The scientific article presents the results of investigating the spinal cord`s morphology of a domestic bull (Bos Taurus). Data on the histo- and cytostructure of the spinal cord are given according to the results of histological, neurohistological, and morphometric studies. For their implementation, the selected material (spinal cord n = 8) was subjected to fixation in 10–12 % neutral formalin solution, followed by pouring into paraffin. Histological sections were made from paraffin blocks on a sliding microtome MS-2 with a thickness of not more than ten μm. Staining of sections with hematoxylin and eosin, according to Van Gieson's methods, as well as neuro-histological methods of impregnation of nerve tissue with silver nitrate according to the Bilshovskym-Gross method, was used for the morphometric studies, investigating the morphology of the cell, conducting and obtaining the review histological preparations. The histostructure of the spinal cord, the localization of neurons in the gray matter, and morphometric studies of structural elements were examined on histological specimens by light microscopy. The entire experimental part of the research was conducted following the requirements of the international principles of the "European Convention for the Protection of Vertebrate Animals for Experimental and Other Scientific Purposes" (Strasbourg, 1986). The spinal cord, medulla spinalis, an organ of the central nervous system of vertebrates, is located in the spinal canal. The spinal cord is protected externally by soft, arachnoid, and hard meninges. The space between the membranes and the spinal canal is filled with cerebrospinal fluid. It is well known that groups of multipolar nerve cells with the same functional value form the nuclei of the gray matter of the spinal cord. According to the results of our histological studies, a pronounced differentiation of nerve cells, which have different shapes and sizes. Among them are large, medium, and small nerve cells. The shape of nerve cells is different, which, in turn, depends on their location in certain areas of the gray matter of the spinal cord and the size of the cell. In general, there are multifaceted, stellate, spindle-shaped, elongated, rounded, and oval neurons. Small nerve cells have an oval or round, less often – irregularly rounded shape, medium – round, oval, spindle-shaped. Large nerve cells are dominated by a multifaceted shape with distinct processes. The nuclei of large nerve cells, in most cases, have a rounded shape, less often – oval, mostly in the center of the cells, seldom – eccentrically. According to the results of morphological studies, it is noted that the neurons of the gray matter of the spinal cord have different shapes and sizes. Consequently, in the gray matter, small cells are the highest quantity (47.91 ± 0.32 %) of the total number of nerve cells. The second place is occupied by average neurons (33.70 ± 0.46 %). The large cells are detected in the smallest amount (18.37 ± 0.50 %).

From among a great number of digestive system diseases in domestic animals there is pancreatitis which is caused by an early zymogenesis in the acinar cells. The problem of studying the structural organization of a pancreata in sick cats is topical because of a progressive spreading of pancreatitis in domestic animals. Thus, the purpose of the research was to study out the morphological changes of cats pancreata under acute pancreatitis. Working with vertebrate animals we were guided by “European Convention for the Protection of Vertebtate Animals used for Experimental and other Scientific Purposes” (Strasbourg, 1986). The results of the histological examination of cats pancreata under acute pancreatitis show some pathological changes both in endocrine and exocrine pancreas. Such changes were manifested in necrosis of exocrine pancreatitis as well as in spreading and swelling of acinar space, that testified to the infancy of an inflammatory process. Some dystrophic changes, followed by karyolysis, were found in the focus of tissue nicrosis. Pancreatocyte cytoplasm was cloudy, its basal and apical zones were obscure, clearly defined interstitial tissue swelling was found between the particles and unequal swelling was found inside the particles. Intercellular space was exaggerated. Morphometrically in a group of sick animals was detected an increase in specific weihgt of stromal component (р<0,05),which equalled 22,44±0,24 %, in a control group it equalled 17,78±0,15 %. Some hemorrhage and distrophicvally changed hormone- active cells as well as nonregular distribution of cells were detected under a histological examination of Langerhans islets. In most islets the cells had swelled vacuolar cytoplasm. While analyzing the morphometric indices it was stated that the cats exocrine pancreas under acute pancreatitis was 1.12 as large and occupied 48258,05±135,07 mkm2, (97,88±0,05 %). The cats endocrine pancreas under this pathology occupied 6858,85±315,05 mkm2, (2,12±0,05 %). In cats of a control group this index equalled 6784,71±285,04 mkm2 (1,95±0,06 %). The diameter of sick cats acinus as well as of Langerhans islets equalled respectively 31,85±0,05 and 71,81±2,45 mkm, which reliably (р<0,001) was 1.13 and 1.15 as large. In clinically healhty cats these indices are 28,12±0,11; 70,20±2,48 mkm.

The study aimed to establish the parameters of chronic toxicity of the newly developed drug based on phosphodiesterase-3 inhibitor and ethylmethylhydroxypyridine succinate in experiments on laboratory animals. The analysis was performed on white sexually mature young male Wistar rats weighing 170–185 g. Four groups of white rats were formed. The first experimental group was administered Bendamine based on a phosphodiesterase-3 inhibitor and ethylmethylhydroxypyridine succinate at a therapeutic dose. Rats of the second experimental group were injected with the experimental drug in a 5-fold dose. Rats of the third experimental group were administered the drug in a 10-fold dose. The fourth group served as control. The study of chronic toxicity of Bendamine in white rats indicates that long-term 30-day administration in therapeutic doses or 5-fold dose does not cause clinical signs of poisoning, as evidenced by the physiological limits of fluctuations in the studied morphological and biochemical parameters of blood rats. Prolonged administration of Bendamine to rats in a 10-fold dose is accompanied by a slight suppression of the body's physiological state, as indicated by a decrease in total erythrocytes and hemoglobin by 10.1 % against an increase in white blood cells by 59.8% (P < 0.001). In addition, there was a decrease in the functional state of the liver, as evidenced by a probable reduction in total protein by 8.0% and urea – by 13.5 %, as well as an increase in ALT, AST, and alkaline phosphatase by 31.6 %, 7.4 %, and 53.9% respectively. Probable changes in the coefficients of liver and spleen mass have been established. When administered intramuscularly to rats with the drug Bendamine for 30 days, the macroscopic and microscopic structure of the studied internal organs is preserved in all groups of animals. The second experimental group revealed reversible moderate histostructural changes in the liver and kidneys. In rats treated with ten times the therapeutic dose of the drug, histologically found hemodynamic disorders and alterations in dystrophic nature, mainly of protein origin, with focal localization in the parenchyma of the liver, kidneys, and myocardium, which in most cases are reversible and result from the compensatory response. Macroorganism on the introduction of a high dose of the study drug.

The varying extents of natural disease induced by coronavirus in dogs are not completely clear because the pathogenesis of coronavirus enteritis is not studied sufficiently. In this study, based on the results of clinical, virological, morphological and histochemical studies, we determined the pathogenic role of coronavirus in infected dogs using experimental infection, per os, of isolated canine coronavirus (Nick) with titer of infectious activity equaling 4.8 ± 0.04 lg TCID50/cm, cultivated on heterologous cell cultures. This allowed us to determine, supplement, and generalize the data on pathogenesis of the disease and determine the histological changes in the small intestine, where the initial replication of the pathogen takes place. It was found that lesions and the pattern of the pathomorphological changes (destruction, necrosis and edema of the stroma of the villi, lysis of the cytoplasm, deformation of the enterocyte nuclei) in the small intestine of experimentally infected dogs depend on the development of the pathological process related not only to the changes in histoarchitectonics of the wall of the intestine, but also to tension of the histochemical statics, and obviously the dynamic of the cells (accumulation of the main and acidic proteins in enterocytes’ cytoplasm, hypersecretion of the mucus by goblet cells, decrease of Schiff iodine acid-positive substances in the enterocytes’ cytoplasm, formation of basophilous inclusion bodies), which leads to disorders in metabolic processes in the organism of infected dogs as a response to the virus infection. The examined dogs were found to have morphological changes in the small intestine similar to those in spontaneously infected animals. During the action of coronavirus, the contacts between the enterocytes become damaged, which leads to inhibition of the protective functions of the intestine. At the same time, the pathological process in the experimentally infected animals developed rapidly and had an acute course. Thus, coronavirus enteritis as a separate disease is practically unobserved in field conditions, which makes microscopic survey of the pathogenic impact of the latter on the organism of dogs impossible. Therefore, experimental mono-infection allows a detailed study to be conducted of pathomorphological changes of the initial place of the reproduction of the virus – the small intestine affected by coronavirus enteritis.

40Науковий вісник Львівського національного університету ветеринарної медицини та біотехнологій імені С.З. Ґжицького Львівський національний університет ветеринарної медицини та біотехнологій імені С.З. Ґжицького, вул. Пекарська, 50, м. Львів, 79010, Україна У роботі на основі морфологічних, паталогоанатомічних, гістологічних та морфометричних досліджень з'ясовано морфологічну будову підшлункової залози клінічно здорових собак та за хронічного панкреатиту. Морфометричними дослідженнями встановлено, що абсолютна маса підшлункової залози собак за хронічного перебігу панкреатиту відносно клінічно здорових тварин збільшувалась у 1,28 рази з 29,83 ± 3,0 г у здорових тварин до 38,33 ± 7,02 г у хворих. Відносна маса органу зростала у 1,19 рази і дорівнювала 0,19 ± 0,04 % у порівнянні з контролем 0,16 ± 0,03%.За результатами гістологічних досліджень виявлено порушення будови панкреатоцитів. В ацинарних клітинах зональність цитоплазми не виявлялась, панкреатоцити погано сприймали забарвлення і містили включення у вигляді краплин. Спостерігали каріолізис ядер. В острівцях Лангерганса виявляються вогнищеві крововиливи та руйнування ендокринних клітин. Міжчасточкові сполучнотканинні прошарки були потовщеними, а у залозистій тканині органу зустрічали сполучнотканинні тяжі, що проникають та розгалужуються у глибину часточки. На основі морфометричних досліджень встановлено, що об'єм панкреатоцитів та їх ядер у хворих тварин достовірно (р<0,05) зростає і дорівнює відповідно 455,51 ± 33,24 та 54,90 ± 7,24 мкм 3 (у клінічно здорових відповідно -356,06 ± 11,37 та 33,69± 1,62 мкм 3 ). Ядерно цитоплазматичне відношення панкреатоцитів підшлункової залози собак за хронічного панкреатиту по відношенню до клінічно здорових збільшується у 1,44 рази і становить 0,177 ± 0,04. У собак контрольної групи такий показник складає 0,123 ± 0,001.Ключові слова: статевозріла собака, підшлункова залоза, гістологічна будова, гістоструктура органа, патоморфологічні зміни, панкреатит, панкреатоцити, ацинуси, острівці Лангерганса, дистрофія, ядерно-цитоплазматичне відношення.

The paper presents the results of macro- and microscopic structure of cattle heart on the organ-, tissue- and cell levels. The samples of the selected material (n = 5) were preserved in a 10–12 % water solution of neutral formaline with its further charging into wax. Histologic sections not more than 10 mkm were made from wax blocks by using a sliding microtome MC-2. Hematoxilin- and eosin staining of histological sections by Heydengine technique was used for studying cell morphology, carrying out morphometrical studies and for receiving review samples. Histoarchitecture of the structural parts of the heart (ventricle and auricle) and their morphometrical parameters were studied on the histological preparations using the light microscopy technique. The experimantal part of the scientific research was carried out in compliance with the requirements of “European Convention for the Protection of Vertebrate Animals used for Experimantal and other Scientific Purposes” (Strussburg, 1986). The cattle heart is located in a thorax between two lungs, in front of a diaphragm and shifted left. In the 3rd–4th rib region the heart adjacents to a thoracic wall. The heart apex is in the 5th rib region. The absolute weight of a cattle heart equals 2143.27 ± 38.76 g, the relative weight equals – 0.43 ± 0.006 %. The net weight of the heart without the epicardial fat equals 1926.12 ± 31.12 g. Herewith, the weight of the aortic ventricle equals 978.54 ± 19.52 g, the weight of the pulmonic ventricle equals 554.17 ± 14.21 g, the weight of both ventricles equals 1539.08 ± 49.74 g. The auricles weight was the least and equaled 397.18 ± 11.21 g. The ratio of the ventricle weight of the heart to its net weight equals 1:0.2, and the ratio of the weight of the auricle myocard to the weight of the ventricle myocard equals 1:0.26. The heart height equaled 23.08 ± 0.11 сm, width – 13.9 ± 0.18 cm and the circumference – 38.08 ± 0.9 cm. According to the analysis of such liniar measurements, the cattle heart in the animals of the experimental group is characterized as that of an enlarged- and short form. The heart wall consists of three sacs – endocardium, myocard and epicardium. The dominating weight of the heart wall is in a muscular layer (myocard), which consists of transversus stripe muscular fibers which are formed on the basis of mononuclear cells – cardiomyocytes which are interlinked into muscular fibers. According to the cytometric analysis of cardiomyocytes, their largest volume – (11225.73 ± 824.42 mkm3) is observed in the aortic ventricle, smaller – (7963.60 ± 627.09 mkm3) – in a pulmonic ventricle and the smallest – (5361.60 ± 583.91 mkm3) in the auricle cardiomyocytes. Herewith, the volumes of cardiomyocytes nuclei in an aortic ventricle (124.55 ± 7.99 mkm3 and in a pulmonuc ventricle (121.67 ± 7.02 mkm3) are nearly the same, and in the auricle cardiomyocytes the nuclei volume is significantly smaller and it equals 101.05 ± 6.04 mkm3 respectively. Such morphometrical parameters of cardiomyocytes and their nuclei are evidenced in their nuclei-cytoplasmatic ratio, which is the smallest in the cardiomyocytes of an aortic ventricle – 0.0113 ± 0.0068, somewhat larger in a pulmonic ventricle – 0.0156 ± 0.0054 and the largest – 0.0234± 0.0058 in the auricle cardiomyocytes, that is connected with the special properties of the muscular tissue of a myocard which is capable of spontaneous rythmic beatings depending on their morphofunctional load: the ventricles pump the blood from the heart to the body performing the gratest load (the aortic ventricle acts a s a pump, and the pulmonic ventricle acts as a container), the auricles receive the blood which returns to the heart from the animal body, performing somewhat smaller load.

Features of histoarchitectonics, cyto-and histometry of mesenteric lymph nodes in ruminants (cattle, sheep) and horses have been clarified. Scientific studies show that the histoarchitectonics of mesenteric lymph nodes in experimental animals are similar but differ in certain morphometric parameters. Lymph nodes are covered with a connective tissue capsule. Its thickness in cattle 1.7 fold greater than the thickness in sheep and horses. The parenchyma of the lymph nodes is formed by cortical and cerebral substances, the boundary between which is clearly expressed on the section of lymph nodes. According to the analysis of morphometric studies, the cortex is more developed in sheep (55.14±16.7 %), the brainin horses (68.6±6.83 %). However, the average area of lymph nodes in sheep (0.19±0.05 mm 2) and horses (0.08±0.01 mm 2) is much smaller than in cattle (0.46±0.07 mm 2). The cytostructure of lymph nodes is represented by various cellular elements, the most pronounced of which are blast forms, lymphocytes, reticular cells, macrophages, which differ in their structure and intensity of staining. In the lymph nodes of mesenteric lymph nodes in cattle, small and medium lymphocytes (47.1±2.53 % and 31.7±1.84 %) occupy a significant share. In large numbers, they are located on the periphery of lymph nodes with pronounced light centers. Reticular cells are 14.6±1.37 %. Lymphoblasts and large lymphocytes, which are mainly localized in the light centers of the lymph nodes, occupy 3.8±0.87 %, and macrophages-1.4±0.3 %. The proportion of destroyed cells is 1.0±0.26 %. The main part of the cerebral substance is occupied by pulp cords. There is a tendency for small lymphocytes to increase, mainly due to a 3.1-fold decrease in the number of blasts and large lymphocytes, a 3-fold decrease in the number of macrophages, and a twofold decrease in the number of destroyed cells. The number of average lymphocytes and reticular cells is almost unchanged compared to the same indicators in the lymph nodes and is 31.0±2.48 % and 13.8±1.5 %. A similar distribution of cellular elements in the lymph nodes and lymph nodes was observed in sheep and horses. However, in sheep, in contrasts to cattle, there was a 1.4-fold increase in the number of blasts and large lymphocytes in the lymph nodes and 1.6-fold in the pulp. In horses, these figures have not changed. An increase in the cytopopulation of reticular cells was observed, especially in pulp cords from 13.8±1.5 % in cattle to 23.0±1.73 % in sheep and to 21.1±0.9 % in horses. The number of macrophages remained almost at the same level as in cattle. The percentage of destroyed cells in ruminants was almost the same, but in horses, this figure increased 1.8 fold in the lymph nodes and decreased 2.5 fold in the pulp, relative to such figures in cattle.

Using anatomical, histological, neurohistological and morphological research methods, the histomorphology of spinal cord nodes in a comparative anatomical series of vertebrates: bony fishes, amphibians, reptiles, birds and mammals, which differ in their motor activity and their place of existence in a certain environment, was clarified in the work. It has been established that in the process of phylogenesis, a certain structural and morphofunctional reorganization of the spinal nodes occurs. They differ in shape and size. Adaptation to various living conditions of animals was formed on the basis of changes in the density and size of neurocytes, an increase in the total number of gliocytes and perineuralneglia cells, and polymorphism in the degree of chromatophilia. Thus, according to neurohistological studies, it has been noted that the neurons of the spinal cord nodes of cold-blooded animals (pond frog, pond lizard) are characterized by a functional degree of relative polymorphism – chromatophilia. Impregnation of spinal cord nodes with silver nitrate in all studied animals revealed different intensity of staining of nerve cells (light, light-dark, dark), which is related to the specifics of species and age-related neuromorphology, the morpho-functional state of the nervous system and the type of higher nervous activity. An important issue of modern neuromorphology of animals is the  study  of  spinal  cord nodes,  which play an important role as primary centers on the way to transmit sensory information from receptors to the central nervous system, providing appropriate reactions to the action of certain factors. The scientific article uses material that is a fragment of the research work of the adjacent departments "Development, morphology and histochemistry of  animal  organs in normal  and pathological conditions", state registration number – 0120U100796. The obtained results of the research have an important general biological significance, which complements and expands the idea of certain regularities of spinal nodes,  which relate  to  their structural organization and comparative characteristics at the cellular and tissue levels in vertebrate animals of various species.