Objective:In order to explore the radioprotective effects of the expression of hematopoietic growth factors regulated by radio-inducible promoter on radiation injury. Methods:The human FL (Flt3 ligand) cDNA and EGFP (enhanced green fluorescent protein) cDNA were linked together with IRES and then inserted into the eukaryotic expression vector pCI-Egr, which was constructed by substituting CMV promoter in pCIneo with the Egr-1 promoter (Egr-EF). The vector was transferred into human bone marrow stromal cell line HFCL by lipofectin. The transduced cell clones (HFCL/EF) had been selected by the addition of G418. The cells were exposed to γ-radiation by 60 Co source for 0.5-20Gy. The expressions of transduced cells were detected with FACS, Northern blot ELISA and CFU assay. The HFCL/EF and CD34+ cells from human umbilical cord blood were one after the other transplanted i.v. into sublethally irradiated severe combined immunodeficient (SCID) mice. The white blood cell amount in peripheral blood and human cell engrafted in recipent mice were detected by flow cytometry and CFU-GM etc. Results:The activity of EGFP in transduced cells increased by 3.1 fold as compared to non-transduced cells at 18h after exposure to 2.5Gy. The amounts of secreted FL in serum-free supernatants of Egr-EF increased by 605.46±107.21pg/ml, which were significantly higher than the control group (214.45±35.61pg/ml). The effects of FL in HFCL/EF cultural supernatants on expansion of CD34+ cells derived from cord blood in the presence of SCF, IL-6 and IL-3 were also studied. The results showed that at day 10 of culture the number of CD34+ cells increased by 173. 09±11.58×103/ml, which was significantly higher than that of non-radiation group(68. 04± 13. 73 × 103/ml). It showed that radiation can enhance the ability of the supernatants containing FL of HFCL/EF to expand early hematopoietic progenitor cells and protect hematopoietic cells from radiation-injury effects. The HFCL/EF and CD34+cells from human umbilical cord blood were one after the other transplanted i. v. into sublethally irradiated severe combined immunodeficient (SCID) mice. In contrast to two control groups (HFCL and HFCL/F), HFCL/EF (the Egr-1 regulatory element-drived expression of FL gene therapy) resulted in a proportionally obvious increase in the number of the white blood cell at early stage after radiation, while no significant differences were found for CD45+ 、CD34+ cells in bone marrow cells. In contrast to two control groups (HFCL and HFCL/F), HFCL/EF (the Egr1 regulatory element-drived expression of FL gene therapy) resulted in a proportionally obvious increase in the number of the white blood cell at early stage after radiation, without significant differences being found for CD45+、CD34+ 、CFU-GM and marrow nucleared cells in bone marrow cells. Conclusions:The results suggested both in vivo and in vitro use of the gene therapy of FL gene regulated by Egr-1 promoter could protect hematopoiesis from irradiation-induced damage.

Turning Marrow into Muscle

In unexpected testimony2 to the versatility3 of the body's cells,researchers have found they can make bone marrow cells turn into muscle, causing mice with muscular dystrophy4 to produce correctly working muscle cells. The experiment suggests that a form of bone marrow transplant- - a well established surgical procedure5- - could in principle treat patients with a variety of diseases.

Recent studies have demonstrated that intravenous transplantation or local injection of bone marrow cells can induce unexpected changes of their fate. The results of these experiments showed that after transplantation or injecton, some of tissue specific somatic cells such as hepatocytes, skeleton, cardiac muscle cells and brain cells expressed the donor cell-specific genes, such as Y chromosome. There are two hypotheses that can explain this phenomenon. One is bone marrow stem cell transdifferentiation and the other is spontaneous cell fusion.

流行性出血热病毒对人体骨髓细胞作用的研究

本文应用免疫荧光染色技术及组织培养技术,结合细胞学检查,研究了流行性出血热(EHF)病毒对骨髓细胞的作用.检测了51例患者骨髓细胞的病毒抗原,37例呈现阳性.抗原从第一病日即出现,持续至第十一病日.用VeroE6细胞从10份患者骨髓细胞中分离病,10份全部阳性.细胞学观察见巨核细胞有成熟障碍,并在细胞胞浆扩张的内质网及高尔基氏体腔内观察到到病毒样颗粒.根据实验结果,认为EHF病毒可侵入骨髓细胞中,并可能引起巨核细胞成熟障碍及免疫细胞发育异常.

流行性出血热病毒对人体骨髓细胞作用的研究

本文应用免疫荧光染色技术及组织培养技术,结合细胞学检查,研究了流行性出血热(EHF)病毒对骨髓细胞的作用.检测了51例患者骨髓细胞的病毒抗原,37例呈现阳性.抗原从第一病日即出现,持续至第十一病日.用VeroE6细胞从10份患者骨髓细胞中分离病,10份全部阳性.细胞学观察见巨核细胞有成熟障碍,并在细胞胞浆扩张的内质网及高尔基氏体腔内观察到到病毒样颗粒.根据实验结果,认为EHF病毒可侵入骨髓细胞中,并可能引起巨核细胞成熟障碍及免疫细胞发育异常.