Development of focal infection model result from infected root canal-associated bacteria on compromised hosts.

对环孢素A(CsA)诱导的免疫抑制与未治疗或残留的根尖周病变随时间的变化进行了三维相关性研究，并进行了组织病理学分析。CsA治疗显著抑制了病变的扩大。停用CsA后，对照组的病灶大小有相同程度的增大。此外，组织病理学观察表明，CsA给药量的差异对CsA的影响不大。然而，CsA可导致纤维组织中的细胞间质增多，尤其是20 mg/kg/d给药组。体外观察了7种感染的根管相关细菌(RCB)对牙胶尖(GP)的生物膜形成能力。粪肠球菌形成生物被膜的频率最高，而未裂解梭杆菌和痤疮丙酸杆菌根本不形成生物膜。用细菌学技术评价了5种RCB对Beagle犬关节外GPs的生物被膜能力。粪肠球菌占受检标本的71.4%，是最适合在小叶外部位形成生物被膜的细菌。根据他们的结果，准备了给药的折衷动物，用于调查浮游细菌从粪肠球菌生物被膜中脱落所引起的菌血症。给药4周，未引起菌血症，而在根尖周病变处，约10^3倍的生物膜细菌体外植入粪肠球菌后，在根尖周病变处形成持续菌血症。对药物浓度和给药时间进行了进一步的研究，并在受损动物身上继续寻找由节外生物膜引起的菌血症。

Correlation between Cyclosporin A (CsA)-induced immunosuppression and untreated or residual periapical lesions has been investigated 3 dimensionally with time, and histopathological analysis were performed. CsA treatment significantly inhibited lesion expansion.. Agter withdrawal of CsA, the lesion increased in size to a same extent in a control group. In addition, histopathological observation revealed that the difference of CsA administration volume did not affected much. However, CsA treatment induced intercellular substance in fibrous tissue to be voluminous, especially in 20mg/Kg/day administration group.In vitro, biofilm forming capacity of 7 infected root canal-associated bacterial (RCB) species to gutta-percha points (GP) was investigated morphologically. Enterococcus faecalis formed most frequently biofilm, but Fusobacterium uncleatum or Propionibacterium acnes did not form it at all. The biofilm forming capacity of 5 RCB species to extraradicular GPs on beagle dogs were evaluated by bacteriologic technique. E. faecalis identified in 71.4% of the examined samples, and was most suitable biofilm forming bacterium in extraradicular area. According to their results, compromised-animals to be administrated methylpredonisolon acetate were prepared for investigation of bacteremia by which planktonic bavteria detached from extraradicular E. faecalis biofilm caused. For 4 weeks administration, bacteremia was not induced, whereas planktonic E. faecalis cells insertion of about 10^3 times biofilm bacteria on GP in vitro in the periapical lesion became continuously bacteremia. Drug concentration and administration period were further studied, and we are continuously searching bacteremia caused by extraradicular biofilm on compromised-animal.