title: β-cryptoxanthin regulates bone resorption related-cytokine production in human periodontal ligament cells.
abstract: OBJECTIVE
  β-cryptoxanthin (β-cry) is a type of carotenoid found in certain fruits and vegetables. Although it has been shown that β-cry inhibits alveolar bone resorption, the molecular mechanisms for this have not yet been clarified. In the present study, we investigated the effects of β-cry on bone resorption related-cytokine production in human periodontal ligament (hPDL) cells.
  
  
  METHODS
  hPDL cells were stimulated with β-cry (1×10(-7)mol/l), mechanical stress (1 or 6MPa), and P. gingivalis. The production of interleukin (IL)-1β, IL-6, IL-8, tumour necrosis factor (TNF)-α, osteoprotegerin (OPG), and receptor activator of nuclear factor kappa-B ligand (RANKL) were analyzed by RT-PCR and ELISA.
  
  
  RESULTS
  The production of IL-1β, IL-6, IL-8, and TNF-α was not induced in hPDL cells after stimulation with β-cry, although these cytokines were produced after stimulation with P. gingivalis. On the other hand, IL-6 and IL-8 were produced after exposure to 6MPa of mechanical stress. The production of IL-6 and IL-8 was significantly decreased by the addition of β-cry. Furthermore, β-cry up-regulated the production of OPG, but not RANKL.
  
  
  CONCLUSIONS
  β-cry inhibited the production of IL-6 and IL-8 induced by mechanical stress and periodontopathogenic bacteria in hPDL cells. Moreover, β-cry up-regulated OPG production. These results suggest that β-cry may prevent bone resorption in periodontitis.
authors: Department of Dental Medicine, Kyoto Prefectural University of Medicine, Graduate School of Medical Science, Japan.
authors: Masaru
authors: M
authors: Nishigaki
authors: Toshiro
authors: T
authors: Yamamoto
authors: Hiroaki
authors: H
authors: Ichioka
authors: Ken-Ichi
authors: K
authors: Honjo
authors: Kenta
authors: K
authors: Yamamoto
authors: Fumishige
authors: F
authors: Oseko
authors: Masakazu
authors: M
authors: Kita
authors: Osam
authors: O
authors: Mazda
authors: Narisato
authors: N
authors: Kanamura
mesh_terms: D016866:Bacteroidaceae Infections; D001862:Bone Resorption / Q000517:prevention & control*; D002478:Cells, Cultured; D065366:Cryptoxanthins; D016207:Cytokines / Q000096:biosynthesis* / Q000235:genetics; D004797:Enzyme-Linked Immunosorbent Assay; D015870:Gene Expression; D006801:Humans; D053244:Osteoprotegerin / Q000096:biosynthesis; D010513:Periodontal Ligament / Q000166:cytology / Q000187:drug effects*; D010518:Periodontitis / Q000503:physiopathology*; D016966:Porphyromonas gingivalis / Q000472:pathogenicity; D012333:RNA, Messenger / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013314:Stress, Mechanical; D015854:Up-Regulation; D024341:Xanthophylls / Q000494:pharmacology*
chemical_list: D065366:Cryptoxanthins; D016207:Cytokines; D053244:Osteoprotegerin; D012333:RNA, Messenger; D024341:Xanthophylls