E-钙黏蛋白在出生后小鼠牙齿发育中的表达和意义

Expression of E-Cadherin in the developing tooth of postnatal mice

目的研究出生后小鼠牙齿发育中E-钙黏蛋白(E-Cadherin)的表达及意义。方法出生后第5～17天的BALB/c小鼠,取含有相当于下颌第一磨牙部位的下颌骨,40g/L多聚甲醛固定,制备5μm连续切片,HE染色,进行牙齿发育的组织学观察。采用免疫组化SABC法,对E-Cadherin的表达进行组织定位。结果在小鼠出生后第5天发育期牙齿中,E-Cadherin主要定位于牙胚组织的中间层细胞,着色位于胞浆中,成釉细胞、星网状层细胞及牙滤泡细胞染色阴性;第12天染色位于成釉细胞中,阳性着色位于成釉细胞的胞浆中,胞核染色阴性;第17天在冠部成釉细胞仍然表达阳性,但与第12天不同的是染色位于胞核之中,在根部染色位于不连续的靠近根面牙骨质的表面上皮根鞘细胞之中。结论E-Cadherin在牙齿发育的后期,参与冠部釉质形成及矿化相关的成釉细胞及中间层细胞的分化与功能,而根部在Hertwig′s上皮根鞘断裂后仍有表达,与其部分维持在牙骨质的表面,并参与牙根的发育有关。

AIM:To study the expression of E-Cadherin in different stages of tooth development in postnatal BALB/c mouse.METHODS:BALB/c mice of 5-17 postnatal days were used to get the specimen.Tissues including the mandibular tooth germs were dissected and fixed in 40 g/L paraformaldehyde,5 μm thickness serial sections were prepared for immunohistochemical study.RESULTS:The expression of E-Cadherin was prominent in the cuboidal cells of stratum intermedium on fifth postnatal day,mainly in ameloblasts on twelfth day,and discontinuously in Hertwig′s epithelial root sheath (HERS) cells,also in the nuclear of ameloblasts on seventeenth day.A strong staining reaction was evident in the stratum intermedium and ameloblasts in late bell stage during the formation of mineralized dental tissues.CONCLUSION:E-Cadherin may play an important role in tooth morphogenesis and calcification concerning its strong expression in polarized ameloblasts and stratum intermedium.The results also suggest that E-Cadherin may contribute to the development of tooth root during the differentiation of cementoblasts and the formation of cementum. [