Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
11430 | Biomaterials | 2006 | 9 Pages |
The aim of the study was to examine the chronological histology of osteoinduction of highly purified β-tricalcium phosphate (β-TCP) implanted in dog dorsal muscles. Specimens were harvested on days 14, 28, 42, 56, 112 and 168 after implantation, and were analyzed by hematoxylin and eosin (HE) staining, tartrate-resistant acid phosphatase (TRAP) staining, immunohistochemistry, in situ hybridization, and silver impregnation. After day 28, abundant TRAP- and cathepsin K-positive multinucleated cells adhered to β-TCP, suggesting that these cells are osteoclasts that can resorb β-TCP. On day 56, new bone was formed and α1 chain of type I procollagen mRNA-positive osteoblasts lined the newly formed bone. Silver impregnation showed abundant collagen fibrils within the β-TCP micropores. These results suggest that micropores function as a storage space for extracellular matrix components, including collagen. Newly formed bone never degenerated in the late stage, suggesting that β-TCP has good biocompatibility and this material retains the conditions appropriate for osteointegration and bioresorption. In conclusion, β-TCP has osteoinductivity after implantation in dog dorsal muscles without use of bone marrow cells or osteoinductive cytokines. The appearance of a large number of active osteoclasts precedes new bone formation.