Abstract: Objective: To explore the potential role of myeloid-derived suppressor cells (MDSC) in the pathogenesis of this disease by establishing a mouse model of Bisphosphonate-related of osteonecrosis of the jaw (BRONJ). Methods: BRONJ-like disease was induced in C57BL/6 mice by intravenous injection of zoledronate to observe gingival healing and alveolar bone repair. In addition, flow cytometry was used to detect the changes in the proportion of MDSC and their subgroups in peripheral blood of BRONJ mice. Results: The extraction cavity of BRONJ mice did not completely heal, showing the empty alveolar fossa. Micro-CT manifested that the extraction socket had scattered high-density images. HE staining showed the absorption of trabecular bone surrounded by multinucleated giant cells. The proportion of MDSC and their subgroups in the peripheral blood of mice was significantly reduced. Conclusions: MDSC differentiation in BRONJ mice model was inhibited which was used to further confirm the mechanism of immune dysfunction in BRONJ.

Key words: Bisphosphonate-related osteonecrosis of the jaws, Myeloid-derived suppressor cell, monocytes