TNF-α Activates NF-κB Signalling Pathway in MG-63 Cells on Titanium and Zirconia Implant Surfaces

Dental implant therapy is a widely used clinical procedure for restoring missing teeth in patients. Zirconia implants were introduced as an alternative to titanium implants due to their excellent biocompatibility and esthetic properties. The nuclear factor kappa B (NF-κB) signalling pathway is responsible for multiple aspects of innate and adaptive immune functions and serves as a significant and crucial mediator of inflammatory processes. The dysregulation of NF-κB activation induces pathological processes in multiple diseases. The purpose of this study was to investigate the activation of the NF-κB pathway upon stimulation with tumour necrosis factor (TNF)-α in osteoblast-like cells (MG-63) cultured on zirconia surfaces in comparison to titanium surfaces. Several methods such as immunoblot, immunofluorescence, MTT assay, and flow cytometry were used in this study. We observed that human recombinant TNF-α caused a strong activation of the NF-κB pathway on both zirconia and titanium discs and in wells without any discs. This activation was marked by the upregulation of MHC class I proteins in MG-63 cells grown on both titanium and zirconia discs; however, there was no effect on MHC class II protein expression. In summary, the present study has shown that TNF-α stimulation equally activates the NF-κB pathway in MG-63 cells cultured on both titanium and zirconia surfaces.