Embryonic Stem Cell Differentiation Of Neural Cell Identity And Differentiation Mechanisms

Embryonic stem (ES) cells are pluripotent cell lines established from undifferentiated embryonic cells characterized by nearly unlimited self-renewal and differentiation capacity. During differentiation in vitro, ES cells were found to be able to develop into specialized somatic cells types and to recapitulate processes of early embryonic development. These properties allow to use ES cells as model system for studying early embryonic development by gain- or loss-of-function approaches, or to investigate the effects of drugs and environmental factors on differentiation and cell function in embryotoxicity and pharmacology. Now, human ES cells may be used for the generation of somatic precursor or differentiated cells in cell and tissue therapy.In order to supply the ES cells needed for the research of transgenic animals and tissue engineering in future, we did some work of isolating ES cells from mouse. The superovulated ICR and Kunming mice were used to get the embryos of 3.5d, then cultured the embryos on the MEF feeder layer derived from ICR or Kunming mice, dispersed the inner cell masses(ICMs) or ES cell colonies in the appropriate time. We analized the effects of feeder layer, trypsin and embryos isolated from uteri of different varietal mice on the ES cell lines. The results showed that the feeder layers prepared by ICR and Kunming mice had no significant effect on adherence of embryos and proliferation of ICMs. The trypsin, which affected the isolation of ES cells remarkedly, should be used with low concentration trypsin and EDTA. Furthermore, it is more easy to isolate embryos and get the ES cells from ICR mouse than Kunming mouse.To investigate the characteristics of neurons differentiated from mouse embryonic stem (ES) cells, embryoid bodies (EBs) were aggregated from ES cells by suspended culture and differentiated into neurons with induction of 1×10~-6 mol/L all trans-retinoic acid (RA) in vitro. The sizes of EBs effect significantly on neuronal differentiation through the evaluation of the count mothed of differentiated neurons.