激光心肌血管重建术结合转染血管内皮生长因子基因治疗心肌缺血的实验研究

Transmyocardial laser revascularization combined with VEGF gene therapy for myocardial ischemia

目的 探讨激光心肌血管重建术 (transmyocardiallaserrevascularization ,TMLR)与转血管内皮生长因子 (vascularendothelialgrowthfactor,VEGF)基因相结合能否更有效地改善心肌缺血。方法在猪的急性心肌缺血模型上行TMLR ,实验组在孔道边缘心肌内注射VEGF裸质粒 2mg,对照组注射等体积灭菌水。术后 4周、8周取材。RT PCR、免疫组化检测VEGFmRNA、蛋白表达 ;碱性磷酸酶组化法显示新生血管。结果 术后 4周VEGFmRNA、蛋白水平实验组高于对照组 ;8周时两组表达均显著下降。血管计数实验组 4周 (4 9 6± 11 5 ) mm2 ,对照组 4周 (2 6 4± 4 1) mm2 ;实验组 8周 (5 9 7±8 0 ) mm2 ;,对照组 8周 (2 8 7± 2 9) mm2 。实验组新生血管多于对照组。结论 与TMLR相比 ,TMLR结合转染VEGF基因能提高VEGF表达 ,促进新生血管形成。

Objective To investigate whether transmyocardial laser revascularization (TMLR) combined with vascular endothelial growth factor (VEGF) gene therapy may further angiogenesis induced by TMLR alone. Methods Acute myocardial ischemia was created in procine hearts by ligating left anterior descending artery with preceding ischemia preconditioning. Twelve pigs were randomized to TMLR+VEGF group ( n = 7) or TMLR alone group ( n = 5). Four to five transmural channels were performed on ischemic myocardium with Nd:YAG laser (λ=1 064 nm). Optical fiber diameter was 1 000 μm. Intramyocardial injections were placed in the vicinity of channels. The TMLR+VEGF group used pcD2/VEGF 121 expression plasmid (800 μl, 2 5 mg/ml). The TMLR alone group used sterile distilled water (800 μl). Animals were sacrificed 4 weeks or 8 weeks post therapy. VEGF mRNA was detected with RTPCR. VEGF protein was detected with immunohistochemistry. Blood vessels were stained with alkaline phosphatase histochemistry. Results TMLR+VEGF group has a significant higher level of VEGF mRNA and protein expression compared with TMLR alone group 4 weeks post therapy. Eight weeks post therapy VEGF mRNA and protein decreased significantly in both groups. Vascular density was significantly elevated in TMLR+VEGF group compared with TMLR alone group (4 weeks post therapy: TMLR+VEGF group 49 6±11 5/mm 2 ,TMLR alone group 26 4±4 1/ mm 2; 8 weeks post therapy: TMLR+VEGF group 59 7±8 0/mm 2; TMLR alone group 28 7±2 9/mm 2). Conclusion Compared with TMLR alone, TMLR combined with VEGF gene therapy can enhance VEGF expression and further angiogenesis.