Matkivska R. Structural changes of aggregated lymphoid nodules of ileum in an experimental burn injury of skin in rats under conditions of infusion solution use

The investigation on establishing the structural differences of the injury and compensatory adaptive changes in aggregated lymphoid nodules of ileum (Peyer's patchs) in rats at different periods after the experimental thermal burn injury under conditions of intravenous infusion of 0.9% NaCl and hyperosmolar solutions (lactoprotein with sorbitol and gekoton) was performed on 126 white male rats. The test animals were divided into 7 groups (each group of 18 animals). With the help of light and electron microscopy it was determined that the general signs of structural changes in Peyer's patchs in rats with the burn injury are necrosis and apoptosis of functionally different cells which occur against the background of significant changes of haemo and lymphatic microvasculature. It is established that basic (physiological) apoptosis enlargement disorder occurs as well as necrotic changes of the initial apoptotically modified lymphocytes (with their apoptotic bodies) and lymphocytes which are not apoptotically modified. It is first found that in case of infusion of 0.9% NaCl necrosis and apoptosis are excessive. They result not only in inadequate apoptotic cells clearance but also in inability to remove cell debris, which is the additional source and factor of inflammation extension, and in development of burn disease related vacuolar and intercellular swelling. Positive effects of intravenous infusion of lactoprotein with sorbitol and gekoton on structure of Peyer's patchs in the test animals involve: 1) necrosis suppression of both lymphocytes and apoptotic lymphocytes; 2) regulation of apoptotic clearance; 3) insuring structural integrity of follicle-associated epithelial cells, dendritic cells and macrophages, which makes normal course of antigen-presenting and phagocytic function possible. Burn injury causes some structural changes in such antigen-presenting cells of the Peyer's patchs as dendritic cells (apoptosis) and macrophages (necrosis). There is detected extensive and local necrosis of all types of follicle-associated epithelial cells, destruction of tight junctions as well as epithelial intercellular swelling, which allows the paracellular route appear for antigenic material to get from the intestinal lumen to antigen-presenting cells. Membranoplastic effect of lactoprotein with sorbitol has traits which present in "exclusion" of range of haemocapillaries from haemomicrocirculatory system due to appearance of circular membrane structure acting as ansa and contributing to vascular lumen closure. It leads to changes in haemomicrocirculation that induce changes in lymphatic microcirculation and relevant changes of selective recirculation of lymphocytes that are not structurally damaged. Infusion of the investigated hyperosmolar solutions leads to saving of typical structure of juxta nodules lymph capillaries. The distinguishing feature of juxta nodules lymph capillaries in the rats with burn injury that were infused with lactoprotein with sorbitol is being overfilled with the lymphocytes of typical structure, cells undergoing mitosis, dendritic cells, apoptotic cells and apoptotic bodies. Infusion of rats with burn injury with gekoton solution is not accompanied by the "overfill" phenomenon, which is another advantage of its use. Therefore, it is established that compensation of the mentioned evidence of alteration in Peyer's patchs is performed not only due to protection of cells from those cell damages which lead to the cell death or due to improvement of proliferation of undamaged cells but also due to engaging of additional mechanisms which are to change the conditions and speed of immunocytes recirculation. For the first time the results indicate the integral reaction of the immune system to the burn. That reaction can be optimized and stabilized upon condition of timely and adequate infusion therapy involving the use of the lactoprotein with sorbitol and gekoton.