OBJECTIVETo investigate the effect of segmental defects reconstruction of canine mandible with allogenenic bone marrow mesenchymal stem cells (BMSC) combined with lyophilized bone.

METHODSA 30 mm segmental defect was created on the left mandibles of beagles. Beagles were randomly divided into three groups. Allogeneic bone marrow mesenchymal stem cells with lyophilized bone were used for segmental defects reconstruction in group A. Autologous bone marrow mesenchymal stem cells with freeze- dried bone were used for segmental defects reconstruction in group B. The defects of group C were repaired with lyophilized bone only. Every three beagles were sacrificed 4, 12, 24, and 48 weeks after surgery respectively. The reconstruction effect was evaluated by CT and histopathological examination.

RESULTSCT examination showed that new bones formed in group A and group B 12 weeks after surgery, but not in group C. The form of the reconstructed mandibles in the three groups recovered in 48 weeks. The small pores on the bone graft were filled with new bones in group A and group B. In group C, the pores were still evident. Histopathological examination showed that bone trabecula between allogeneic bone and autogenous bone was completely joined in group A and group B. A large number of fibrous tissue appeared around the implanted bone and new bones were formed. In group C, the lyophilized bone resorption was still not obvious, the new bone formation was significantly slower than the other two groups. There was no difference between group A and group B.

CONCLUSIONSBoth allogeneic bone marrow mesenchymal stem cells and autologous mesenchymal stem cells could accelerate the bone formation.