Abstract: Objective To investigate the effect of high concentration of zoledronate on proliferation, apoptosis and osteogenic differentiation of healthy human periodontal stem cells. Methods Human periodontal ligament stem cells （hPDLSCs）were isolated from health tissues and exposed to zoledronate with different concentrations (0 μmol/L, 5μmol/L，10 μmol/L) in vitro. Cell proliferation ability was detected using CCK-8 kit and flow cytometry was applied to identity cell apoptosis. ALP staining and Alizarin red staining were used to evaluate the osteogenesis differentiation of hPDLSCs. Real-time PCR were used to measure the gene expression of COL1A1 and OCN and immunofluorescence was used to detect the levels of protein expression of COL1A1 and OCN. Osteogenesis was analyzed with ectopic osteogenesis in nude mice. Results Zoledronate inhibited proliferation of hPDLSCs in a dose dependent manner. Flow cytometry results indicated higher proportion of apoptosis cells in zoledronate treated groups. ALP staining and Alizarin red staining both revealed decreased osteogenesis differentiation ability in zoledronate treated groups. Significant down-regulation of the levels of mRNA expression and protein expression in COL1A1 and OCN were also found in zoledronate treated groups. Conclusion High concentration of zoledronate significantly inhibited the proliferation and osteogenic differentiation of hPDLSCs and induced their apoptosis.

Key words: zoledronate, human periodontal ligament stem cell (hPDLSCs), Osteonecrosis of the jaw, Apoptosis, Osteogenesis differentiation