ABSTRACT
BACKGROUND: Beta-tricalcium phosphate (β-TCP)/alpha-calcium sulfate hemihydrate (α-CSH) artificial composite bone has a porous morphology and good biocompatibility, and it is helpful to improve the fusion rate in a spinal fusion model, which however has not yet been confirmed.OBJECTIVE: To investigate the preparation methods, biocompatibility and application effect of β-TCP/α-CSH composite bone in the spinal fusion model.METHODS: (1) Calcium sulfate dihydrate under certain conditions and at a proper temperature can be dehydrated to prepare α-CSH. Healthy bovine cancellous bone was decellularized, degreased and sintered under the certain condition and at the certain temperature to prepare β-TCP particles. Then, the β-TCP particles were dissolved in anhydrous ethanol, suspended, dried, and then used to prepare the β-TCP/α-CSH composite bone. Osteoblasts from the rabbit periosteum were co-cultured with the composite bone, and then cell morphology, adhesion and proliferation were observed. (2) Twenty New Zealand white rabbits were selected to make bilaterally posterolateral spinal fusion models of the multiple thoracic vertebrae, in which β-TCP/α-CSH composite bone was implanted into the left side (experimental group) and autogenous bone implanted into the right side (control group). The spinal fusion rate was compared between the two groups.RESULTS AND CONCLUSION: (1) Under the phase contrast microscope, a relatively small amount of L929 cells adhered to the composite bone after 3 days of co-culture, while the number of adherent cells became relatively dense. Under the scanning electron microscope, there were many crystalline particles on the surface of the composite bone,indicating a higher number of adherent cells on the composite bone surface. (2) The spinal fusion rate was increased at 4 weeks after implantation of β-TCP/α-CSH composite bone, which was significantly higher than that after implantation of autogenous bone (P < 0.05). (3) At 4 weeks after autogenous bone implantation, the bone trabecular bone was scarce and clumped, and newborn bone tissues and the boneless autograft bone were dominant. After 8 weeks after spinal fusion, the newborn bone tissues around the autograft were further increased. At 4 weeks after β-TCP/α-CSH composite bone implantation, there was no degradation of debris, but existed a few new bone tissues; at 8 weeks after implantation,the composite bone was surrounded by newborn bone tissues, and thickened trabecular bone and degradation of the composite bone were found. To conclude, the prepared β-TCP/α-CSH composite bone can achieve a higher fusion rate in the spinal fusion model.