Expression of Notch1 in developing mouse molar tooth germ

Objective To investigate the expression of Notch1 in developing mouse molar tooth germ. Methods Cryosections of developing ICR mouse first molar tooth germ at different developmental stages were made. The expression of Notch1 in the tooth germ tissues was examined by immunohistochemistry. Results Notch1 was expressed in the oral epithelium above or surrounded by the dental placode at initial dental lamina and tooth bud stages,but not expressed in dental placode. From dental cap to bell stage,Notch1 was expressed in stratum intermedium but not in inner enamel epithelium. At enamel and dentin secreting stage,Notch1 was still expressed in the stratum intermedium of the cervical loop. Moreover,Notch1 was also expressed in the mesenchyme,dental papillae and early dental pulp throughout the developing process. Conclusion Notch1 may play an important role in the dental epithelial cell,especially the inner enamel epithelial cell differentiation during the mouse molar tooth germ development and may also be needed in dental follicle,dental papillae and dental pulp cell development and homeostasis.