title: Effects of hypoxia, hyperoxia on the regulation of expression and activity of matrix metalloproteinase-2 in hepatic stellate cells.
abstract: OBJECTIVE
  To study the effects of hypoxia, hyperoxia on the regulation of expression and activity of matrix metalloproteinase-2 (MMP-2) in hepatic stellate cells (HSC).
  
  
  METHODS
  The expressions of MMP-2, tissue inhibitor of matrix metalloproteinase-2 (TIMP-2) and membrane type matrix metalloproteinase-1 (MT1-MMP) in cultured rat HSC were detected by immunocytochemistry (ICC) and in situ hybridization (ISH). The contents of MMP-2 and TIMP-2 in culture supernatant were detected with ELISA and the activity of MMP-2 in supernatant was revealed by zymography.
  
  
  RESULTS
  In the situation of hypoxia for 12h, the expression of MMP-2 protein was enhanced (hypoxia group positive indexes: 5.7 +/- 2.0, n=10; control: 3.2 +/- 1.0, n = 7; P<0.05), while TIMP-2 protein was decreased in HSC (hypoxia group positive indexes: 2.5 +/- 0.7, n = 10; control: 3.6 +/- 1.0, n = 7; P < 0.05), and the activity (total A) of MMP-2 in supernatant declined obviously (hypoxia group: 7.334 +/- 1.922, n = 9; control: 17.277 +/- 7.424, n = 11; P < 0.01). Compared the varied duration of hypoxia, the changes of expressions including mRNA and protein level as well as activity of MMP-2 were most notable in 6h group. The highest value(A(hypoxia)-A(control)) of the protein and the most intense signal of mRNA were in the period of hypoxia for 6h, along with the lowest activity of MMP-2. In the situation of hyperoxia for 12h, the contents (A(450)) of MMP-2 and TIMP-2 in supernatant were both higher than those in the control, especially the TIMP-2 (hyperoxia group: 0.0499 +/- 0.0144, n = 16; control: 0.0219 +/- 0.0098, n = 14; P < 0.01), and so was the activity of MMP-2 (hyperoxia group: 5.252 +/- 0.771, n = 14; control: 4.304 +/- 1.083, n = 12; P < 0.05), and the expression of MT1-MMP was increased.
  
  
  CONCLUSIONS
  HSC is sensitive to the oxygen, hypoxia enhances the expression of MMP-2 and the effect is more marked at the early stage; hyperoxia mainly raises the activity of MMP-2.
authors.affiliation: Department of Pathology, School of Basic Medical Sciences, Fudan University, 138 Yixueyuan Road, Shanghai 200032, China.
authors.forename: P S
authors.initials: PS
authors.lastname: Chen
authors.forename: W R
authors.initials: WR
authors.lastname: Zhai
authors.forename: X M
authors.initials: XM
authors.lastname: Zhou
authors.forename: J S
authors.initials: JS
authors.lastname: Zhang
authors.forename: Y E
authors.initials: YE
authors.lastname: Zhang
authors.forename: Y Q
authors.initials: YQ
authors.lastname: Ling
authors.forename: Y H
authors.initials: YH
authors.lastname: Gu
mesh_terms: D000818:Animals; D002455:Cell Division; D015687:Cell Hypoxia / Q000502:physiology; D002478:Cells, Cultured; D015971:Gene Expression Regulation, Enzymologic; D022781:Hepatocytes / Q000166:cytology / Q000201:enzymology*; D018496:Hyperoxia / Q000378:metabolism*; D020778:Matrix Metalloproteinase 2 / Q000235:genetics* / Q000378:metabolism*; D053504:Matrix Metalloproteinases, Membrane-Associated; D008666:Metalloendopeptidases / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000235:genetics / Q000378:metabolism
chemical_list: D012333:RNA, Messenger; D019716:Tissue Inhibitor of Metalloproteinase-2; D053504:Matrix Metalloproteinases, Membrane-Associated; D008666:Metalloendopeptidases; D020778:Matrix Metalloproteinase 2