Role of osteoprotegerin and receptor activator of nuclear factor-κB ligand in bone toxicity in rats co-exposed to fluoride and arsenite / 中华地方病学杂志

ABSTRACT

Objective To analyze the role of osteoprotegerin (OPG) and receptor activator of nuclear factor-κB ligand (RANKL) in bone toxicity in rats co-exposed to fluoride and arsenite.Methods One hundred and ninety-two 8-week-old clean-grade Wistar rats weighing (200 ± 50) g were divided into 16 groups by weight using random number table method of 12 rats in each group by 2 × 4 factorial experimental design (half female and half male),and treated with different doses of fluoride,arsenite and fluoride plus arsenite in deionized water (untreated control group containing 0.0 mg/kg fluoride and 0.0 mg/kg arsenite;low-,moderate-,and high-fluoride groups supplemented with 5.0,10.0 and 20.0 mg/kg fluoride and 2.5,5.0 and 10.0 mg/kg arsenite) for 6 months.Rats were divided into control (F0As0),low fluorine (F5.0As0),moderate fluoride (F10.0As0),high fluoride (F20.0As0),low arsenic (F0As2.5),moderate arsenic (F0As5.0),high arsenic (F0As10.0),low fluorine and low arsenic (F5.0As2.5),low fluorine and moderate arsenic (F5.0As5.0),low fluorine and high arsenic (F5.0As10.0),moderate fluorine and low arsenic (F10.0As2.5),moderate fluorine and moderate arsenic (F10.0As5.0),moderate fluorine and high arsenic (F10.0As10.0),high fluorine and low arsenic (F20.0As2.5),high fluorine and moderate arsenic (F20.0As5.0),high fluorine and high arsenic (F20.0As10.0) groups.The protein expressions of OPG and RANKL in bone were measured via the enzyme-linked immunosorbent assay method.The mRNA expressions of OPG and RANKL were measured with quantitative real-time PCR.Results Compared with F0As0 [(2.678 ± 0.136) ng/mg,(29.658 ± 0.662) pg/mg],the protein expressions of OPG [(2.857 ± 0.162),(2.983 ± 0.272),(3.117 ± 0.143) ng/mg],and RANKL [(32.533 ± 0.999),(32.698 ± 1.932),(33.331 ± 1.140) pg/mg] in F5.0As0,F10.0As0,F20.0As0 were increased with increasing of fluoride doses;increased first and then decreased was observed in levels of RANKL protein [(32.348 ± 2.838),(31.589 ±1.359),(28.843 ± 1.908) pg/mg] in F0As2.5,F0As5.0,F0As10.0 with increasing of arsenic doses (P＜0.05).Compared with F0As0 (0.83 ± 0.19,0.92 ± 0.23),the mRNA expressions of OPG (1.14 ± 0.27,1.33 ± 0.39,1.69 ± 0.77) and RANKL (1.02 ± 0.21,1.17 ± 0.15,1.25 ± 0.31) in F5.0As0,F10.0As0,F20.0As0 were increased with increasing of fluoride dose.Fluoride had a significant effect on protein and mRNA expressions of OPG and RANKL (F=11.530,21.765,6.320,3.543,P ＜ 0.05).There was interaction between fluoride and arsenite on the expressions of RANKL protein and mRNA,OPG protein (F =9.496,2.217,3.375,P ＜ 0.05).Conclusion When rat is co-exposed to fluorine and arsenic,fluorine plays a leading role in regulating RANKL and OPG,and arsenic is indirectly involved in the fluorine bone toxicity in rats,fluorine and arsenic has a antagonistic effect on OPG and RANKL expressions.