[The roles of macrophage on the mechanism of development of periapical lesion. The response of macrophage stimulated with bacteria isolated from infected root canals].

It has been proposed that bacteria in infected root canals are most important agents to pathogenesis of the periapical lesion. The aim of the present study was to examine the roles of macrophage on the mechanism of development of periapical lesion. Therefore the influences of bacteria isolated from infected root canals to macrophage functions and the effects of products from macrophage stimulated with bacterial components to periodontal tissue were investigated. In this study, sonic extracts prepared from Bacteroides buccae predominantly isolated from root canals were tested for its capacity of induction of chemotaxis and production of prostaglandin E2 and collagenase from human peripheral monocyte. Furthermore prostaglandin E2, collagenase production and alkaline phosphatase activity of fibroblasts from human periodontal ligament (HPLF), pulp (HPF) and gingiva (Gin 1) stimulated with macrophage conditioned medium (MCM) stimulated with B. buccae sonic extracts were examined. The results obtained were as follows. The sonic extract of B. buccae showed capacity to induce macrophage chemotaxis directly and by activation of serum complement, and the serum activated with sonic extract of B. buccae was more active than the serum activated with LPS of Salmonella typhimurium. Prostaglandin E2 production of macrophage was increased when the cells were stimulated by sonic extracts of B. buccae, but collagenase activity. toas not increased. MCM stimulated with sonic extracts of B. buccae fot 48 hours strongly induced PGE2 and collagenase production from HPLF and HPF, at the same time sonic extract showed the similar capacity of induction of the PGE2 production of MCM. But, HPF stimulated with sonic extract showed the low activity of induction of the PGE2 production. On the other hand, Gin 1 cell produced a few amount of the PGE2 when it was stimulated with MCM, but not produced collagenase. Alkaline phosphatase activity of HPLF and HPF had been inhibited by addition of MCM stimulated with B. buccae sonic extract.