Immunohistochemical Study of Age-dependent Changes in the Gingival Tissue

对出生后1周至80周的小鼠下颌第一磨牙牙周组织的年龄相关性变化进行了免疫荧光和免疫电镜研究。20周完成的牙槽骨数量逐渐减少，与牙周膜接壤的表面变得不规则，呈波浪状。牙周韧带所占的空隙随着年龄的增长而减少，可能是由于牙根表面新形成的牙骨质沉积所致。此外，牙周膜和牙龈组织中的细胞数量也随着年龄的增长而减少，I型和I型胶原和纤维连接蛋白与牙周组织和牙龈组织的纤维密切相关。出生后2~20周龄的小鼠牙周膜纤维束靠近牙槽骨，IIl型胶原染色较深。这一事实表明，该区域发生了III型胶原的活性合成。在产后30周的小鼠中，连接上皮细胞增殖，并沿着牙骨质向顶侧迁移。纤维连接蛋白在移行连接上皮细胞的外基底膜上呈强阳性表达。提示纤维连接蛋白在连接上皮细胞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.