无翅型MMTV整合位点家族成员5A/受体酪氨酸激酶样孤儿受体2在大鼠牙囊细胞中的表达及其意义

Expression and significance of wingless-type MMTV integration site family, member 5A/receptor tyrosine kinase-like orphan receptor 2 in the rat dental follicle

目的：观察在牙齿正常萌出过程中无翅型MMTV整合位点家族成员5A（Wnt5A）/受体酪氨酸激酶样孤儿受体2（Ror2）信号在大鼠体内外牙囊细胞表达的特点，探讨其与成熟破骨细胞形成及牙齿萌出的相关性。方法分离出生后1-13 d的SD大鼠下颌骨，苏木精-伊红染色观察牙囊及牙槽骨生长发育过程，免疫组织化学法观察在下颌第一磨牙萌出过程中Wnt5A和Ror2在牙囊细胞中的表达。体外培养出生后5-6 d的SD大鼠第一磨牙牙囊细胞，免疫组织化学法观察Wnt5A、Ror2在牙囊细胞中的表达。结果SD大鼠出生后第2天牙囊开始分化为牙周组织，1-3 d牙槽骨变化不明显，第4天起，破骨细胞数量明显增多。Wnt5A在出生后第1-3天的大鼠牙囊组织内无明显表达，第4天开始出现阳性表达，并持续表达至第13天。Ror2在出生后第1-3天的大鼠牙囊组织表达呈强阳性，而在第4-13天呈弱阳性。结论 Wnt5A、Ror2在牙萌出过程中有特定的时间分布，提示其可能参与牙齿萌出的调控。

ObjectiveTo observe the expression of wingless-type MMTV integration site family, member 5A （Wnt5A）/receptor tyrosine kinase-like orphan receptor 2 （Ror2） signal in the dental follicle cells during the normal eruption of the teeth as well as to explore the relationship between the expression of dental follicle cells and the formation of mature osteoclasts and eruption of the teeth.Methods The mandibulars of 1–13 d old SD rats were separated to observe the growth and develop-ment of the teeth and alveolar bone through hematoxylin-eosin（HE） staining. Ror2 and Wnt5A expressions in rat dental follicle were also observed through immunohistochemistry. Dental follicle cells from the lower first intact molar germs of 5-6-day old SD rats were separated and cultured.Results On the second day after birth, the dental follicle began to differentiate into periodontal tissues, but no obvious changes were observed in the alveolar bone one to three days after birth. On the fourth day, the number of osteoclasts increased significantly. The results of immunohistochemistry showed that Wnt5A was not significantly expressed in rat dental follicle tissues before the fourth day, but positive expression was expressed in the next day and continued to express to thirteenth days. Ror2 was expressed in the rat dental follicle at postnatal days 1–3, but weak expression was found in days 4–13.Conclusion Wnt5A and Ror2 expressions in the process of tooth eruption have specific time distributions, suggesting that these expressions may participate in the regulation of the eruption of the teeth.