Abstract:

BACKGROUND: In the biological study of dental development, signal transduction is a hot issue, and β-catenin is the key effector of the Wnt signaling pathway. β-catenin expresses in the tooth germ development and shows a temporal changes in the expression in the inner enamel epithelium, enamel knot, stellate reticulum, and intermediate layer.
OBJECTIVE: To investigate the morphologic changes of tooth germ development during cleft palate induced by all-trans retinoic acid in C57BL/6J mice, and to detect the effect of excess all-trans retinoic acid on the expression of β-catenin in tooth germ development.
METHODS: Eighteen pregnant mice which were divided into experimental group, vegetable oil control group and blank control group were examined by slight microscopy. Mice in the experimental group were treated with 100 mg/kg all-trans retinoic acid at E10 d to make cleft palate models. Mice in the vegetable oil control group received intragastric administration of 10 mL/kg olive oil. The blank control group had no treatment.
RESULTS AND CONCLUSION: During E13 d, E14 d, and E16 d, positive expression of β-catenin was found in the oral epithelium and the dental lamina, gradually became stronger where cells actively proliferated in the blank control group. The experimental group had similar changing tendency with the blank control group. The level of β-catenin in the blank control group was lower than that of the experimental group during all stages. The same expression level of β-catenin occurred both in the vegetable oil control group and blank control group. The changes of β-catenin expression induced by excess all-trans retinoic acid in the epithelium-mesenchymal interaction regulating morphogenesis of tooth germ may be related to the cleft palate induced by all-trans retinoic acid, and the expression of β-catenin displays an up-regulation tendency, which thus interferes with the development of tooth germ.