Detection of bacterial species using 16S rDNA existed in deep layers of carious lesions with pulp exposure embedded with plastic material and analysis of the pathogenesis of pulpitis

以树脂包埋的人龋牙本质为模板，采用聚合酶链反应（PCR）检测龋病深层细菌16rdna。39份人龋标本共检出34种细菌。每个龋样检出4.8种细菌，每个龋样检出3.9种细菌。研究了人牙髓中toll样受体（TLR）表达细胞的特性。逆转录聚合酶链反应（RT-PCR）分析证实了TLR-2 Mrna在所有炎症髓质中的表达。使用地高辛标记的单链Crna探针原位杂交分析发现，在炎症髓质中可以发现TLR-2、4和9 mrna表达细胞。光镜下免疫组织分析显示，胞体中存在TCR-2和4蛋白。在抗原呈递细胞（APC）中，树突状细胞表达TLR-2蛋白，巨噬细胞样细胞在细胞体中表达TLR-4蛋白。这些结果提示TLR可能参与牙髓炎的发病机制。

Resin-embedded human carious dentin was used as template for polymerase chain reaction (PCR) detection of bacterial 16 rDNA existed in deep layers of carious lesions. A total of 34 bacterial spesies were detected from 39 human carious samples. 4.8 bacterial species per carious sample of coronal caries, 3.9 species of root caries were detected.Characteristics of Toll-like receptor (TLR)-expressing cells in human dental pulp were studied. Reverse transcriptase polymerase chain reaction (RT-PCR) analysis comfirmed the expression of TLR-2 Mrna in all of the inflamed pulps. In situ hybridization analysis using digoxigenin-labeled single strand Crna probe showed that TLR-2, 4 and 9 Mrna-expressing cells could be found in the inflamed pulps. Immunohistological analysis at a light microscopic level showed that TCR-2 and 4 protein in the cell body. In antigen-presenting cell (APC), dendritic cells were expressed TLR-2 protein, and macrophage-like cells were expressed TLR-4 protein in the cell body. These results suggested that TLR might be involved in the pathogenesis of pulpitis.