Poly(DL-lactic-glycolic acid)/tricalcium phosphate scaffolds loaded with recombinant human bone morphogenetic protein-2 chitosan microspheres for treatment of bone defects in rabbits

Abstract

Objective To investigate the feasibility and efficacy of using the poly(DL-lactic-glycolic acid)/tricalcium phosphate(PLGA/TCP)scaffolds loaded with recombinant human bone morphogenetic protein-2(rhBMP-2)chitosan microspheres to treat bone defects in rabbits.Methods The rhBMP-2 chitosan microspheres were incorporated into the PLGA/TCP scaffold.The composites of rhBMP-2 microspheres and the PLGA/TCP were then used to bridge the bone defects(diameter: 0.6 cm,depth: 1.0 cm)at the condyle of the left femur in rabbits.Altogether 45 rabbits were randomized into 5 groups in the present study.In group A(n = 10)the defects were not treated.The PLGA scaffold was used in group B(n = 10),the rhBMP-2/PLGA scaffold in group C(n = 10),and the rhBMP-2 micorsphere/PLGA scaffold in group D(n = 10).Group E(n = 5)was the normal control.Ⅹ-ray,Micro-CT and histological studies were conducted to identify new bone formation in groups A to D at 4 and 12 weeks after surgery.Results At 4 weeks postoperatively,plenty new bone and mature trabecular bone were observed,and most of the PLGA/TCP scaffolds were degraded in group D.At 12 weeks postoperatively,the PLGA/TCP scaffolds and chitosan microspheres were completely degraded,and the bone defects were filled with mature bone in group D.In addition,the ratio of new bone formation was significantly higher in group D(74.25%±8.91%)than in group B(5.78% ±1.21%)and group C(37.26% ±6.45%)(P < 0.05).Conclusion The PLGA/TCP composites loaded with rhBMP-2 microspheres are effective in stimulating new bone formation when used to bridge bone defects in rabbits,highlighting their potential application in clinical settings. Key words: Bone morphogenetic proteins; Femur; Chitosan; Tissue engineering; Bone defect