ABSTRACT
The hepatic hemopoiesis in intrauterine lifeis predominently erythropoiesis,and the erythroblasts undergo the differentiation process finally to form reticulocytes.In this syudy, the development of erythropoiesis in human fetal liver was observed using transmission electron microscope. The immature erythroblasts were more prominent in earlier fetal liver and proliferated rather than went through final differentiation process. The erythroblasts of different differentiation stages exhibited apoptosis in addition to the normal differentiation process. The nuclei of acidophilic erythroblasts were removed by the excessive condensation and dissociation of nuclei from the cytoplasm or by the displacement of nuclei to one side of the cell with deformation of nuclei. The deformed nuclei restored the round shape after the completion of enucleation and engulfed by hepatocytes and Kupffer cells. Two types of erythroblast islands were present in hepatic plate by the differentiation stages of erythroblasts, id est, islands of the same and the different differentiation stages. And several erythroblasts and enucleated nuclei were included in hepatocytes, intrahepatic macrophages and Kupffer cells, and the intrahepatic macrophages resembling Kupffer cell could be suggested to be originated from the Kupffer cell. But there was no morphological evidence of phagocytosis of erythroblasts and nuclei by these cells. In summary, human fetal hepatic erythropoiesis occurred by forming erythroblastic islands and some erythroblasts proceeded to apoptosis during the differentiation. Hepatocytes and macrophages were present in close relation to erythroblast islands and were suggested to influence the development and differentiation of erythroblasts.