Egr-1启动子调控的造血因子基因疗法对SCID小鼠辐射防护的初步探讨

Radioprotective effect of hematopoietic growth factor gene therapy regulated by Egr-1 promoter on radiation injury of SCID mice

目的 探讨辐射诱导启动子调控的造血因子基因表达对照射后造血保护的作用。方法 将构建的携带有Egr 1启动子的Flt3配基 (FL)cDNA和增强型绿色荧光蛋白 (EGFP)cDNA双顺反子表达载体导入基质细胞后 ,联合人CD34 +细胞输入经亚致死剂量照射的重症联合免疫缺陷(SCID)小鼠体内 ,观察外周血象动态改变和人造血细胞及其基质细胞植入的变化。结果 实验组与对照组相比外周血白细胞下降幅度明显减轻 ,恢复加快 ,骨髓可见绿色荧光阳性的基质细胞 ,而各组间骨髓中CD45 +细胞、CD34 +细胞、CFU GM及骨髓有核细胞计数差异无显著性。结论 Egr

Objective To explore the radioprotective effect of the expression of hematopoietic growth factors regulated by radio-inducible promoter on radiation injury. Methods The human FL cDNA and EGFP cDNA were linked together with an internal ribosome entry site(IRES) and then inserted into the eukaryotic expression vector pCI-neo with the Egr-1 promoter(Egr-EF),and further transduced into bone marrow stromal cell lines HFCL (HFCL/EF).The HFCL/EF and CD34 + cells from human umbilical cord blood were transplanted i.v. one after the other into sublethally irradiated severe combined immunodeficient (SCID) mice.The number of peripheral blood WBC and human cells engrafted in recipent mice were detected by flow cytometry and CFU-GM assay. Results 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 WBC at early stage after irradiation.Significant diifferences were found for CD45 +,CD34 +,CFU-GM,and nucleared cells in the bone marrow. Conclusion Hematopoietic growth factor gene therapy regulated by radio-inducible promoter has radioprotective effect on radiation hematopoietic injury.;