慢性牙周炎患者牙龈卟啉单胞菌感染与血清HMGB1、IL-1β、IL-6以及牙周临床指标的相关性研究

摘要 目的：研究慢性牙周炎患者牙龈卟啉单胞菌（Pg）感染与血清高迁移率族蛋白1（HMGB1）、白细胞介素-1β（IL-1β）、白细胞介素-6（IL-6）以及牙周临床指标的相关性。方法：将2019年1月～2020年12月在长沙市第三医院口腔科接受诊治的300例慢性牙周炎患者纳入研究,按照慢性牙周炎严重程度分成轻度组169例、中度组92例、重度组39例。对所有受试者进行Pg检测,同时检测血清HMGB1、IL-1β、IL-6水平和牙周临床指标水平。比较各组上述各项指标的差异,并以Pearson相关性分析慢性牙周炎患者Pg感染与血清HMGB1、IL-1β、IL-6水平以及牙周临床指标的相关性。结果：重度组和中度组的Pg感染阳性率、Pg感染浓度均高于轻度组,且重度组上述指标高于中度组（P＜0.05）。重度组和中度组的血清HMGB1、IL-1β、IL-6水平均高于轻度组,且重度组上述指标高于中度组（P＜0.05）。重度组和中度组的探诊深度（PD）、龈沟出血指数（SBI）以及附着丧失（AL）均高于轻度组,且重度组上述指标高于中度组（P＜0.05）。Pearson相关性分析显示：慢性牙周炎患者的Pg感染浓度与血清HMGB1、IL-1β、IL-6水平以及PD、SBI、AL均呈正相关（P＜0.05)。结论：慢性牙周炎患者的Pg感染浓度与血清HMGB1、IL-1β、IL-6水平及牙周健康状况密切相关,早期明确Pg感染浓度以及检测上述血清学指标水平,可能对抑制病程进展以及提高治疗效果具有指导意义。     

龈沟液miR-155、miR-223表达水平与慢性牙周炎伴2型糖尿病患者牙周临床指标、口腔龈下菌群以及Th17/Treg失衡的相关性分析

摘要 目的：探讨龈沟液miR-155、miR-223表达水平与慢性牙周炎伴2型糖尿病（T2DM）患者牙周临床指标、口腔龈下菌群以及外周血辅助性T细胞17（Th17）/调节性T细胞（Treg）失衡的相关性。方法：选择2018年1月至2022年1月安徽理工大学第一附属医院口腔科收治的86例慢性牙周炎患者,根据是否伴T2DM将患者分为慢性牙周炎伴T2DM组15例和单纯慢性牙周炎组71例,另选择65例健康体检志愿者为对照组。检测龈沟液miR-155、miR-223表达水平,口腔龈下菌群以及外周血Th17细胞占比、Treg细胞占比、血清白细胞介素（IL）-17、转化生长因子-β（TGF-β）水平。Pearson相关分析龈沟液miR-155、miR-223表达水平与牙周临床指标、口腔龈下菌群、外周血Th17/Treg以及血清IL-17、TGF-β的相关性。结果：慢性牙周炎伴T2DM组、单纯慢性牙周炎组龈沟液miR-155、miR-223表达水平高于对照组（P＜0.05）,且慢性牙周炎伴T2DM组高于单纯慢性牙周炎组（P＜0.05）。慢性牙周炎伴T2DM组龈沟出血指数（SBI）、菌斑指数（PLI）、探诊深度（PD）、附着丧失（AL）、牙龈卟啉单胞菌、二氧化碳噬纤维菌、中间普氏菌、变黑普氏菌数量、外周血Th17细胞占比、Th17/Treg比值、血清IL-17水平高于单纯慢性牙周炎组（P＜0.05）,外周血Treg细胞占比低于单纯慢性牙周炎组（P＜0.05）。龈沟液miR-155、miR-223表达水平与PLI、SBI、AL、PD、牙龈卟啉单胞菌、二氧化碳噬纤维菌、中间普氏菌、变黑普氏菌数量、外周血Th17细胞占比、Th17/Treg比值、血清IL-17水平呈正相关（P＜0.05）,与外周血Treg细胞占比呈负相关（P＜0.05）。结论：慢性牙周炎伴T2DM患者龈沟液中miR-155、miR-233表达均上调,且与牙周组织破坏程度、龈下菌群紊乱和Th17/Treg失衡有关。     

桥本甲状腺炎患者外周血miR-142-3p、miR-125a-5p水平与甲状腺功能和Th1/Th2及Th17/Treg细胞平衡的关系

摘要 目的：探讨桥本甲状腺炎（HT）患者外周血微小核糖核酸（miRNA）-142-3p、miR-125a-5p水平与甲状腺功能和辅助性T细胞（Th）1/Th2及Th17/调节性T细胞（Treg）细胞平衡的关系。方法：选取2020年1月～2023年8月我院收治的HT患者90例作为HT组和同时间段90名体检健康者作为对照组,根据甲状腺功能减低程度将HT患者分为甲状腺功能正常组（26例）、亚临床甲状腺功能减退组（31例）和临床甲状腺功能减退组（33例）。采用实时荧光定量聚合酶链式反应检测外周血miR-142-3p、miR-125a-5p水平,酶联免疫吸附法检测甲状腺功能指标[甲状腺球蛋白抗体（TgAb）、甲状腺过氧化物酶抗体（TPOAb）、促甲状腺激素（TSH）、游离三碘甲状腺原氨酸（FT₃）、游离甲状腺素（FT₄）],流式细胞术检测外周血Th1、Th2、Th17、Treg细胞比例,并计算Th1/Th2及Th17/Treg比值。通过Pearson/Spearman相关性分析HT患者外周血miR-142-3p、miR-125a-5p与甲状腺功能、Th1、Th2、Th17、Treg的相关性。结果：HT组外周血miR-142-3p、miR-125a-5p、TgAb、TPOAb、TSH、Th1、Th17、Th1/Th2、Th17/Treg比值高于对照组,FT₃、FT₄、Th2、Treg比例低于对照组（P＜0.05）。甲状腺功能正常组、亚临床甲状腺功能减退组、临床甲状腺功能减退组外周血miR-142-3p、miR-125a-5p、TgAb、TPOAb、TSH、Th1、Th17、Th1/Th2、Th17/Treg比值依次升高,FT₃、FT₄、Th2、Treg比例依次降低（P＜0.05）。Pearson/Spearman相关性分析显示,HT患者外周血miR-142-3p、miR-125a-5p与TgAb、TPOAb、TSH、Th1、Th17、Th1/Th2、Th17/Treg呈正相关,与FT₃、FT₄、Th2、Treg呈负相关（P＜0.05）。结论：HT患者外周血miR-142-3p、miR-125a-5p水平升高,与甲状腺功能减退和Th1/Th2、Th17/Treg细胞失衡有关。     

亚甲基蓝/光化学法辅助治疗慢性牙周炎对牙龈卟啉单胞菌的影响

目的研究亚甲基蓝/光化学法辅助治疗慢性牙周炎对牙龈卟啉单胞菌(Porphyromonas gingivalis,Pg)检出率的变化。方法经伦理委员会同意后,本研究拟筛选出45例慢性牙周炎患者(每位患者经过详细牙周检查及X线检查后确认为牙周炎,有4个以上≥5 mm的牙周袋并分布在2个以上口腔区域),随机分3组:其中A组在SRP之后接受1次PERIOWAVE光化学治疗,B组在SRP后接受1次PERIOWAVE治疗以及在6周后再一次接受光化学治疗,而SRP组仅接受SRP治疗,各组患者取治疗前后相同4个位点龈下菌斑,聚合酶链式反应(Poly-merase chain reaction,PCR)检测Pg,观察Pg菌的检出率,采用卡方检验,并计算χ2值。结果 SRP组、A组、B组3组各组治疗后均较治疗前检出率降低(P<0.001),A组与SRP组治疗后比较差异无统计学意义[A组:40%(24/60),SRP组:45%(27/60),χ2=1.4815,P>0.05],B组与SRP治疗后比较检出率降低[SRP组:45%(27/60),B组:20%(12/60)χ2=8.547,P<0.01];B组与A组治疗后比较检出率降低[A组:40%(24/60),B组:20%(12/60),χ2=5.7143,P<0.05]。结论亚甲基蓝/光化学法辅助治疗慢性牙周炎后牙龈卟啉单胞菌的检出率较治疗前降低;结合临床试验结果,尚可认为2次激光疗效较1次激光好。     

牙龈卟啉单胞菌影响牙龈上皮细胞miR1555p 通过JAK/STAR信号通路作用牙周炎的机制

目的 通过生物信息学对GEO数据库进行分析筛选miRNA后运用分子生物学手段验证并对机制进行深入探讨,为未来牙周炎治疗的生物标志物筛选及靶向治疗提供理论依据。 方法 通过生物信息学分析GEO数据库发现牙周炎患者中差异表达的miRNA。在DIANA生信预测网站中发现了与JAK/STAT信号传导方式有关的miRNA。随后,TargetScan被用于预测miRNA的靶mRNA,该mRNA不仅在牙周炎中差异表达,而且与JAK/STAT信号传导有关。利用基因集富集分析(GSEA)寻找与JAK/STAT信号转导途径紧密相关的基因集。通过实时定量PCR(qRTPCR)和免疫印迹法(Western blot)检测在牙周炎中差异表达并与JAK/STAT信号有关的miRNA和mRNA的表达。通过免疫组织化学(IHC)观察组织中IL6ST的表达。通过双重荧光素酶测定法证实了miRNA和mRNA之间的关系。此外,采用细胞内氧化活性氧红色荧光检测试剂盒检测活性氧(ROS)的变化。 结果 在牙周炎患者中,与正常组织比较,MiR1555p被下调,mRNA IL6ST被上调且差异均具有统计学意义(t=9.188 7、2.852 1,P=0.000 6、0.015 7)。与对照组比较,miR1555p在P.gingivalis处理组表达情况出现明显下降且IL6ST在处理后表达量出现明显升高,差异均有统计学意义(t=2.125 3、1.852 0,P=0.013 5、0.015 7)。miR1555p具有IL6ST 3′非翻译区的靶结合位点。通过过表达miR1555p能够明显抑制JAK/STAT信号通路pSTAT3、pJAK2、IL6ST蛋白的表达(t=1.924 8、2.530 8、3.107 5,P=0.023 1、0.011 6、0.010 0)。感染牙龈卟啉单胞菌后,细胞中的ROS产生增加(t=3.051 2、9.632 7,均P结论 牙龈卟啉单胞菌可抑制miR1555p表达,激活GECs中的JAK/STAR信号,促进牙周炎的发生和发展。     

口腔扁平苔藓患者外周血单个核细胞TL1A、sPD-1mRNA表达与Th17/Treg失衡的相关性分析

摘要 目的：探讨口腔扁平苔藓（OLP）患者外周血单个核细胞肿瘤坏死因子样配体1A（TL1A）、可溶性程序性死亡受体1（sPD-1）信使核糖核酸（mRNA）表达与辅助性T细胞17（Th17）/调节性T细胞（Treg）失衡的相关性分析。方法：根据133例OLP患者损害类型分为糜烂型组（74例）和非糜烂型组（59例）。检测外周血单个核细胞TL1A mRNA、sPD-1 mRNA表达和外周血维甲酸相关孤核受体γt（RORγt）mRNA、叉头框蛋白P3（FOXP3）mRNA表达以及Th17、Treg细胞比例。Pearson/Spearman相关性分析TL1A mRNA、sPD-1 mRNA表达与Th17/Treg相关因子的关系。结果：与非糜烂型组比较,糜烂型组外周血单个核细胞TL1A mRNA、sPD-1 mRNA、RORγt mRNA表达水平和外周血Th17比例、Th17/Treg比值升高,外周血Treg比例、FOXP3 mRNA表达降低（P＜0.05）。相关性分析显示,OLP患者外周血单个核细胞TL1A mRNA、sPD-1 mRNA表达与外周血Th17比例、RORγt mRNA表达、Th17/Treg比值呈正相关,与外周血Treg比例、FOXP3 mRNA表达呈负相关（P＜0.05）。结论：OLP患者外周血单个核细胞TL1A 、sPD-1 异常高表达,与Th17/Treg失衡密切相关,TL1A、sPD-1可能通过引起Th17/Treg失衡参与OLP的发生发展。     

牙龈卟啉单胞菌感染通过激活NLRP3小体诱导牙周膜细胞炎症反应及凋亡效应

目的观察牙龈卟啉单胞菌感染通过激活含NLR家族PYRIN域蛋白3(NLRP3)小体诱导人牙周膜细胞(hPDLCs)炎症反应及凋亡的效应。方法取健康前磨牙样本并分离培养hPDLCs,分为牙龈卟啉单胞菌感染的感染组和常规处理的对照组,检测细胞中NLRP3小体[NLRP3、凋亡相关斑点样蛋白(ASC)、含半胱氨酸的天冬氨酸蛋白水解酶(Caspase)-1]、凋亡基因[自杀相关因子(Fas)、Fas配体(FasL)、B淋巴细胞瘤-2基因(Bcl-2)、Bcl-2相关x蛋白(Bax)、Caspase-3]的表达量及培养基中炎症细胞因子[白细胞介素(IL)-1β、IL-18、肿瘤坏死因子-α(TNF-α)]的含量。结果感染组hPDLCs中NLRP3、ASC、Caspase-1、Fas、FasL、Bax、Caspase-3的表达量及培养基中IL-1β、IL-18、TNF-α的含量明显高于对照组,细胞中Bcl-2的表达量明显低于对照组。结论牙龈卟啉单胞菌感染能够诱导hPDLCs的炎症反应及凋亡且该作用与NLRP3小体的激活有关。     

木犀草素调节SIRT3/AMPK/mTOR信号通路对溃疡性结肠炎小鼠Th17/Treg免疫平衡的影响CSCD

探究木犀草素对溃疡性结肠炎(ulcerative colitis,UC)小鼠模型中辅助性T细胞17(Th17)/调节性T细胞(Treg)免疫平衡的影响,并分析其潜在机制。60只BALB/c雄性小鼠随机分为正常组、模型组、阳性对照组、木犀草素组、木犀草素+3-TYP组,每组12只。采用葡聚糖硫酸钠(DSS)诱导建立UC模型,观察并记录小鼠体重变化、大便稠度和大便潜血情况,计算疾病活动指数(DAI);HE染色观察结肠组织病理学变化;流式细胞术检测脾脏Th17、Treg细胞比例,计算Th17/Treg比值;ELISA检测结肠组织中IL-6、IL-10、IL-17和IL-23含量;RT-qPCR检测结肠组织RORγt和Foxp3的mRNA表达;Western blot检测结肠组织SIRT3、AMPK、p-AMPK、mTOR、p-mTOR蛋白表达。与正常组相比,模型组小鼠DAI评分、组织病理学评分、脾脏Th17/Treg比值、结肠组织IL-6、IL-17、IL-23、RORγt mRNA水平和p-mTOR/mTOR比值升高,IL-10、Foxp3 mRNA和SIRT3蛋白水平以及p-AMPK/AMPK比值降低(P<0.05)。经药物干预后,小鼠DAI评分、组织病理学评分、脾脏Th17/Treg比值、结肠组织IL-6、IL-17、IL-23、RORγt mRNA水平和p-mTOR/mTOR比值降低,IL-10、Foxp3 mRNA和SIRT3蛋白水平以及p-AMPK/AMPK比值升高(P<0.05);3-TYP可减弱木犀草素对UC小鼠Th17/Treg细胞分化平衡的影响(P<0.05)。木犀草素可改善DSS诱导的UC小鼠模型中Th17/Treg失衡,其机制可能与激活SIRT3/AMPK/mTOR通路有关。     

牙龈卟啉单胞菌脂多糖通过TXNIP/Nlrp3炎性通路对小鼠牙周膜成纤维细胞迁移的影响

目的：研究牙龈卟啉单胞菌脂多糖（Porphyromonas lipopolysaccharide,LPS-PG）对牙周膜成纤维细胞（mouse periodontal Ligament:Normal Fibroblasts,m PDLFs）增殖及迁移的影响,探讨TXNIP/Nlrp3炎性体途径在其中的作用。方法：采用不同浓度的LPS-PG刺激小鼠m PDLFs细胞不同时间,CCK-8法检测细胞增殖抑制率。然后将细胞分为对照组（培养基作用24 h）和LPS-PG组（2 M的LPS-PG作用24 h）,划痕实验检测细胞迁移,ELISA法检测白细胞介素-1β(Interleukin-1β,IL-1β)和高迁移率族蛋白B1(High mobility group protein B1,HMGB1)的水平,Western Blot检测Nod样受体蛋白3(Nod-like receptor pyrin domain3,NLRP3)、凋亡相关斑点样蛋白（Apoptosis-associated speck-like protein,ASC）、活化半胱氨酸蛋白酶（cleaved-caspase-1）和...     

HPV感染患者阴道微生态、Th17/Treg细胞及相关细胞因子表达分析

目的分析人乳头瘤病毒（HPV）感染患者阴道微生态、辅助性T细胞17（Th17）/调节性T细胞（Treg）及相关细胞因子表达情况,为该类患者的治疗提供参考。方法选取2020年5月至2022年6月厦门大学附属妇女儿童医院收治的HPV感染患者108例作为研究组,另选取我院同期健康体检者108例作为对照组。两组受试者均进行HPV筛查、阴道菌群检测以及阴道微生态检测,采用流式细胞仪检测Th17/Treg细胞;采用酶联免疫吸附法（ELISA）检测白细胞介素-6（IL-6）、IL-10和IL-17水平;采用Spearman法分析HPV感染患者阴道菌群和Th17/Treg细胞及相关细胞因子的相关性。结果HPV共检出9种亚型,主要以HPV 16和HPV 18为主。研究组患者阴道乳杆菌阳性率显著低于对照组,衣原体、解脲支原体、滴虫和细菌性阴道病阳性率均显著高于对照组（均P＜0.05）。研究组患者阴道pH＞4.5、阴道菌群密集度Ⅱ～Ⅳ级、阴道菌群多样性Ⅱ～Ⅳ级和微生态失调率均显著高于对照组（均P＜0.05）。研究组患者Th17/Treg、IL-6、IL-10和IL-17水平显著高于对照组（均P＜0.05）。Spearman相关性分析显示,阴道中乳杆菌与Th17/Treg、IL-6、IL-10和IL-17水平均呈负相关;衣原体、解脲支原体、滴虫和细菌性阴道病与Th17/Treg、IL-6、IL-10和IL-17水平均呈正相关（均P＜0.05）。结论HPV感染患者存在阴道微生态失调,而且Th17/Treg细胞、IL-6、IL-10和IL-17水平均异常升高。     

Cloning and characterization of heavy and light chain genes encoding the FimA-specific monoclonal antibodies that inhibit Porphyromonas gingivalis adhesion

FimA of Porphyromonas gingivalis, a major pathogen in periodontitis, is known to be closely related to the virulence of these bacteria and has been suggested as a candidate for development of a vaccine against periodontal disease. In order to develop a passive immunization method for inhibiting the establishment of periodontal disease, B hybridoma clones 123-123-10 and 256-265-9, which produce monoclonal antibodies (Mabs) specific to purified fimbriae, were established. Both mAbs reacted with the conformational epitopes displayed by partially dissociated oligomers of FimA, but not with the 43 kDa FimA monomer. Gene sequence analyses of full-length cDNAs encoding heavy and light chain immunoglobulins enabled classification of the genes of mAb 123-123-10 as members of the mVh II (A) and mVκ I subgroups, and those of mAb 256-265-9 as members of the mVh III (D) and mVκ I subgroups. More importantly, 50 ng/mL of antibodies purified from the culture supernatant of antibody gene-transfected CHO cells inhibited, by approximately 50%, binding of P. gingivalis to saliva-coated hydroxyapatite bead surfaces. It is expected that these mAbs could be used as a basis for passive immunization against P. gingivalis-mediated periodontitis.     

Porphyromonas gingivalis infection and cell death in human aortic endothelial cells

Porphyromonas gingivalis is a periodontal pathogen that promotes a proatherogenic response in endothelial cells. Cell death responses of human aortic endothelial cells to P. gingivalis at various multiplicities of infection (MOI) were investigated by assessment of cell detachment, histone-associated DNA fragmentation, lactate dehydrogenase release and ADP:ATP ratio. Porphyromonas gingivalis at MOI 1:10-1:100 did not have a cytotoxic effect, but induced apoptotic cell death at MOI 1:500 and 1:1000. Monocyte chemoattractant protein-1 production was significantly enhanced by P. gingivalis at MOI 1:100. At higher MOI, at least in vitro, P. gingivalis mediates endothelial apoptosis, thereby potentially amplifying proatherogenic mechanisms in the perturbed vasculature.     

Induction of monocyte chemoattractant protein-1 by Porphyromonas gingivalis in human endothelial cells

The association between periodontal and cardiovascular diseases could be mediated by direct interaction of periodontal pathogens with cardiac tissue. In order to explore this possibility, the effect of the periodontal pathogen Porphyromonas gingivalis on monocyte chemoattractant protein-1 (MCP-1) production by endothelial cells was investigated. When incubated with live P. gingivalis 381, MCP-1 production by human umbilical vein endothelial cells (HUVEC) was potently increased. Compared to the type strain 381, non-adhesive/invasive strains (W50 and DPG3) did not increase MCP-1 production, which was also demonstrated at the mRNA level. Killed P. gingivalis 381 was much less effective than live bacteria for MCP-1 induction. Treatment of HUVEC with cytochalasin D, an inhibitor of endocytosis, prevented MCP-1 mRNA up-regulation by P. gingivalis 381, suggesting that internalization of P. gingivalis is necessary for MCP-1 induction. In conclusion, the secretion of high levels of MCP-1 resulting from interactions of P. gingivalis with endothelial cells could enhance atherosclerosis progression by contributing to the recruitment of monocytes.     

牙龈卟啉单胞菌对牙龈上皮细胞调控作用的研究进展

牙周炎(periodontitis)是一种常见的口腔疾病,是成年人牙齿缺失的主要原因。牙龈上皮组织是抵御外界侵袭的第一道防线,牙周炎的发生发展与多种致病菌侵袭破坏牙龈上皮组织密切相关。已有研究表明,牙周炎致病菌通过一系列毒力因子,破坏牙龈上皮组织,侵入深层组织,并引发炎症反应。其中,牙龈卟啉单胞菌(Porphyromonas gingivalis)是牙周炎的主要致病菌。本文将从牙龈卟啉单胞菌对牙龈上皮的调控进行综述,以期为牙周炎的治疗提供参考。     

Genotype variation and capsular serotypes of Porphyromonas gingivalis from chronic periodontitis and periodontal abscesses

Porphyromonas gingivalis is considered an important pathogen in periodontal disease. While this organism expresses a number of virulence factors, no study combining different virulence polymorphisms has, so far, been conducted. The occurrence of combined virulence (Cv) genotypes in 62 isolates of P. gingivalis was investigated from subjects displaying either chronic periodontitis or periodontal abscess. The Cv genotypes, based on gene variation of fimbriae (fimA), Lys-specific cystein proteinase (kgp) and Arg-specific cystein proteinase (prpR1/rgpA), were evaluated by PCR. The isolates were also subjected to capsular polysaccharide K-serotyping. A total of 18 Cv genotype variants based on fimA: kgp: rgpA were identified, of which II:I:A and II:II:A Cv genotypes (53.3%) were the two most frequently detected combinations. Moreover, 36% of the isolates were K-typeable, with the K6 serotype being the most prevalent (23%). Two isolates had the same genotype as the virulent strain W83. The results indicate that chronic periodontitis is not associated with a particularly virulent clonal type. A highly virulent genotype (e.g. strain W83) of P. gingivalis can be found in certain periodontitis patients.     

Isolation and quaternary structure of the photosynthetic core of the marine purple sulfur bacterium Chromatium purpuratum

Abstract Porphyromonas gingivalis produces a trypsin-like enzyme, Protease I, which is thought to be an important virulence determinant of the organism in adult periodontal disease. Protease I is transiently inhibited by physiological inhibitors of human thrombin. The aim of the present work was to establish whether Protease I was able to mimic thrombin by activation of the thrombin receptor on human platelets. Protease I caused true platelet activation at concentrations comparable to thrombin as measured by aggregometry, morphology and fluorescence flow cytometric analysis of CD63 expression. The effect was blocked by protease inhibitors but not by anti-thrombin receptor antibodies which, by contrast, blocked platelet activation by thrombin. We conclude that the activation of platelets by P. gingivalis Protease I involves proteolysis, but not scission of the thrombin cleavage site of the thrombin receptor.     

Synergistic effects of antibiotics and an N-acyl homoserine lactone analog on Porphyromonas gingivalis biofilms

Aims: To investigate the effects of the combined application of an N‐acyl homoserine lactone (HSL) analog and antibiotics on biofilms of Porphyromonas gingivalis, a major pathogen of periodontal disease. Methods and Results: Antibiotics used were cefuroxime, ofloxacin and minocycline. A flow‐cell model was used for biofilm formation. Samples were divided into four groups: control, analog‐treated, antibiotic‐treated and combined application groups. Biofilm cell survival was determined using adenosine triphosphate (ATP) bioluminescence and confocal laser microscopy (CLSM). In the combined application group, the ATP count in biofilm cells was significantly decreased compared with the antibiotic‐treated group (Games–Howell test, P < 0·05). A combination of cefuroxime and the analog was most effective against the P. gingivalis biofilm. CLSM observations revealed that the proportion of dead cells was highest in the combined application group. Conclusions: The combined application of the N‐acyl HSL analog and antibiotics was effective at reducing the viability of P. gingivalis cells in biofilms. Significance and Impact of the Study: The combined application of the N‐acyl HSL analog and antibiotics may be successful for eradicating infections involving bacterial biofilms, such as periodontitis.