小鼠下颌切牙胚发育的动态组织学观察

Kinesis Histology Observation on Development of Mouse's Incisor Germ in Submaxilla

目的:牙齿发育生物学研究是当今口腔医学领域研究的热点,国内外对切牙胚发育机制的研究仍较少见。本研究对小鼠切牙胚发育过程进行动态观察,从细胞水平上了解切牙胚存在的时空位置和形态变化规律。方法:选取孕12、13、14、15、16、17、18天胎鼠及新生1、2、3天乳鼠,在体视显微镜下观察含有切牙胚的颌骨,并分离取得下颌骨,常规固定包埋,进行连续切片及HE染色,在光学显微镜下进行动态观察,了解切牙胚发育大小和形态的时空变化规律。结果:观察发现小鼠切牙胚位于下颌突内,牙胚由远中向近中斜向上前方走行,牙胚前端表面被一层矿化的硬组织覆盖;发现E13d胎鼠切牙胚发育进入蕾状期,E16d的胎鼠切牙胚处于帽状期,E18d的胎鼠切牙胚处于钟状早期,新生1d的乳鼠切牙胚处于钟状晚期。结论:本实验明确了小鼠切牙胚发育的时空变化规律,为进一步阐明小鼠切牙胚发生发育机制奠定了重要的实验基础。

Objective： Dental developmental bioresearch has become a hot spot in the research of oral medical domain. The research about developmental mechanism of the mouse＇s incisor germ is few neither at home nor abroad. This study is to make dynamic observation on the process of the development of the mouse＇s incisor germ so as to obtain the massage about the space-time position and the rule of shape changing at cell level. Methods： Embryo mice of 12, 13, 14, 15, 16, 17, 18 days old and suckling mice of 1, 2, 3 days old were selected. The jaw bones containing the incisor germ were observed under stereomicroscope. Then the jaws were isolated, fixed and embedded, and its serial sections were taken and stained by HE.dynamic observations of the histological sections were made under optical microscope. Results： The results showed that cutting teeth of fetal mice were at the condition of bud stage, cap period, early bell-shaped at 13-day-old, 16-day-old, 18-day-old embryo mice, respectively. And cutting teeth of the 1-day-old newborn mice were at the condition of late bell-shaped. Conclusions： This study explicated the space-time changing rules of development of mice＇ incisive teeth,which would provide an important basis of the experiment for further research of development of mice＇ incisive teeth.