生长因子浓度梯度诱导细胞增殖移行对糖尿病创面愈合的影响

Diabetic wound is a chronic and refractory ulcer, which is generally due to the microcirculatory disturbances combined with the reduced levels of endogenous growth factors.Studies have shown that,if the granulation tissue barrier can be formated on the surface of wound in the early stage, it will effectively prevent the occurrence of exogenous infection, and the limited number of cells in the edge of the wound can be sustainedly stimulated and induced by the growth factors，therefore,the cells will migrate to the center of the wound quickly and directly，which promotes wound healing process..Induced technique of growth factor concentration gradient combined with targeted drug carrier systems is able to achieve the goals. In this study, we build a concentration gradient induced collagen scaffold(CGICS), which means bFGF and VEGF were binded to the scaffold from the surround to the center according to the cycle concentration gradient from low to high(CGICS-CBD-bFGF、CGICS-CBD-VEGF)by using the CBD(collagen binding domain) technique. These CGICSs are applied in pig diabetic wound model,aimed to investigate if the fibroblasts,vascular endothelial cells and epithelial cells are able to perform quickly and orderly proliferation and migration toward the wound center by inducing of the bFGF and VEGF concentration gradient, which will accelerate the formation of the granulation tissue barrier and the coverage of epithelial cells，and finally promote wound healing process..This study provides a new idea for improving the speed and quality of clinical diabetic wound healing in future.

糖尿病创面是一种慢性、难愈性创面，与创面局部微循环紊乱和内源性生长因子水平显著降低有关。研究表明,如果能够早期快速地在创面上形成肉芽屏障，就能够有效地阻止外源性感染的发生，利用创面边缘有限的细胞资源，在细胞生长因子持续作用和诱导下快速向创面中心移行，则有利于创面愈合。靶向药物承载系统和细胞因子浓度梯度诱导技术有可能实现这一目标。本研究利用CBD绑定技术,从胶原支架外周向中心按照由低到高的环形浓度梯度加载bFGF和VEGF，制成具有快速靶向修复活性的生长因子浓度梯度诱导型胶原支架（CGICS-CBD-bFGF、CGICS-CBD-VEGF），并应用于猪糖尿病创面，探讨成纤维细胞、上皮细胞、血管内皮细胞等能否在生长因子浓度梯度诱导下快速而有序地向创面中心增殖移行，从而完成肉芽屏障建立、上皮覆盖，加速创面愈合。为提高糖尿病创面愈合速度和质量提供新的思路。

慢性糖尿病创面与创面局部微循环紊乱和内源性生长因子水平显著降低有关。研究表明,如果能够早期快速地在创面上形成肉芽屏障，就能够有效地阻止外源性感染的发生，利用创面边缘有限的细胞资源，在细胞生长因子持续作用和诱导下快速向创面中心移行，则有利于创面愈合。靶向药物承载系统和细胞因子浓度梯度诱导技术有可能实现这一目标。本研究利用胶原绑定技术,从胶原支架外周向中心按照由低到高的环形浓度梯度加载bFGF和VEGF（5ng/mL、25ng/mL、100ng/mL），制成具有快速靶向修复活性的生长因子浓度梯度诱导型胶原支架（VEGF与胶原膜片的结合率为42.35%，bFGF与胶原膜片的结合率为38.23%）。经体外实验研究表明VEGF对血管内皮细胞的增殖和移行活性有促进作用，并成一定的浓度依赖关系。同样bFGF对成纤维细胞的增殖和移行活性有促进作用，并成一定的浓度依赖关系。VEGF浓度梯度对于血管内皮细胞迁移活力有促进作用，而对于血管内皮细胞的增殖活力没有明显影响。bFGF浓度梯度对于成纤维迁移活力有促进作用，而对于成纤维细胞的增殖活力没有明显影响。在体内实验中，将前期制备的胶原支架用于猪糖尿病创面，使成纤维细胞、上皮细胞、血管内皮细胞等在生长因子浓度梯度诱导下快速而有序地向创面中心增殖移行，从而完成肉芽屏障建立、上皮覆盖，加速创面愈合。该方法为提高糖尿病创面愈合速度和质量提供新的思路。