细胞凋亡在小鼠牙釉质形成中的作用

The role of apoptosis during amelogenesis in mouse molars

目的检测小鼠牙釉质形成过程中成釉细胞的凋亡及调控基因Bcl-2的表达,探讨细胞凋亡在釉质形成过程中的作用。方法制备出生后3、5、9及15 d发育阶段的BALB/C小鼠牙胚的石蜡标本,采用原位末端标记法(TUNEL法)及SP免疫组织化学技术,观察成釉细胞分化各阶段细胞凋亡及Bcl-2的表达情况。结果凋亡在分化各期的成釉细胞中皆有表达,在成熟期表达增强,近颈环处处于分泌前期及分泌期的成釉细胞Bcl-2表达阳性,而在冠方尤其牙尖处的成釉细胞中则表达下调或消失。结论细胞凋亡在釉质形成的过程中起到一定的作用,Bcl-2作为凋亡抑制基因参与了成釉细胞的增殖与凋亡的调控。

Objective To identify the role of apoptosis and inhibiting apoptosis gene bcl-2 during amelogenesis in developing mouse molars. Methods BALB/C mice on postnatal days from 3 days to 15 days were used to get the specimen. Tissues including the mandibular tooth germs were dissected and fixed in 40 g/L paraformaldehyde, 4 μm thickness serial sections were prepared for studying the apoptosis by Tdt-mediated Dutp nick end labeling （TUNEL）, and the other were used for immunohistochemical study by SP Method. Results TUNEL staining of apoptosis cells were observed in every stage of ameloblasts, especially in the mature stage. Bcl-2 positive cells were expressed in the proliferating pre-ameloblasts and secretory stage ameloblasts, but the immunoreactivity gradually weakened and disappeared in the cusp. Conclusions The results indicated that Bcl-2 may play a role in the process of amelogenesis with its proposed mechanisms of action in the control of apoptosis.