Effect of lithium ions on cementoblasts in the presence of lipopolysaccharide in vitro

The applications of lithium ions as an agent to facilitate bone formation have been widely documented; however, the effect of lithium ions in the periodontitis model has not yet been elucidated. The aim of the present study, therefore, was to investigate the effect of single lithium ions in the presence of lipopolysaccharide (LPS). A periodontitis model was induced in cementoblasts using LPS. The cytotoxic effect of the lithium ions on the cementoblasts was studied through the MTT assay. Alkaline phosphatase analysis and alizarin red staining were performed to investigate the effect of the lithium ions on differentiation. To examine the effect of lithium ions on osteoclastogenesis, osteoprotegerin (OPG) and receptor activator of nuclear factor-κB ligand (RANKL) mRNA and protein expression levels were assessed using reverse transcription-polymerase chain reaction analysis and ELISA, respectively. Compared with the effect induced by lithium ions on normal cementoblasts, proliferation and differentiation were downregulated following the co-incubation of the cementoblasts with LPS and lithium ions. Furthermore, the lithium ions appeared to alter osteoclastogenesis by regulating the OPG/RANKL ratio. In conclusion, the present findings suggest that lithium ions can downregulate proliferation and differentiation in a periodontitis model. Further studies should be undertaken prior to the acceptance of lithium ions for use in the clinic.