Cell sheet-engineered bones used for the reconstruction of mandibular defects in an animal model.

The aim of the present study was to investigate the generation of cell sheet-engineered bones used for the reconstruction of mandibular defects. Bone marrow stem cells (BMSCs) were cultured and induced to generate osteoblasts. Poly(lactic-co-glycolic acid) (PLGA) scaffolds were wrapped with or without cell sheets and then implanted into dogs with mandibular defects in the right side (experimental group) or the left side (control group), respectively. Subsequently, X-ray analyses, and hematoxylin and eosin staining were performed at various time points (at 4, 8, 12 or 16 weeks post-implantation; n=4 at each time point). The osteogenesis in the experimental group was significantly improved compared with that in the control group. At 16 weeks after implantation, numerous Haversian systems and a few lamellar bones were observed at the periphery. In the control group, the engineered bone (without BMSC sheets) presented fewer Haversian systems and no lamellar bones. The optical density of the fresh bone in the experimental group was significantly higher compared with that in the control group (P<0.05). In conclusion, tissue-engineered bone with the structure of lamellar bones can be generated using BMSC sheets and implantation of these bones had an improved effects compared with the control group. Cell sheet transplantation was found to enhance bone formation at the reconstruction site of the mandibular defects.