中文摘要：

目的：研究机械损伤后小鼠切牙成釉器细胞中Notch信号的表达及变化。方法：通过磨除小鼠下颌切牙牙冠的1／2部分建立小鼠下颌切牙的机械损伤模型，并将其随机分为损伤后3、5、7d组，同时以不做切牙磨除处理的小鼠作为正常对照；用免疫组织化学染色方法观察各组成釉器细胞中Notch1、Notch2的表达变化情况。结果：对照组中，Notch1、Notch2仅在中间层和星网状层细胞中微弱表达；损伤后3 d组，Notch1、Notch2在成釉细胞和中间层细胞均呈密集的阳性表达，在星网状层细胞有散在阳性表达；损伤后5 d 组， Notch1、Notch2在成釉细胞、中间层、星网状层细胞仍呈明显的阳性表达；损伤后7 d组，Notch1、Notch2在各层细胞中的表达均较损伤后3、5 d组有所减弱。结论：机械损伤可激活小鼠切牙成釉器细胞中Notch信号的表达，从而参与调控切牙的损伤修复。

英文摘要：

AIM：To investigate the expression and role of Notch signaling in enamel organ of mouse incisor after mechanical injury.METHODS：The animal model of mechanical injury was established by grinding off 1/2 crown of mouse mandibular incisor.The animals were sacrificed at 3,5 d and 7 d respectively （n=5）after injury,the expression of Notch1 and Notch2 in cells of enamel organ was observed by immunohistochemical staining.Animals without crown grinding served as the controls（n=5 ）.RESULTS：In control group,Notch1 and Notch2 were weakly expressed in stratum intermedium and stellate reticulum cells.3 days after injury,an intense expression of Notch1 and Notch2 was observed in ameloblasts and stratum intermedium cells,the expression in stellate reticulum cells was spo-radic.5 days after injury,Notch1 and Notch2 were still strongly expressed in ameloblasts,stratum intermedium and stellate reticulum cells.7 days after injury,the expression of Notch1 and Notch2 decreased in all cell layers.CON-CLUSION：Notch signaling in enamel organ cells can be activated by mechanical injury,suggesting that Notch signa-ling may be involved in the repair of incisor injury.