HISTOLOGICAL AND MORPHOLOGICAL CHANGES OF THE VASCULAR BED OF THE THYMUS IN WHITE RATS UNDER THE INFLUENCE OF MONOSODIUM GLUTAMATE
Authors: Kochmar Mykhailo Yu. , Havrylets Mykhailo M. , Hoblyk Kalyna M. , Zayachuk Illya P. , Griga Vasyl I. 
Published: December 2023

The aim: To evaluate the effect of 28-day oral administration of MSG at the rate of 30 mg/kg of body weight on histological and morphometric parameters of the vascular bed of the thymus in rats.
Materials and methods: The scientific experiment was conducted on 20 white non-linear rats of reproductive age (4-5 months) weighing from 220 to 280 g, which were divided into two groups (10 rats each). Depending on the term of decapitation, the experimental animals were divided into two groups (10 rats in each group). We studied the effect of 14 and 28 days of MSG administration on the body of rats (I and II groups of experimental rats). The experimental animals were daily orally treated with MSG at a dose of 30 mg/kg body weight, which was dissolved in 0.5 ml of dechlorinated tap water at room temperature. Control rats of III and IV groups (5 rats in each of the control groups) were injected with a placebo (0.5 ml of dechlorinated tap water at room temperature) for 14 and 28 days. Intact animals of III and IV groups were also decapitated on the 14th and 28th days of the experiment, respectively.
After the end of the experiment, animals were decapitated under light ether anesthesia. After decapitation, the animals were dissected into the chest cavity to remove the thymus. Histological preparations were studied using a MICROmed SEO SСAN light microscope and a Vision CCD Camera. Morphometric studies were carried out using VideoTest-5.0, KAARA Image Base and Microsoft Excel programs on a personal computer.
Results: During the microscopic examination of histological preparations of the retrosternal gland in experimental animals of the 1st group (daily administration of MSG at the rate of 30 mg/kg of body weight for 14 days), it was established that the lumen of the arteries is moderately filled with blood elements. The veins are dilated with a changed shape and filled with blood. The following ultrastructural changes were detected in the experimental animals of group I: the lumen of arteries, arterioles and venules is slightly expanded, the nuclei of endotheliocytes are enlarged, occupy a significant part of the cytoplasm, the karyolem forms intussusceptions. The plasmolemma of the lumenal surface of endotheliocytes forms numerous microvilli. At the same time, organelles in the cytoplasm of endotheliocytes lose their contours. After 28 days of exposure to MSG at a dose of 30 mg/kg of body weight in rats (II group of experimental animals), structural changes in the vascular bed of the thymus worsened. The wall of arteries and arterioles is more thickened and swollen, collagen fibers are stratified. In their lumen, there are many uniform elements attached to the vascular wall and testify to thrombus formation. Perivascular edema is determined. The diameter of hemocapillaries is increased, their basal membrane is swollen. Veins and venules are also dilated, full blood, interendothelial contacts in the vessel wall are dilated, the basement membrane is damaged. This contributes to the diapedesis of blood plasma through the vessel wall, which leads to perivascular edema.
Conclusions: Administration of MGS to rats at a dose of 30 mg/kg of body weight for 14 days leads to violations of the morphometric indicators of the vascular bed in the thymus, namely, to an increase in the outer and inner diameter of the arteries, an increase in the area of the middle membrane and the lumen of the vessels, which tend to progress with maximum indicators on the 28th day of the experiment. 2. The study of the vascular bed of the thymus against the background of taking MSG in a dose of 30 mg/kg of the weight of rats indicates the most pronounced changes in hemocapillaries, mainly on the 28th day of the experiment, which is manifested by an increase in their outer diameter. In the lumen of the hemocapillaries, deformed erythrocytes are identified, arranged in the type of “coin columns”.