Immunohistochemical Study of Age-dependent Changes in the Gingival Tissue

免疫荧光和免疫电镜观察了出生后1周至80周龄小鼠下第一磨牙牙周组织的年龄依赖性变化。牙槽骨在20周完成后，数量逐渐减少，与牙周韧带相邻的牙槽骨表面不规则，呈波浪状。牙周膜所占据的空间随着年龄的增长而宽度减小，可能是由于新形成的牙骨质沉积在牙根表面。此外，牙周韧带和牙龈组织的细胞数量也随着年龄的增长而减少。ⅰ型、ⅱ型胶原蛋白和纤维连接蛋白分布与牙周组织和牙龈组织纤维密切相关。出生后2 ~ 20周龄小鼠的牙周韧带纤维束靠近牙槽骨时，ⅱ型胶原染色强烈。这一事实表明，III型胶原蛋白的活跃合成发生在这个区域。产后30周的小鼠，结上皮增生并沿骨质向根尖侧迁移。纤维连接蛋白在移行性结上皮外基底膜上染色强烈。这表明纤维连接蛋白在连接上皮的增殖和迁移中起重要作用。

Immunofluorescent and immunoelectron microscopic studies of age-dependent changes of the periodontal tissues were performed in the lower first molars of mice ranging in age from one week to eighty weeks after birth. The alveolar bone which was completed by 20 weeks, was gradually decreased in amount and its surface bordered upon the periodontal ligament became irregular resulting in wavy appearance. A space which was occupied by the periodontal ligament decreased in width with aging, probably because of deposition of newly formed cementum on the surface of the root. In addition, cells in the periodontal ligament and in the gingival tissue also decreased in number with aging.The typeI and type Ill collagens, and fibronectin were distributed in close association with the fibers of the periodontal tissue and the gingival tissue. TypeIIl collagen was intensely stained in association with the fiber bundles of the periodontal ligament being close to the alveolar bone of mice ranging in age from 2 to 20 weeks after birth. This fact indicates that an active syntheses of type III collagen occurred in this region. In mice of after 30 weeks postpartum, the junctional epithelium proliferated and migrated down to the apical side along the cementum. The fibronectin was strongly stained on the external basement membrane of migrating junctional epithelium. This finding suggests that the fibronectin played an important role in the proliferation and migration of the junctional epithelium.