Ag2 O-TiO2 -NTs enhance osteogenic activity in vitro by modulating TNF-α/β-catenin signaling in bone marrow-derived mesenchymal stem cells

Abstract

The toxic effects of nanoparticles-silver oxide (Ag₂ O) limited its use. However, loading Ag₂ O nanoparticles into titanium dioxide (TiO₂ ) nanotubes (Ag₂ O-TiO₂ -NTs) has more efficient biological activity and safety. The aim of this study was to observe the effect of Ag₂ O-TiO₂ -NTs on osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs) and its mechanism. The enzyme activity of lactate dehydrogenase (LDH) and the expression of RUNX family transcription factor 2 (Runx2), OPN, OCN in BMSCs were detected by quantitative real time polymerase chain reaction. At 14 days of induction, the mineralization ability and alkaline phosphatase (ALP) activity of cells in each group were observed by Alizarin Red S staining and ALP staining. In addition, the protein levels of tumor necrosis factor-α (TNF-α) and β-catenin in BMSCs of each group were observed by western blot. After 14 days of the induction, the mineralization ability and ALP activity of BMSCs in the Ag₂ O-TiO₂ -NTs group were significantly enhanced compared with those in the Ag₂ O and TiO₂ groups. Western blot analysis showed that the BMSCs in the Ag₂ O-TiO₂ -NTs group exhibited much lower protein level of TNF-α and higher protein level of β-catenin than those in the Ag₂ O and TiO₂ groups.Ag₂ O-TiO₂ -NTs enhance the osteogenic activity of BMSCs by modulating TNF-α/β-catenin signaling.

Keywords: Ag2O-TiO2-NTs; TNF-α/β-catenin; mesenchymal stem cells; osteogenic activity.