Abstract
The effects of HAP granules on soft tissue were studied histologically. HAP granules in the present study have irregular shape and many continuous pores ranging from 50 μm to 200 μm in diameter, which have a Ca/P molar ratio of 1:1.65. They are sintered at 1,200℃. These granules were grafted into the abdominal subcutaneous region of Wister-rats. Spacemens were removed at verious intervals and observed with light and electron microscopy.
The results were as follows: Macrophages were observed around HAP granules right after grafting, and they showed engulfing HAP particles during 0.4～1.2 μm at one week or two weeks after grafting.
After 4 weeks, mufti-nuclear giant cells engulfing HAP particles ranging from 2 to 6 μm were observed, however they did not have digesting and absorpting abilities.
Larger HAP particles, which were coated with overlap of multi-nuclear giant cells and connective tissue, were recognized. It seemed that multinuclear giant cells in contact with HAP granules, which were observed later, were formed with fusion of macrophages.
This suggested that macrophages and multinuclear cells in contact with HAP granules do not have the ability of osteoclast-like-cells.
