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I. ДИАГНОСТИКА И ЛЕЧЕНИЕ
STRUCTURAL CHANGES IN THE THYROID AND ADRENAL GLANDS IN ACUTE HYPOXIA
МРНТИ 76.29.37
Yagubova S.M.
Department of Pathological Anatomy of Azerbaijan Medical University, Baku, Azerbaijan
ABOUT THEАUTHORS
Yagubova S.M. - Senior lecturer of the Department of patalogical anatomy. Candidate of medical Scinces.
e-mail: [email protected]
Abstract
The article provides information about the research work carried out to study the patho- and morpho-genetic features of morphofunctional changes occurring in the tissue structures of the thyroid and adrenal glands under the influence of barocamera hypoxia.
The object of the study were the thyroid and adrenal glands of adult male white rats with a mass of 180200 grams. In the course of the study, anatomic, histological and morphometric examination methods were used.
During the morphological study of the thyroid and adrenal glands parenchyma and stroma of the glands in all animals under the infuence of acute hypoxia, diffuse edema, acute dilatation of the vessels in the microcirculatory bed, fragmentation of the walls, violation of the completeness of the endothelial layer, absorption of blood plasma into the vascular wall were observed. These dystrophic changes are more pronounced in the adrenal gland than in the thyroid gland. This is explained by the fact that the adrenal gland is more sensitive to stress factors and cells are more damaged, and the thyroid gland is more early to hypoxia.
Keywords
thyroid gland, adrenal glands, acute hypoxia, structure
Жт гипоксия кезшдеп бYЙрек yctï безшщ жэне калканша безшщ курылымдьщ e3repicTepi
Ягубова С. М.
Эзiрбайжан Медицина Университет Патологиялык, анатомия кафедрасы, Баку, Эзiрбайжан
Андатпа
Макалада барокамеральщ гипоксияныц eœpiHeH бYЙрек yctî безшщ жэне калканша безшщ тшдш курылымдарында жYретiн морфофункционалдык взгерiстердiц пато- жэне морфогенетикалык ерекшелiктерiн зерттеу максатында жYргiзiлген тлыми-зерттеу жумыстары туралы мэл'меттер келт'р'ше^.
Зерттеу нысаны ретнде салмаш 180-200 грамды курайтын ак густ'! ересек егеукуйрыктардыц аталыктары алынды. Зерттеу барысында анатомиялык, гистологияпыкжэне морфометрикалык зерттеу эдстерi пайдаланылды.
БYЙрек Y^i безнщ жэне калканша безнщ паренхималарын, бездердщ стромаларын морфологиялык зерттеу кезнде жт гипоксияныц эсерiнен барлык жануарларда диффуздык сну, микроциркуляторлык арнадагы тамырлардыц жт кецеюi, кабырралардыц фрагментациясы, эндотели-алды кабат Yздiксiздiгiнiц бузылуы, тамыр кабырраларына кан плазмаларыныц енуi байкалды.
Бул дистрофиялык взгер'ютер калканша безне караганда, бYЙрек Y^i безнде айкын кврiнедi. Муныц себеб'!, бYЙрек Y^i без '! куйзел'ю факторларына аса сез 'шал, ал калканша без '! гипоксияга ер-терек ушырайды деп тYсiндiрiледi.
АВТОРЛАР ТУРАЛЫ
ЯГУБОВА С.М. - Патологиялык, анатомия кафедрасыныц ара окытушысы, м.р.к. e-mail: [email protected]
Туйш сездер
калканша без'1, буйрек устi без'1, жтi гипоксия, курылым
Структурные изменения щитовидной железы и надпочечников при острой гипоксии
ОБ АВТОРАХ
ЯГУБОВА С.М. - старший преподаватель кафедры патологической анатомии, к.м.н. e-mail: [email protected]
Ключевые слова
щитовидная железа, надпочечники, острая гипоксия, строение
Ягубова С. М.
Кафедра Патологической анатомии Азербайджанского Медицинского Университета, Баку, Азербайджан
Аннотация
В статье приводятся сведения о научно-исследовательской работе, проведенной с целью изучения пато- и морфогенетических особенностей морфофункциональных изменений, происходящих в тканевых структурах щитовидной железы и надпочечников под влиянием барокамерной гипоксии.
Объектом исследования служили щитовидная железа и надпочечники взрослых самцов белых крыс массой 180-200 грамм. В ходе исследования использовались анатомические, гистологические и мор-фометрические методы исследования.
При морфологическом исследовании паренхимы щитовидной железы и надпочечников и стромы желез у всех животных под влиянием острой гипоксии наблюдались диффузный отек, острое расширение сосудов в микроциркуляторном русле, фрагментация стенок, нарушение непрерывности эндотелиаль-ного слоя, пропитывание плазмы крови в сосудистую стенку. Эти дистрофические изменения более выражены в надпочечниках, чем в щитовидной железе. Это объясняется тем, что надпочечники более чувствительны к стрессовым факторам, а щитовидная железа более рано подвергается гипоксии.
Currently, hypoxia - oxygen deficiency is one of the main problem in medicine, an integral part of modern human life [1]. Hypoxia is the basis of various pathological processes in a number of serious diseases and extreme conditions and is often found in the clinic. Hypoxia affects the development of ischemia in the tissues of the respiratory system, nervous system, organs of the cardiovascular system, as well as organs of the endocrine system, especially the thyroid and adrenal glands, causes polyorgan deficiency, as well as stress conditions in the body [2,3].
Thyroid and adrenal glands, which are the main organs of the neuroendocrine system with a complex biological structure, play an important role in regulating the level of basal metabolism of all cells of the body, normal development and growth of the body, as well as in the formation of compensatory and adaptive processes in the body against various stress factors [4,5]. These glands have different origins, structure and shape. Thus, the thyroid gland consists of the central and peripheral parts, and the adrenal gland consists of the cortex and medulla, which is 70-80% of the volume of the organ.
Corticosteroids synthesized and secreted by the adrenal cortex affect the immune system, the course of inflammatory processes and metabolism, and catecholamines secreted by the adrenal medulla affect the activity of the cardiovascular and nervous system, glandular epithelium, mainly carbohydrate metabolism and thermogenesis [5]. Hormones (thyroxine, triodtrionine) synthesized and secreted by follicular epithelial cells of the thyroid
gland are also important for normal growth and development of the body [6,7,8,9].
A group of authors identified barometric pressure and oxygen levels at various altitudes from sea level, as well as describing the symptoms of «mountain diseases», and found that the effect of oxygen deficiency on the body, most diseases of the thyroid [10,11] and adrenal glands, and stress conditions associated with these diseases are directly or indirectly related to oxygen deficiency. Other authors note that morphological changes occurring in the glands under the influence of hypoxia are a nonspecific reaction to stress-syndrome caused by compensatory-adaptive reorganization of the structure of the gland and brain hypoxia.
Analysis of literature data shows that despite numerous microscopic studies devoted to the structure of the tissues of the thyroid and adrenal glands, which play a key role in the life processes of the organism, the study of the hypofunctional state of organs, a number of questions still remain unresolved, contradictory and unanswered in the literature [12,13,14].
The aim of the study was to study the pathogenic and morphogenic properties of morphofunctional changes in the tissue structures of the thyroid and adrenal glands under the influence of acute hyper-baric chamber hypoxia.
Materials and methods
The object of the study was healthy adult male white rats weighing 180-200 grams. Research on animals was conducted in the Department of Phar-
ВЕСТНИК ХИРУРГИИ КАЗАХСТАНА № 4-2019
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macology and Experimental Surgery of the Scientific Research Center of AMU on the basis of ethical rules specified in Protocol No. 31 of the ethics rules Commission and bioethics committee under the Ministry of health of the Republic of Azerbaijan on 21.04.2008.
Animals are divided into 2 groups - control and experience groups. The animals included in the control group were not intervened, and the second group of experimental animals were experimented in the daytime (about 10-15). To this end, they were put into the barocamera for 2 hours and created a model of acute hypoxia, 5 times a week with a break of 1 hour, 2 times a day and 2 hours every other day. In the barocamera, the temperature was 19-20aC, atmospheric pressure was equal to the pressure 2000-3000 m above the sea level, the particles of natron lime (Ca(OH)2 81%+NaOH 3,4%+H2O 15,6%) were used to absorb the CO2 generated during respiration. The animals removed from the barocamera were provided with water and food and kept under control in standard vivarium conditions. On the 2nd and 5th day of the experiment, intraperitoneal anesthesia was performed by introducing 2-2.5% theopental-sodium solution (100mg/kg) into the peritoneal cavity of animals. Preparations for histological and morphometric examination were taken from the thyroid and adrenal glands of decapitated animals.
The sections are stained with hematoxilin-eosin and PAS, covered with encrusted glass through Canadian balm. Microscopic examination was performed under x8, x20 and x40 magnification. Mi-crophotography of the structural elements of the thyroid and adrenal glands was performed by a digital camera of the microscope "Olympus BX-41", and morphometric parameters were calculated by Microsoft Excel computer program.
Results and discussion
In the rats included in the macroscopically controlled group, the thyroid gland is located at the front of the neck, in front of the trachea and the larynx, and the adrenal glands in the peritoneal area, on the upper poles of the kidneys, under the diaphragm. The relative weight of the thyroid gland of rats included in the control group is 19.5 mg/g, and the relative weight of the adrenal gland is 13,4mq/q. During the visual examination of histological preparations taken from animals, the capsule consisting of dense connective tissue covering both glands from the outside, thin septums going from the capsule to the inside of the gland, the lobules of the thyroid gland separated from each other by the tra-beculae, the cortex and medullaryn substances of the adrenal gland are clearly visible. The connective tissue capsule consists of a small amount of glucosaminoglycan and other organic substances.
In the norm, the main structural components of the parenchyma of the thyroid gland are closed corpuscles or slightly tightened follicles of different sizes with a cavity inside, and the main mass of the follicles is thyrocytes. The main cellular elements of the parenchyma of the adrenal glands are the rounded, mainly small-sized adrenocytes (fig.1).
During the microscopic examination, it is possible to see follicles and a few columnar epithelial cells covering them, as well as cuboid tyrositis, round nuclei in the cytoplasm of tyrosites stained with hematoxylin-eosine. In histological sections, in the center predominate follicles made up by prizmatic cells, and follicles made up by cuboid cells in the periphery. In comparison with the periphery in the central part of the gland, the follicles differ in their small size. The size of the follicles and the thyrocytes that make them varies in normal physiological conditions. Microscopically, follicular komplexes (microvillies) consisting of a
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Figure 1.
Normal histological structure of the thyroid gland. Stain: Stain: Hematoxilin-eosin: x40.
Figure 2.
Normal histological structure of the adrenal gland. Stain: Hematoxi-lin-eosin: x20.
group of follicles surrounded by a thin connective tissue capsule are distinguished in the lobules of the thyroid gland.
In the cavity of the follicles marked colloid, collected in liquid form. Depending on the degree of colloid filling, the volume of follicles increases. Colloid is a product of follicular endocrinocytes, mainly composed of thyroglobulin, fills the lumen of follicles in the center as a homogeneous mass, positively stained with PAS. In the peripheral part of the gland there are follicles covered with a single layer cuboid epithelium, in which the cavity is not filled with colloids. In the peripheral part of the gland, there is a single layer of gobaban-like epithelium-covered follicles with some formation of which the cavity is not filled with colloids. In histological preparations, a very elongated shape follicles filled with colloid are also detected.
In the microscope, the well-developed interlobular and interfollicular connective tissue of the thyroid gland is poorly noticeable. Angioarchitectonics of the gland is characterized by a thick network of capillaries, forming strange plexuses, which are in close contact with thyrocytes from all sides.
In the microscopic preparations taken from the adrenal glands and stained with hematoxylin-eosin, thin trabeculae going from the capsules to the thickness of the cortical substance and having the vessels and nerves inside and reticular fibers arising from them are clearly distinguished. Reticular fibers are directed towards the depth of the organ, forming a thin network around the cortex and medulla of parenchyma. Microscopically 3 cortical zones, separated from each other by a not very clear boundaries, are distinguished - the outer glomerular zone; the middle - the fascicular zone, which forms the main part (mass) of the cortical substance, and the inner thin reticular zone, resting to the medulla. The cells of the glomerular
and fascicular zones are large, the nuclei are large and rounded, and the cells of the reticular zone are relatively small (fig.2).
The glomerular zone consists of cells that have a uniformly colored cytoplasm, forming arches («glomeruli»), the cells are grouped in the form of small clusters, separated by capillaries from each other. In the cytoplasm of this zone compared with the fascicular zone little fat droplets are noticeable. Under the glomerular zone, the cells of the fascicular zone with a more homogeneous cytoplasm are visible. The cells of the fascicular zone have a radial structure perpendicular to the surface of the gland. Fascicular zone consists of a large vacuolated oxyphilic cells - spongiocytes; they form a radially oriented trabeculae («bundles») having a sinusoidal capillaries. Spongiocytes have bright cytoplasm and seem vacuolated. The cells of the reticular zone are smaller compared to cells of the fascicular zone, attracting the attention by the presence of dark and light adrenocytes inside. In this area, cells subjected to apoptosis are also visible. Microscopic examination in the cytoplasm of the reticular zone found lipofuscin granules. Capillaries of the reticular zone consist of epithelial trabeculae, going in different directions and forming anastomoses with each other.
The amount of lipids in the glomerular and reticular zones of the adrenal gland is less and in the fascicular zone is more. Therefore, cells with transparent cytoplasm forming the fascicular zone are not stained with PAS. This is explained by the fact that in spongiocytes there are fewer glycogen grains, and on the contrary a large amount of fat drops.
The reticular zone of the adrenal cortex is separated from the adrenal medulla by a thin connective tissue covering. This cover like the continuation of connective tissue located perpendicular to the sur-
Figure 3.
2nd day of acute hypoxia model. Pathohystological structure of the thyroid gland. Stain: PAS x40
face of the gland. The cytoplasm of the adrenocytes of the medullary substance is pale stained in comparison to the cytoplasm of the cortical substance. The medullary substance is made up of chromaffin, gangliose and supporting cells that have a round or oval shape. Chromaffin cells are the main cells of the medullary substance, which are in the form of «throws» and «nests», have a large polygonal shape nuclei, fine-grained and vacuolated cytoplasm. Ganglious cells are few in number and are vegetative in nature; supporting cells have processes, there are glial in origin and contain chromaffin cells.
In the microscopic examination, the interzonal, intracellular connective tissue of the adrenal gland is poorly noticeable, and capillaries covering the adrenocytes from all sides and forming thick plexuses are clearly visible. The lumen of the capillaries in the medulla is wide, compared with the cortical substance.
2 days after the creation of the hypoxia model, the morphological and morphometric changes associated with hypoxia in histological preparations made from the thyroid and adrenal glands of animals are noted. However, compared with the control group, attention is drawn to the presence of weak dystrophic and destructive changes in both gland cells. In the morphometric indicators obtained as a result of the study, a significant difference is also not noted in the control group, only the relative weight of the glands is increased.
The thyroid and adrenal glands of the experimental animals included in this group have grown in volume, in particular, the consistency of the adrenal gland has softened, the color is pale. The capsule of the glands, which has a large number of collagen fibers, is slightly loosened, its lobules are relatively swollen, the border between the central and peripheral parts of the thyroid gland is clearly visible with the naked eye, and the cortex and medullary substances of the adrenal gland are poorly distinguished from each other.
Microscopically, no noticeable changes in the structure of the thyroid gland - parenchyma - follicles, epithelial cells of thyrocytes are observed; weak dystrophy of stroma - interlobular and inter-follicular connective tissue, as well as endothelial cells covering the vessels is noted. Follicles as a whole have not changed their structure properties and normal staining properties. Prismatic epithelial cells of the follicles of the central part of the gland are poorly swollen, but do not lose their shape. In this case, the intrafollicular colloid has a liquid and foamy consistensy and is pierced by numerous resorption vacuoles, the cytoplasm of the cell is foamy, slightly edematous, the nuclei appear in the direction of the edge of the cytoplasm. The colloid, which fills the nucleus of the cell and the cavity of the follicle, is poorly stained. Morphometric parameters of follicles are relatively changed (fig.3).
In the peripheral parts of the thyroid gland, the follicles have a large size, flattened epithelium, thickening and stagnation of the colloid, a significant increase in the diameter and volume of the follicles is noted. As a result of this, the thyrocytes of the follicles get a flattened shape. Unlike the control group, by the action of hypoxia colloid is partially replaced with edema fluid in the cavity of peripheral follicles and pronounced PAS-positive reaction noticeable. The nuclei of thyrocytes are stretched parallel to the surface of the follicle and poorly stained with hematoxylin-eosin. In the cytoplasm of both the central and peripheral part of the gland, the individual micro-sized fat drops are clearly visible.
On the second day of hypoxia, the interlobular connective tissue of the thyroid gland is poorly visible. Cellular elements of connective tissue -fibroblasts, reticular cells, collagen fibers, mainly fibrous structures of the interstitial substance, are slightly swollen, but have not been targeted. Endo-
thelial cells that cover the walls of the capillaries are bulging towards the lumen, edema does not cover wide areas, although weak interstitial edema is detected in the vascular areas. However, dystrophic changes in glandular stroma relative to parenchyma are noticeable. The microcirculatory bed of the thyroid gland attracts attention with its weak plethora. In connection with an increase in vascular permeability, signs of plasmorrhagia, focal diapedesis bleeding are detected.
Microscopically, the boundaries of the cortical substance of the adrenal gland appear weak, the capsule becomes loose, loosening and irregular placements of the trabeclae arising from the capsule into the cortical substance are noticeable. The sinusoid capillaries of the cortical substance are enlarged and filled with blood. The size of the fascicular zone has decreased, and the glomerular and reticular zones have not changed. The cells of the glomerular zone are of small size, have a «matte» cytoplasm and a hyperchrome nucleus.
In the fascicular zone, in particular, in its outer layer (subzonal part), foam «transparent» cytoplasm cells, in the area close to the reticular zone (inner subzonal part), «matte» cytoplasm cells predominate. The «matte» cytoplasm and the small sizes nuclei of of the reticular zone appear weak. The nucleus of the adrenocorticocytes of the cortical substance is located not in the center of the cytoplasm, but slightly outside and poorly stained with hematoxylin-eosin. An unequal amount of lipid drops are noted in the cytoplasm of the fascisular and reticular zones.
The connective tissue covering separating the medulla from the cortical substance, is poorly visible. Under the influence of hypoxia, weak pronounced dystrophic changes in the cells of the medllary substance are noted. Thus, the «slots» of chromaffin cells, the main component of the brain substance, and the «protrusions» of the supporting cells surrounding them, were poorly deformed, the size of the ganglious cells are decreased. The cytoplasm of cells is lightly edematos, foamy, the nuclei are dark, the nucleoli are not noticeable, but the cell membrane is clearly visible. In some ad-renocytes, nuclei with karyopyknosis are found. In the cytoplasm of the adrenocyte of the medullary substance, fat droplets are not detected, the cytoplasm is weakly stained with PAS. Histochemically, glycogen in the adrenocorticocytes of the adrenal gland is not detected with the PAS reaction.
In the intracellular connective tissue of the adrenal gland, poor edema, areas of loosening, signs of mucoid swelling are noticeable. Fibrous structures of connective tissue, especially collagen fibers, are relatively swollen but don't disintegrate. The noticeable edema in the interstitial area leads
to the interstitial separation of tissue elements, tropocollagen microfibrils, resulting in the manifestation of the phenomenon of metachromasia in tissues stained with hematoxylin-eosin. The reticular fibers of the capsule trabeculae are poorly defined, and the plexus formed around the cells of the parenchyma of the gland is not noticeable.
Thickening of the walls and deformation of some parts of capillaries of the microcirculatory bed of the gland, weak dystrophic changes such as the fullness of veins, interstitial edema in paravasal areas can be seen with a light microscope. In histological preparations, endothelial cells of large vessels were swollen and subjected to desquamation, and their walls became brittle. In the microscopic examination, the walls of the capillaries of the medullary substance are edematous, dispersed, poorly stained with PAS. The effect of hypoxia is a consequence of increased vascular permeability, dilatation of the capillaries - in particular, with the formation of signs of focal plasmorrhagia in the fascicular zone and perivascular areas of the medullary cub-stance. Hemolysis of erythrocytes is observed in the detachment zone. The cells of the detachment zone, based on the hemorrhages, are clear and the capillaries are emptied. As a result of the influence of hypoxia, vascular permeability increases, the lumen of capillaries dilates - in particular, signs of focal plasmorrhagia appear in the perivascular areas of the fascicular zone and medullary substance (fig.4).
Microscopically, there is an increase in the relative weight of the adrenal glands, although the boundaries of the cortex are clearly visible, the thickness has decreased significantly, especially in the fascicular zone. The thickness of the reticular zone of the cortex and medulla does not differ from that of the control group.
On the 5th day of the acute hypoxia model, acute pathomorphological changes, diffuse edema, and disruption of tissue metabolism are noted in the histotopography of the thyroid and adrenal gland cells due to a decreased oxygen supply of tissues. As a result of hypoxia, most tissues, cells, organelles of the glands completely lost their structural properties, suffered acute dystrophy and destruction. Also in the statistical indicators of the experiment, sharp changes characteristic of the effect of hypoxia are noted. It appears that these pathological changes are deeper in the adrenal gland cells than in the thyroid gland.
In the macroscopic examination, the color of the thyroid and adrenal glands were dimmed, the volume of which grew sharply, and the consistency became soft and brittle. The growth of its volume led to the release of connective tissue fibers, roughening and deformation of the capsule cover-
I
ing the gland. Microscopically, the appearance of grayish-pink in the transverse section of the gland tissue reflects its damage. The release of connective tissue fibers is manifested by the breakdown of trabeculae directed from the capsule into the gland. The central and peripheral parts of the thyroid gland parenchyma and the adrenal gland parenchyma are visually swollen.
Microscopically, the border between the central and peripheral parts of the thyroid gland is not observed, the follicles are sharply hypertrophied. Among the follicles, noticeable signs of interstitial edema are noted, which leads to their separation and it is clear that there are no connections between them. It is observed that the follicles of the central part of the gland swell and pass from the prismatic form into the round. In the cavity of some follicles of the central part of the gland, ruptured thyrocytes, resorbed vacuoles in a colloid are found along the periphery of the follicles. Desquamated thyrocytes are absorbed by colloid.
The structure of the follicles located outside the center differs from the follicles located in the central part, the epithelial cells that cover the thyrocytes are acute edematous, colloid fills the lumen of the follicle. Along the peripheral part of the gland, an increase in the size of the follicles is noted; large-sized follicles are more common. In the cytoplasm, there is a complete breakdown of chromatin in some cells, as well as nuclei with karyopyknosis and karyolysis.
Noticeable destruction of the epithelial cells of the thyrocytes, loss of the nucleus in the group of many cells, pallorization of some cells is detected. The nuclei are observed on one edge of the cell, in a swollen, pale, flattened form. The absence of glycogen grains in the cytoplasm is associated with the use of glycogen by thyrocytes since the resto-
ration of intracellular energy sources is more often compensated by glycogen (fig.5).
In the biopsy materials taken from the thyroid gland, the fibrous carcass of the stroma is deeply deformed, has lost its normal staining properties, acute alterations, signs of total edema in the interstitial area are detected. Thus, the fibrous structures of the connective tissue are swollen, fragmented, especially collagen fibers are fragmented and dispersed, in some places they are destroyed. Fibroblastic structures are not detected. Most cells are on the verge of necrobiosis. In the microscopic examination, small-sized foci of inflammation consisting of lymphocytic leukocyte elements appear in the peripheral parts of the stroma of the gland.
In the histological preparations, acute destructive changes in the microcirculatory bed, productive endovasculitis of the vascular walls, non-selection of contours, plethored capillaries and loss of the border of pericapillary cells in some areas are also observed. Acute plasmorrhagia, localized diapedez hemorrhages are noticeable. As a result of the increase in vascular permeability, the lumen of the vessels was emptied and the walls became brittle, some parts lost their continuity. A weak PAS reaction mainly in peripheral capillaries is noted.
In the case of microscopic examination of experimental animals with a hypoxia model, the boundaries between the cortex and medullar substances of the adrenal gland, as well as the zones of the cortical substance, the cytoplasm and nuclei of the adrenocytes are not noticeable, acute hypertrophy of the cells is noted. Histotopographically as a result of hypoxia, the inability to visualization the border of cells of the parenchyma of the gland is explained by acute edema of the tissues. In this connection, deep dystrophic and destructive changes in the cells of the gland are noted. Thus, «glomeruli»
Figure 4.
2nd day of acute hypoxia model. Pathohystological structure of the adrenal gland. Stain: Hematoxilin-eosin: x10
Figure 5.
5th day of acute hypoxia model. Pathohystological structure of the thyroid gland. Stain: Hematoxilin-eosin:x20
of the glomerular zone, «fascicles» of the fascicular zone, «epithelial trabecuale» of the reticular zone, chromaffin, ganglious and supporting cells of the medullar substance have lost their forms, subjected to acute structural changes. Therefore, in the histological preparations, there is no border between the zones, it is impossible to distinguish them from each other. In the fascicular zone, «light» and «dark» cells change each other, and in the glomerular and reticular zones, «dark» cells prevail. The radial direction of spongiocytes was violated, the size of their cells connection with perivascular edema was repeatedly increased, and the size of adrenocytes of glomerular and reticular zones was relatively increased.
Adrenocorticocytes of the adrenal cortex are large, cytoplasm eosinophilic, acute edematous and pale. The nucleus of the cells of the cortical substance is located adjacent to the wall of the cytoplasm and is not stained with hematoxylin-eosin. An unequal amount of microvesicular (small granular) lipid droplets are noted in the cytoplasm of the fascicular and reticular zones (fig.6).
The connective tissue covering between the fascicular zone and the medullary substance is disintegrating, and the boundary is not visible. There are also acute dystrophic changes in the cells of the medullary substance of the gland, noticeable signs of interstitial edema between the cells are observed, cytoplasm is acute edematous, the nucleus is sharply shrunk and is visualized in the periphery of the cytoplasm. The detection of a large amount of fat droplets in the cytoplasm is explained by dena-turation of cytoplasmic proteins. Due to hypoxia, the complete dystrophy of some cells of the medullary substance causes the destruction of the nucleus, the development of necrobiosis and necrotic processes.
Some fibers of the fibrous components of the connective tissue of the adrenal gland are swollen, in particular, the fibrous structure of the brain sub-
stance is brittle and subjected to mucoid swelling. The reticular fibers, which go from the connective tissue trabecules to the depth of the organ, are noticeable due to interstitial edema. In some areas of stroma, signs of destruction - mucoid swelling and edema not only in fibrous structures but also in main substance are observed.
Microangioarchitectonics of the cortical substance of the gland is characterized by an unequal plethora of different zones of the organ. Thus, when the plethora of the glomerular zone is weak and the capillaries are empty compared to the 2nd day of the experiment, sinusoid capillaries in the fascicular and reticular zones are sharply enlarged, blood-filled, and as a result, the distance between the cell columns is reduced. Enhanced plethora of the medulla and signs of plasmorrhagia are more pronounced. Sinusoid capillaries are maximally enlarged, their walls are conjoined, the walls of some capillaries are scattered, and the points of diape-desis in the stroma are visualized. In the histological samples, a vascular network formed by various loops appears between the medullary substance and the reticular zone.
Microscopically, the thickness of the adrenal cortex is less than the control group, and the adrenal medulla is closer to the control group. Unlike the first day of the experiment, the glomerular and reticular zones are thicker. Interstitial edema leads to the incompletion of cells.
In conclusion, it should be noted that powerful short-term hypoxic stimulants, besides the visible changes in the cells of the thyroid and adrenal glands, also change their histofunctional state. These dystrophic changes are more pronounced in the adrenal gland than in the thyroid gland. This is explained because the adrenal gland is more sensitive to stress factors, and the thyroid gland is earlier to hypoxia. Thus, the effect of hypoxia leads to an earlier change in the interaction of glomerular, fascicular and
BECTHMK XMPVPrMM KA3AXCTAHA № 4*9019
reticular zones of the cortical substance of the adrenal gland, an increase in the activity of the medullary substance. Increased adrenocortical activity during the initial effect of hypoxia provokes the synthesis and secretion of adrenocorticotropic hormone.
Thus, the early stage of hypoxia is characterized by the appearance of acute pathomorpho-logical changes in the cells of both glands. Under the influence of acute hypoxia, in the central part of the thyroid gland there are separate prismatic follicles, liquid colloid, and in the periphery there
are flattened follicles, condensed colloid, and in the adrenal gland there is an earlier change in the interaction of the glomerular, fascicular and reticular zones, increased activity of the medullary substance. Despite the fact that there is a dilatation of the capillaries in both glands, focal diapedesis, par-enchymatous and interstitial edema, accompanied by an increase in the density of the vessels, edema in the thyroid gland does not cover large areas and is of focal nature. This is explained by more damage to the cells of the adrenal gland.
Figure 6.
5th day of acute hypoxia model. Pathohystological structure of the adrenal gland. Stain: Hematoxilin-eosin: x20
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