Effect of Selenium Supplementation on the Morphometric Parameters and Cellular Composition of the Spleen

The aim of the study was to evaluate the morphometric parameters and cellular composition of the splenic white and red pulp in rats at 1 and 6 months after a 30-day course of selenium supplementation. Material and methods . The study object was the spleen harvested at 1 and 6 months after the completion of a 30-day oral administration of selenium at a dose of 20 µg/kg of body weight per day. The spleen of intact animals, whose age corresponded to the age of rats in the experimental group, served as the control. Morphometric parameters of the spleen were determined; the Kernohan index and lymphoid coefficient were calculated; and an immunohistochemical assessment of the distribution of CD3+, CD21+, and CD68+ cells was performed. Results. One month after selenium administration, lymphoid nodules (LN) without germinal centers predominated; the LN area and the thickness of the marginal zone were reduced. An increase in the lymphoid coefficient was observed, along with a strong positive correlation between the expansion of the periarterial lymphoid sheath and the number of CD3+ T-lymphocytes, as well as a strong inverse correlation between the number of CD3+ T-lymphocytes and the Kernohan index. In the experimental group at 6 months, a reduction in the severity of involutional processes was observed compared to control animals. An increase in CD3+ T-lymphocyte content was also noted in all splenic structures, accompanied by a decrease in the number of CD21+ and CD68+ cells. Conclusion . Oral selenium supplementation activates T-lymphocyte differentiation and promotes the migration of macrophages and B-lymphocytes from the spleen to other organs. This process is accompanied by an increase in CD3+ cell count and a decrease in the number of CD68+ and CD21+ cells across its various structures.