title: Insulin modulates cytokines expression in human periodontal ligament cells.
abstract: OBJECTIVE
  Periodontal disease (PD) has recently been recognized as the 'sixth' major complication of diabetes but the mechanisms involved in diabetic PD remain unclear. This study was to elucidate the potential bone-sparing effect of insulin in diabetic PD conditions.
  
  
  METHODS
  The human periodontal ligament (hPDL) cells were obtained from the healthy hPDL tissue and were treated with high concentrations (25 or 45mM) of glucose with or without different concentrations (10(-6), 10(-7) or 10(-8)mM) of insulin.
  
  
  RESULTS
  High concentrations of glucose increased the production of pro-inflammatory cytokines interleukin-1 beta (IL-1β), tumour necrosis factor alpha (TNF-α), Interleukin-6 (IL-6) at both mRNA and protein levels, and receptor activator of NF-кB ligand (RANKL) at mRNA levels in hPDL cells. Insulin treatment alleviated the stimulatory effects of high glucose on pro-inflammatory cytokines and RANKL expression by hPDL cells. Moreover, insulin up-regulated OPG expression and therefore attenuated the reduction of OPG vs. RANKL ratio.
  
  
  CONCLUSIONS
  Insulin plays significant roles in modulating the periodontal tissue responses to hyperglycemia, and thus exerts its bone-sparing effects on periodontal tissues via altering the inflammatory cytokines expression in hPDL cells.
authors.affiliation: Department of Dentistry, Chinese PLA General Hospital, Beijing 100853, China.
authors.forename: Yingying
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Department of Prosthodontics, School of Stomatology, Fourth Military Medical University, Xi'an 710032, China.
authors.forename: Fuwei
authors.initials: F
authors.lastname: Liu
authors.affiliation: Department of Prosthodontics, School of Stomatology, Fourth Military Medical University, Xi'an 710032, China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Dentistry, 101 Hospital of Chinese People's Liberation Army, Wuxi 214044, China. Electronic address: leishumd@gmail.com.
authors.forename: Lei
authors.initials: L
authors.lastname: Shu
mesh_terms: D000293:Adolescent; D001862:Bone Resorption / Q000503:physiopathology; D002478:Cells, Cultured; D002681:China; D016207:Cytokines / Q000187:drug effects* / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005947:Glucose / Q000494:pharmacology; D006801:Humans; D006943:Hyperglycemia / Q000188:drug therapy / Q000378:metabolism*; D007328:Insulin / Q000494:pharmacology*; D053244:Osteoprotegerin / Q000187:drug effects* / Q000378:metabolism; D010513:Periodontal Ligament / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D016207:Cytokines; D007328:Insulin; D053244:Osteoprotegerin; D005947:Glucose
keywords: Cytokine; Glucose; Insulin; Periodontal ligament cells