Efeito da anodização com CaP em superfícies de titânio sobre a resposta de osteoblastos

Abstract

The aim of this study was to investigate the influence of anodization with CaP incorporation on titanium surfaces in the process of osteogenesis in vitro. For this, human fetal osteoblasts (hFOB 1.19) were seeded over commercially pure titanium disks (8x4 mm) with three surface treatments (n= 21 disks/group): machined (Screw®), acid etching (Porous®) and anodized with calcium phosphate (CaP) incorporation (Vulcano®). After 3, 7 and 14 days of culture, the following parameters were evaluated: cell viability (MTT); gene expression of Runx2, alkaline phosphatase (ALP) and bone sialoprotein (BSP) (Real time RT-PCR); and quantification of BMP-2 e TGF-β1 (ELISA). The association between growth factors secretion and Runx2 expression, as well as between this transcription factor with ALP/BSP expressions was also evaluated. Results concerning cell viability showed a greater number of viable cells for rough surfaces, especially for Porous and Vulcano at 7 days (p=0.005) and for Porous at 14 days (p<0.001). There were significant differences regarding gene expression of Runx2, ALP and BSP for all surfaces at 7 days (p<0.05), but with greater fold induction for Porous and Vulcano. Regardless of the surface treatment, a strong positive correlation was observed between Runx2 and ALP/BSP expressions (p<0.0001). Growth factors secretion was not significantly affected by surface treatment in any experimental period (p> 0.05). Vulcano modulated significantly the correlation between the TGF-β1 secretion and Runx2 expression (p<0.05), which did not happen for BMP-2 or for other surfaces studied. The CaP incorporation favored the biological parameters evaluated at 7 days, but in a manner similar to the acid etched surfaces. The results presented here support the observations that surface roughness may play a more important role in determining cellular response than surface composition does.