Study on Inducing Angiogenesis of Regenerated Silk Fibroin Film Modified by the Ad-Ang-1 Transgenic Fibroblasts

To research the regenerated silk fibroin film (SF) as a biomedical material, we investigate the effects of its modified by the fibroblasts infected by adenovirus mediated-Ang-1 (Ad-Ang-1) on inducing angiogenesis. The WI-38 fibroblasts cultured on the SF and no any film were infected with Ad-Ang-1, they were also infected with adenovirus-green fluorescent protein (Ad-GFP) and treated by phosphate buffered saline (PBS). We observed the cell growth morphology and detected the expression of aim gene Ang-1. The effect of Ad-Ang-1 on the angiogenesis of the chick chorioallantoic membrane was assessed by chorioallantoic membrane (CAM) assay and that inducing corneal neovascularization through the SF modified by transgenic cells implanted into the corneal stroma of rabbits. The expression levels of vascular endothelial growth factor (VEGF), fibroblast growth factor 2 (FGF2), and platelet-derived growth factor (PDGF) were detected by enzyme-labeled immunosorbent assay (ELISA).We demonstrated that adenovirus vector can be efficiently infected into fibroblasts cultured on the SF; the expression levels of Ang-1 in WI-38 cells infected by Ad- Ang-1 cultured on the SF enhanced(P<;0.05);CAM assay suggested that the SF modified by Ad-Ang-1 transgenic fibroblasts had a marked promoting angiogenesis activity. The SF modified by transgenic cells implanted into the corneal stroma of rabbits can induce corneal neovascularization. The ELISA result showed that the VEGF, FGF2, and PDGF expression increased significantly in the Ad-Ang-1 transgenic WI-38 fibroblasts (P<;0.05). The possible reasons why the SF modified by transgenic fibroblasts can induce angiogenesis may be that it can express VEGF and Ang-1 with highly biological activity and increase the expression of FGF2 and PDGF which are related to angiogenesis. It lays a foundation for future research on the biomedical materials of inducing angiogenesis.