The features of proliferative processes in the thyroid gland of the Wistar rat’s offspring after intrauterine action of dexamethasone were studied. Animals were divided into 3 groups: I – intact rats; II – control – animals, which on the 18th day of the dated pregnancy transuterine, transdermal, subcutaneously in the interscapular area was injected with 0.9 % saline in the amount of 0.05 ml; III – experimental group – animals, which during laparotomy by intrauterine, transdermal subcutaneous injection in the interscapular area was injected with a solution of dexamethasone at a dose of 0.05 ml at a dilution of 1:40 intrauterinely on the 18th day of pregnancy (Ukrainian patent No.112288). In the experimental subgroups used the allowable, generally accepted number of animals for statistical processing and obtaining reliable results – 6 animals. The thyroid gland with the tracheal area was removed on the 21st, 30th, 45th, 60th, 90th, 120th days of life. Immunohistochemical study was performed according to the protocol recommended for a particular antibody manufacturer. Monoclonal antibodies ki-67 (Ki-67), Fox-1 Antibody (A-12) were used to assess proliferative activity, the company Santa Cruz Biotechnology, Inc. (USA). The study found that the thyroid gland of rats of infantile period, which prenatally exposed to dexamethasone, is structurally represented by chaotically located follicles of different diameters with a predominance of large with desquamated cells in the lumen, and proliferative changes aimed at forming extrafollicular which is confirmed immunohistochemically by the presence of Ki-67-positive cells. Intracellularly, protein- synthesizing organelles of thyrocytes also proliferate, to which there is a clear cytoplasmic and nuclear reaction with Fox-1 antibodies. Dining the juvenile period, proliferative processes in the thyroid gland of animals of the experimental group are stabilized while maintaining the morphological structure of the hypofunctional type, and remain lower compared to the control and intact groups. Morphological signs of functional tension of the thyroid gland animals exposed prenatally to dexamethasone, which correlate with a decrease in proliferative activity, indicate a functional compensatory response of synthetic and hormone-producing function, but suppression of proliferative processes, despite the slight manifestations. The thyroid gland of morphological hypofunctional type after prenatal action of dexamethasone in young rats, indicates an adaptogenic compensatory response and morphofunctional immaturity of the organ during this period, which may be the basis for provoking the preservation of such morphogenetic factors under the influence of stressors. Keywords: thyroid gland, proliferation, dexamethasone, experiment, rats.
Antigenic influence at critical terms of ontogenesis can cause significant changes in the child's immune system. It is known that the entry of antigens into the fetus causes premature release of T-lymphocytes from the thymus and their migration to various organs. The paper was aimed at the study of the folliclegenesis of the thyroid gland in postnatal period at norm and after prenatal influence of staphylococcal toxoid. In the experimental research as a material were thyroid glands of Wistar rats aged 1 to 60 days of postnatal development (162 animals), about 6 animals in each group. Three animals groups were studied on 1, 3, 7, 11, 14, 21, 30, 45, 60 days after bith. I gr. - intact animals (norm); ІІ gr. - control, animals which were injected intrauterine 0.9% NaCl solution; III - experimental animals injected with staphylococcal toxoid liquid purified adsorbed (10-14 units of binding in 1 ml, diluted 10 portions) by operation intrauterinely on the 18th day of dated pregnancy. Histological sections 3-5 μm thick were stained by hematoxylin and eosin, histochemicaly by alcian blue and azan staining. Immunohistochemical study was performed according to the protocol recommended for a particular antibody of the manufacturer. Used ki-67 (Ki-67), TTF-1 (8G7G3/1), Fox-1 (A-12) monoclonal antibodies by Santa Cruz Biotechnology, Inc. A set of morphometric studies was performed by microscope Carl Zeiss Primo Star equipped with the Axiocam digital microphoto attachment with using program complex Zeiss Zen 2011. The results were considered reliable at p≤0,05. For processing of statistical material was used the standard software package Microsoft Office Excel and Statistica 10.0.The results were obtained about morphogenesis of rat’s thyroid after intrauterine antigenic action of staphylococcal toxoid. Morphofunctional homeostasis and stromal-parenchymal proportional relationship to thyroid gland closely associated with the activity of immune cells, including special role of lymphocytes, macrophages, and mast cells. Prenatal influence of staphylococcal toxoid led to the formation of a more pronounced structure of the parenchyma and stroma, but they showed signs of functional immaturity after birth. During the sucking period, the simultaneous presence of intra-, extrafollicular, septal and intramural types of folliculogesis is determined, which is a local reaction to systemic antigenic irritation with activation of compensatory-adaptive reactive folliclegenesis. The revealed changes in the process of folliclegenesis, accompanied by venous plethora, the formation of intraorgan diffuse lymphoid tissue and nodules, desquamation of the follicular epithelium, redistribution of the follicle diameter is a reaction to the systemic antigenic effect on the body during the critical period of prenatal development and normalizes by 45 days.Keywords: morphogenesis, thyroid gland, antigen, staphylococcal toxoid, experiment.
Background. In recent years, the prevalence of thyroid pathologies of various origins among children in the world has reached a significantly high level. The use of glucocorticoids during pregnancy remains a debatable issue in obstetrics today, as they can both positively and negatively affect the processes of organ morphogenesis and be the cause of pathological conditions in the postnatal period. Objective: to establish the features of morphofunctional transformations during the morphogenesis of the thyroid gland of the offspring of rats at an early age in normal and after intrauterine action of dexamethasone. Methods. 108 thyroid glands of rats of 3 experimental groups were microscopically examined using histological and immunohistochemical methods, followed by statistical processing of the obtained results. Results. Against the background of high levels of total follicular thyrocytes per 1 day of life in animals that received prenatal dexamethasone, cytoplasmic expression of TgAb was expressed, which correlated with the indicators of nuclear and cytoplasmic Fox-1 expression. From the 7th to the 11th day, a decrease in the total number of thyrocytes per unit area was observed due to the accumulation of colloid in the follicles, an increase in Fox-1 cytoplasmic expression and a decrease in nuclear expression, against the background of increased proliferative activity. By day 21, Fox-1 cytoplasmic and nuclear expression were almost identical. There was a decrease in the intensity of TgAb expression in the cytoplasm of thyrocytes and its expression in the colloid, a decrease in the number of Ki-67 positive thyrocytes per conditional unit area compared with the previous observation period. Conclusion. It was found that prenatal exposure of dexamethasone causes the offspring accelerate the development of morphological structures of the thyroid gland, but functionally they are in a state of stress of both the synthesizing apparatus and the process of hormone excretion, which is expressed in the imbalance of immunohistochemical expression of Fox-1 and TgAb. Such thyrocytes with signs of disturbances in synthetic activity desquamate into the lumen of the follicles, while on the 11th day we compensatory increase in the proliferative activity of the thyroid epithelium.
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