Enterococcus faecalis promotes orthodontic tooth movement in mice by M1-like macrophage polarization.

OBJECTIVE

Probiotic-mediated therapy has potential role in influencing bone remodeling. In this study, we aim to explore the impact of microorganisms on accelerating orthodontic tooth movement (OTM).

DESIGN

Potential probiotic candidates were identified through 16S rRNA gene sequencing in a mouse model of OTM. To investigate the osteoimmunomodulatory impact, primary mouse periodontal ligament cells (PDLCs) were cultured with or without conditioned media (CM) derived from macrophages post-incubation with microorganisms. The microbiota of the mice has be depleted using broad-spectrum antibiotic mixture (ABX) before being administered with microorganisms. The distance of OTM have been measured, and the alveolar bone have been analyzed using micro-CT and immunohistochemical staining.

RESULTS

The relative abundance of Enterococcus faecalis (E. faecalis) increased in the move group. The results demonstrated that E. faecalis increased the number of M1-polarized macrophages, and a decreased osteogenic level in PDLCs treated with CM E. faecalis group. The distance of OTM in ABX mice has been increased via administration of E. faecalis.

CONCLUSIONS

This study has explored the potential effects of E. faecalis administration on the OTM process through immunomodulation. By elucidating this mechanism, our work lays the groundwork for developing future microorganism-interventions that could safely accelerate OTM with non-invasive strategy.