PRENATAL ANTIGEN CONTAMINATION INFLUENCE ON CYTO- AND HISTOCHEMICAL ASPECTS OF MORPHOLOGICAL TRANSFORMATIONS OF THE THYROID IN INFANT RATS

Abstract

Summary. Glycosaminoglycans and proteoglycans are involved in important biological events such as cell proliferation, adhesion, migration and differentiation. It has also been shown that these molecules are involved in the development of neoplastic and hyperplastic lesions. In the field of thyroidology, glycosaminoglycans, proteoglycans and related molecules have been shown to play an important role in the development of both physiological properties and pathological conditions of the thyroid gland. Under the influence of prenatal antigenic load there is a premature exit of T-lymphocytes from a thymus which in fabrics change not only terms of development of structural elements but also their immunological tolerance, etc.

The aim of the study – using a comprehensive histochemical study to determine the cyto- and histochemical features of the morphological transformations of the thyroid gland of infant rats after prenatal antigen contamination.

Materials and Methods. Study material – thyroid gland of Wistar rats 21 to 45 days of the postnatal period (54 animals), 6 animals in each group. Three groups of animals were studied: group 1 – intact animals (norm); group 2 – control, animals which were injected with 0.9 % NaCl solution on the 18th day of the dated pregnancy; group 3 – experimental animals injected with staphylococcal liquid purified adsorbed (10–14 binding units in 1 ml, diluted 10 times) on the 18th day of dated pregnancy (US Pat.  No. 49377, Ukraine, 2010 and US Pat. No. 63020, Ukraine, 2011). In order to visualize and identify glycosaminoglycans (GAG) and proteoglycans, staining of serial sections with alcyan blue at pH 2.5 was used to detect unsulfated GAG, at pH 1.0 – weakly sulfated GAG and proteoglycans in combination with PAS. Morphometry was performed using a Carl Zeiss microscope "Primo Star" using an AxioCam camera, a set of morphometric studies was performed using the Zeiss Zen program (2017). The calculation of the Pearson correlation coefficient (r) was performed using Microsoft Office Excel 2010.

Results. A characteristic feature of the thyroid glands of experimental animals was the detection of a substance that is cleaved by hyaluronidase and reacts with alcyan blue at pH-2.5. It can be assumed that hyaluronate is present in the experimental group of animals. In the form of a moderate reaction, hyaluronate is localized in the cytoplasm of thyrocytes and intensely in the form of inclusions in the colloid. The degree of staining is higher in the walls of large blood vessels, slightly decreased the level of sialoglycoproteins in comparison with the control, and their distribution in the tissues of the gland remains identical compared to intact and control groups. At the end of the infantile period there is a decrease in the content of acidic sulfated proteoglycans in the connective tissue layers of the gland in the norm, other significant differences in the level of distribution and content of carbohydrate components compared to previous age was not observed. In the cytoplasm of thyrocytes decreases the intensity of the reaction to acid sulfated glycoproteins and hyaluronate in animals prenatally contaminated with staphylococcal toxoid.

Conclusions. Thus, we used histochemical research methods to analyze the dynamics of the content of carbohydrate components in the thyroid gland of infant rats in normal and after prenatal antigen contamination. It was found that glycogen, acting as the main energy material, is consumed with age for the synthesis of more complex hydrocarbon biopolymers. In particular, it binds to a protein, resulting in the synthesis of glycoproteins and proteoglycans. We identified different groups of glycoproteins and identified sialoglycoproteins in thyrocytes of extrafollicular proliferative clusters in the structural elements of the thyroid gland of infant rats of the experimental group in the study period, which could be identified as an element of formation of synthetic activity of thyrocytes.