Effects Of Superparamagnetic Iron Oxide Nanoparticles On Proliferation And Differentiation Of Bone Marrow Mesenchymal Stem Cells

Objective:In this study,we cultured and preserved bone marrow mesenchymal stem cells,then we explored the appropriated concentrations of superparamagnetic iron oxide(SPIO)nanoparticles labeled on bone marrow mesenchymal stem cells in vitro,quantitative the lowest cell density of MRI for bone marrow mesenchymal stem cells.Moreover,we proved superparamagnetic iron oxide nanoparticles has no significant effect on bone marrow mesenchymal stem cells when they differentiate into the chondrocytes,so we could provide some basis and foundation of research for the further animal experiments and so on.Methods:In this research,we isolated and cultured primary bone marrow mesenchymal stem cells in vitro,we observed cell proliferation,apoptosis and other biological activities after superparamagnetic iron oxide nanoparticles labeled bone marrow mesenchymal stem cells,then using magnetic resonance imaging equipment to detect and judge effects and image quality of superparamagnetic iron oxide nanoparticles labeled bone marrow mesenchymal stem cells in vitro.In addition,we made superparamagnetic iron oxide nanoparticles labeled on stem cells and differentiated into chondrocytes in vitro and observed the differentiation effect.Results:1.The effect of superparamagnetic iron oxide nanoparticles on proliferation of bone marrow mesenchymal stem cells.In this experiment,we isolated and cultured the primary bone marrow mesenchymal stem cells from the bone tissue of tibia and femur of SD rats.Cells could be continuously passaged and amplified,while maintaining a good state of cell biology.It is proved by CCK-8 assay that when the concentrations of superparamagnetic iron oxide nanoparticles were less than 7.5μg/ml,the proliferation activity of bone marrow mesenchymal stem cell had not been affected significantly.It is found that the labeling rate of superparamagnetic iron oxide nanoparticles was very high by Prussian blue staining.2.MRI of superparamagnetic iron oxide nanoparticles labeled on bone marrow mesenchymal stem cells in vitro.We could get high quality images of superparamagnetic iron oxide nanoparticles labeled on bone marrow mesenchymal stem cells in vitro by using 3.0T MRI scanning,it could be found with the increase of bone marrow mesenchymal stem cells density,cells signal in T2WI and T2*WI are reduced gradually,we could find the lowest cell density in T2WI is 25×104/ml,but in T2*WI,we could find the lowest cell density is 12.5×104/ml,so the susceptibility of T2*WI is higher than T2WI.3.The effect of superparamagnetic iron oxide nanoparticles on differentiation of bone marrow mesenchymal stem cells.In addition,the superparamagnetic iron oxide nanoparticles labeled on bone marrow mesenchymal stem cells were induced to differentiate into chondrocytes,and it is identified by alcian blue staining.We found superparamagnetic iron oxide nanoparticles labeled bone marrow mesenchymal stem cells and unlabeled bone marrow mesenchymal stem cells equally secreted acid mucopolysaccharide.Conclusion:1.It had no significant effect on cell proliferation of bone marrow mesenchymal stem cells when the concentration of magnetic iron oxide nanoparticles was 0,2.5,5,7.5μg/ml,but when the concentration was 10,12.5μg/ml,the cell proliferation of bone marrow mesenchymal stem cells was affected obviously.2.Prussian blue staining showed when superparamagnetic iron oxide nanoparticles concentration was 0,2.5,5μg/ml,the labeling effciency was lower than the concentration is 7.5,10,12.5p,g/ml.3.In vitro MRI,it showed that when the concentration of superparamagnetic iron oxide nanoparticles was 7.5μg/ml,the T2 and T2*value of labeled cells were decreased with cell density increasing,,we could find the lowest cell density in T2WI is 25×104/ml,but in T2*WI,we could find the lowest cell density is 12.5×104/ml,so the susceptibility of T2*WI is higher than T2WI.4.In vitro differentiation experiments,it showed that 7.5 μg/ml superparamagnetic iron oxide nanoparticles labeled bone marrow mesenchymal stem cells also secreted acid mucopolysaccharide,but it was not sure for differentiated cells were chondrocytes.