Juyong Wang1, Juqiang Wang2, Asou Yoshinori3, Fu Paul4, Huiliang Shen5, Jiani Chen3, Shinichi Sotome6, Zhao Liu1, Kenichi Shinomiya6. 1. Department of Orthopaedic Surgery, Xuanwu Hospital, Capital Medical University, Beijing 100053, China. 2. Department of Orthopaedics, First Hospital of China Medical University, Shenyang, Liaoning 110001, China. 3. Department of Orthopaedic Surgery, Graduate School, Tokyo Medical and Dental University, Tokyo 1138519, Japan. 4. Department of Neurological Surgery, Wayne State University School of Medicine, Detroit, MI 48201, USA. 5. Department of Orthopaedic Surgery, Xuanwu Hospital, Capital Medical University, Beijing 100053, China. Email: wangjywh@yahoo.com. 6. Department of Orthopaedic Surgery, Graduate School, Tokyo Medical and Dental University, Tokyo 1138519, Japan; COE Program for Frontier Research on Molecular Destruction and Reconstruction of Tooth and Bone, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo 1138519, Japan.
Abstract
BACKGROUND: A practical problem impeding clinical translation is the limited bone formation seen in artificial bone grafts. Low-pressure/vacuum seeding and dynamic culturing in bioreactors have led to a greater penetration into the scaffolds, enhanced production of bone marrow cells, and improved tissue-engineered bone formation. The goal of this study was to promote more extensive bone formation in the composites of porous ceramics and bone marrow stromal cells (BMSCs). METHODS: BMSCs/β-tricalcium phosphate (β-TCP) composites were subcultured for 2 weeks and then subcutaneously implanted into syngeneic rats that were split into a low-intensity pulsed ultrasound (LIPUS) treatment group and a control group. These implants were harvested at 5, 10, 25, and 50 days after implantation. The samples were then biomechanically tested and analyzed for alkaline phosphate (ALP) activity and osteocalcin (OCN) content and were also observed by light microscopy. RESULTS: The levels of ALP activity and OCN content in the composites were significantly higher in the LIPUS group than in the control group. Histomorphometric analysis revealed a greater degree of soft tissue repair, increased blood flow, better angiogenesis, and more extensive bone formation in the LIPUS groups than in the controls. No significant difference in the compressive strength was found between the two groups. CONCLUSION: LIPUS treatment appears to enhance bone formation and angiogenesis in the BMSCs/β-TCP composites.
BACKGROUND: A practical problem impeding clinical translation is the limited bone formation seen in artificial bone grafts. Low-pressure/vacuum seeding and dynamic culturing in bioreactors have led to a greater penetration into the scaffolds, enhanced production of bone marrow cells, and improved tissue-engineered bone formation. The goal of this study was to promote more extensive bone formation in the composites of porous ceramics and bone marrow stromal cells (BMSCs). METHODS: BMSCs/β-tricalcium phosphate (β-TCP) composites were subcultured for 2 weeks and then subcutaneously implanted into syngeneic rats that were split into a low-intensity pulsed ultrasound (LIPUS) treatment group and a control group. These implants were harvested at 5, 10, 25, and 50 days after implantation. The samples were then biomechanically tested and analyzed for alkaline phosphate (ALP) activity and osteocalcin (OCN) content and were also observed by light microscopy. RESULTS: The levels of ALP activity and OCN content in the composites were significantly higher in the LIPUS group than in the control group. Histomorphometric analysis revealed a greater degree of soft tissue repair, increased blood flow, better angiogenesis, and more extensive bone formation in the LIPUS groups than in the controls. No significant difference in the compressive strength was found between the two groups. CONCLUSION: LIPUS treatment appears to enhance bone formation and angiogenesis in the BMSCs/β-TCP composites.