ICR小鼠下颌第一磨牙牙胚发育的动态组织学观察

Establishment of first mandibular molar development of the time sequence in ICR mice

目的了解ICR小鼠下颌第一磨牙牙胚的发育时序特点,为使用小鼠研究牙齿发育机制和相关影响因素提供实验基础。方法分别取E(胚胎)11.5、E12.5、E13.5、E14.5、E15.5、E16.5、E17.5和E18.5 d的胎鼠和PN(出生后)2 d的新生小鼠的头部或下颌骨,固定脱钙包埋后行连续切片,进行HE染色,在显微照相系统下进行观察记录,分析ICR小鼠磨牙牙胚发育的动态变化规律。结果 E11.5 d为牙胚发育始动,E12.5 d牙胚向蕾状期过渡,E13.5 d进入蕾状期,帽状期为E14.5~E15.5 d,钟状期开始于E16.5 d,出生后2 d牙体硬组织开始逐渐形成。结论 ICR小鼠胚胎11 d至出生后第2天是研究下颌第一磨牙牙胚发育机制的最佳时机。

Objective This study aims to understand the characteristics of the time sequence of ICR mouse first mandibular molar tooth germ development through dynamic observation. Methods Tooth germ of Embryos（E11. 5,E12. 5,E13. 5,E14. 5,E15. 5,E16. 5,E17. 5 and E18. 5） and postnatal（PN1,PN2） mice were obtained. The heads（E11. 5-E15. 5） and mandibles（E16. 5-PN2） of mice were dissected,fixed and embedded for serial sections and HE staining. All the results were assessed under light microscopy. Results The tooth germ underwent various development stages including the bud,cap and bell stages. Mouse odontogenesis was initiated at E11. 5. Proliferation of oral epithelium formed the bud stage at E13. 5. Then the cap stage was observed at E14. 5-E15. 5 and the bell stage was appeared beginning from E16. 5. The pre-dentin was observed at PN1,as well as the dentin at PN2. Conclusions Establishing the regular development pattern of the first mandibular molar of ICR mice will provide a reliable basis for the future use in the specific tooth germ developmental research.