The grafts modified by heparinization and catalytic nitric oxide generation used for vascular implantation in rats

Small-diameter (<6 mm) vascular grafts are increasingly needed in peripheral vascular surgery but have few successes because of acute thrombosis, incomplete endothelialization and intimal hyperplasia after implantation. This study used electrospun poly(ε-caprolactone) as the matrix material. Heparin and selenium-containing catalyst-organoselenium modified polyethyleneimine were introduced through layer-by-layer assembly in order to build a vascular graft with in situ nitric oxide (NO) generation. The aim of this study was to explore the application of the graft with improved histocompatibility and biological function for vascular implantation in rats. After implantation in rats, compared to poly(ε-caprolactone), the modified grafts could promote the adhesion and proliferation of endothelial cells, and inhibit the adhesion of smooth muscle cells. The modified grafts remarkably promoted endothelialization, inhibited intimal hyperplasia and increased the ratio of alternatively activated macrophages (M2) to classical activated macrophages (M1). This work constructed a vascular graft with heparinization and catalytic NO generation for improving the vascularization, and accelerating the tissue regeneration by regulating the inflammatory response. The present study indicates that it is a promising method for regulating response and tissue regeneration of small diameter vascular grafts by a novel approach of combining heparinization and catalytic NO generation.