| Objective:The ideal scaffold materials of tissue engineering should have the good biocompatibility,proper biodegradation,porous structure,proper mechanical function and obvious osteogenic ability, which will meet the need of the cell adhesiveness, growth, proliferation and differentiation.Now biomaterial research focus on how to make acellular tissue matrix.Acellular bone extracellular matrix(ABECM)as scaffold materials which had been proven excellent in bone tissue engineering.The scaffold provides the base of cell adhesion, growth and differentiation; also the scaffold is the structure that fixes growth factors in cell components and maintains three dimension spatial configuration to create new tissue.Bone marrow stromal stem celIs(BMSCs)can easily expand in vitro,and can give rise to a broad spectrum of fully differentiated connective tissues under appropriate perimental conditions.BMSCs have a numher of potential therapeutic applications.Their applications in the tissue engineering of bone are not enough.We used BMSCs as seed cells and cultured the cells combined with ABCB in vitro,and observed theintegration of the donor cells.This provided the morphologic foundation for new natural supporting scaffold of tissue engineering of bone.To study the biocompatibility of bovine acellular bone extracellular matrix ,a new bone repair material , for the clinical use in the bone reconstruction field. To investigate the ability of repairing segmental bone defects with antigen extracted xenogeneic callcellous bone(ABCB)combined with bone marrow stromal stem cells(BMSCs),and the feasibility with ABCB as bone tissue engineering substitute material.Methods:1 Evaluated the biocompatibility through acute toxicity test, pyrogen test, hemolysis test ,muscle bone implant test and lymphocyte transformation test. 2 The culture ,induction , purification and identification of BMSCs in vitro.The primary culture of New Zealand Rabbit's BMSCs, which were collected from the femur and tibia marrow of rabbit about a month old by PBS,centrifugalized in the rate of 2000r/min,mixed with DMEM +20%NBCS,cultured in the condition of 37℃,5% CO2, and refreshed the DMEM every three day.Harvested them after they formed one layer,the cells were washed,trypsinized for 3 min, and suspended in DMEM +20%NBCS.BMSCs are capable of differentiating along multiple mesenchymal lineages in specified conditions.When exposed to 100nmol dexamethasone(Dex),50ug/ml ascorbic(ASA)and 10mmolβ-gIycerophosphate.Part of them was stained Von Kossa's staining after 14d.3 The animal models of bilateral radius bone defects were created by surgery in the New Zealand white rabbits.Rabbit bone marrow stromal stem cells(BMSCs)were cultured and expanded in vitro.BMSCs were loded into ABCB at the density of 5×106/ml,and ABCB -BMSCs complexes were implanted into rabbit radius bone defects in the diameter of 1.5cm.Cell-free ABCB or nothing was implanted into the defects respectively as contro1.The effects were observed by gross specimen inspection,X-ray examination and histological observation at 8,16 and 24 weeks after operation.Result:1 All results indicated that the material had no toxicity, no hemolysis activities and did not contain the pyrogen material. It could be biodegradated and replaced by fibrous after implant into muscle, by bone after implant into bone defects in rabbits. It does not cause immunological rejection. 2 Gross histological and X-ray examinations indicated that the bone defects were perfectly repaired with ABCB-BMSCs at 24 weeks,the bone defects were approximately repaired with cell-free ABCB,but unrepaired in the group without implant.Conclusion: 1 Bovine acellular bone matrix owns good biocompatibility. It is a kind of ideal scaffold material. 2 ABCB-BMSCs has obvious osteogenic ability and can be used as a substitute of autograft. |
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