Repair of critical-sized bone defect by a novel bone bioengineering construct after co-transfection of recombinant human bone morphogenetic protein-2 and basic fibroblast growth factor into bone marrow stem cells and combination with nano-hydroxyapatite/recombinant human-like collagen/polylactic acid scaffold

Abstract

Objective To repair a 1.5 cm critical-sized rabbit bone defect model by a novel bone bioengineering construct after co-transfection of recombinant human bone morphogenetic protein-2 （rhBMP-2） and basic fibroblast growth factor （bFGF） into bone marrow stem cells （BMSCs） and combination with nano-hydroxyapatite/recombinant human-like collagen/polylactic acid （nHA/RHLC/PLA） scaffold. Methods A 1.5 cm critical-sized bone defect model was created. BMSCs after gene transfeetion were combined with nHA/RHLC/PLA scaffolds to fabricate various biocomposites. Six groups were established： rhBMP-2- bFGF/BMSCs/nHA/RHLC/PLA （A）, rhBMP-2/BMSCs/nHA/RHLC/PLA （B）, bFGF/BMSCs/nHA/ RHLC/PLA （C） , BMSCs/nHA/RHLC/PLA （ D）, nHA/RHLC/PLA （E） and untreated bone defect group （F）. At 6th and 12th week postoperation, the samples were harvested and subjected to radiographic and histologic analyses. Results At 6th week after transplantation, obvious new bone tissue was formed in group A with bone area of （47.24 ± 4. 37 ） %, significantly greater than in group B [（28.24 ± 2. 35 ） %] and group C [（ 13.46 ± 2. 27 ） %] （ P 〈 0. 05 ）. No bone formation was observed in groups D and E. Twelve weeks later, bone integrity was restored and medullary cavity recanalized in group A with bone area of （ 96.84 ± 2. 28 ） % ; bone integrity was restored but medullary cavity was not recanalized yet in group B with bone area of （ 92. 24 ± 1.75 ） % ; slightly enhanced bone tissue formation was seen in group C [（24.73 ±2. 01 ）%] and few new bone tissue was found in group D; no bone tissue was formed in group E. The therapeutic effect for bone defect in group A was superior to other groups （ P 〈 0. 05 ）, and the bone defect in groups C, D and E was not repaired. Conclusion A new bone tissue engineering biocomposite by the combination of nHA/RHLC/PLA and BMSCs after double-transfection of rhBMP-2 and bFGF can produce apparently bone tissue in orthotopic site, which provides a new view relating to tissue-engineering repair of larze bone defect in clinical area. Key words: Recombinant bone morphogenetic protein-2; Basic fibroblast growth factor; Bonemarrow stem cells; Bone defect