Wang Yanzhi, Lv Linlin, Yu Xijiao, Zhang Ting, Li Shu
Shandong Provincial Key Laboratory of Oral Biomedicine, Department of Periodontology, School and Hospital of Stomatology, Shandong University, 44-1# West Wenhua Road, Jinan, 250012, Shandong, People's Republic of China.
J Mol Histol. 2014 Feb;45(1):1-10. doi: 10.1007/s10735-013-9527-2. Epub 2013 Aug 2.
It has been demonstrated that Hertwig's epithelial root sheath (HERS) has an important role in root development, closely related to development of cementum epithelial rests of Malassez (ERM) as the residuum after HERS fragment, and is the exclusive epithelial structure in the mature periodontal ligament. Some studies reported that ERM may play a role in maintaining a stable environment of periodontal, and likely to be involved in regeneration of periodontal tissue, especially of cementum. However, the function of the ERM is not well understood. In this study, we observed the morphology and biological characteristics of ERM of the maxillary 1st molar with surrounding periodontal tissues of BALB/c mice during the period of tooth cusp erupted out of the gingiva to occlusion stability. Immunohistochemistry revealed ERM predominately located at the cervical and root furcation regions of the periodontal ligament. The number of ERM cells at the cervical and root furcation regions of the post-built occlusion stage decreased compared to pre-built occlusion stage and occlusion building stage. Transmission electron microscopy analysis showed that epithelial cell nuclei with typical features of apoptosis were observed at the post-built occlusion stage, and consistent with positive bodies labeled by TUNEL(terminal deoxy-transferase (TdT)-mediated dUTP-biotin nick end labeling), while proliferating cell nuclear antigen positive bodies mainly located at occlusion built stage. It suggests that ERM may regulate in alveolar bone remodeling in association with the periodontal ligament during tooth erupting to occlusion stability and may play important roles potentially in regeneration and homeostasis of the periodontal tissues.
已经证明，赫特维希上皮根鞘（HERS）在牙根发育中起重要作用，与赫特维希上皮根鞘片段后残留的马拉瑟斯牙骨质上皮剩余（ERM）的发育密切相关，并且是成熟牙周韧带中唯一的上皮结构。一些研究报道，ERM可能在维持牙周稳定环境中发挥作用，并且可能参与牙周组织的再生，尤其是牙骨质的再生。然而，ERM的功能尚未完全了解。在本研究中，我们观察了BALB/c小鼠上颌第一磨牙的ERM与周围牙周组织在牙尖穿出牙龈至咬合稳定期间的形态和生物学特性。免疫组织化学显示ERM主要位于牙周韧带的颈部和根分叉区域。与建牙合前期和建牙合期相比，建牙合后期颈部和根分叉区域的ERM细胞数量减少。透射电子显微镜分析显示，在建牙合后期观察到具有典型凋亡特征的上皮细胞核，并且与TUNEL（末端脱氧转移酶介导的dUTP生物素缺口末端标记）标记的阳性小体一致，而增殖细胞核抗原阳性小体主要位于建牙合期。这表明ERM可能在牙齿萌出至咬合稳定期间与牙周韧带共同调节牙槽骨重塑，并且可能在牙周组织的再生和稳态中发挥重要潜在作用。
