建期上皮剩余的形态学和细胞活性研究

Reaction of epithelial cell rests of Malassez to tooth emergence and occlusal function reaction of epithelial cell rests of Malassez to tooth emergence and occlusal function

目的追踪观察上皮剩余在牙齿萌出和建!过程中的形态分布和细胞活性改变。方法细胞角蛋白14(CK14)标记小鼠上皮剩余细胞,光镜观察其分布和细胞形态,透射电镜观察上皮剩余细胞的超微结构。PV免疫组化两步法检测CK14和增殖细胞核抗原(PCNA)在上皮剩余细胞中的表达。结果自牙齿萌出前到建后期上皮剩余的外形和分布改变明显,建后期上皮细胞簇更为规则,分布由牙根表面的较广泛分布向根分叉和牙颈等部位局限,与成熟期上皮剩余相似。建阶段,上皮剩余沿牙根表面呈现类网格样布局,细胞数量较萌出前期明显增加,细胞增殖活性检测显示此时上皮剩余特别是根分叉水平细胞增殖活跃。建后期上皮剩余细胞数量开始减少,透射电镜结果显示簇内出现细胞凋亡征象。结论上皮剩余不是仅仅作为无功能的剩余物,其可能是上皮根鞘功能的延伸或持续,在建过程中发挥积极作用,从而完成牙周组织的发育和维持牙周内环境的稳定。

Objective To observe the morphology and proliferation of epithelial cell rests of Malassez（ECRM） during tooth emergence and occlusal function,and to evaluate its roles.Methods Cytokeratin 14（CK14） was applied as special marker of ECRM cells.The morphology and distribution of ECRM were examined by light and transmission electron microscopy.PV two-step immunohistochemical method was used to detect the expression of CK14 and proliferating cell nuclear antigen（PCNA） in ECRM.Results ECRM experienced instinct morphological changes during tooth emergence and occlusal function.They were observed as network of epithelial cells labeled by CK14,especially in furcation level regions of mouse molars and active cell proliferation during occlusion found period.Cell apoptosis was observed in many ECRM by transmission electron microscopy during late stage of the progess.Conclusion ECRM may not only an accidental left-over of early embryonic development but rather play significant roles in occlusion found period.