Effects of hypoxia, hyperoxia on the regulation of expression and activityof matrix metalloproteinase-2 in hepatic stellate cells

AIM To study the effects of hypoxia! hyperoxia on the regulation of express ion and activity of matrix metalloproteinase-2 (MMP-2) in hepatic stellate cells (HSC). METHODS The expressions of MMP-2, tissue inhibitor of matrix metalloprotein ase-2 (TIMP-2) and membrane type matrix metalloproteinase-1 (MT1-MMP) in cu ltured rat HSC were detected by immunocytochemistry (ICC) and in situ hybri dization (ISH). The contents of MMP-2 and TIMP-2 in culture supernatant wer e detected with ELISA and the activity of MMP-2 in supernatant was revealed by zymography. RESULTS In the situation of hypoxia for 12 h, the expression of MMP-2 prote in was enhanced ( hypoxia group positive indexes: 5.7 +/- 2.0, n = 10; cont rol: 3.2 +/- 1.0, n = 7; P < 0.05), while TIMP-2 protein was decreased in H SC (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 dec lined 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 chan ges of expressions including mRNA and protein level as well as activity of MMP-2 were most notable in 6 h group. The highest value (A(hypoxia)-A(contr ol)) Of the protein and the most intense signal of mRNA were in the period of hypoxia for 6 h, along with the lowest activity of MMP-2. In the situati on of hyperoxia for 12 h, the contents (A(450)) of MMP-2 and MMP-2 in super natant were both higher than those in the control, especially the MMP-2 (hy peroxia group: 0.0499 +/- 0.0144, n = 16; control: 0.0219 +/- 0.0098, n = 1 4; 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 expressio n of MTI-MMP was increased. CONCLUSION 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.