重组腺病毒AdEGFP/hVEGF165快速构建及在骨髓移植小鼠体内的分布和表达效率

Distribution and efficiency of recombinant adenovirus mediated hVEGF165 gene transfer in bone marrow transplanted mice

目的 研究增强型绿色荧光蛋白 (EGFP)标记的人血管内皮细胞生长因子 16 5(hVEGF16 5 )重组腺病毒载体的快速构建及在骨髓移植后小鼠体内的分布和表达效率。方法 利用细菌内质粒间同源重组法快速构建EGFP标记的重组腺病毒Ad EGFP hVEGF16 5 ;通过体外试验观察病毒的形态、滴度和安全性 ;经尾静脉注射 3× 10 8PFU的重组腺病毒给同基因骨髓移植BALB c小鼠 ,在不同时间检测重组腺病毒在小鼠体内分布和hVEGF16 5的表达。结果 通过细菌内质粒间同源重组法在短期内成功构建了复制缺陷型重组腺病毒载体Ad EGFP hVEGF16 5 ;纯化的病毒颗粒在电镜下成分均一 ,滴度可达 10 1 0 ～ 10 1 1 PFU ml。Hela细胞感染病毒后经多次传代未见细胞病变。借助于荧光显微镜在不同时期观测到小鼠心、肺、肝、脾、肾、小肠组织EGFP ;RT PCR分析和免疫组化染色显示脏器内有显著VEGF表达。各脏器未见明显毒性反应。ELISA法检测小鼠血浆中VEGF水平升高可达(86 6 6 7± 97 13)pg ml。结论 本研究结果证实细菌内同源重组法构建腺病毒载体具有高效、省时、省力的特点 ,并成功介导了hVEGF16 5基因在骨髓移植小鼠体内的安全、稳定表达 ,为今后在骨髓移植过程中开展基因治疗奠定了基础。

Objective To investigate the rapid construction of enhanced green fluorescent protein (EGFP) labeled recombinant adenovirus containing hVEGF165 and its distribution and efficiency in bone marrow transplanted mice. Methods The recombinant adenovirus Ad-EGFP/hVEGF165 was rapidly constructed by using Ad-Easy system based on the homologous recombination in bacteria,and its property was studied in vitro . Then 3×10 8PFU adenovirus was injected into BALB/c mice via the tail vein accepted syngeneic bone marrow transplantation. The in vivo distribution of adenovirus and plasma levels of VEGF were measured at different phases. Results The adenovirus Ad-EGFP/hVEGF165 was quickly constructed by homologous recombination in bacteria using AdEasy system. The purified particles were homogenous hexagon with titers between 10 10 PFU/ml and 10 11 PFU/ml. The Hela cells infected with Ad-EGFP/hVEGF165 did not show cytopathic effects after several times passages. Under the fluorescent microscope, EGFP was revealed in the heart,lung,liver,spleen,kidney and intestine of mice at different phases. RT-PCR and immunohistochemistry showed hVEGF165 expressed significantly. No obvious damages were observed in different organs by HE staining. The plasma level of hVEGF165 was up to 866.67±97.13 pg/ml. Conclusion These results suggested that the construction of adenovirus vector by homologous recombination in bacteria was an efficient and time-saving method,and high titer adenovirus could successfully mediate the safe and stable expression of hVEGF165 in post bone marrow transplanted mice. All these would make further gene therapy in bone marrow transplantation possible.