POSSIBLE CAUSES OF CHANGES IN SEROTONIN CONTENT IN THE LIVER OF RATS IN CONDITIONS OF CHRONIC INTAKE OF SILICON WITH DRINKING WATER

Abstract

The paper presents data on changes in the intensity of serotonin luminescence in the liver structures of rats who were in an experiment with the intake of silicon with drinking water for two and nine months. The possible causes of identified changes are also considered and discussed. The aim of the study was to correlate the serotonin status of the liver with the number of immunocompetent cells (eosinophils, mast cells, CD68–positive cells) and with peripheral blood indicators in different periods of the experiment with the intake of silicon with drinking water. Material and methods. The rats were divided into two groups: the control group (n = 20) received bottled drinking water, the experimental group (n = 20) received the same water, but supplemented with Na2SiO3*9H2O at the concentration of 10 mg/l in terms of silicon. The animals had free access to a water source. Blood was taken from the caudal vein for analysis before the start of the experiment, as well as in 2 and 9 months after its start. After two and nine months, the rats were withdrawn from the experiment. Fresh frozen slices with a thickness of 10 microns were prepared from one part of the liver to perform the Falk–Hillarp reaction, the other part of the liver was placed in a 10% formalin solution for subsequent paraffin embedding. After deparaffination, the sections were processed by various methods for counting immunocompetent cells: by hematoxylin and eosin (eosinophils), by Unna's toluidine blue (mast cells), by indirect immunohistochemical method (CD68-positive cells). The differences in all cases were considered statistically significant at p < 0.05. Results and their discussion. An increase in the intensity of serotonin luminescence was found in the studied liver structures (hepatocytes, central vein membranes, luminescent granular cells and their microenvironment) in rats of the experimental group. At this, an increase in their intensity by 2-3 times was recorded in the liver of rats who were in the experiment for 9 months. It was revealed that the number of platelets, erythrocytes, hemoglobin, leukocytes, a mixture of monocytes, eosinophils, basophils and immature cells in the blood of rats treated with silicon with drinking water at a concentration of 20 mg/ l is inversely dependent on the duration of the experiment. At both terms, an increase in the number of eosinophils in the portal zones was observed, as well as an increase in the area of mast cells. After 2 months of the experiment, the number of CD68-positive cells and mast cells increased in the liver of rats of the experimental group, and after 9 months their number equalized and decreased, respectively. Attention is drawn to the participation of the above-mentioned immunocompetent cells in serotonin metabolism. Serotonin involvement in the processes of physiological and reparative liver regeneration is discussed. Conclusions. Changes in the number and areas of immunocompetent cells (eosinophils, mast cells, macrophages) in the liver of rats making the experimental groups, as well as a decrease in the platelet content in their blood are associated with an increase in the intensity of serotonin luminescence in the liver structures containing it.