Development Of A Novel Polysaccharide-based Iron Oxide Nanoparticle To Prevent Iron Accumulation-related Osteoporosis By Scavenging Reactive Oxygen Species

Background:In the treatment of iron deficiency anemia with traditional ionic iron supplements,there is a clinical risk of iron-accumulating osteoporosis.Nanoiron agent material has the advantage of replacing the traditional iron supplement as a new oral iron supplement.However,whether nano-iron agent material is also likely to cause iron-accumulating osteoporosis are less explored.In this work,the biological polysaccharide-based antioxidant polyglucose-sorbitol-carboxymethyl ether(PSC)was used as the precursor to synthesize Fe2O3@PSC nanoparticles,which are expected to scavenge excess reactive oxygen species(ROS)to inhibit osteogenesis and promote osteoclast differentiation in iron accumulation(IA)-related osteoporosis.Methods:NPs was synthesized by hydrocooling and magnetically internal heating coprecipitation(HMIHC)method using PSC,ferrous chloride hexahydrate and ferrous chloride tetrahydrate as precursors.The electron microscope structure,hydrodynamic size,diffraction pattern and element composition of NPs were characterized.We used different iron agents to establish a high-iron mouse model in ICR mice,and performed microCT,X-ray detection and histological morphological analysis on femur of mice.Elisa was used to detect the bone metabolism-related indicators PINP and iron metabolism-related indicators TF in serum.In vitro experiments,osteoblasts and osteoclasts were treated with different iron agents.Flow cytometry was used to analyze the ROS production of the two kinds of cells,and the effects of different iron agents on the antioxidants of the two kinds of cells were observed.The effects of two iron agents on the differentiation and proliferation of osteoclasts were observed.Meanwhile,the expressions of related proteins and genes were detected by Western blot and QPCR.Results:The Fe2O3@PSC nanoparticles obtained were of a uniform particle size of 7.3 nm with elemental O/Fe/Cl/C at a ratio of 190:7:2:88.In addition,the Fe2O3@PSC nanoparticles showed the ability to supply equivalent amounts of iron as the typical iron agent ferric ammonium citrate(FAC)in vitro and in vivo.Importantly,the Fe2O3@PSC nanoparticles not only induced antioxidative MC3T3-E1 and Raw 264.7 cells to scavenge ROS but also promoted osteogenic differentiation by activating Akt-GSK-3ββ-catenin and inhibiting osteoclast differentiation by inhibiting the MAPK and NF-κB pathways in vitro.In vivo,no IA-related osteoporosis was induced in a mouse model when enough iron was supplied by the Fe2O3@PSC nanoparticles.Conclusions:We proved that the accumulation of iron caused by traditional iron supplementation can lead to the decrease of bone mineral density and osteoporosis.However,NPs with the same dose has similar effect of iron supplementation without affecting the bone mineral density.Therefore,compared with traditional iron supplementation,NPs shows more advantages for long-term iron supplementation.Overall,the biological polysaccharidebased antioxidant PSC can supply iron and prevent IA-related osteoporosis,indicating that it is a promising novel iron agent for applications to treat iron deficiency diseases.