Journal of Molecular Histology

, Volume 49, Issue 3, pp 329–338 | Cite as

Osteoprotegerin deficiency causes morphological and quantitative damage in epithelial rests of Malassez

  • Yunfei Wang
  • Mengmeng Liu
  • Shijian Deng
  • Xin Sui
  • Linlin Fan
  • Qi Zhang
Original Paper


Epithelial rests of Malassez (ERM), the only odontogenic epithelial structures in periodontal tissue, are proposed to correlate with root resorption, but the detailed mechanism remains unclear. Osteoprotegerin (OPG), the main inhibitor of osteoclastogenesis, plays a pivotal role in inhibiting root resorption, and ERM cells express OPG mRNA in vitro. Thus, in this study, we aimed to clarify OPG expression in ERM in vivo and to explore the role of OPG in ERM to determine whether ERM are associated with root resorption via OPG. We established Opg-knockout (Opg-KO) mice and detected the OPG expression in ERM by immunohistochemical staining in 4-, 6-, 10-, 26- and 52-week-old mice. The ERM of wild-type (WT) mice and Opg-KO mice were evaluated histologically at 4, 10 and 26 weeks of age. Orthodontic root resorption models were established, maxillae were collected after 4 weeks, and ERM were analysed by histomorphometric analysis. In our study, OPG displayed sustained expression in ERM, and OPG deficiency caused the destruction of ERM, characterized by irregular morphology and reduced numbers. Moreover, after orthodontic treatment, the loss of OPG severely damaged ERM, aggravating root resorption. Together, our results demonstrated that ERM expressed the OPG protein in vivo and that OPG deficiency resulted in morphological and quantitative damage to ERM. Furthermore, ERM may be associated with root resorption via OPG, thus helping to explain the mechanism underlying root resorption.


Epithelial rests of Malassez Osteoprotegerin Root resorption Orthodontic tooth movement 



This work was supported by grants from the National Natural Science Foundation of China (Grant Nos: 81570966, 81371141).

Compliance with ethical standards

Conflicts of interest

The authors declare that they have no conflicts of interest.

Supplementary material

10735_2018_9771_MOESM1_ESM.tif (69.3 mb)
Supplementary material 1. Fig. 1. The magnification of the ERM distribution in WT and Opg-KO mice. a The distribution of ERM (yellow arrow) in the cervical region of the periodontium. b The distribution of ERM (yellow arrow) in the furcation region of the periodontium. D dentin, P pulp (TIF 70970 KB)
10735_2018_9771_MOESM2_ESM.tif (45.7 mb)
Supplementary material 2. Fig. 2. The IgG control for the expression of OPG protein in WT mice. D dentin, PDL periodontal ligament, D dentin, PDL periodontal ligament (TIF 46835 KB)


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Copyright information

© Springer Science+Business Media B.V., part of Springer Nature 2018

Authors and Affiliations

  • Yunfei Wang
    • 1
  • Mengmeng Liu
    • 1
  • Shijian Deng
    • 1
  • Xin Sui
    • 1
  • Linlin Fan
    • 1
  • Qi Zhang
    • 1
  1. 1.Department of Endodontics, School & Hospital of Stomatology, Tongji UniversityShanghai Engineering Research Center of Tooth Restoration and RegenerationShanghaiChina

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