Objective: To study the feasibility of core-binding factor alpha1 (Cbfal) gene modified marrow mesenchymal stem cells (MSCs) composed with porcine acellular bone extracellular matrix in repairing the radial defects.
Methods: Radial defects of 1.2 cm in length were created in 40 Japanese white rabbits and they were divided into four groups. In group A, MSCs isolated from homogeneous rabbits were infected with Cbfal recombinant adenovirus and implanted into acellular bone extracellular matrix, and then the complexes were implanted into defects. In group B, the complexes including the MSCs without Cbfal gene-modified and scaffold material were implanted into defects. In group C, only the scaffold material was implanted. In group D, defects were not treated as the control. The macroscopic, X-ray and histologic analysis were performed to evaluate the repair effect at 4, 8 and 12 weeks postoperatively. The repaired radius were examined by biomechanical test at 12 weeks postoperatively.
Results: By gross examination,mature hard new bone formed at grafted areas at 12 weeks postoperatively in group A, osteotomized ends connected by much callus in group B and less callus in group C at grafted areas. In contrast, bone nonunion formed in group D. X-ray and histological examination showed that the repaired results of defects in the group A were better than those in others groups evidently in extracellular matrix degradation, new bone remodeling and marrow cavity rebuilding at 4 and 8 weeks postoperatively. At 12 weeks postoperatively, the cortical bone became mature lamellar bone, new bone remodeling was complete and marrow cavity was smooth in group A. Only proximal end of defects showed that marrow cavity was refolded partially in group B. The continuous callus could be observed in bone defect, and no obvious marrow cavity remodeling was observed in group C. Lots of fibrous connective tissue filled in defect and bone nonunion was shown in group D. There was no significant difference in the damage compress loading of repaired radius between groups A, B and D (P>0.05), but there was significant difference between groups C and D (P<0.01).
Conclusion: These results demonstrate that Cbfal gene modified MSCs combined with acellular bone extracellular matrix can be used to repair rabbit radial defects.