Experimental Study Of Tissue-engineered Bone Constructed With Simvastatin Carried By PLGA/CPC And Bone Marrow Stromal Cells

In recent years, the atrophy of alveolar bone caused by various factors has brought greatdifficulties for the restoration, it becomes a major problem about how to prevent the atrophyof the alveolar bone and promote the bone regeneration at present, the main treatmentsinclude: preventive therapy and operative treatment, but both of them have drawbacks. Withthe development of tissue engineering, constructing tissue engineered bone to repair bonedefects has achieved good results, but the bone tissue engineering can only achieve boneconduction but osteoinduction. Therefore, the composite scaffold material that has both boneconduction and induction effect was born. In the previous experiments of our team,wesuccessfully constructed simvastatin carried by composite PLGA/CPC scaffold metarialwhich has the ability of bone conduction and induction effect. Meanwhile, we also foundthat the small scaffold porosity, uneven distribution of cells, poor adhesion rate of cells to thescaffold, and the uncertainty of simvastatin concentration remain to be resolved.With the development of cell biology, cell seeding therapy has been paid more attention,cells may provide a scaffold biological characteristics, promoting the bone regeneration byincreasing cell proliferation and differentiation. Bone marrow stromal stem cells have thecharacteristics of embryonic stem cells, owning the ability of self-renewal and differentiation,it can differentiate into osteogenic, adipogenic and cartilage cells at the conditionedmedium. They’ re good seed cells, having good biological and easy-separatingcharacteristics.This study used the solvent casting-particle leaching technology combined with phaseseparation to prepare different concentrations of simvastatin carried by PLGA/CPC scaffoldcombing with bone marrow stem cells to construct tissue engineered bone, screening theoptimal concentration of simvastatin in the scaffold and observing the mechanism of itseffect to the bone marrow stromal cells.objectives: To verify the feasibility of constructing tissue-engineering bone withsimvastatin carried by PLGA/CPC and bone marrow stromal cells, to screen the best drugconcentration of simvastatin. Method:1) Using adherent method to separate bone marrowstromal cells of rats, observing the growth state of cells by inverted microscope anddrawing the cell growth curve, identifying bone marrow stromal cells by CD44, CD105, bone marrow stromal cells was induced by the osteogenic medium and simvastatin in vitroand stained by Alizarin Red and type I collagen;2) Using the solvent casting-the particleleaching technology combined with phase separation to prepare different concentrations ofsimvastatin PLGA/CPC composite scaffold, which were cut into5mm diameter,1mm thick,each scaffold contained simvastatin0.1mg,0.5mg,1mg and blank group. Observing theporosity by Scanning electron microscopy, drawing the drug release profile;3)Seeding thethird generation BMSCs stained by dil in different concentrations of composite scaffolds,observing the adhesion of cells on the scoffold by scanning electron microscopy andconfocal laser scanning microscopy, CCK-8and alkaline phosphatase examined theirproliferation and differentiation. Results:1) BMSCs grew well, The positive expression ofCD44, CD105, type I collagen. Alizarin red staining showed significant calcium nodules.2)The scaffold porosity of four groups have been more than90%,average porosity diameterwas200-300μm, drugs released continuously and slowly in the experimental group;3) Fourgroups of scaffolds had better cell adhesion, the0.5mg group had the best cell growth state.CCK-8and AKP detected0.5mg group could significantly promote cell proliferation anddifferentiation. Conclusions:1) Tthe combination of simvastatin and osteogenic mediumcould promote BMSCs to the osteogenic differentiation effectively;2) PLGA/CPCcomposite scaffolds containing simvastatin was the ideal scaffold for tissue engineering;3)0.5mg Simvastatin was the best drug concentration to build the tissue engineered boneconstructed with simvastatin carried by PLGA/CPC and bone marrow stromal cellsThe experiment studied the concentration of simvastatin on the scaffold, combiningscaffold, drug and cells to build tissue engineering bone, providing theoretical andpractical guidance to prevent alveolar bone atrophy and promoting bone regeneration.