Role of macrophages on periodontal destruction in rat experimental periodontitis caused by topical application of lipopolysaccharide

本研究试图从实验上阐明巨噬细胞/单核细胞系统在脂多糖(LPS)引起的牙周边缘组织炎性改变中的作用。从雄性Wistar大鼠的磨牙牙龈沟分别注射一次和两次大肠杆菌脂多糖，用免疫组织化学方法观察大鼠牙周边缘组织中巨噬细胞的动态变化、IL-1β等细胞因子的合成以及破骨细胞和淋巴细胞的动态变化。由于本研究是在继承前人研究项目的基础上进行的，是本文的一部分。用新获得的数据再次报告了结果的一部分。结果表明：1.局部应用脂多糖后，ED1阳性巨噬细胞和Ia阳性巨噬细胞增多，尤以上皮下结缔组织为主。提示部分巨噬细胞可能产生IL-1β，激活破骨细胞性牙槽骨吸收。2.两次应用程序…更多的内毒素在早期引起ED1阳性细胞和Ia阳性细胞的显著增加。推测这些Ia阳性细胞可能参与了皮损内特异性免疫反应的建立。3.一次注射脂多糖后未检测到PAN T细胞和PAN B细胞，但二次注射后3小时，牙周联合上皮下结缔组织和腭部牙龈上皮下结缔组织中PAN T细胞明显增多。由于二次注射后ED1阳性细胞和Ia阳性树突状细胞明显增多，提示这些巨噬细胞大部分转化为Ia阳性细胞，Ia阳性抗原提呈细胞的增加可能诱导了T细胞的出现。综上所述，在体内实验条件下，内毒素刺激后炎性病变中诱导的ED1阳性巨噬细胞可能通过产生IL-1β而导致牙槽骨破坏，并可能通过建立免疫应答来保护病变。较少

In this research, we tried to elucidate experimentally a role of macrophage/monocyte system on inflammatory changes in marginal periodontal tissue caused by lipopolysaccharide (LPS). The LPS from E. coli were administered once and twice from the molar gingival sulcus of a male Wistar rats, and the dynamics of macrophages in the rat marginal periodontal tissue, synthesis of the cytokines such as IL-1 β and dynamics of the osteoclasts and lymphocytes were investigated using an immunohistochemical method. As this research was done succeeding from the previous research projects, a part. of the results were reported again with the newly obtained data. As a result, 1. After once topical application of LPS, it was revealed that ED1 positive macrophages and Ia positive macrophages increased especially in the subepithelial connective tissue of the gingiva. It was suggested that some of these macrophages might produce IL-1β and activate osteoclastic alveolar bone resorption. 2. Twice application … More of LPS caused remarkable increase of ED1 positive cells and Ia positive cells in an early stage. It was suspected that these Ia positive cells might participate establishment of specific immune response in the lesion. 3. Although Pan T and pan B cells were not detected after once application of LPS, pan T cells increased 3 hours after second application of LPS in the connective tissue under the junctional epithelium and palatal gingival epithelium. As ED1 positive cells and Ia positive dendritic cells markedly increased after second LPS administration, It was suggested that much of these macrophages changed to Ia positive cells and increase of Ia positive antigen presenting cells might have induced appearance of T cell. In conclusion, it was demonstrated under the in vivo experimental condition that ED1 positive macrophages induced in the inflammatory lesion after LPS-stimulation might cause destruction of alveolar bone due to production of IL-1 β, and also might protect the lesion by establishment of immune response. Less