New method to improve the perfusion of a skeletal muscle in cardiomyoplasty -study of angiogenesis promoted by bFGF-.

组织血流量是影响骨骼肌功能的主要因素。在背阔肌成形术中，穿孔血管的结扎会导致骨骼肌移植物缺血，从而导致肌肉移植物的疲劳和性能下降。血管延迟法改善了肌肉移植物的缺血，但需要4~8周的时间，不足以提供长期的心脏辅助。为了建立改善移植物血流灌注的新方法，我们研究了血管生成因子(bFGF和VEGF)对缺血组织的影响。碱性成纤维细胞生长因子在心肌成形术中促进血管生成的实验：应用胶原热交联肝素化方法建立碱性成纤维细胞生长因子缓释系统，并将其移植于5只犬心肌成形术中的心肌和背阔肌之间。术后4周取材进行大体及显微镜检查。碱性成纤维细胞生长因子移植部位结缔组织和血管内皮细胞增多。此外，还可见许多毛细血管形成。这些结果提示：1.碱性成纤维细胞生长因子促进血管生成，改善缺血肌的血流灌注。电穿孔辅助血管内皮生长因子基因编码体注射侧支循环：将裸露的血管内皮生长因子165编码质粒肌肉注射到Wistar/ST大鼠的缺血后肢肌肉中。立即，在一半的组中加入了电刺激[EP]。通过测量与对侧肢体的血压比值[BPR]，并计算血管数量[血管造影评分；AS]来评估疗效。基因转导后BPR、AS升高，且[IM+EP]组高于[IM]组。这些结果表明，通过电穿孔提高裸露的血管内皮生长因子载体DNA对缺血组织直接IM基因转移的效率是可行的。

Tissue blood flow is the major factor of the function of skeletal muscle. In latissimus dorsi cardiomyoplasty, the ligation of perforation vessels causes skeletal muscle graft ischemia, and it contributes to the fatigue and lower performance of the muscle graft. Vascular delay methods improve the ischemia of muscle graft, but it needs 4 to 8 weeks long and not sufficient for long term cardiac assistance. To establish new method to improve the perfusion of the graft, we investigated an influence of angiogenic factors (bFGF and VEGF) on ischemic tissue.1. Experiment on the angiogenesis promoted by bFGF in cardiomyoplasty : We developed bFGF slow release system applying thermal crosslinking heparinization method of collagen, and transplanted it between myocardium and latissimus dorsi muscle in cardiomyoplasty of five dogs. Four weeks after operation, macroscopic and microscopic examination was performed. At the bFGF transplanted site, connective tissue and vascular endothelial cell were increased. Moreover, many capillary formations were seen. These results suggest that bFGF promote angiogenesis and improve the perfusion of ischemic muscle.2. Collateral circulation development by electroporation-assisted VEGF cDNA-encoding plasmid injection : A naked VEGF165-encoding plasmid was injected intramuscularly [IM] into the ischemic hind limb muscles of Wistar/ST rats. Immediately, electoporation [EP] was added in the half of the groups. The effect was assessed by measuring blood pressure ratio [BPR] comparing to the opposite limb, and counting the number of vessels [angiographic score ; AS]. After gene transfer, the BPR and AS increased, and was higher in [IM+EP] group than in [IM] group. These results suggest that the feasibility of enhancing the efficiency of direct IM gene transfer of naked VEGF plasmid DNA for ischemic tissue, by electroporation.