Study On Biological Properties Of Porous Hydroxyapatite Bone Repair Materials Prepared By Spark Plasma Sintering With BMSCs Of Rabbit

ObjectivePrepare the porous hydroxyapatite (HA) material by spark plasma sintering (SPS) and combine with artificial bone of rabbit bone marrow mesenchymal stem cells (BMSCs). Detect the degradability, toxicity, hemolytic and cytocompatibility of this composite material, and observe it under electron microscope. Study the biological properties of the porous HA material prepared by SPS to supply scientific experiment evidence and theoretical basis for preparing new substitute material of bone reparation clinically.MethodsAmplify rabbit BMSCs by red blood cell lysis adherence, and observe cellular morphology, identify BMSCs’immunologic characteristics and capacity of induced differentiation. Study the in vitro degradation of porous HA which is prepared by SPS by PBS soaking. Study the cytotoxicity of porous HA with MTT. Observe the cytocompatibility of porous HA by scanning electron microscopy (SEM). Detect the hemolytic of porous HA by in vitro hemolytic test. Research the influence of porous HA to BMSCs’differentiative capacity by in vitro induction esperiment.Results1. Lots of fusiform adherent cells that were active and in strong proliferating ability can be observed by inverted phase contrast microscope. High expression of BMSCs’ surface marker-CD44, CD90and CD105and low expression of hematopoietic cell’s surface marker-CD34、CD45were analyzed in cells by flow cytometry. The above results can confirm the cells to be rabbit BMSCs.2. The degradation rate of porous HA prepared by SPS increased with time passing in PBS. The degradation velocity is fast in early period but become slowly in later period. The degradation rate tend to steady after10weeks.3. The OD value with MTT shows that there’s no statistical differences between HA+BMSCs group and the control group (P=0.1542) which means porous HA prepared by SPS has no nontoxicity.4. Cell adhesion on the surface and lots of cells in the holes of porous HA can be seen through SEM, which indicate that the porous HA prepared by SPS has excellent cytocompatibility.5. The hemolysis ratio of porous HA prepared by SPS has not exceeded5%that can indicate there’s no hemolytic reaction in vitro experiment.6. Circular and oval mineralization nodes can be observed by osteoblastic induction experiment in vitro and the lizarin red stain is positive. Circular lipid droplet can be observed by adipogenesis induction experiment in vitro and the oil red O staining is positive. The above indicate that the compound of porous HA prepared by SPS and BMSCs has osteogenic and adipogenic differentiation capacity.ConclusionsThe porous HA prepared by SPS has a good cytocompatibility, nontoxicity, non-hemolytic reaction and also in vitro degradation behavior. The osteogenic and adipogenic differentiation capacity won’t be affected by combining with BMSCs. BMSCs can adhere on the surface of porous HA, grow by static adherence and even adhere to grow in the holes of porous HA. The compound of porous HA prepared by SPS and BMSCs can be a new reparative material of artificial bone.