牙齿发育中程序性细胞死亡的研究

Role of programmed cell death in the development of tooth

目的：阐明程序性细胞死亡在牙齿发生、发育过程中的意义。方法：采用原位末端标记法（ＴＵＮＥＬ法）及ＨＥ染色技术，对纯系ＳＤ大鼠牙胚发育不同阶段的程序性细胞死亡现象进行观察。结果：在牙齿发育的蕾状期、帽状期、钟状期均有程序性细胞死亡现象。蕾状期主要出现在上皮细胞增殖内陷形成的蕾状突起的顶端，帽状期、钟状早期集中出现在细胞增殖生长中心（原发性釉结节，颈环）处，钟状晚期及牙体组织形成后成釉器星网层及牙乳头细胞中多见，外釉上皮及已分化的成釉细胞、成牙本质细胞中散在。结论：在牙齿发育形成过程中，程序性细胞死亡参与上皮－间充质相互作用。控制着不同状态下细胞增生的数量，及时清除多余细胞，完成其对牙齿发育的重要塑形作用。

Aim: To investigate the role of programmed cells death (PCD) in development of tooth. Methods: PCD was detected by TdT-mediated dUTP nick end labelling (TUNEL) in different stages of tooth development of SD rat. Results: The TUNEL showed that there was consistent PCD present in the bud stage, cap stage and bell stage. The PCD appeared at the top of concave surface of bud stage ,and proliferative growth center (primary enamel knot and dental cervical loop) in the cap stage and earlier bell stage. PCD was also detected in the degenerated stellate reticulum cells of enamel organ and dental papilla, and was also detected scarcely in the differentiated ameloblast and odonfoblast in the late bell stage. Conclusions: PCD was involved in the interaction of epithelial-mesenchymal, and controlled the cell numbers of both proliferation and differentiation, which contributed to the sculpture of the shape of developmental teeth.