HOMESTASIS OF THE PERIODONTAL LIGAMENT

牙周膜位于牙骨质和牙槽骨之间，在不同条件下保持牙周膜的宽度，如老化、正畸牙齿垂直或水平移动而无强直。本研究的目的是阐明Hertwig上皮根鞘、Malassez上皮静止细胞和成纤维细胞在牙周膜动态平衡中的作用。应用常规免疫荧光、免疫组织化学和激光扫描显微镜对SD大鼠1~12周牙周组织、培养的猪Malassez上皮静止细胞和实验性慢性牙周炎大鼠牙周组织中细胞角蛋白、IV型胶原、层粘连蛋白、连接蛋白43、32、肌动蛋白的免疫定位进行了研究。细胞角蛋白-19和连接蛋白43定位于Malassez上皮细胞。层粘连蛋白定位于Hertwig上皮根鞘和Malassez上皮静息细胞周围的基底膜，在成牙本质细胞发育和牙本质形成过程中，Hertwigts上皮根鞘的牙髓侧阳性反应减少和消失。用核仁组成区嗜银染色和增殖细胞核抗原免疫组织化学染色检测牙周膜连接上皮、长连接上皮、成纤维细胞的增殖活性。在连接上皮和长连接上皮中，结缔组织侧均可见到增殖细胞。

The periodontal ligament is located between cementum and alveolar bone and the width of the periodontal ligament is kept in the various condition such as aging, vertical or horizontal orthodontic tooth movement without ankylosis. The purpose of this study was to elucidate the role of Hertwig's epithelial root sheath, Malassez epithelial rests cell and fibroblasts in the homeostasis of periodontal ligament. Cytokeratin, type IV Collagen, Laminin, Connexin 43, 32, Actin immunolocalization was examined by conventional Immunofluorescence, immunohistochemistry and laser scanning microscope in the 1 to 12 weeks S.D.rat periodontal tissue, cultured pig Malassez epithelial rests cells and experimental chronic periodontitis in S.D.rat. Cytokeratin-19 and Connexin 43 were located in the Malassez epithelial rests. Laminin was located in the basement membrane surrounding the Hertwig's epithelial root sheath, Malassez epithelial rests cell, and positive reaction was reduced and disappear in the pulp side of the Hertwigts epithelial root sheath during odontoblasto developing and dentinogenesis. Proliferative activity of the junctional epithelium, long junctional epitheliun-i, fibroblasts of the periodontal ligament were examined using argyrophilic nucleolar organizer region (AgNORs) staining and PCNA immunohistochemical staining. Proliferative cells were recognized at the connective tissue side in the both junctional and long junctional epithelium.