2001 Volume 21 Issue 1 Pages 52-57
To clarify the effects of enamel matrix derivative (Emdogain : EMD) on the wound-healing processes of bone defects in rat femurs, cylindrical bone defects were formed with round bars and filled with either EMD or its carrier PGA (control). On postoperation days 7 to 30, dissected femurs were examined histologically. On days 7 and 14 new trabecular bones, which were immunoreactive for bone sialoproteins, were formed postoperatively in the medullary cavities of circular bone defects. This new trabecular bone formaiton was much more prominent in EMD-treated groups than in PGA-treated controls. BSE and μ-CT examinations also revealed that the repair of bone defects by new trabecular bone formation was significantly more accelerated in EMD-treated groups than in controls. The bone volume fraction in the medullary cavities and the internal trabecular bone architecture were clearly indicated by μ-CT analysis, and BSE analysis showed low-and high-resolution views and the calcification rate of newly formed trabecular bones. In EMD-treated tissues, osteoblastic cells accumulated around the bone trabeculae. The production of bone sialoproteins by these osteoblastic cells was clearly demonstrated by immunoelectron microscopy. Multinucleated osteoclasts, which were strongly immunostained for cathepsin K, a lysosomal cysteine protease highly expressed in osteoclasts, were also present on bone trabeculae. Our results suggest that EMD is an effective biological tool in enhancing the differentiation of bone-forming cells and resulting new bone induction and remodeling during the regeneration of long bones.
