腭裂小鼠牙胚发育中β-连环蛋白的表达

背景:牙齿发育生物学中信号传导是热点问题,β-连环蛋白是Wnt信号传导通路中的关键效应因子,其在发育的牙胚中有普遍表达,并且在内釉上皮、釉结、星网状层、中间层的表达有时空变化。目的:通过苏木精-伊红染色和免疫组化技术,观察牙胚在维甲酸诱导腭裂发生中的形态学变化及β-连环蛋白的表达变化。方法:选取C57BL/6J近交系小鼠,按雌雄比2:1于晚8时合笼,次日8时检查雌鼠,发现阴栓视为妊娠,定为E0d。18只孕鼠随机分为3组:在E10d,实验组以维甲酸100mg/kg对孕鼠行一次性灌胃,制备腭裂动物模型;植物油对照组给予10mL/kg橄榄油灌胃;空白对照组不做任何处理。结果与结论:β-连环蛋白在空白对照组E13d牙胚蕾状期、E14d帽状期、E16d钟状期上皮内均有表达,且空白对照组的表达随着牙胚发育的成熟而逐渐增加,实验组的变化趋势与空白对照组相同。3个时期的实验组β-连环蛋白在牙胚中的表达水平均高于空白对照组,植物油对照组和空白对照组表达无明显差异。提示维甲酸在诱导腭裂发生过程中,可能通过干扰上皮-间充质间的相互作用,上调β-连环蛋白在牙胚中的表达,使牙胚发育受阻。

Expression of beta-catenin in tooth germ development of mice with cleft palate

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.