2009 年 6 巻 3 号 p. 180-188
We had previously developed hydroxyapatite fiber material (HF) consisting of 100% hydroxyapatite fibers of 5-15µm in diameter. The purpose of the present study was to examine whether HF supports proliferation and differentiation of osteogenic cells as scaffold and whether it is effective as bone substitute.
Firstly, rat bone marrow cells were prepared and cultured. Then, these cells were incorporated into HF and cultured in osteogenic medium. After 7, 10 and 14 days of culture, DNA content, alkalinephosphatase (ALP) activity and gene expression of osteogenic genes (osteocalcin and type I collagen) were examined.
Secondary, the bone defects of 3mm in diameter were prepared in tibias of nine Japanese rabbits. The defects of the right tibias were filled with HF while the defects of the other side were untreated. The animals were sacrificed at 1, 2 and 3 months. The defects were analyzed with soft X-ray and micro CT and histologically.
In the culture experiment increase in DNA content and ALP activity and osteogenic gene expression was evident suggesting that bone marrow cells can grow and differentiate to osteoblastic cells in HF. Radiological and histological analyses in animal experiments demonstrated disappearance of HF from bone marrow without eliciting inflammatory response to the surrounding tissue and complete regeneration of the bone defects at 3 months. These results indicate that HF could be favorable scaffold for bone regeneration and effective as resorbable bone substitute.