Effects of implant surface microtopography on osteoblast gene expression

Abstract

The promotion of osteoblast attachment and differentiation has been evaluated on various implant surfaces. However, the effects of different implant surface properties on gene expression of key osteogenic factors are not fully understood. The objectives of this study were to evaluate how topographical effects on titanium surface alter the expression of bone-related genes and transcription factors. Osteoblasts were cultured on titanium disks prepared with a titanium dioxide grit blasting (TiOBlast) or grit blasted and etched with hydrofluoric acid (Osseospeed), grit blasted and etched (SLA-1), or grit blasted, etched and rinsed with N2 protection and stored in isotonic NaCl (SLA-2) commercially pure titanium implant discs. High-density cultures of human mesenchymal pre-osteoblastic cells (HEPM 1486, ATCC) were grown for 72 h and real-time PCR used for quantitative analysis of alkaline phosphatase (ALP), core-binding factor alpha1 (Cbfa1), Osterix, Type I Collagen, Osteocalcin and bone sialoprotein II gene expression. Real-time PCR showed significant (P<0.001) increases in ALP gene expression in osteoblasts grown on SLA-2, relative to all other surfaces. Cbfa1/RUNX-2 gene expression was significantly (P<0.01) increased on Osseospeed and TiOBlast surface as compared with SLA-1 and SLA-2 surfaces. The expression of Osterix had a trend similar to that of Cbfa1. In conclusion, implant surface properties may contribute to the regulation of osteoblast differentiation by influencing the level of bone-related genes and transcription factors in human mesenchymal pre-osteoblastic cells.