Effect of anaerobic bacteria in apical periodontitis on intracellular signal transduction of the host

分析根管渗出物对阐明持续性根尖牙周炎的发病机制具有重要意义。本研究比较了两种方法对肛管内渗出液的细菌检测能力。一种是常规方法，即取样后立即将样品运送到厌氧室，然后转移到外部实验室进行细菌鉴定。另一种是预培养法，即取样后立即将样品接种到半固体培养基中，厌氧培养24小时，然后移至实验室。预培养法检出细菌18例22例，常规法检出细菌6例22例。预培养法的细菌检出率明显高于预培养法。革兰氏阳性球菌如肠球菌多见。结果表明，预培养法可以有效地检测根管内细菌，提高抗生素治疗的效率。当细菌侵入宿主时，可能涉及细胞内反应。我们比较了从临床病例中分离的5株肠球菌提取的DNA的限制性内切谱，并研究了它们对HeLa细胞酪氨酸磷酸化的影响，因为酪氨酸在信号转导中起重要作用。所有分离菌株的DNA模式都不同，这表明它们的来源不同。然而，临床症状和x线表现有一定的刺激。因此，人们认为，即使菌株不同，细菌也可能在宿主细胞中引起相同的反应。肠球菌的刺激没有改变酪氨酸磷酸化。这表明细菌的直接刺激可能不会影响信号转导。然而，细胞内和细胞间的反应具有复杂的网络，需要进一步的研究来分析内生细菌和宿主之间的关系。少

Analysis of root canal exudate is important to clarify the mechanism for persistent apical periodontitis. This study compared the ability of bacterial detection from the intracanal exudate by two methods. One is a conventional method, i.e.the samples were transported into anaerobic chambers immediately after sampling and then moved to an outside laboratory for bacterial identification. Another is a pre-culture method, i.e.the samples were inoculated into semi-solid medium immediately after sampling, incubated for 24 hours anaerobically, and moved to the laboratory. The pre-culture method detected bacteria in 18 cases of 22 persistent cases, while the conventional method detected bacteria in 6 cases from 22 cases. The pre-culture method showed the significantly higher frequency of bacterial detection. Gram positive cocci like Enterococcus were detected in many cases. These results suggested that the pre-culture method could be helpful for detecting the intracanal bacteria and contribute … More efficient endodontic treatment using antibiotics.Intracellular reaction might be involved when the bacteria invaded into the host. We compared the restriction profiles of the DNA extracted from five strains of Enterococcus isolated from clinical cases and investigated the effect of them on tyrosine phosphorylation in HeLa cell because it plays an important role in signal transduction. DNA patterns were different in all strains isolated and it revealed that the origin of them were different. However, there were some stimulation in clinical symptoms and X-ray appearance. Therefore, it was thought that the bacteria might have caused same reactions in the host cell even if the bacteria strains were different. The stimulation by Enterococcus did not alter the tyrosine phosphorylation. This suggested that the direct bacterial stimulation might not affect the signal transduction. However, intracellular and intercellular reactions have complex networks and further studies will be needed to analyze the relationships between the endopathogenic bacteria and the host. Less