| Hematopoietic stem cell(HSC) engineering supply all blood cells throughout life by making use of their self-renewal and multilineage differentiation capabilities. The techniques have become available that allow the extensive proliferation, orderly differentiation, functional activation and gene transfer of hematopoietic stem/progenitor cells in ex vivo culture systems. These techniques have now developed to the point at which clinical trials are now underway in a variety of settings for the applications of hematopoietic stem cell transplantation, hematopoietic support after high-dose chemotherapy, immunotherapy of cancers, and gene therapy. Hematopoietic stem cell engineering is one of the most challenging fields in life science at present. Its present state of study has shown that it has important theory value and many potential applications in the domain of clinical medicine, and brings new chance into modernization study of Chinese medicine. The results of study on effect of the effective fractions extracted from Chinese medicine on biologies of HSC suggested that many Chinese herbal medicine can act on HSC in different cycles, and effect proliferation and differentiation of HSC at the level of protein and molecule, then achieve the objective of recovering the hematopoietic function of bone marrow. So, the study on mechanism and effection of Chinese medicine and its effective fractions on HSC will benefited to raise the technological content of Chinese medicine study, bring effectively into full play of Chinese medicine, establish new techniques of severe disease therapy.Panax ginseng is a well-known Chinese traditional medicine in "invigorating qi", Saponins of Panax ginseng(SPG) is one of the main effective fractions extracted from Panax ginseng. Our previous study have suggested that total saponins of panax ginseng(TSPG) can markedly promote the proliferation and differentiation of human CFU-GEMM,CFU-GM, CFU-E, BFU-E and CFU-MK. To investigate deeply the effect of TSPG on purified CD34+HSC/HPC in vitro and elucidate the potential of TSPG applied in hematopoietic stem cell engineering , we have performed the following studies: 1. To establish the technique of separation, purification and identification of CD34+ hematopoietic stem/progenitor cells from human bone marrow cells and umbilical cord blood. 2. To study the effects of TSPG in combination with other growth factors on the proliferation and differentiation of CD34+ hematopoietic progenitor cells. 3. Gradual cooling methods were used to investigate the effect of TSPG on the recoverable ability from cryopreservation damage of human bone marrow hematopoietic progenitor cells. 4. To select the Epo/EpoR-mediated JAK2/STAT5 signals to investgate the signal transduction and regulation in erythropoiesis by TSPG to clarify the molecular mechanism for Panax ginseng promoting hematopoiesis. 5. To investigate the effects of GM-CSF gene transfected derminal fibroblast from human embryo on the ex vivo expansion of CD34+ cells from human umbilical cord blood. Each chapter is introduced as the followings:1. Separation, purification and identification of CD34+ hematopoietic stem/progenitor cells from human bone marrow cells and umbilical cord blood: A new sterilized separation system for purification of CD34+HSC/HPC was established by means of StemsepTM according to the strategy of negative selection on immunomagnetic separation. We used the separation system to select CD34+ HSC/HPC from human bone marrow and umbilical cord blood. The results show: The percentage of CD34+ HSC/HPC was increased from 0.5%~3.5% in MNC to 92.8~98% post-separation. The viability of cell by trypan blue exclusion was 99%~100%. The colony yield of CD34+ cells was enriched to 19 fold. The present study suggested that negative selection on immunomagnetic separation was effective in separating CD34+HSC/HPC and the availability of pure population of CD34+HSC/HPC will facilitate further study on biological characteristics and functions of human HSC/HPC.
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