Construction of tissue-engineered bone using a xenogenic deproteinized bone scaffold for spinal intertransverse fusion

Gang LI; Chunyang GAO; Lianjin JIN

ABSTRACT

BACKGROUND:

Xenogenic deproteinized bone is generally collected and has unique biological properties;however,its immunogen hopes be resolved so as to discover a new type of bone graft material.

OBJECTIVE:

To explore the performance of xenogenic deproteinized bone scaffold for tissue-engineered bone and the effect on spinal intertransverse fusion in goats.DESIGN,TIME AND

SETTING:

An in vivo cell-scaffold study was performed at the Key Laboratory of Fibrotic Biotherapy of Heilongjiang Province between February and October 2008.MATERIALSTwelve healthy male goats aged 6-8 months were provided by Animal Center of Mudanjiang Medical College.

METHODS:

Cancellous bone at distal femur of adult swine was obtained to prepare xenogenic deproteinized bone scaffold using physical and chemical methods.Effects of the scaffold on morphology,structure,component,biomechanical property,and biological behavior of seed cells were detected and analyzed.Bone marrow was extracted from ilium of goat and gradient-centrifuged to obtain the third-passaged bone marrow mesenchyme stern cells (BMSCs).A certain quantity of autologous BMSCs and recombinant human bone morphogenetic protein 2 (rhBMP-2) were plated onto the scaffold to achieve tissue-engineeried bone.Models of bilateral L3,4 intertransverse bone graft were established on 12 goats.Tissue-engineeried bone was implanted into the left side in a repairing group,while the same volume of autologous ilium was implanted into the right side in a control group.MAIN OUTCOME

MEASURES:

X-ray examination and histological detection were performed at 4,8,and 12 weeks after implantation.

RESULTS:

Deproteinization-treated cancellous bone exhibited a spatial grid structure of variously sized,crossing and opening pores,composing hydroxyapatite and collagen.The pore diameter was 200-500 μm,and porosity was about 60%.Mechanical property and cell compatibility were well.X-ray examination demonstrated that at 4 weeks after implantation,some or even lateral intertransverse bridging regions were unclear,and material density in the repairing group was lower than control group;at 8 weeks after implantation,interspace between up and down bridging was shrunk,and a great quantity of calluses were successively formed;at 12 weeks after implantation,complete confluence was observed,and the density in the repairing group was closed to that in the control group.Histological detection indicated that at 4 weeks after implantation,new bone was multidrop-formed in the repairing group;at 8 weeks after implantation,bone tissue like the islet shape was passed through the whole implanted materials;at 12 weeks after implantation,woven bones arranged across,medullary cavity was formed,and osteogenic activity in the repairing group was closed to that in the control group.On the other hand,at 4 weeks after implantation,a large quantity of new bones were formed in the control group;at 8 weeks after implantation,a great quantity of collagen fibers were observed,and osteogenesis was clear in marginal region;at 12 weeks after implantation,fibrous tissues were reduced,and osteogenesis was active.

CONCLUSION:

BMSCs and rhBMP-2 incubated on xenogenic deproteinized cancellous bone is an ideal tissue-engineeried bone scaffold,characterizing by an excellent histocompatibility and a strong osteogenesis,based on in vitro X-ray diffraction analysis,mechanical test,and in vivo osteogenesis experiment.