Osteoinductive Activity of DFDBA Materials versus Growth Factors on Gene Expression of MG-63 Cells: An In Vitro Study

Guided bone regeneration using demineralized freeze-dried bone allograft (DFDBA) and growth factors (GFs) is a current goal in implant dentistry because of their potential osteoinductive abilities. Regarding controversial results, the purpose of this study was to compare the osteoinductivity of three different DFDBAs from two different banks with two different GFs: transforming growth factor-beta (TGF-β) and platelet-derived growth factor (PDGF). MG-63 osteoblast-like cells were exposed to two different concentration of commercial DFDBAs (10 and 20 mg/mL) and growth factors (5 and 10 ng/mL). Cell viability and proliferation were evaluated using a quantitative MTT assay (24 and 72 hours after treatment). For the assessment of cell differentiation, the expression of osteogenic marker genes was evaluated using quantitative real-time polymerase chain reaction 72 hours after treatment. Cell viability and proliferation in different concentrations of GFs was similar but significantly different in the DFDBA groups. Although water-soluble materials released from DFDBAs reduced viability and even caused cytotoxicity (viability <70%) in first 24 hours after treatment, increased viability and proliferation were seen after 72 hours. Dose-dependent up-regulation of osteocalcin (OC) was seen in the two DFDBA groups and in TGF-β-treated cells. In contrast, dose-dependent down-regulation of OC was seen in PDGF-treated cells. The results show that induction of osteogenic differentiation (osteoinduction) at higher concentrations of DFDBAs (with the exception of one group) is more rapid than in the GF groups. In addition, TGF-β at higher concentrations but PDGF at lower concentrations were associated with better results.