靶向转染纳米tPA基因预防狗冠脉搭桥术吻合口血栓形成和再狭窄的研究

目的探讨构建的白蛋白纳米组织型纤溶酶原激活物（tPA）基因质粒超声微泡载体靶向转染心肌组织预防冠状动脉搭桥术后吻合口再狭窄。方法建立狗冠状动脉搭桥术吻合口再狭窄模型,制备tPA基因白蛋白纳米超声微泡,超声波靶向转染心肌并获得tPA表达,观察对吻合口局部血栓形成、血管内膜细胞增殖细胞核抗原（PCNA）和PDGF-BmRNA表达以及内膜增生的影响。结果成功靶向心肌转染tPA基因并获得了tPA基因有效表达。显著减少了动脉搭桥吻合口血栓形成,抑制率100%。抑制冠状动脉吻合口处内膜细胞表达PCNA和PDGF-B mRNA。显著减少局部血管内膜厚度、内膜面积,使吻合口狭窄率减少68.29%。结论白蛋白纳米-超声微泡载体靶向转染tPA基因可预防狗冠状动脉搭桥术后吻合口血栓形成和再狭窄,这为人冠状动脉搭桥术吻合口血栓形成和再狭窄的防治提供实验基础。

Targeting transfection of tissue-type plasminogen activator gene to prevent the thrombosis and vascular anastomotic restenosis after coronary bypass

Objective To elucidate the effect of constructed ultrasound microbubble crosslinked to albium nanoparticle packaged with tissue-type plasminogen activator（tPA） gene plasmid on targeting transfection to heart tissue to prevent the thrombosis and vascular anastomotic restenosis after coronary bypass.Methods A dog model of vascular anastomotic restenosis after coronary bypass was constructed.A highly expressive gene plasmid for tPA was constructed and packaged into prepared namoparticle with bovine serum albumin.This albium nanoparticle packaged with tPA gene plasmid was crosslinked to an ultrasound microbubble prepared with sucrose and bovine serum albumin to form the vector system for tPA gene transfection.Using ultrasound for targeting transfection for it at the same time of coronary bypass,the tPA expression was made in heart tissue.The effects of this gene on thrombosis in local anastomotic vessels,the expressions of proliferating cell nuclear antigen（PCNA） and platelet-derived growth factor B（PDGF-B） mRNA by vSMCs and the proliferation of vascular intima was observed with methods of routine pathological,immuno-histochemical staining,in situ hybridization and morphometry.Results The targeting transfection tPA gene to the cardiocytes and effective expression of tPA protein by local heart tissue were successfully made.This expressive product could significantly inhibit expressions of PCNA and PDGF-B mRNA by intimal vSMCs,markablely reduce local intimal thickness,area,prevent the anastomotic thrombosis with inhibited rate of 100% and restenosis with reduced stenitic rate of 68.29%.Conclusion The vector system of ultrasound microbubble crosslinked to albium nanoparticle packaged with tPA gene plasmid could used to prevent the thrombosis and experimental anastomotic restenosis after coronary bypass,which provide the bases for prevention of human thrombosis and restenosis after coronary bypass.