Influence of fluoride on Runx2 mRNA and protein expression in rat osteoblasts

Abstract

Objective To study the influence of fluoride on the expression of Runx2 in suckling rat osteoblasts. Methods Osteoblasts obtained from calvarium of suckling Wistar rats were cultured in the media supplemented with NaF at different doses(0, 1,2 and 4 rag/L), and Runx2 Mrna expression and protein expression were evaluated by RT-PCR and ELISA, respectively. Results Runx2 Mrna expression in suckling rat osteoblasts cultured in vitro significantly increased after exposure to NaF for 48 h at different doses (0.613±0.055, 0.773±0.070 and 0.775±0.070 for 1,2 and 4 mg/L,respecfively) compared to the control (0.482±0.043 ,P< 0.05). Runx2 Mrna expression further increased after 72 h exposure to NaF(0.969±0.048,1.229±0.061,1.255± 0.063 for 1,2 and 4 mg/L, respectively) ,which is significantly higher than the control(0.724±0.036,P<0.05) and corresponding groups at 48 h. NaF doses and exposure time exhibited a significant synergistic effect on Runx2 Mrna expression (P<0.05). Similarly, NaF also enhanced Bunx2 protein expression in suckling rat osteoblasts cultured in vitro. Significant differences were observed between groups exposed to NaF (1,2 and 4 rag/L) and control at48 h post-exposure (0.141±0.007, 0.143±0.008, 0.143±0.011 vs 0.129±0.012, P<0.05) as well as 72 h post-expesure(0.156±0.014, 0.168±0.018, 0.162±0.0100 vs 0.137±0.016, P<0.05). In addition, Runx2 protein expression at 72 h post-exposure was significantly higher than that at 48 h. Conclusions The results suggested that NaF could increase Runx2 expression in suckling rat osteoblasts with a synergistic effect between the doses and exposure time. Key words: Runx2; Sodium fluoride; Osteoblast; Reverse transcription polymerase chain reaction; Enzyme-linked immunosurbent assay