title: [Effect of hypoxia on the expression of matrix metalloproteinase and tissue inhibitors of matrix metalloproteinase mRNA in human periodontal ligament fibroblasts in vitro].
abstract: OBJECTIVE
  To investigate the effect of hypoxia on the expression of matrix metalloproteinase (MMP) and tissue inhibitors of matrix metalloproteinase (TIMP) in human periodontal ligament fibroblasts (HPDLF).
  
  
  METHODS
  HPDLF were cultured in α-minima essential medium (α-MEM) and subcultured at confluence. In the hypoxic groups, cells were incubated in a humidified atmosphere of 1%O(2), 5%CO(2), 94%N(2) at 37°C for 12, 24 and 48 h, respectively. In the normoxic control group, cells were incubated under normoxic conditions of 20%O(2), 5%CO(2), 75%N(2). The mRNA expression of MMP and TIMP was measured using reverse transcription-polymerase chain reaction (RT-PCR). The data was analyzed by Student's t test, one-way ANOVA and LSD test with SPSS 13.0 software package.
  
  
  RESULTS
  The expression of MMP-2, TIMP-1 and TIMP-2 mRNA in the hypoxia groups was higher than that in control. The expression of MMP-2 mRNA in hypoxic groups showed a significantly increasing trend. There was significant difference between the hypoxic group and the normoxic control group in the expression of MMP-2 mRNA in HPDLF (P < 0.01). The expression of TIMP-1, TIMP-2 mRNA in hypoxic groups of 12 h was momentarily increased. There was significant difference between the hypoxic 12 h group and the normoxic control group in the expression of TIMP-1, TIMP-2 mRNA in HPDLF (P < 0.05). However, with prolonged hypoxia time, the expression of TIMP-1, TIMP-2 mRNA in hypoxic groups showed a significantly declining trend, there were significant differences between the hypoxic 12, 24 and 48 h group and the normoxic control group in the expression of TIMP-2 mRNA in HPDLF (P < 0.05). The expression of MMP-1 mRNA in hypoxic groups of 12 h was momentarily decreased and then increased after 24 h of hypoxia. There were significant differences between the hypoxic 48 h group and the normoxic control group in the expression of MMP-1 mRNA in HPDLF (P < 0.05). There were significant differences between the hypoxic 12 h group and the normoxic control group in the ratio of MMP-1/TIMP-1 mRNA (P < 0.05). The ratio of MMP-2/TIMP-2 mRNA in the hypoxia group significantly increased compared with normoxic group. There were significant differences between the hypoxic group and the normoxic control group in the ratio of MMP-2/TIMP-2 mRNA (P < 0.05).
  
  
  CONCLUSIONS
  Hypoxia could change the expression of MMP and TIMP mRNA and other relevant growth factors and also lead to the imbalance of MMP-2/TIMP-2 mRNA expression. It is suggested that the imbalance of MMP-2/TIMP-2 expression may be closely correlated with the occurrence and development of periodontal disease and play an important role in the process of periodontal tissue destruction in periodontitis.
authors.affiliation: Department of Periodontology, School of Stomatology, Shandong University, Jinan 250012, China. lishu@sdu.edu.cn
authors.forename: Ai-mei
authors.initials: AM
authors.lastname: Song
authors.forename: Chao
authors.initials: C
authors.lastname: Hou
authors.forename: Jia-fang
authors.initials: JF
authors.lastname: Chen
authors.forename: Jing
authors.initials: J
authors.lastname: Sun
authors.forename: Tian
authors.initials: T
authors.lastname: Tian
authors.forename: Shu
authors.initials: S
authors.lastname: Li
mesh_terms: D000293:Adolescent; D015687:Cell Hypoxia; D002478:Cells, Cultured; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D006801:Humans; D020781:Matrix Metalloproteinase 1 / Q000235:genetics / Q000378:metabolism*; D020778:Matrix Metalloproteinase 2 / Q000235:genetics / Q000378:metabolism*; D010513:Periodontal Ligament / Q000166:cytology*; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000235:genetics / Q000378:metabolism*; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000235:genetics / Q000378:metabolism*
chemical_list: D012333:RNA, Messenger; C560822:TIMP1 protein, human; C560823:TIMP2 protein, human; D019715:Tissue Inhibitor of Metalloproteinase-1; D019716:Tissue Inhibitor of Metalloproteinase-2; C522361:MMP2 protein, human; D020778:Matrix Metalloproteinase 2; C522360:MMP1 protein, human; D020781:Matrix Metalloproteinase 1