Effects Of Nano-CeO₂, La₂O₃and Y₂O₃on Proliferation, Differentiation And Mineralized Function Of Primary Osteoblasts In Vitro

In this article, the physical and chemical properties of nano-CeO₂, La₂O₃and Y₂O₃werecharacterized. Then the3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyl tetrazolium bromide （MTT）test, alkaline phosphatase （ALP） activity, oil red O assays and alizarin red-S （ARS） stain wereemployed to evaluate the effects of nano-CeO₂, La₂O₃and Y₂O₃on the proliferation,differentiation and mineralization function of primary osteoblasts （OBs） in vitro. Thedistribution of CeO₂nanoparticles in OBs was studied by flow cytometry.The results showed that:1. Two types CeO₂nanoparticles were approximately30nm and50nm in diameter andthe single nanoparticle was nearly spherical particles. The morphologies of two kinds ofLa₂O₃were irregular flakes and short nanorod, respectively. Y₂O₃nanoparticles werespherical particles and the particle size was approximately30nm.2. The effects of CeO₂nanoparticles on the proliferation, differentiation andmineralization of OBs depended on size, concentration and incubation time and other factors.We found that CeO₂nanoparticles with diameters of50nm inhibited the proliferation of OBsin a time-dependent manner. But CeO₂nanoparticles with diameters of30nm showed nosignificantly cytotoxicity at the same concentrations and time points. Two types CeO₂nanoparticles promoted the mineralization function of OBs in a dose-dependent manner.Moreover, the promotion rate of30nm CeO₂nanoparticles was higher than that of50nmCeO₂nanoparticles.3. The effects of nano-La₂O₃on the mineralization of primary OBs depended on themorphology, dosage, chemical composition of nanoparticles and incubation time, and otherfactors. The flake La₂O₃inhibited the proliferation of OBs higher than nanorod La₂O₃at thesame doses, and the cell toxicity of nano-Y₂O₃is lower than nano La₂O₃; two types of nanoLa₂O₃, above the concentration0.6μg/mL, all can promote the formation of mineralizationnodules in a dose-dependent manner, and the promotion rate of flake La₂O₃was higher thanthe nanorod La₂O₃.4. The uptake of CeO₂nanoparticles in OBs was studied at24h, we found that the amount of CeO₂nanoparticles inside OBs increased with the concentration increasing.