Abstract:

Vascular diseases are one of the leading causes of death in China and even in the global population. Currently, common vascular grafts can be broadly divided into autologous vascular grafts, xenogeneic vascular grafts as well as vascular tissue engineering. Autografts are the gold standard in a clinical surgery, but they are unfavorable for the subsequent treatment of patients because of repeated surgeries and poor sources. In addition, easily producing rejection reaction with the body to cause damages due to poor biocompatibility, xenogeneic vascular transplantation not only has immunogenicity, but may also spread diseases to cause infection. Therefore, it is difficult to meet the requirements of vascular transplantation. However, the rapid development of tissue engineering technology provides a new solution for the treatment of vascular diseases.

At present, all the vascular scaffolds developed at home and abroad have their advantages and disadvantages, which often require multiple composite materials to achieve advantage complementation. Traditional decellularized scaffolds may have lower cell permeability due to their dense extracellular matrix network. Recently, it has been shown that decellularized vascular matrix gel (DVMG) is a promising material that not only has the advantage of decellularized vascular matrix (DVM), but can also control the mechanical properties of vascular scaffolds by changing the concentration or cross-linking density of hydrogels. This study complexes DVMG with polycaprolactone (PCL), and the resulting composite scaffolds can retain the vascular regenerative properties of the native vascular matrix and overcome the deficiency its rapid degradation, expanding its applications in the field of tissue engineering. DVM powder is obtained through decellularization and delipidation of fresh porcine aorta in a series of treatments, after which the DVMG is enzymatically dissociated, the PCL solution configured with glacial acetic acid is mixed with DVMG with different proportions, and the molds are repeatedly wrapped by the mixed solution after being cooled at a room temperature to obtain different groups of composite vascular scaffolds.

In this study, a total of four groups of DVMG/PCL scaffolds are prepared. The scaffolds are observed by a scanning electron microscope (SEM) to have a relatively uniform surface with obvious pores in the cross-sectional structure, which is beneficial to cell adhesion and migration. The tensile modulus values of pure PCL scaffold and the other three scaffolds with a ratio of DVMG:PCL at 1∶1,1.5∶1 and 5∶1 detected by mechanical tensile experiments are in an order of 49.00±9.52 MPa, 46.29±3.08 MPa, 38.77±2.07 MPa and 31.18±2.80 MPa respectively. The in vitro degradation experiments show that all of the four groups of scaffold materials have some degradation abilities, and the degradation rate is related to the content of DVMG. By changing the ratio of DVMG to PCL, composite vascular scaffolds with different mechanical properties and degradation properties can be produced. Compared with the pure PCL scaffold, the higher the content of DVMG in the composite scaffold is, the lower the stiffness of the scaffold is, and the faster the degradation rate is, which shows a better overall performance of the DVMG/PCL scaffolds. The findings are of great reference value to the further application of DVM and DVMG and the improvement of the biological response of polymeric materials.