The Experimental Study Of Repairing Bone Defect With Three-dimensional Porous Scaffolds Of Ploly-L-lactic Acid/chitosan Nanofibers Composite BMSCs

ObjectiveTo isolate and cultivate BMSCs from New Zealand rabbits, fabricate three dimensional PLLA/CSNF composite porous scaffolds, and then evaluate the compatibility of the PLLA/CSNF composite porous scaffolds and the BMSCs of rabbits in vitro and in vivo. To evaluate the effect of planting cell-scaffold compound fabricated in vivo to repair bone defect of rabbits and explore the new tissue engineering method preliminarily.Methods1. BMSCs from New Zealand rabbits were isolated and cultured by the whole bone marrow adherence method.2. BMSCs were induced directionally and differentiated into osteoblasts by using the induction culture medium. Their capability of osteogenic differentiation is evaluated through morphologic observation, ALP staining, etc.3. The two tpyes of scaffolds were co-cultured with BMSCs and observed by scanning electron microscope(SEM).4. PLLA/CSNF scaffolds were planted into the subcutaneous tissue of the rabbit, and were taken out after 1,2 and 4 weeks later separately. The histocompatibility of PLLA/CSNF scaffolds was analyzed by general observation and HE staining.5. The rabbits'femoral condyle defects were modeled and divided into 4 groups randomly. PLLA/CSNF/BMSCs compound was planted into the defected position in the experimental group; autogenous bone in the criterion group; PLLA/CSNF scaffolds in matched group; and the blank group was left without any treatment. General observation, radiology examination, HE staining and scanning electron microscope were made to evaluate the status of defect repairing at 4,8 and 12 weeks postoperatively.Results1. BMSCs of rabbit can be obtained through whole bone marrow adherence method and also can be cultured in vitro.2. Observed by scanning electron microscope, the BMSCs adhered to the scaffold wonderfully. 3. No tissue rejection was seen after the planting of the material, and no distinct inflammation and rejection was found in the HE staining,which shows wonderful tissue compatibility4. The following results were observed after the operation:bone tissue was formed in the defected position of the experimental group, the scaffolds degraded and the effect of repairing defects was similar to that in the criterion group; some new bone tissue was formed and the scaffolds degraded partly in matched group while the defect was mainly filled with fibrillar connective tissue in blank group.Conclusion1. The BMSCs of rabbit can be obtained through the whole bone marrow adherence method.They also can be cultured stably for a long term and be induced into osteoblasts. They are the ideal seed cells of tissue engineering.2.PLLA/CSNF porous scaffold is characterized with good adhesion and tissue compatibility and can be degraded gradually in vivo.3. PLLA/CSNF porous scaffold composited with rabbit's BMSCs can repair the bone defect finally because of good abliity to accelerate the formation of new bone.The experimental result shows PLLA/CSNF is fine scaffold for bone tissue engineering.