中文摘要：

目的：探讨G4PAMAM／VEGFASODN复合物体外对乳腺癌细胞MDA—MB-231VEGF、VEGF mRNA表达的影响及血管内皮细胞生长的抑制作用。方法：用透射电镜观测G4PAMAM／VEGFASODN的粒径，在不同的酸碱度下观察G4PAMAM／VEGFASODN的稳定性；将G4PAMAM／VEGFASODN进行体外转染，流式细胞仪测定其转染率，激光共聚焦检测转染阳性细胞，MTT法检测转染后细胞的存活率；免疫组化检测VEGF蛋白的表达，RT—PCR检测VEGFmRNA的表达，MTT法测定此复合物对血管内皮细胞生长的抑制作用。结果：G4PAMAM／VEGFASODN的直径约10nm，呈较均匀的网状排列；酸碱度在5到10的范围内具有较高的稳定性，不同电荷比的G4PAMAM／VEGFASODN均没有出现被解离的现象；48h时G4PAMAM／VEGFASODN组在1：40的条件下转染率明显高于脂质体组；各组转染物均对细胞无明显毒性；VEGF蛋白在G4PAMAM／VEGFASODN转染后的MDA—MB-231细胞胞浆中的染色强度明显减弱，阳性表达率显著降低，VEGFmRNA的表达也受到有效的抑制。结论：G4PAMAM／VEGFAsODN复合物稳定性好、转染率高，是一种有良好应用前景的新型纳米载体基因转移系统；G4PAMAM／VEGFASODN复合物能够高效特异地抑制目的基因VEGF的表达，为进一步进行体内动物实验提供了依据。

英文摘要：

Objective： To investigate the effect expression of VEGF and VEGF mRNA in MDA inhibition of vascular endothelial cells. Methods： of G4PAMAM/VEGFASODN compound on -MB-231 breast cancer cells and the growth The diameter of G4PAMAM/VEGFASODN granule was measured by transmission electron microscopy,and its stability under different pH was also observed. The efficiency of transfection in vitro was detected by flow cytometer and the positively transfected cells were detected by laser scanning confocal microscope. The survival rate and the inhibitory rate of vascular endothelial cells were determined by MTT assay. The expression of protein VEGF was detected by immunohistochemical method and the expression of VEGF mRNA was detected by RT-PCR. Results.. The diameter of G4PAMAM/VEGFASODN granules was about 10nm and it arranged as homogeneous netlike. Under pH 5-10 G4PAMAM/ VEGFASODN presented highly stable and no dissociation was observed with different charge ratios. The 48-hour transfection rate of G4PAMAM/VEGFASODN in charge ratio of 1 ： 40 was significantly higher than that of the lipofectamine group. None of the transfection products in each group showed cell toxicity. The staining of VEGF protein in the cytoplasm of MDA MB-231 cells after G4PAMAM/ASODN transfection weakened markedly, and the positive expression rate decreased. Meanwhile,the VEGF mRNA expression was also decreased. Conclusion： With good stability and transfection rate, compound G4PAMAM/VEGFASODN can be a promising new nanometer vector of gene transfer system. The G4PAMAM/VEGFASODN can inhibit the expression of VEGF gene specifically and efficiently, which may be used for in vivo animal experiment.