中文摘要：

目的通过构建血管内皮生长因子（VEGF）基因的真核表达质粒，并将其转入受照小鼠机体，研究VEGF蛋白表达对放射损伤的救治作用及其分子机制。方法昆明种小鼠通过随机化分组表法随机分为正常对照组、单纯照射组和转基因组。转基因组应用VEGF重组质粒进行肌肉注射，注射后24h接受8Gy X射线照射，进行小鼠临床表现和死亡率观察。并于照后不同时间处死动物，进行组织器官病理学和原位胸腺和脾细胞凋亡检测。结果用PCR方法从pSP73／HVECF165质粒扩增得到VEGF165基因片段，经双酶切后与酶切的pcDNA3．1载体连接，构建重组质粒pcDNA3．1／VEGF165，经电泳和测序表明序列与GeneBank完全一致。X射线8Gy照射小鼠，单纯照射组14d内死亡率为64％，而转基因组为36％，两组比较差异有统计学意义（t=3．92，P〈0．05）。转基因组小鼠胸腺和脾组织的细胞凋亡率显著降低（t=3．11、3．53，P〈0．05），放射病理损伤明显改善。结论成功构建了重组质粒pcDNA3．1／VEGF165重组质粒转基因治疗可显著降低严重辐射损伤小鼠的死亡率，显著减低胸腺和脾脏细胞凋亡率，明显改善免疫器官的病理变化。

英文摘要：

Objective To study the effect of VEGF gene expression in the treatment of radiation damage, and to explore its molecular mechanism by transferring eukaryotic expression plasmid containing VEGF gene into irradiated mice cells. Methods Normally Kunming mice were divided randomly into three groups as control group, irradiated group and transferred VEGF gene group. The mice were administered with 8 Gy X-ray exposure after intramuscular injection of VEGF recombinant plasmid in the transgenic group. The animals were killed at different times after X-ray exposure. Their clinical manifestation, mortality rate, pathology of tissues and organs and in situ apoptosis in thymus and splenic cells were observed. Results VEGF~6s gene fragments were amplified from pSP73/Hvszvj6s plasmid by PCR method,and then linked with pcDNA3. 1 vector after incision by double enzyme. The recombinant plasmid pcDNA3. I/VEGF16s was constructed. Electrophoresis and sequencing showed that the recombinant plasmid sequence was exactly the same with the data in GenBank. The mortality of irradiated group and transgenic group 14 d post-irradiation was 64% and 36% , respectively, with the statistical difference （t = 3.92, P 〈 0. 05 ）. Compared with irradiated group, the apoptosis rate in thymus and spleen cells in transgenic group were decreased significantly （t = 3.11, 3.53, P 〈 0.05）. The radiation-induced pathologic damage was obviously attenuated. Conclusions The recombinant plasmid pcDNA3. 1/ VEGF165 was successfully constructed. Transgenic treatment with recombinant plasmid can remarkably decrease the mortality and apoptosis rate of thymus and spleen cells in mice suffering from severe radiation damage, and improve the pathologic change of immune organs. VEGF transgenic technique is one of the effective methods for treating severe radiation injury.