Objective: To detect the inhibitory ability of histatin 5 on the auto-aggregation of Porphyromonas gingivalis (Pg), and the co-aggregation of Pg with Fusobacterium nucleatum (Fn); and to provide a theoretical basis for the role of oral innate immunity played in the inhibition of chronic periodontitis. Methods: Saliva and supragingival, subgingival plaque samples were collected from 49 chronic periodontitis patients in School of Stomatology, China Medical University and 27 periodontal healthy individuals. Enzyme linked immunosorbent assay was used to assess the amount of histatin 5 in saliva, absolute quantitative real-time PCR (qPCR) was applied to detect the DNA copies of Fn, Pg and total bacteria in supragingival and subgingival plaque samples. The effects of histatin 5 on auto- and co-aggregation were assessed by bacterial adhesion test and scanning electron microscopy. Hemagglutinin gene, arginine-gingipains gene in Pg and FomA gene in Fn were tested by relative qPCR. Independent samples t-test was used to calculate the significance between the experimental group and the control group. P-value<0.05 was considered statistically significant. Results: For chronic periodontitis patients, there was an inverse correlation between the concentration of histatin 5 and Fn and Pg in supragingival plaque samples (r=-0.379, r=-0.624). Similarly, an inverse correlation was also observed between the concentration of histatin 5 and subgingival Fn and Pg, respectively (r=-0.404, r=-0.314). As for periodontally healthy individuals, there was an inverse correlation between the concentration of histatin 5 and supragingival and subgingival Pg (r=-0.572, r=-0.533). Bacterial adhesion test and scanning electron microscopy certified that 25 mg/L histatin 5 inhibited the auto-aggregation of Pg-Pg and the co-aggregation of Pg-Fn. Results of qPCR showed that 25 mg/L histatin 5 up-regulated hemagglutinin gene by (14.52±3.25) fold and down-regulated FomA gene to (0.22±0.10) fold. Conclusions: Histatin 5 could inhibit the auto-aggregation of Pg-Pg and the co-aggregation of Pg-Fn by regulating hemagglutinin gene and FomA gene expression.
目的： 研究唾液富组蛋白5抑制牙龈卟啉单胞菌与具核梭杆菌共聚的能力并进行初步的机制分析，以期揭示富组蛋白5在抑制慢性牙周炎发生过程中的作用。 方法： 收集49例就诊于中国医科大学口腔医学院牙周科的慢性牙周炎患者（慢性牙周炎组）和27名牙周健康者（牙周健康组）的唾液及龈上、龈下菌斑，采用酶联免疫吸附测定试剂盒检测唾液中富组蛋白5的含量，实时荧光定量PCR（绝对定量）检测龈上、龈下菌斑中牙龈卟啉单胞菌（Porphyromonas gingivalis，Pg）、具核梭杆菌（Fusobacterium nucleatum，Fn）和总细菌的DNA拷贝数；采用黏附实验和扫描电镜分别检测25 mg/L富组蛋白5对Pg-Pg、Pg-Fn共聚的影响；实时荧光定量PCR（相对定量）技术检测25 mg/L富组蛋白5对Pg血凝素基因、精氨酸牙龈素基因及Fn FomA基因表达的影响。实验组（加入25 mg/L富组蛋白5）与对照组（未加入富组蛋白5）之间差异的比较采用独立样本t检验，以双侧P<0.05为差异有统计学意义。 结果： 慢性牙周炎组唾液富组蛋白5与龈上菌斑中Fn、Pg均呈负相关关系（r=-0.379，r=-0.624）；与龈下菌斑中的Fn、Pg也均呈负相关关系（r=-0.404，r=-0.314）。牙周健康组富组蛋白5仅与龈上、龈下菌斑中的Pg呈负相关关系（r=-0.572，r=-0.533）。25 mg/L的富组蛋白5能抑制Pg-Pg及Pg-Fn的共聚；实时荧光定量PCR（相对定量）结果显示，唾液富组蛋白5使Pg血凝素基因表达升高（14.52±3.25）倍，使Fn FomA基因表达下降至原来的（0.22±0.10）。 结论： 唾液富组蛋白5可能通过调节Pg血凝素基因、Fn FomA基因的表达抑制Pg-Pg和Pg-Fn的共聚。.
Keywords: Co-aggregation; Fusobacterium nucleatum; Gene expression; Histatins; Porphyromonas gingivalis.