THE ROLE OF APOPTOTIC BONE MARROW CELLS IN ACTIVATION OF LIVER REGENERATION

Objective: using an adoptive transfer model to study the cellular mechanisms involved in the formation of the initial stage of liver regeneration during intraperitoneal injection of a healthy recipient with apoptotic bone marrowderived mononuclear cells (BM-MNCs) from a donor after extended liver resection. Materials and methods. Male Wistar rats (n = 40) were used to create a model of adoptive transfer of apoptotic BM-MNCs (a-BM-MNCs) taken from the donor after extended liver resection to a healthy recipient. During the experiments, the animals were divided into five groups. Four experimental groups with intraperitoneal injection of the same doses to the recipient: freshly isolated BM-MNCs (group 1); BM-MNCs subjected to apoptosis for 48 hours by storage at t = 4-6 degrees C in phosphate-buffered saline (PBS) (group 2) or in a Custodiol HTK solution (group 3). In group 4, the animals were injected with PBS after storing BM-MNCs in it. The control animals were animals injected with saline (group 5). For selection of effective modes of apoptosis induction, BM-MNCs stained with 7AAD after incubation in solutions were analyzed by flow cytometry. Targeted transfer of regenerative signals to the recipient was assessed by the mitotic activity of hepatocytes in the liver and tubular epithelium in the kidneys, as well as by the intensity of microstructural changes in the liver 24, 48 and 72 hours after injection of the studied material. Results. BMC incubation in PBS and HTK for 48 hours at t = 4-6 degrees C provides the most effective accumulation of a-BM-MNCs in early apoptosis. It was shown that a-BM-MNCs retain the ability to target-focused transmission of regulatory signals to the liver supported by autophagy process during adoptive transfer. It was established that a-BM-MNCs (groups 2 and 3) in comparison to native BM-MNCs (group 1) at adoptive transfer increased the regenerative potential of the liver due to pronounced increase in the activity of autophagy processes and directed infiltration of immunomodulatory mononuclear cells in the liver. Conclusion. a-BM-MNCs create a stronger basis for development and implementation of a targeted and effective regeneration program by enhancing autophagy processes and immunomodulatory effect on mononuclear cells, which are regenerative signal carriers.