β-catenin在小鼠下颌第一磨牙发育过程中的表达

目的检测β-catenin在小鼠下颌第一磨牙牙冠形成的表达,探讨其在小鼠牙胚发育过程中的作用。方法取孕11天(E11.5)、孕13.5天(E13.5)、孕14.5天(E14.5)、孕16.5天(E16.5)、孕18.5天(E18.5)的ICR胎鼠及出生后24h、出生后3天及出生后7天(PN0、PN3、PN7)的小鼠,常规组织学处理并制备下颌第一磨牙冠状或矢状切片,用免疫组织化学实验方法检测β-catenin在下颌第一磨牙相关组织中的表达情况。结果β-catenin在小鼠下颌第一磨牙早期发育不同阶段呈现特异性的表达模式。在E11.5,上皮层可检测到β-catenin的表达；在E13.5,β-catenin的表达集中在向下方间充质凹陷的牙蕾上皮；在E14.5,在内釉上皮层及釉结节可以检测到β-catenin的强阳性表达；在E16.5、E18.5,在内外釉上皮、第二釉结节及邻近上皮的成牙本质细胞层可检测到β-catenin的表达。从出生后开始,在冠方的成牙本质细胞层、成釉细胞层,以及根方邻近上皮根鞘和上皮隔的牙乳头中的成牙本质细胞层内,可观察到β-catnein的阳性表达。结论 在牙胚发育过程中,β-catenin在牙源性上皮、釉结节及成牙本质细胞、成釉细胞中强表达,与牙冠形态发育及间充质细胞向成牙本质细胞分化密切相关。
ObjectiveTo detect the expression pattern of β-catenin in the first mandibular molar tooth germs of mice and its relation to early tooth development. Methods Serial paraffin sections of the first mandibular molars at different development stages of mice(E11.5,E13.5,E14.5,E16.5,E18.5,PN0,PN3,PN7)were made. The expression of β-catenin was analyzed by immunohistochemistry.Results The expression patterns of β-catenin in the first lower molars varied among the mice with different development stages. It was positively expressed in the dental epithelium at tooth initiation stage; and it was detected in the central areas of the tooth bud during the bud stage, while the immunostaining was focused on the inner and outer enamel epithelium, especially on the enamel knot, during the cap stage. At the bell stage, the β-catenin was strongly expressed in the outer and inner enamel epithelium and the second enamel knot. During the early postnatal stage, the expression of β-catenin was detected in the areas where the ameloblasts or the odontoblasts were located. Conclusion The expression of β-catenin was in a temporal-spatial specific pattern; particularly, it is strongly expressed in the dental epithelial, enamel knot and odontoblasts with the development of tooth germ. This result indicates that-catenin may be involved in tooth morphogenesis of the mouse molars and the biological process of the odontoblast differentiation