OBJECTIVELiver development needs a number of growth factors and components of the extracellular matrix. The study is to explore how growth factors and extracellular matrix regulate proliferation and differentiation of fetal liver progenitor cell.

METHODSWe demonstrate isolation of hepatic progenitor/stem cells from ED 14.5 SD rat liver, which contains a large number of hepatoblasts. Proliferation assay-3H thymidine incorporation was used to detect the effect of growth factors on proliferation of hepatic progenitor cell. Growth factor and extracellular matrix were added and stem cell clone formation was counted. Mark of bile duct and hepatocyte were detected with double-marker immunocytochemistry.

RESULTSProgenitor liver cells displayed clonogenic capacity, expressed markers of hepatocytes and bile duct cells and G-6-P. HGF, EGF can accelerate DNA synthesis and stem cell clone formation of hepatic progenitor cell. Extracellular matrix collagen I, collagen IV or laminin were essential for formation of stem cell clone. Single cell culture needed HGF, EGF, extracellular matrix and supernatant of mix cell (which contained fetal parenchymal cells, mesenchymal cells and hematopoietic cells) culture.

CONCLUSIONGrowth factors especially HGF and EGF play crucial role in proliferation and differentiation of liver progenitor cell. Some factors secreted from mesenchymal cell and hematopoietic cells may be involved.