The Role of Liver Progenitor Cells in Postembryonic Development of <i>Rana terrestris</i> under Normal Physiological Conditions

Abstract

The liver plays an essential role in the metabolism of animals, acting as a central hub for metabolic reactions. It serves as a “peripheral integrator” and balances the body’s energy needs. Its regenerative capacity is remarkably high and is maintained by the proliferation of hepatocytes, as well as hematopoietic and regional liver progenitor cells (LPC). This study investigated LPC-driven liver regeneration during postembryonic development in Rana terrestris under normal physiological conditions. The analysis of intrahepatic and hematopoietic markers by immunohistochemistry and flow cytometry revealed that progenitor cells with the immunophenotypes of CK19+ (intrahepatic progenitor cells), CD34+CD45+ (hematopoietic progenitor cell population), and CD34+CD45– (hemangioblast population) equally promote liver regeneration during the first year of postembryonic development. However, in the second and third years of postembryonic development, liver regeneration was found to be primarily associated with CK19+-positive cells, with a smaller contribution from CD34+CD45– cells. The results obtained were largely determined by the habitat of the amphibians, thermoregulation, and the completion of morphogenetic processes in the third year of postembryonic development. It is also noteworthy that the liver of the examined specimens remained the major hematopoietic organ throughout all observed stages of postembryonic development.