title: Effect of heat stress on the expression levels of receptor activator of NF-κB ligand and osteoprotegerin in human periodontal ligament cells.
abstract: OBJECTIVE
  To investigate the expression levels of the receptor activator of NF-κB ligand (RANKL) and osteoprotegerin (OPG) in human periodontal ligament fibroblasts (PDLs) when stimulated with heat.
  
  
  METHODS
  Periodontal ligament fibroblasts were subjected to various temperature increases for 5 min and then maintained at 37 °C. After that, cell viability was determined using an MTT assay. The expression levels of RANKL and OPG were investigated using real-time RT-PCR and ELISA. As a control, the cells were cultured at 37 °C. Data were analysed using one-way anova at a significant level of P = 0.05. Results  Cell viability was reduced significantly in the heated groups (P < 0.05). Heat stress downregulated the mRNA expression levels of RANKL and OPG (P < 0.05). When the cells were heated at 39 °C, the protein release of OPG was increased (P < 0.05). There were no significant differences between the heated groups and the control in the release of soluble RANKL (P > 0.05). The relative RANKL/OPG expression ratios were decreased at 39, 43 and 50 °C (P < 0.05), but increased at 47 °C (P < 0.05).
  
  
  CONCLUSIONS
  Heat influenced the balance between RANKL and OPG in PDLs. Low heat downregulated their relative ratio, whilst high heat upregulated it.
authors: State Key Laboratory of Oral Diseases             Department of Conservative Dentistry, West China College of Stomatology, Sichuan University, Chengdu, China.
authors: L
authors: L
authors: Zhang
authors: X
authors: X
authors: Zhou
authors: Q
authors: Q
authors: Wang
authors: Y
authors: Y
authors: Wang
authors: L
authors: L
authors: Tang
authors: D
authors: D
authors: Huang
mesh_terms: D002470:Cell Survival / Q000502:physiology; D002478:Cells, Cultured; D004396:Coloring Agents; D015536:Down-Regulation / Q000502:physiology; D004797:Enzyme-Linked Immunosorbent Assay; D005347:Fibroblasts / Q000378:metabolism*; D018869:Heat-Shock Response / Q000502:physiology*; D006801:Humans; D053244:Osteoprotegerin / Q000032:analysis*; D010513:Periodontal Ligament / Q000166:cytology* / Q000378:metabolism; D053245:RANK Ligand / Q000032:analysis*; D012333:RNA, Messenger / Q000032:analysis; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013778:Tetrazolium Salts; D013844:Thiazoles; D015854:Up-Regulation / Q000502:physiology
chemical_list: D004396:Coloring Agents; D053244:Osteoprotegerin; D053245:RANK Ligand; D012333:RNA, Messenger; C506030:TNFRSF11B protein, human; C505688:TNFSF11 protein, human; D013778:Tetrazolium Salts; D013844:Thiazoles; C022616:thiazolyl blue