细胞极性相关蛋白CDC42和PAR3在小鼠牙胚发育过程中的表达

目的：研究细胞极性相关蛋白CDC42和PAR3在小鼠牙胚发育过程中的表达，探讨其在牙胚发育中的可能作用。方法：取13.5、14.5、16.5和18.5d（E13.5、E14.5、E16.5和E18.5）的小鼠胚胎以及出生后1和5d（PN1和PN5）的小鼠，分离头部，固定、脱钙、脱水、石蜡包埋、切片，HE染色观察牙胚的组织形态表现，采用免疫组织化学染色方法观察CDC42及PAR3在牙胚发育过程中的表达。结果：HE染色观察，E13.5~E18.5分别为小鼠牙胚发育的蕾状期、帽状期、钟状早期和钟状晚期，PN1小鼠的牙胚中可见分化成熟的成牙本质细胞和成釉细胞，PN5小鼠牙胚可见牙冠部发育完成。免疫组织化学染色，CDC42在E13.5、E14.5和E16.5小鼠牙胚中有广泛表达，在E18.5小鼠牙胚中表达较E13.5、E14.5和E16.5减少，在PN1和PN5小鼠牙胚中主要表达于成牙本质细胞和成釉细胞的分泌端；PAR3弱表达于E13.5和E14.5小鼠牙胚，在E16.5和E18.5小鼠牙胚上皮处表达明显增强，在PN1和PN5小鼠牙胚中表达较E18.5减弱。结论：CDC42和PAR3参与小鼠牙发育的过程，在牙胚发育早期可能参与小鼠牙胚的增殖及迁移，在牙胚发育晚期可能参与了成牙本质细胞和成釉细胞的分化，尤其在成牙本质细胞和成釉细胞极性的形成与维持中可能具有重要作用。

Expressions of cell polarity related proteins CDC42and PAR3 during tooth germ development in mice

Objective:To study the expressions of cell polarity related proteins CDC42 and PAR3 during tooth germ development in the mice,and to discuss their possible roles during tooth development in the mice.Methods:The whole heads were obtained from the mouse embryo on the days 13.5,14.5,16.5 and 18.5 (E13.5,E14.5,E16.5 and E18.5) and the mice on the postnatal days 1 (PN1) and 5 (PN5).The tissues were fixed in paraformaldehyde,decalcified,dehydrated,embedded in paraffin,and sectioned.The histology of tooth germ was observed by HE staining.The expressions of CDC42 and PAR3 during tooth germ development were detected by immunohistochemistry staining.Results:The HE staining results showed that E13.5,E14.5,E16.5 and E18.5were the bud stage,the cap stage,the early and the late bell stage of tooth germ development,respectively;the tooth germ of PN1 mice showed the matured odontoblasts and ameloblasts;the tooth germ of PN5 mice showed the completed tooth crown development.The immunohistochemistry staining results showed that CDC42 expressed in the tooth germ of the mice at E13.5,E14.5 and E16.5;the CDC42 expression at E 18.5 was reduced compared with E13.5,E14.5 and E16.5;CDC42 mainly expressed in the odontoblasts and ameloblasts of the tooth germ of the mice at PN1 and PN5;PAR3 weakly expressed in the tooth germ of the mice at E13.5 and E14.5,and it was increased at E16.5 and E18.5.At PN1 and PN5,the expressions of PAR3 were decreased compared with E18.5.Conclusion:CDC42 and PAR3 partieipat in the mouse tooth development;during the early stage of tooth germ development,they may be involved in the proliferation and migration of mouse dental germ;during the late stage,CD42 and PAR3 may be involved in the differentiation of the odontoblasts and the ameloblasts,especially in the establishment and maintenance of cell polarity.