title: Interleukin-17 is involved in orthodontically induced inflammatory root resorption in dental pulp cells.
abstract: BACKGROUND
  The objectives of this study were (1) to investigate the expressions of interleukin (IL)-17, RANKL (the receptor activator of NF-kappaB ligand), and osteoprotegerin (OPG) in root resorption areas during experimental tooth movement in rats, and (2) to determine the effect of IL-17 on the expressions of RANKL and OPG mRNA from human dental pulp cells.
  
  
  METHODS
  Twelve male 6-week-old Wistar rats were subjected to an orthodontic force of 50 g to induce a mesially tipping movement of the maxillary first molars for 7 days. The expression levels of tartrate resistant acid phosphatase (TRAP), interleukin (IL)-17, IL-17 receptor (IL-17R), receptor activator of nuclear factor-kappa B ligand (RANKL), and OPG proteins were determined in dental pulp by immunohistochemical analysis. Furthermore, the effects of IL-17 on the expressions of RANKL and OPG mRNA were investigated using human dental pulp cells in vitro.
  
  
  RESULTS
  In the experimental tooth movements in vivo, resorption lacunae with multinucleated cells were observed in the 50-g group. The immunoreactivities for IL-17, IL-17R, and RANKL were detected in dental pulp tissues subjected to the orthodontic force on day 7. Moreover, IL-17 increased the mRNA expression of RANKL from human dental pulp cells in vitro.
  
  
  CONCLUSIONS
  The results of this study suggest that IL-17 and RANKL may be involved in the process of orthodontically induced inflammatory root resorption in dental pulp cells.
authors.affiliation: Assistant professor, Department of Orthodontics, School of Dentistry, Nihon University, Matsudo, Chiba, Japan.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Nakano
authors.affiliation: Associate professor, Department of Orthodontics, School of Dentistry, Nihon University, Matsudo, Chiba, Japan. Electronic address: yamaguchi.masaru@nihon-u.ac.jp.
authors.forename: Masaru
authors.initials: M
authors.lastname: Yamaguchi
authors.affiliation: Assistant professor, Department of Orthodontics, School of Dentistry, Nihon University, Matsudo, Chiba, Japan.
authors.forename: Mami
authors.initials: M
authors.lastname: Shimizu
authors.affiliation: Assistant professor, Department of Orthodontics, School of Dentistry, Nihon University, Matsudo, Chiba, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Kikuta
authors.affiliation: Assistant professor, Department of Orthodontics, School of Dentistry, Nihon University, Matsudo, Chiba, Japan.
authors.forename: Tomokazu
authors.initials: T
authors.lastname: Yoshino
authors.affiliation: Associate professor, Department of Dental Biomaterials, School of Dentistry, Nihon University, Matsudo, Chiba, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Tanimoto
authors.affiliation: Professor, Department of Orthodontics, School of Dentistry, Nihon University, Matsudo, Chiba, Japan.
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Kasai
mesh_terms: D000135:Acid Phosphatase / Q000032:analysis; D000293:Adolescent; D000818:Animals; D018929:Cell Culture Techniques; D002478:Cells, Cultured; D003782:Dental Pulp / Q000187:drug effects; D005260:Female; D006801:Humans; D020381:Interleukin-17 / Q000032:analysis* / Q000494:pharmacology; D007527:Isoenzymes / Q000032:analysis; D008297:Male; D010010:Osteoclasts / Q000473:pathology; D053244:Osteoprotegerin / Q000032:analysis* / Q000187:drug effects; D053245:RANK Ligand / Q000032:analysis* / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D053722:Receptors, Interleukin-17 / Q000032:analysis; D012391:Root Resorption / Q000276:immunology* / Q000473:pathology; D013314:Stress, Mechanical; D000071681:Tartrate-Resistant Acid Phosphatase; D014087:Tooth Movement Techniques
chemical_list: D020381:Interleukin-17; D007527:Isoenzymes; D053244:Osteoprotegerin; D053245:RANK Ligand; D053722:Receptors, Interleukin-17; C506030:TNFRSF11B protein, human; C506032:Tnfrsf11b protein, rat; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase