title: Inhibitory effects of IL-12 on experimental tooth movement and root resorption in mice.
abstract: OBJECTIVE
  Interleukin (IL)-12 is an important cytokine for innate and adaptive immunity. We previously reported that IL-12 inhibits tumour necrosis factor (TNF)-α-mediated osteoclast formation by inducing apoptosis. We also reported that TNF-α plays an important role in mechanical loading-induced osteoclast formation and bone resorption during orthodontic tooth movement. In this study, we investigated the effects of IL-12 on mechanical tooth movement in mice.
  
  
  METHODS
  A Ni-Ti closed coil spring was inserted between the upper incisors and the upper left first molar in mice. IL-12 was injected locally adjacent to the first molar every other day during the experimental period, at doses varying from 0 to 1.5μg/day. After 12 days, the animals were killed and their jaws were processed for histological evaluation using tartrate-resistant acid phosphatase (TRAP) and TdT-mediated dUTP-biotin nick end-labelling (TUNEL) staining, and measurements of the root resorption area.
  
  
  RESULTS
  In the IL-12-treated mice, tooth movement and root resorption appeared to be reduced. In TUNEL-stained sections, many apoptotic cells were recognized on the pressure side in the IL-12-treated mice.
  
  
  CONCLUSIONS
  Our findings suggest that IL-12 inhibits not only mechanical tooth movement, but also root resorption during orthodontic tooth movement. These findings may arise through apoptosis induced by IL-12.
authors.affiliation: Department of Orthodontics and Dentofacial Orthopedics, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki, Japan.
authors.forename: Masako
authors.initials: M
authors.lastname: Yoshimatsu
authors.forename: Hideki
authors.initials: H
authors.lastname: Kitaura
authors.forename: Yuji
authors.initials: Y
authors.lastname: Fujimura
authors.forename: Haruka
authors.initials: H
authors.lastname: Kohara
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Morita
authors.forename: Toshiko
authors.initials: T
authors.lastname: Eguchi
authors.forename: Noriaki
authors.initials: N
authors.lastname: Yoshida
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D020287:In Situ Nick-End Labeling; D018664:Interleukin-12 / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D010010:Osteoclasts / Q000187:drug effects; D012391:Root Resorption / Q000517:prevention & control*; D013314:Stress, Mechanical; D014087:Tooth Movement Techniques; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
chemical_list: D014409:Tumor Necrosis Factor-alpha; D018664:Interleukin-12