A Polylactic Acid/Calcium Phosphate Scaffold with rhBMP-2 for Spinal Fusion in Rabbit

Spinal fusion is a commonly used method for the treatment of spine degenerative diseases. To achieve spine fusion successfully, the osteogenic activity of bone-graft materials needs to be high enough to promote bony fusion. Recombinant human bone morphogenetic protein-2 (rhBMP-2) is a growth factor that promotes new bone formation and induces bone repair rapidly. In this study, a porous polylactic acid/calcium phosphate scaffold was prepared, to which rhBMP-2 was loaded by physical adsorption to make the scaffold osteoinductive. Furthermore, the rhBMP-2-loaded scaffold was coated with hydroxypropyl methylcellulose (HPMC) for the sustained release of rhBMP-2. The HPMC coated scaffold bearing rhBMP-2 was implanted in rabbit spines. We observed a continuous bone tissue generation at 12 weeks post-operation, and the spines were bony fused. Our results suggest the promise of using the HPMC-coated polylactic acid/calcium phosphate scaffold bearing rhBMP-2 as a bone-repairing material for spinal fusion.