Effects of vascular endothelial growth factor on MC3T3-E1 cell line

Abstract

AIM: Bone support and blood supply are necessary for effective orthodontic tooth movement. Osteogenesis and angiogenesis are closely correlated. Vascular endothelial growth factor (VEGF) is believed to play a critical role in skeletal development including mandibular condylar growth, by enhancement of angiogenesis. This aim of this study was to investigate whether VEGF has any direct effect on increasing bone cell activity, in an attempt to better understand how VEGF promotes bone remodelling. MATERIALS AND METHOD: A preosteoblastic cell line, MC3T3-E1, was cultured with and without VEGF in vitro. The cells in both the control and test groups were collected at different culture time points of 24, 48 and 72 hours (n = 3 for each time point). Real-time polymerase chain reaction (PCR) was carried out to quantify the expressions of two markers related to bone formation [alkaline phosphatase (ALP) and osteocalcin (OCN)] and two factors related to osteoclastogenesis [osteoprotegerin (OPG) and receptor activator of nuclear factor kappa ß ligand (RANKL)] at the mRNA level. RESULTS: The expression of OPG significantly decreased by 7 per cent compared with the control at 24 hours (P < 0.001), while it increased by 133 per cent at 72 hours (P < 0.001). RANKL remained unchanged at all three time points (P > 0.05). ALP was upregulated by 73 per cent at 24 hours (P < 0.001), but decreased by 14 and 41 per cent at 48 and 72 hours, respectively (P < 0.05). OCN showed the same trend of expression change as that of OPG, which was down-regulated by 41 per cent at 24 hours but upregulated by 149 per cent at 72 hours (P < 0.001). CONCLUSION: VEGF promotes bone remodelling by direct effects on osteoblastic cells via regulating gene expressions of ALP, OCN and OPG.