Narrow Results

Effects of porous hydroxyapatite granules (HAGs) on osteogenesis were examined in vitro using cells from adult rabbit femurs. Cultures in the space of 30-600 μm between glass plates with two-dimensionally arranged HAGs on the horizontal bottom glass surface induced thin insular tissue formation within 2 weeks. It was induced earlier and more than that without HAGs. Von Kossa staining-positive tissues were found at 1-2 weeks after their formation, suggesting their mineralization. No cells or several cells in monolayer were included within some of them. Several grew quadrate tissues. Similar thin tissues were formed in inclined and rotated glass tubes with three-dimensionally arranged HAGs. They were almost irregular in shape. By contrast, little extracellular matrix deposition and no mineralization were seen in the spaces over 600 μm and under 30 μm between the glasses with HAGs. These results suggest that osteoblastic cells from adult femurs form mineralized quadrate tissues with or without embedded cells on the horizontal glass in the space of 30-600 μm, while mechanical loading without system induces irregular-shaped tissue formation. Porous HAGs in the space seem to accelerate extracellular matrix accumulation and its mineralization.