Cell-surface components Actinobacillus actinomycetemcomitans promote osteoclast formation in vitro

在小鼠器官培养和小鼠骨髓培养体系中，研究了牙周病细菌放线杆菌细胞表面成分诱导破骨细胞性骨吸收的机制。伴放线放线菌Y4的脂多糖和壳多糖在小鼠颅骨器官培养中诱导骨吸收小鼠骨髓细胞与放线菌Y4衣壳多糖或脂多糖共同培养9d后，可形成大量多核细胞。多核细胞表现出破骨细胞的几个特征，包括抗酒石酸酸性磷酸酶的产生和吸收钙化牙本质的能力。在本研究中，单特异性重组白介素2-Lα血清和消炎痛完全抑制破骨细胞在伴随放线菌Y-4胶囊多糖存在下的形成。IL-1受体拮抗剂能显著抑制小鼠骨髓破骨细胞的形成。放线菌Y4壳多糖刺激小鼠骨髓细胞培养上清液中可检测到具有生物活性的IL-1。提示IL-1α参与了伴放线放线菌Y4荚膜多糖诱导破骨细胞样细胞形成的机制。小鼠骨髓培养中形成的破骨细胞数与培养液中前列腺素E_2的释放量也有很好的相关性。提示放线菌荚膜多糖可能通过促进破骨细胞的形成在牙周病的炎症性骨吸收中发挥重要作用。

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-l alpha serum and indomethacin completely inhibited the formation of osteoclasts in the presence of A.actinomycetem comitans Y 4 capsular polysaccharide. An IL-1 receptor antagonist significantly inhibited the osteo clast 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 alpha 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 E_2 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.