing of the lumen). 2. Unlimited consumption of fluids on the first day of the fluid resuscitation period causes increased vascular reactions that have evolved during dehydration, especially in consumption of normal water compared to the physiological solution. 3. Dosage correction of drinking water is the most effective method of fluid resuscitation, as it immediately promotes a gradual, almost complete restoration of the morphofunctional state of the lung blood vessels.

Keywords

• blood vessels
• lungs
• dehydration
• fluid resuscitation
• morphometry.