牙龈卟啉单胞菌菌毛蛋白A参与诱导小鼠牙槽骨吸收

目的探讨牙龈卟啉单胞菌菌毛蛋白(Fim)A是否参与该菌引起牙槽骨吸收的作用。方法用牙龈卟啉单胞菌ATCC33277野生菌株感染BALB/c小鼠,建立其诱导的牙周病动物模型。用ATCC33277及其fimA基因敲出的牙龈卟啉单胞菌KDP150变异菌株分别感染实验动物BALB/c小鼠(每组5只小鼠),测量其牙槽骨的改变情况,且与未接种细菌的阴性对照组相比较,采用t检验进行统计学分析。结果 ATCC33277组小鼠牙槽骨吸收量高于阴性对照组(P0.05),而fimA基因敲除菌株KDP150与对照组相比较,牙槽骨吸收量差异无统计学意义(P0.05)。野生菌株组小鼠牙槽骨吸收量高于fimA基因敲除菌株组(P0.05)。结论牙龈卟啉单胞菌fimA可能是该菌引起牙槽骨吸收的重要毒力因子。     

牙龈卟啉单胞菌对小鼠肠道炎症的影响研究

目的:研究牙龈卟啉单胞菌(Porphyromonas gingivalis,P.g)对小鼠肠道炎症的诱导作用及机制探究。方法:将12只BALB/C小鼠随机均分为2组,P.g组灌饲0.2 mL OD₆₀₀=0.5的P.g菌液,对照组灌饲等量无菌BHI液体培养基。每只小鼠每日灌饲1次,起始和每次灌饲1周时小鼠称重,7周后采用颈椎脱臼法处死小鼠,采取小肠组织并收取粪便。粪便进行16S rRNA测序分析肠道菌群多样性;小肠组织行HE染色分析肠道炎症进展。免疫组化分析炎症因子IL-17的表达及铁死亡指标(ACSL4,SLC7A11,GPX4)的水平变化。结果:对照组和P.g灌饲组小鼠体重第7周时存在差异(P<0.05)。HE染色显示P.g组小鼠小肠黏膜下炎症细胞浸润增加,绒毛间质轻微水肿,提示肠道炎症浸润。免疫组化结果显示,P.g灌饲组小鼠小肠组织IL-17明显升高。小肠组织中ACSL4水平显著增高,SLC7A11和GPX4水平降低,小鼠小肠组织在P.g作用下发生了铁死亡。16S rRNA结果显示P.g组与对照组间肠道菌群差异明显(P<0.05)。结论:P.g可...     

牙龈卟啉单胞菌研究进展

牙周炎是常见的口腔疾病之一,是中国成年人失牙的主要原因.牙龈卟啉单胞菌在引发牙周组织破坏过程中发挥着重要的作用,成为国内外学者研究的热点之一.本文就牙龈卟啉单胞菌与口腔疾病和其他全身性疾病的关系、牙龈卟啉单胞菌全基因组,牙龈卟啉单胞菌与牙龈上皮细胞的相互作用等研究作一综述,以拓宽牙龈卟啉单胞菌的研究思路,进血为牙周炎的...     

牙龈卟啉单胞菌与动脉粥样硬化

大量流行病学证据已经证实牙周病和动脉粥样硬化存在一定的相关性,目前的研究主要偏向于牙周病在动脉粥样硬化病因中的作用机制,牙周病的病原体如牙龈卟啉单胞菌是否为动脉粥样硬化的病原体尚不清楚.本文对牙龈卟啉单胞菌在动脉粥样硬化发生、发展过程中所起的作用作一综述.     

牙龈卟啉单胞菌膜泡对牙龈上皮细胞MMPs基因表达的影响

目的:探讨牙龈卟啉单胞菌膜泡对牙龈上皮细胞基质金属蛋白酶(MMPs)基因表达的影响,揭示牙龈卟啉单胞菌在牙周炎中的致病作用.方法:以Real-time RT-PCR法检测牙龈卟啉单胞菌膜泡刺激下牙龈上皮细胞MMP-1和MMP-3的mRNA表达水平.结果:牙龈卟啉单胞菌膜泡显著地上调MMP-1和MMP-3 mRNA表达水平.结论:牙龈卟啉单胞菌诱导牙龈上皮细胞发生细胞炎症反应,可能是牙周炎发生、发展的重要因素.     

牙龈卟啉单胞菌与冠心病

牙周病是引起冠心病的危险因素之一,牙龈卟啉单胞菌是引起牙周病的主要致病菌,它可以侵入血管内膜导致血管壁增厚及释放内毒素,释放细胞因子促进血小板的聚集,血栓形成,从而导致心血管疾病的发生。     

牙龈卟啉单胞菌及其牙龈蛋白酶K对青少年牙龈健康的影响

目的：分析牙龈卟啉单胞菌（P. gingivalis）及牙龈蛋白酶K（Kgp）对青少年牙龈健康的影响。方法???收集12~17岁青少年牙龈正常组（50例）、牙龈炎症指数Ⅰ级组（25例）和牙龈炎症指数Ⅱ级组（32例）的3组龈沟液标本,应用16S?rDNA?PCR技术检测各样本中的P. gingivalis及Kgp。3组P. gingivalis和Kgp阳性检出率的比较采用χ2检验;P. gingivalis和Kgp的相对含量与牙龈炎症指数之间的关系采用Spearman相关分析。结果???P. gingivalis在牙龈炎症指数Ⅰ级组的检出率大于牙龈正常组,牙龈炎症指数Ⅱ级组的检出率大于牙龈炎症指数Ⅰ级组和牙龈正常组,牙龈炎症指数Ⅰ级组、Ⅱ级组与牙龈正常组间有明显差异（P<0.01）,牙龈炎症指数Ⅰ级组与Ⅱ级组间差异具有统计学意义（P<0.05）。Kgp在牙龈炎症指数Ⅰ级组的检出率大于牙龈正常组,牙龈炎症指数Ⅱ级组的检出率大于牙龈炎症指数Ⅰ级组和牙龈正常组,牙龈炎症指数Ⅰ级组与牙龈正常组间差异具有统计学意义（P<0.05）,牙龈炎症指数Ⅱ级组与牙龈正常组间有明显差异（P<0.01）。P. gingivalis和Kgp的检出率随着牙龈炎症指数的增加而升高。结论???P. gingivalis和Kgp与青少年牙龈健康密切相关。     

阳离子诱导牙龈卟啉单胞菌FtsZ的聚合

在细菌细胞分裂过程中 ,一系列的相关蛋白质参与这一过程 ,其中FtsZ(filamentoustemperature sensitiveproteinZ)通过在未来细菌细胞分裂的中点处聚合成FtsZ环发挥着极其重要的作用。在本实验中 ,我们探讨了牙龈卟啉单胞菌(Porphyromonasgingivalis,Pg)的FtsZ(PgFtsZ)的体外聚合特性 ,以期为研制和开发干扰Pg菌细胞分裂的抗菌剂奠定实验基础。1.材料和方法 :(1)PgFtsZ的C末端缺失变异型质粒 pYW 1和 pYW 4在以前的实验中构建。(2 )PgFtsZ的N末端缺失变异型质粒的构建 :使用相同的downstream引物和两个不同的upstream引物 ,通过PC…     

牙龈卟啉单胞菌侵入牙龈上皮细胞的分子机制

牙龈卟啉单胞菌是慢性牙周炎的主要致病菌,牙龈上皮细胞是宿主牙周组织防御机制的第一道天然屏障。牙龈卟啉单胞菌可通过特异性粘附素与牙龈上皮细胞相应配体结合,激活该细胞内多种信号传导途径,最终内化于牙龈上皮细胞。内化后可通过某些细胞因子的合成和分泌减少以及抑制细胞凋亡等机制造成该细胞功能紊乱。本文从分子水平对牙龈卟啉单胞菌侵入牙龈上皮细胞的机制作一综述,以进一步阐明牙龈卟啉单胞菌的致病机理。     

黏性放线菌对牙龈卟啉单胞菌生长的影响

目的:研究黏性放线菌(Actinomyces viscosus,A.viscosus)对牙龈卟啉单胞菌(Porphyromonas gingivalis,P.gingivalis)生长的影响。方法:将细菌分为3组,即A.viscosus组、P.gingivalis组和2种细菌等量、等浓度混合组。3组细菌专性厌氧培养48h,绘制生长曲线;混合细菌组每隔2h取菌悬液梯度稀释,接种于BHI血琼脂平板,培养72h,计数P.gingivalis占菌落总数的百分比;制备P.gingivalis BHI血琼脂平板,将不同浓度的A.viscosus菌悬液及除菌后的上清液滴注于已经接种P.gingivalis的固体血琼脂平板,厌氧条件下培养72h,测量抑菌圈直径。实验数据采用SPSS10.0软件包进行单因素方差分析。结果:3组中,A.viscosus2h已处于对数生长期,8h达平台期;P.gingivalis在12h进入对数生长期,32h达平台期;混合细菌组在2h开始进入对数生长期,12h达平台期;混合细菌组前8h P.gingivalis所占总菌落数的百分比随时间延长呈下降趋势﹙P<0.05﹚,8h后平板上已经没有P.gingivalis的存在;1×109、108、107、106A.viscosus对P.gingivalis的抑菌圈平均直径(mm)为19.3、17.4、13.2和9.8,差异具统计学意义﹙P<0.05﹚;A.viscosus的上清液对P.gingivalis无抑制作用。结论:A.viscosus对P.gingivalis生长的抑制作用是由于前者生长速度快,造成营养性竞争所致。     

Heterogeneity of Porphyromonas gingivalis strains in the induction of alveolar bone loss in mice

These experiments examine alveolar bone loss in a model in which specific pathogen-free mice are exposed orally with Porphyromonas gingivalis. Alveolar bone loss was induced as a result of a specific infection with P. gingivalis, rather than other environmental antigens. Infection with live P. gingivalis was required, as significant bone loss did not follow gavage with formalin-killed P. gingivalis. The virulence of different strains of P. gingivalis was compared. Two laboratory strains of the bacteria (ATCC 53977 and W50) and a mutant strain lacking the 43-kDa fimbrillin (strain DPG3) induced bone loss. P. gingivalis 381, however, did not induce bone loss. There was a strong immunoglobulin G (IgG) antibody response to infection with each strain but a significant serum IgA response only to strain 381. These studies show that in mice with a background oral microflora bone loss is induced by a specific infection with P. gingivalis and that bacterial strain variation is important in determining whether alveolar bone loss will ensue.     

Serum antibody response to oral infection precedes but does not prevent Porphyromonas gingivalis–induced alveolar bone loss in mice

The purpose of this study was to determine whether humoral immunity prevents bacterially induced alveolar bone loss. BALB/cByJ mice were orally infected with the human periodontopathic bacterium Porphyromonas gingivalis, and were compared with sham-infected mice. Specific serum antibody titers to P. gingivalis were measured by enzyme-linked immunosorbent assay. Alveolar bone levels were measured as the distance from the cementoenamel junction to the alveolar bone crest and bone loss was defined as a change in bone levels over time or between infected and sham-infected animals. The specific humoral response was predominantly of the IgG isotype, although low levels of specific serum IgA were also present. Antibody titers in the infected animals were significantly different from those in the sham-infected animals by 18 days and remained at maximal levels at 47 days. Bone loss became significant by 26 days and continued to progress at 47 days. Thus the serum antibody response to oral infection with P. gingivalis preceded detectable bone loss and remained elevated while bone loss increased. The presence of specific antibody did not prevent the onset or progression of bone loss.     

Serum antibody response to oral infection precedes but does not prevent Porphyromonas gingivalis–induced alveolar bone loss in mice

The purpose of this study was to determine whether humoral immunity prevents bacterially induced alveolar bone loss. BALB/cByJ mice were orally infected with the human periodontopathic bacterium Porphyromonas gingivalis, and were compared with sham-infected mice. Specific serum antibody titers to P. gingivalis were measured by enzyme-linked immunosorbent assay. Alveolar bone levels were measured as the distance from the cementoenamel junction to the alveolar bone crest and bone loss was defined as a change in bone levels over time or between infected and sham-infected animals. The specific humoral response was predominantly of the IgG isotype, although low levels of specific serum IgA were also present. Antibody titers in the infected animals were significantly different from those in the sham-infected animals by 18 days and remained at maximal levels at 47 days. Bone loss became significant by 26 days and continued to progress at 47 days. Thus the serum antibody response to oral infection with P. gingivalis preceded detectable bone loss and remained elevated while bone loss increased. The presence of specific antibody did not prevent the onset or progression of bone loss.     

The gingipains from Porphyromonas gingivalis do not directly induce osteoclast differentiation in primary mouse bone marrow cultures

Background and Objective:  Porphyromonas gingivalis is a major aetiological agent in the development of periodontitis, the major clinical hallmark of which is bone resorption. The cysteine proteases (gingipains) produced by P. gingivalis have a critical role in the pathogenesis of the disease, and previous studies on whole bacteria have implicated these enzymes in osteoclastogenesis, a process which serves to upregulate bone resorption. The effects of the gingipains from P. gingivalis on osteoclast differentiation were investigated here to determine whether the enzymes directly contribute to osteoclastogenesis and thus to bone resorption.
Material and Methods:  The effects of the gingipains on osteoclast differentiation were investigated in primary mouse bone marrow cultures. The cultures harvested from C57BL6/J mice were incubated in the presence of parathyroid hormone, a known osteoclastogenic factor, or active/inactivated forms of three gingipains. Osteoclast differentiation was quantified by counting the number of multinucleated cells positive for tartrate-resistant acid phosphatase, an enzyme marker for these cells.
Results:  After 10 days of culture, the gingipains, either active or inactive, failed to stimulate osteoclast differentiation in comparison to the parathyroid hormone.
Conclusion:  The data presented here demonstrate that the gingipains do not induce osteoclast differentiation in this system, indicating that the bacterium uses other mechanisms to induce bone loss.     

A tumor necrosis factor-alpha antagonist inhibits inflammatory bone resorption induced by Porphyromonas gingivalis infection in mice

BACKGROUND: A tumor-necrosis factor-alpha (TNF-alpha) antagonist, the WP9QY peptide, was designed based on the crystal structure of the TNF-beta/TNF-receptor complex in order to overcome the disadvantages of macromolecules such as antibodies or soluble receptors by reducing the molecular size of TNF-alpha antagonists. It efficiently antagonizes the effect of TNF-alpha binding to the TNF receptor (I). OBJECTIVES: The aim of the present study was to assess the effects of the WP9QY peptide on inflammatory bone resorption and osteoclast formation in the periodontal pathogen-infection model. MATERIAL AND METHODS: Live Porphyromonas gingivalis ATCC 33277 was injected once daily for 6 days into the subcutaneous tissue overlying the calvariae in mice. At the same time, the WP9QY peptide (1 mg/kg, 2 mg/kg or 4 mg/kg per day) was administrated via osmotic minipumps for 7 days. Histological observations and the radiological assessments of the calvariae as well as bone mineral density measurements were performed. RESULTS: The WP9QY peptide significantly prevented the P. gingivalis-induced reduction in the bone mineral density at the calvariae. The histomorphometric assessments revealed the inhibitiory effects of the WP9QY peptide on the P. gingivalis-induced increase in the number of the inflammatory cells and in the area of sagittal suture at the calvariae. Furthermore, there was also an inhibitory effect on the P. gingivalis-induced increase in the number of osteoclasts per unit bone surface at the calvariae. CONCLUSION: These results suggest that the strategy for the design to reduce the molecular size of the TNF-alpha antagonists would be beneficial for the treatment of local inflammatory bone loss induced by periodontal-pathogen infection.