Endotoxin tolerance refers to a state refractory to subsequent lipopolysaccharide (LPS) stimulations following a primary LPS exposure. To study the relationship between endotoxin tolerance and macrophage polarization, endotoxin tolerance was induced by 1 μg/mL LPS from the periodontal pathogen, Porphyromonas gingivalis (P. gingivalis), in peritoneal macrophages (PMs) and bone marrow-derived macrophages (BMDMs). Repeated P. gingivalis LPS challenges increased the quantities of CD206+ PMs, while the number of CD86+CD206+ PMs was reduced compared with the non-tolerant group (p < 0.05). However, there were no changes in BMDMs (p > 0.05). Down regulations of TNF-α, IL-12, nitric oxide and MMP-2 production, and upregulated IL-10, MMP-9 levels and arginase-1 activities occurred in tolerant PMs and BMDMs (p < 0.05). P. gingivalis LPS-tolerant PMs and BMDMs also enhanced scrape-wound healing abilities of 15p-1 cells (p < 0.05). Expressions of phospho-signal transducer and activator of transcription 6 (p-STAT6) and protein tyrosine phosphatase 1B (PTP1B) were increased, while p-MEK1/2 levels were downregulated in tolerant PMs and BMDMs (p < 0.05). IL-10 production in tolerant Stat6 knockdown RAW264.7 cells was lower than tolerant control cells (p < 0.05). P. gingivalis LPS-tolerant macrophages represented an intermediate state between M1/M2 polarization, which functioned as M2-like cells, and led to limited inflammatory responses and enhanced wound healing activities. The PTP1B-MEK1/2-STAT6 signaling pathway might be involved in the polarization of tolerant macrophages.

Tolerance is defined to be a hyporesponsive state following repeated stimulations with bacteria or their virulence factors and has potential impacts on the development of periodontitis. Recently, macrophages have been reported to release chromatin and antimicrobial peptides to form extracellular traps upon bacterial or chemical stimulations. Thus, we explored the roles and mechanisms of tolerance induced by Porphyromonas gingivalis (P. gingivalis) in macrophage extracellular traps (METs). Tolerance in peritoneal macrophages from mice was triggered by repeated P. gingivalis stimulation. METs were observed using fluorescence microscopy, and the levels of extracellular DNA were determined by microplate reader assays. The expression of p-RAF, p-MEK, and p-ERK was examined by Western blot, and reactive oxygen species (ROS) production was explored using flow cytometry. Moreover, the levels of intracellular Ca2+ were also determined by confocal microscopy to identify the possible mechanisms related to the changes in METs in P. gingivalis–pretreated macrophages. Repeated P. gingivalis stimulation contributed to the formation of METs and increased levels of extracellular DNA (p < 0.05). ROS generation and RAF/MEK/ERK phosphorylation were decreased in P. gingivalis–pretreated macrophages compared with non-pretreated cells (p < 0.05), which was inconsistent with the changes in METs. However, in P. gingivalis–pretreated macrophages, the levels of intracellular Ca2+ were significantly increased compared with the single stimulation group. Additionally, inhibition of intracellular Ca2+ resulted in a decrease in the levels of extracellular DNA in P. gingivalis–pretreated cells (p < 0.05). Taken together, P. gingivalis–pretreated macrophages released more METs, possibly related to the increased levels of intracellular Ca2+.

目的:探讨牙周基础治疗对一氧化氮(NO)代谢和血压的影响.方法:纳入45名血压正常的中、重度牙周炎患者,记录牙周基础治疗前及治疗后1月患者的菌斑指数、牙龈指数、探诊深度、临床附着丧失(CAL)及血压,采用Griess法测量治疗前后唾液及血浆NO氧化产物亚硝酸钠(NaNO2)水平,实时定量PCR技术检测治疗前后龈下菌斑中牙龈卟啉单胞菌(P.gin-givalis)、中间普氏菌(P.intermedia)及总菌水平,ELISA法检测治疗前后龈沟液(GCF)和血清中的白介素(IL)-6水平,以及血清C-反应蛋白(CRP)水平,并对治疗前血压、牙周临床指标、细菌数量、NaNO2、CRP、IL-6水平间的关系进行相关性分析.结果:牙周基础治疗后1月,患者各牙周临床指标、血压、唾液及血浆NaNO2水平、龈下菌斑中的P.gingivalis、P.intermedia及总菌水平、血清及GCF中的IL-6及CRP水平均显著下降(P<0.05).治疗前收缩压与GCF中IL-6水平、唾液NaNO2水平、CAL均存在中度相关性;舒张压与总菌水平、P.intermedia存在中度相关性(P<0.05).结论:牙周基础治疗能降低唾液及血浆NO水平,同时改善全身炎症状态,为伴高血压的牙周炎患者的治疗提供参考.

目的:从龈下菌斑总菌数、牙龈卟啉单胞菌(P.gingivalis)、伴放线聚集杆菌(A.actinomycetemcomitans)及白细胞毒素(LTX)在江苏汉族牙周炎人群中分布的角度,比较牙周病2018年新分类与1999年分类.方法:纳入73名牙周炎患者和26名牙周健康者,分别按照牙周病2018年新分类与1999年分类对牙周炎人群分组.初诊时记录全口探诊深度(PD)、临床附着丧失(CAL)、牙龈指数(GI)和菌斑指数(PLI),并收集龈下菌斑.采用实时定量PCR检测龈下菌斑中总菌、P.gingivalis和A.actinomycetemcomitans数量,采用PCR检测A.actinomycetemcomitans毒力因子LTX的携带率,比较上述指标在不同的牙周炎分类法间的分布差异.结果:慢性牙周炎和侵袭性牙周炎患者之间,总菌和P.gingivalis数量无显著差异(P>0.05),A.actinomy-cetemcomitans数量和LTX阳性率存在差异(P<0.05),所有检出的LTX均为低毒型.不同牙周炎分期分级组间,菌量和LTX阳性率存在差异(P<0.05).PD、CAL、GI与总菌、P.gingivalis、A.actinomycetemcomitans数量间存在相关性(P<0.05).结论:2018年牙周病新分类能较好地反映江苏汉族牙周炎患者的微生物学特征.