1995 Volume 37 Issue 4 Pages 605-617
The mechanism of osteoclastic bone resorption induced by periodontopathic bacteria Actinobacillus actinomycetemcomitans cell-surface components was investigated in mouse organ cultures and in a mouse bone marrow culture system. Lipopolysaccharide and capsular polysaccharide isolated from A. actinomycetemcomitans Y 4 induced bone resorption in C 3 H/HeN mouse calvarium organ culture. Many multinucleated cells were formed when mouse bone marrow cells were cultured with A. actinomycetemcomitans Y 4 capsular polysaccharide or lipopolysaccharide for 9 days. The multinucleated cells showed several characteristics of osteoclasts, the production of including tartrateresistant acid phosphatase and the ability to resorb calcified dentine. in this study, monospecific antimouse recombinant interleukin-1 a serum and indomethacin completely inhibited the formation of osteoclasts in the presence of A. actinornycetemcomitans Y 4 capsular polysaccharide. An IL-1 receptor antagonist significantly inhibited the osteoclast formation in mouse marrow cultures. Bioactive IL-1 was detected in the culture supernatant of mouse bone marrow cells stimulated with A. actinomycetemcomitans Y 4 capsular polysaccharide. These results indicate that IL-1 a is involved in the mechanism of formation of osteoclast-like cells induced by A. actinomycetemcomitans Y 4 capsular polysaccharide. There was also a good correlation between the number of osteoclasts formed in the mouse marrow culture and the amount of prostaglandin E2 released into the culture medium. These findings suggest that A. actinomycetemcomitans capsular polysaccharide may play an important role in inflammatory bone resorption by promoting osteoclast formation in periodontal diseases.
