Electrospun Fibers Loading Astragaloside And Ferulic Promote Angiogenesis

Ischemia or poor blood circulation may be caused by a lot of factors, like primary lesions and trauma. In addition, sufficient blood vessels are necessary to delivery enough oxygen and nutrients and remove metabolic waste in the fields of organizations and organ transplants, which otherwise cause necrosis of tissue and organs. It is the key that oxygen and nutrients can be inputted for survival of transplanted tissue and organs, which determined that the distance between cells and the nearest blood, should be less than200μm. Therefore, sufficient angiogenesis is very crucial for transplanted tissues and organs.Due to characteristics like large surface area, high porosity, structure similar to the extracellular matrix (ECM) and pore connectivity, electrospun fibers are profit for cell adhesion, spreading growth and tissue formation. Besides, electrospun fibers loading drugs, biologically active substances promote tissue repair and regeneration effectively. The clinical application demonstrated that traditional Chinese medicine astragalus and angelica can nourish the "Blood" and raise the "Qi", and they showed unique advantages in promoting the expression of angiogenic factors, vascular cell growth and migration of mature blood vessel formation. Electrospun fibers were applied to carry astragaloside IV (AT, the main active ingredient of astragalus) and ferulic acid (FA, the main ingredient of angelica) for tissue engineering. Vascular cell proliferation and ECM secretion were assayed to evaluate the effect of promoting angiogenesis.The best concentration and proportion of AT and FA to proliferation of human vascular endothelial cells (HUVEC) and human vascular smooth muscle cells (HUVSMC) were selected using cytotoxicity, which indicated the highest cell viability at the total concentration of5.0μg/mL and the AT/FA ratio of7/3. Then PELA nanofibers with loading of AT, FA and both of them were prepared by electrospinning. In vitro release study indicated that PELA fibers loading0.25%AT and0.5%FA cumulatively released50.5%of AT and69.1%of FA during20days, FA released slightly faster. In vitro evaluation showed that drug-loaded fibers promote cell adhesion and proliferation, and promote ECM secretion compared to blank fibers and fibers infiltrated free drug, especially when the drug ratio is7/3. In vivo research showed the fiber degradation and inflammatory responses have no significant difference between different fibers groups. There are few fibers fragments and slight inflammatory responses until the4th week. There are angiogenesis in tissue around fiber scaffold, and the vascular density increase with time in the drug-loaded fiber group. The effect of promoting angiogenesis and vascular mature by drug-loaded fibers is more obviously than blank fibers or fibers infiltrated drug.