The effect and relative mechanism of deferoxamine on bone mass in ovariectomized mice companied with iron accumulation

Abstract

Objective To observe the effect of iron chelator deferoxamine mesylate (DFO) on ovariectomized mice plus iron intervention, and to explore the relative mechanism. Methods 8-weeks old C57BL/6J female mice were underwent oophorectomy and randomly divided into ovariectomized (OVX) group, ovariectomized+ iron intervention group (OVX+ Fe group) and ovariectomized+ iron+ deferoxamine group (OVX+ Fe+ DFO group). After two weeks, the OVX+ Fe group mice and the OVX+ Fe+ DFO group mice were treated with 0.12 g/kg per week ferric ammonium citrate intervention four weeks via intraperitoneal injection three times a week, while the OVX group mice were treated with saline via the same methods and frequency. Afterwards, the OVX+ Fe+ DFO group mice were administrated with 4 000 mg/kg per week of DFO for two weeks via intraperitoneal injection twice a day, while mice in the other two groups administrated with saline in the same manner and frequency. Mice were sacrificed at the end of the administration. The serum ferritin, osteoprotegerin (OPG) or receptor ativator for nuclear factor-κB ligand (RANKL) level were detected by enzyme-linked immuno sorbent assay. Distal femur three-dimensional analysis was detected by micro computed tomography (Micro-CT). The prussian blue staining was conducted to observe bone iron deposition in femur. Real-time quantitative polymerase chain reaction (Real-time PCR) was conducted to analyze the expression of OPG and RANKL in bone tissue. Results The serum ferritin in OVX+ Fe group [(408.90±17.20) μg/ml] was significantly higher than the other groups [OVX group (87.53±3.73) μg/ml and OVX+ Fe+ DFO group (162.30±10.58) μg/ml, respectively] (P=0.000). Besides, prussian blue staining showed that the iron deposition in bone of OVX+ Fe group mice was the most, and in bone of OVX group mice was the least. These results suggested that iron accumulation could increase systemic and local bone tissue iron accumulation, while DFO could reduce the iron accumulation no matter in serum and in local bone tissue. The bone mass in the OVX+ Fe group [(0.09±0.02) mg/mm3] was significantly lower than the OVX groups [(0.13±0.01) mg/mm3,P=0.000]. However, after administrated with DFO, the bone mass in the OVX+ Fe+ DFO group [(0.12±0.01) mg/mm3] was significantly increased compared with OVX+ Fe group [(0.09±0.02) mg/mm3,P=0.000]. The bone tissue OPG expression in OVX+ Fe group (0.75±0.15) was down regulated when compared with the OVX group (1.00±0.20, P=0.019, 0.012). But after administrated with DFO (0.89±0.15), the bone tissue OPG expression was increased significantly compared with the OVX+ Fe group (0.75±0.15, P=0.000). The bone tissue RANKL expression and RANKL/OPG ratio in OVX+ Fe group (2.20±0.12 and 2.80±0.40, respectively) was up regulated when compared with the OVX group (1.00±0.13 and 1.00±0.50, respectively, P=0.000). But after administrated with DFO, the bone tissue RANKL expression (1.3±0.2) and RANKL/OPG ratio (1.4±0.3) was decreased significantly compared with the OVX+ Fe group (P=0.000, 0.015). The levels of OPG and RANKL in serum were as the same as the results of real-time PCR (P=0.000, 0.017). Conclusion Iron accumulation decreased bone mass in OVX mice through affecting the RANKL/receptor ativator for nuclear factor-κB (RANK)/OPG axis, while DFO might reduce iron accumulation and partially restored this effect. Key words: Iron accumulation; Desferrioxamine mesylate; Postmenopausal osteoporosis; Receptor ativator for nuclear factor-κB ligand/receptor ativator for nuclear factor-κB/osteoprotegerin axis