title: Compressive force regulates ephrinB2 and EphB4 in osteoblasts and osteoclasts contributing to alveolar bone resorption during experimental tooth movement.
abstract: OBJECTIVE
  To investigate the involvement of ephrinB2 in periodontal tissue remodeling in compression areas during orthodontic tooth movement and the effects of compressive force on EphB4 and ephrinB2 expression in osteoblasts and osteoclasts.
  
  
  METHODS
  A rat model of experimental tooth movement was established to examine the histological changes and the localization of ephrinB2 in compressed periodontal tissues during experimental tooth movement. RAW264.7 cells and ST2 cells, used as precursor cells of osteoclasts and osteoblasts, respectively, were subjected to compressive force in vitro. The gene expression of EphB4 and ephrinB2, as well as bone-associated factors including Runx2, Sp7, NFATc1, and calcitonin receptor, were examined by quantitative real-time polymerase chain reaction (PCR).
  
  
  RESULTS
  Histological examination of the compression areas of alveolar bone from experimental rats showed that osteoclastogenic activities were promoted while osteogenic activities were inhibited. Immunohistochemistry revealed that ephrinB2 was strongly expressed in osteoclasts in these areas. Quantitative real-time PCR showed that mRNA levels of NFATc1, calcitonin receptor, and ephrinB2 were increased significantly in compressed RAW264.7 cells, and the expression of ephrinB2, EphB4, Sp7, and Runx2 was decreased significantly in compressed ST2 cells.
  
  
  CONCLUSIONS
  Our results indicate that compressive force can regulate EphB4 and ephrinB2 expression in osteoblasts and osteoclasts, which might contribute to alveolar bone resorption in compression areas during orthodontic tooth movement.
authors.affiliation: Department of Oral Pathology, School and Hospital of Stomatology, Jilin University, Changchun, China. ; Department of Orthodontics, School and Hospital of Stomatology, Jilin University, Changchun, China.
authors.forename: Jianhua
authors.initials: J
authors.lastname: Hou
authors.affiliation: Department of Oral Pathology, School and Hospital of Stomatology, Jilin University, Changchun, China.
authors.forename: Yanze
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Department of Endodontics, School and Hospital of Stomatology, Jilin University, Changchun, China.
authors.forename: Xiuping
authors.initials: X
authors.lastname: Meng
authors.affiliation: Department of Oral Pathology, School and Hospital of Stomatology, Jilin University, Changchun, China.
authors.forename: Ce
authors.initials: C
authors.lastname: Shi
authors.affiliation: Department of Oral Pathology, School and Hospital of Stomatology, Jilin University, Changchun, China.
authors.forename: Chen
authors.initials: C
authors.lastname: Li
authors.affiliation: Department of Orthodontics, School and Hospital of Stomatology, Jilin University, Changchun, China.
authors.forename: Yuanping
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Department of Oral Pathology, School and Hospital of Stomatology, Jilin University, Changchun, China.
authors.forename: Hongchen
authors.initials: H
authors.lastname: Sun
keywords: Bone biology; Cell/molecular biology; EphB4; EphrinB2; Tooth movement