Implants of type I collagen gel containing MG-63 osteoblast-like cells can act as stable scaffolds stimulating the bone healing process at the sites of the surgically-produced segmental diaphyseal defects in male rabbits.

Background: Three-dimensional (3-D) type I collagen gel culture systems allow long-term growth of osteoblast-like cells, in vitro. Whether the implantation of 3-D collagen systems can stimulate new bone formation was assessed in male rabbits. Materials and Methods: A 10-mm segmental diaphyseal defect was surgically produced at the left and right limbs of 50 adult male rabbits. The 3-D systems containing MG-63 osteoblast-like cells were implanted at the right-limb defects of all 50 animals. Twenty-five left-limb defects were implanted with 3-D collagen gels containing no MG-63 cells, while the rest were left empty. The bone repair process was serially assessed by radiography for up to 8 weeks and by histological analysis for up to the week 32 post-surgery. Results: Ninety-four per cent (94%) of the right-limb defects, presented radiographic evidence of complete bone-end bridging within 8 weeks. None of the 50 left-limb defects presented radiographic post-implantation evidence of bone-end bridging. The radiographic evidence of the bone-end bridging was corroborated with histological evidence of new bone formation, while the medullar canals were filled with bone marrow elements. Conclusion: Implants of the 3-D collagen gels containing osteoblast-like cells can be used as stable scaffolds allowing the migration/proliferation of the bone regenerating cells in male rabbits. Three-dimensional (3-D) type I collagen-based cell culture systems composed of reconstituted collagen fibres have been used as 3-D culture systems for studying aspects of the biology of various cancer cell lines, endothelial cells, endometrial cells, hepatocytes, osteoblasts and fibroblasts, in vitro (1-8).