Apoptosis in regenerative histogenesis of the liver after partial hepatectomy in rats

Study of liver regeneration after partial hepatectomy in last few decades enabled to understand hourly changes of expression of different genes, levels of cytokines, determine proliferation kinetics of liver cell types. Unfortunately, processes of apoptosis, which always activates together with regeneration was not given enough attention. In a practical point of view, understanding of apoptosis is needed for development of new therapeutic approaches in liver treatment based on enhancing of anti-apoptotic signals and inducing cells into proliferation. This work was dedicated to study apoptosis during liver regeneration after partial hepatectomy in rats. We analyzed expression of PCNA, caspase 3 and 9, Bcl-2 immunohistochemically during liver regeneration on 1, 2, 3, 5, 7, 14 postoperative days. Our results have showed that caspase 9 and Bcl2 are expressed during first postoperative week, caspase-3 only in first three days. Maximal expression of caspase 9 in hepatocytes and sinusoidal cells occurs after 2 days, in cholangiocytes - after 5 days. Maximal expression of Bcl-2 in sinusoidal cells occurs after 3 days, in hepatocytes and cholangiocytes - after 5 days. So, during liver regeneration after partial hepatectomy in rats mechanisms of apoptosis and antiapoptosis are activated simultaneously. Irreversible apoptosis is possible only during first 3 postoperative days and involves only minor fraction of hepatocytes and sinusoidal cells

liver, apoptosis, regeneration, partial hepatectomy, caspase