Reconstruction of Rabbit Critical-size Calvarial Defects Using Autologous Bone Marrow Stromal Cell Sheets

The reconstruction of bone defects remains a significant clinical problem. In this study, we constructed cell sheet from bone marrow stromal cells on normal culture plates by a simple method. The cell sheets showed evident mineralized nodules, high alkaline phosphatase activities, indicating their in vitro osteogenic potential. Then its osteogenic capability to heal critical-size rabbit calvarial defect was investigated. Forty adult New Zealand White rabbits were randomly divided into 4 groups of 10 animals each: (1) empty, (2) demineralized bone matrix (DBM) alone, (3) DBM/cell suspension, and (4) DBM/cell sheet. Specimens were harvested 6 and 12 weeks after implantation, respectively. Radiographic, histologic, and histo-morphometric analyses were performed to evaluate the new bone formation inside the defect. The results revealed that the defect treated with DBM/cell sheet showed significantly more bone formation than other 3 groups (P < 0.05). Our study indicates that the cell sheet enhances bone regeneration in healing critical-size rabbit calvarial defect, and cell sheet-based engineered bone might be considered as potential substitutes for bone reconstruction.