Effects of vascular endothelial growth factor on osteoblasts around dental implants in vitro and in vivo

Abstract

Vasculogenesis is a pivotal procedure during dental implant osseointegration and bone repair process. Vascular endothelial growth factor (VEGF), regarded as one of the most important vasculogenesis factor, also plays a central role in bone repair, but its role around dental implants is still unknown. In the present study, rat primary osteoblasts seeded on titanium discs were tested using proliferation, enzyme-linked immunosorbent assay, Real-time PCR, and alkaline phosphatase (ALP) expression. Chicken embryo chorioallantoic membrane (CAM) was used to test the vasculogenesis property. In vivo VEGF-coated implants assay was used to test the osteocalcin (OCN)- and CD31-positive cells around an implant. VEGF could significantly promote osteoblasts seeded on titanium surfaces proliferation and secretion of VEGF protein (P < 0.05); increasing of VEGF, VEGFR1, VEGFR2, NRP-1, ALP and Runx2 mRNA expression (P < 0.05); up-regulating ALP expression on days 7 and 11 (P < 0.01). Supernatant of VEGF-induced osteoblasts could promote CAM vasculogenesis (P < 0.05). In vivo, VEGF-coated implants could promote OCN- and CD31-positive cells around bone lacunas. The present study shows that VEGF could induce primary rat osteoblasts proliferation, VEGF protein secretion, ALP expression, and VEGF-related mRNA expression in vitro. Osteoblasts co-cultured with VEGF could promote neovascularization in chicken embryos. In the in vivo experiments, coating the implant with VEGF could promote osteoblasts and endothelial cell expression.