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A Reliable and Reproducible Critical-Sized Segmental Femoral Defect Model in Rats Stabilized with a Custom External Fixator
Published on: March 24, 2019
BMP-silk composite matrices heal critically sized femoral defects
C Kirker-Head1, V Karageorgiou, S Hofmann
1Tufts Cummings School of Veterinary Medicine, North Grafton, MA, USA.
Bone
|June 8, 2007
Summary
Silk fibroin scaffolds combined with recombinant human BMP-2 (rhBMP-2) show promise for bone regeneration. These silk scaffolds effectively promoted bone healing in critical-sized defects, demonstrating significant mineralization compared to controls.
Area of Science:
- Biomaterials Science
- Regenerative Medicine
- Orthopedic Surgery
Background:
- Bone grafting has limitations, driving research into alternative bone augmentation technologies.
- Osteopromotive matrices are crucial for controlled delivery of growth factors and cell therapies.
- Silk fibroin, derived from silkworms, offers potential as an osteoconductive scaffold.
Purpose of the Study:
- To evaluate silkworm-derived silk fibroin scaffolds as an osteoconductive matrix for healing critical-sized bone defects.
- To assess the efficacy of silk scaffolds combined with recombinant human BMP-2 (rhBMP-2) and human mesenchymal stem cells (HMSCs) in promoting bone regeneration.
- To compare different treatment groups, including pre-differentiated HMSCs, undifferentiated HMSCs, rhBMP-2 alone, and empty defects.
Main Methods:
- Critical-sized mid-femoral segmental defects were created in nude rats.
- Four treatment groups were established: pdHMSC/rhBMP-2/SS, udHMSC/rhBMP-2/SS, rhBMP-2/SS, and empty defects.
- Bone healing was assessed over eight weeks using radiography, dual energy x-ray absorptiometry, micro-computed tomography, and histology.
Main Results:
- Groups I-III (with rhBMP-2) showed significantly greater defect mineralization than Group IV (empty defects) by post-operative week 8.
- No significant differences in healing were observed among Groups I-III via radiographic, DXA, micro-CT, or mechanical testing.
- Histology revealed bone bridging in Groups I and III, with less bone formation in Group II and minimal new bone in Group IV.
Conclusions:
- Silk scaffolds combined with rhBMP-2 demonstrate clinical potential for osteopromotive implants.
- The addition of rhBMP-2 to silk scaffolds enhanced bone formation compared to previous studies with undifferentiated cells or scaffolds alone.
- Further studies in larger animal models are warranted to explore the clinical applicability of these silk-based bone augmentation strategies.
