| Leukemia is a malignant hematopoietic tumor which threatens the health of humanity. Until now, traditional chemotherapy and radiotherapy are still the main therapies in leukemic treatment. But the therapy have many side effects and ratio of relapse is very high. What's more, it greatly damages the immunity and hematopoiesis. In recent years, finding effective ingredients of induced differentiation has become the hope for the therapy of leukemia. More and more scientists think that the Chinese traditional medicines can play an important role in the therapy for it's two sides affection on body. Finding natural effective ingredients extracted from Chinese traditional medicine, which has both the effects of promoting normal hematopoiesis and inducing the leukemia cell differentiate towards normal states, has become the new hope of leukemia therapy. It is an well-known that Panax Ginseng is Chinese traditional important medicine on "buqi",it has been used in clinical treatment for thousands of years, Ginseng polysaccharide(GPS)is one of the main effective ingredients extracted from Ginseng. The "qixue" theory of Chinese medicine consider that the Ginseng has the effect of "buqi" and promoting hematopoietiesis. Our previous study suggested that GPS is the effective ingredients of promting hematopoiesis, can markedly promote the proliferation and differentiation of murine multipotential hematopoietic stem cell(CFU-S) ,murine and human hematopoietic progenitor cells (BFU-E,CFU-GM,CFU-MK,CFU-E), and also can inhibit the proliferation of leukemia cells. At present, molecular biological mechanism for GPS have almost no reports about the induced differentiation of leukemia cell. The human erythroleukemia K562 cell is a low-differentiated blast cell with differentiating potentialities towards erythrocyte,monocyte,granulocyte or megakaryocyte lines ,it is the idea model of research the proliferation and differentiation of leukemia cell. In this study ,by using techniques of modern biology, systemly explore the effect of GPS on proliferation and differentiation of K562 cell, our purpose is to clarify the modern biological mechanism for GPS "buqi and sheng xue" and inhibiting tumor, and to provide the theoretical basis and theexperimental evidence for study natural inducer . By using techniques of 5-diphenyl tetrazolium bromide (MTT) and flow cytometry(FCM), the effects of GPS on proliferation and cell cycle distribution of K562 are detected . Employing light, electron microscopy and photo analysis , we observed the morphological changes of K562 cells induced by GPS(including nucleus mature aspiration , nucleus/cytoplasm ratio , cell diameter, cell volume and so on) . Cytochemistry is employed to study the effects of GPS on the expressions of hemoglobin,myeloperoxidase, α-naphtholacetate escerase. By the ways of immunocytochemistry, the effects of GPS on expressions of surface differential antigen(CD,HIR2)and oncogene proteins (c-myc, bcl-2) have been studied. We also used the methods of TUNEL and Fas,Fas-L to study the apoptosis of K562 cells treated with GPS. By techniques of using immunocytochemistry, RT-PCR , Western blot, we observed the expression of EPO,GM-CSF protein and it's receptor protein of K562 cells induced by GPS. Signal transduction pathways of proliferation and differentiation of K562 cells induced by GPS are detected . By using genechip techniques, we scalp and analyze the expression of differential gene of K562 cells induced by GPS. After successfully copy the leukemia animal model(SCID mice) by transplanting human leukemia cells (K562), we observe the effects of GPS on leukemia mice.Our experimental results indicted that: 1. The effects of GPS on the inhibitory proliferation and inducing differentiation of human leukemia cells line (k562) 1.1 GPS has two different effects on normal CFU-Mix and K562 cells: GPS can markedly stimulate the proliferation of CFU-Mix at the concentration of 10-100 μg /ml, ex vivo(previous research data);GPS also can significantly inhibit the proliferation o... |
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