Combined effect of fluoride and arsenate on gene expression of osteoclast differentiation factor and osteoprotegerin.

OBJECTIVE To study the combined effect of fluoride and arsenate on the expression of SD rat osteoblastic osteoclast differentiation factor (ODF) mRNA and osteoprotegerin (OPG) mRNA. METHODS Osteoblasts were obtained by enzymatic isolation from newborn SD rats. A factorial experiment was performed. Osteoblasts were exposed to NaF (0.5 mmolF/L, 4 molF/L) and Na3AsH2 (12.5 micromolAs/L and 200 micromolAs/L) separately or F plus As and cultured for 48 h. The gene expression of osteoblastic ODF and OPG was observed by RT-PCR. RESULTS The expression of ODF mRNA increased in F0.5, F4 groups compared with control group and two groups of F0.5As200, F4As200 compared with As200 group, and decreased significantly in groups of F4Asl2.5, F0.5As200, and F4AS200. The expression of OPG mRNA decreased in groups of F4, As200, F4As12.5, F0.5AS200, and F4AS200. CONCLUSION The joint effect of fluoride and arsenate on the gene expression of ODF is antagonistic, while the combined effect on the gene expression of OPG is synergistic. F4, F4As12.5, and F0.5As200 promote bone resorption of rat osteoclasts, whereas F0.5As12.5 inhibits osteolytic effect of rat osteoclasts.