Shroff B, Kashner J E, Keyser J D, Hebert C, Norris K
Department of Orthodontics, Dental School, UMAB 21201, USA.
Arch Oral Biol. 1996 Jun;41(6):613-7. doi: 10.1016/0003-9969(96)00147-1.
When the role of exogenous epidermal growth factor (EGF) during tooth eruption was first demonstrated it was strongly suggested that EGF was a natural regulator of eruption. Recent immunohistochemical studies have shown that EGF and EGF-receptors are localized in the dental follicle, alveolar bone and ameloblasts before and during the prefunctional stage of eruption. Localization of mRNA for EGF has also been successfully attempted in mouse incisors and molars. The purpose now was to study the temporal expression of EGF and EGF-receptor genes in the coronal aspect of the dental follicle. First molars from 2-, 5-, 9- and 11-day-old CD-1 mouse neonates were incubated in 1% trypsin for 1.5 h at 4 degrees C. Follicles were carefully separated from the coronal aspect of the molar and processed for RNA extraction. Reverse transcriptase-polymerase chain reaction was performed on each mRNA sample. EGF expression was detected at day 2, 5 and 9 in the coronal aspect of the follicle whereas EGF-receptor expression was found at day 9 only. These findings strongly suggest that cells of the dental follicle are the target of EGF at a specific stage of their development and therefore may have a very important role during eruption.
当外源性表皮生长因子（EGF）在牙齿萌出过程中的作用首次被证实时，人们强烈认为EGF是萌出的天然调节因子。最近的免疫组织化学研究表明，在萌出的功能前期之前及期间，EGF和EGF受体定位于牙囊、牙槽骨和成釉细胞中。在小鼠切牙和磨牙中也已成功尝试对EGF的mRNA进行定位。现在的目的是研究牙囊冠部EGF和EGF受体基因的时间表达。将2日龄、5日龄、9日龄和11日龄的CD-1小鼠新生仔的第一磨牙在4℃下于1%胰蛋白酶中孵育1.5小时。小心地从磨牙冠部分离出牙囊并进行RNA提取处理。对每个mRNA样本进行逆转录聚合酶链反应。在第2天、第5天和第9天在牙囊冠部检测到EGF表达，而仅在第9天发现EGF受体表达。这些发现强烈表明，牙囊细胞在其发育的特定阶段是EGF的靶细胞，因此在萌出过程中可能具有非常重要的作用。
