Tissue engineering using mesenchymal stem cells with periosteal wrap for bone defect repair in rabbits

Aim:Mesenchymal stem cells(MSCs)are an excellent potential source of cells for bone tissue engineering due to their excellent renewal ability and osteogenic differentiation capabilities.This study was designed to evaluate the bone formation properties of a demineralized cancellous bone scaffold seeded with MSCs,with or without periosteum,in a critical size bone defect model in rabbits.Methods:Rabbit culture-expanded bone marrow(BM)-MSCs were seeded onto a human demineralized cancellous bone(HDCB)scaffold.Bone defects measuring 15 mm in length were created in each radius.A total of 56 bone defects in 28 rabbits were randomly assigned to one of the 4 groups for scaffold implantation:Group 1:HDCB graft only;Group 2:periosteum-wrapped HDCB graft;Group 3:HDCB graft seeded with BM-MSCs and Group 4:periosteum-wrapped HDCB graft seeded with BM-MSCs.All rabbits were sacrificed 12 weeks after surgery for gross observation,radiological assessment,histological analyses and biomechanical measurements.Results:New bone(NB)formation and bone healing were successfully achieved,both radiologically and histologically,on demineralized cancellous bone graft seeded with BM-MSCs.Results were improved when BM-MSCs were associated with periosteum.Conclusion:This study demonstrates that repair of bone defects in a rabbit model can be achieved through bone grafting using BM-MSCs,implanted on a demineralized cancellous bone scaffold.The formation of NB was optimized when combined with the preservation of periosteum at the site of injury.