Abstract
Recently, it has been reported that the guided tissue regeneration (GTR) method produces new attachment and alveolar bone, and that bone mor-phogenetic protein (BMP) induces new bone in artificial bone defects or ectopic sites. However, it is still unclear if new attachment can be gained with BMP. As the first step in obtaining bone regenera-tion with new attachment, we have investigated the heterotopic bone formation of hybrid materials combined with osteogenetic cells and porous hydroxyapatite (HAP) in vivo.
We used rat bone marrow cells and first sub-cultured cells of bone marrow as osteogenetic cells which have the possiblility of differentiating into osteoblasts. These cells were cultured with porous HAP granules for 1 week using a-MEM sup-plemented with dexamethazone, β-glycerophos-phate and ascorbic acid.
Hybrid materials combined with osteogenetic cells and HAP granules were cultured with PBS for 3 hours before implantation, and then implanted into ectopic (subcutaneous) sites in rats. At 5 weeks after implantation, these specimens were examined histologically. New bone formation was observed on the surface of HAP and the inside of HAP. However, HAP implantation without osteogenetic cells produced no bone formation.
Our results demonstrate that the hybrid materials (containing both bone marrow cells and first sub-cultured cells of bone marrow) can form new bone at ectopic (subcutaneous) sites.
