Effect of fluoride on proliferation, differentiation and mRNA expression of osteoprotegerin and receptor activator of nuclear factor κβ ligand in mouse osteoblasts

Abstract

Objective To investigate the effect of sodium fluoride(NaF) on proliferation, differentiation and the mRNA expression of osteoprotegerin (OPG) and receptor activator of nuclear factor κβ ligand (RAN KL) of mouse osteoblasts. Methods Osteoblasts were isolated from calvarias of Kunming mice born in 1 - 2 d and cultured. Various concentrations of NaF(0, 10-8, 10-7, 10-6, 10-5, 10-4, 10-3mol/L) were added to the culture medium, the proliferation and activity of alkaline phosphatase(ALP) was determined after 72 h or 120 h. The expression of OPG mRNA and RANKL mRNA was analyzed by semi-quantification RT-PCR. Difference among groups was analyzed by One-Way AN0VA. Difference between two groups was analyzed by LSD-t test. Results There was significant difference in cell proliferation among groups after 72 h(F = 13.806, P 0.05). The ratio of RANKL/OPG decreased with increasing doses of fluoride and increased in 10-4, 10-3 mol/L groups, but there was no difference between groups(F = 1.376, P> 0.05). Conclusions A biphasic pattern of proliferation and differentiation has been induced in mouse osteoblasts, which manifests stimulation effect in low doses and suppression in higher doses. Low doses of sodium fluoride suppress differentiation and maturation of osteoblasts by increasing expression of OPG mRNA, while high doses of sodium fluoride enhance differentiation and maturation of osteoblasts by decreasing expression of OPG mRNA. Key words: Fluoride; Osteoblasts; Osteoprotegerin; Receptor activator of nuclear factor κβ ligand