“分子搭桥术”基因治疗闭塞性血管病的实验研究

Molecular .bypass , the application of VEGF to gene therapy of limb ischemia

目的 应用血管内皮生长因子（ＶＥＧＦ）基因治疗实验性闭塞性外周血管病。方法构建重组ＶＥＧＦ１６５基因的真核表达载体，其上游含巨细胞病毒（ＣＭＶ）启动子；通过基因缝线，向一侧髂外动脉结扎引起血管闭塞症大鼠的肌肉内转移ＶＥＧＦ基因（２００μｇ／只）；应用逆转录－聚合酶链反应，Ｗｅｓｔｅｒｎｂｌｏｔ以及免疫组织化学方法观察ＶＥＧＦ基因的表达，并通过血管造影技术观察ＶＥＧＦ基因导入大鼠体内的生物效应。结果转ｐｃＤＮＡ３／ＶＥＧＦ基因７天后，肌肉组织内ＶＥＧＦｍＲＮＡ及其表达产物明显高于对照组单纯转ｐｃＤＮＡ３组；血管造影可见大量新生血管和侧支循环的形成，在１４天和３０天时更明显，转ＶＥＧＦ基因可以明显促进闭塞性下肢血流的恢复和改善组织坏死的程度。结论肌肉内转移ＶＥＧＦ基因，通过促进血管新生和侧支循环建立，促进血流恢复，为闭塞性血管病的治疗，提供一种新的可能性──分子搭桥术。

Objective To investigate the feasibility of using VEGF gene directly for treating limb ischemia. Methods The human VEGF165 cDNA was cloned into the eukaryotic expression vector pcDNA3 under the control of cytomegalovirus immediate-early promoter/enhancer. When gene suture was used , the re- combinant plasmid was transferred into the hindlimb' s adductor of rat , of which the distal extreme of external iliac artery was ligated and the femoral artery was completely excised. With RT-PCR , Western blot , immunohistochemistry analysis , and angiography . the expression and biological effects of VEGF gene in experimental animals were investigated. Results Seven days after initiation of therapy , the transcription and expression of VEGF gene in experimental group were significantly higher than those of control groups. The results from angiography , feet temperature measuring and observation of clinical symptom showed that the transfer of VEGF gene can stimulate the formation of focal neovessles , estab- lish colleteral circulation , augment blood perfusion , and ameliorate distal limb necrosis. Conclusion These findings reveal that the ' molecular bypass' using VEGF gene may represent a potential therapeu- tic modality for treating tissue ischemia.