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

AIM: 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. 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.

AIM 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 mjatrix metalloproteinese-2 ( TIMP-2 ) and membrane type matrix metalloproteiness-l (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 supematant was revealed by zymography.``RESULTS In the situation of hypoxia for 12 h, the expression of MMP-2 protein wss enhenced (hypoxiagroup positive indexes: 5.7 ± 2.0, n = 10; control: 3.2 ±1 .0. n -- 7; P＜0.05). while TIMP-2 protein wss decreased in HSC ( hypoxia group positive indexes: 2.5 ± 0.7, n =10: control: 3.6 ± 1.0, n = 7; P＜O.05), and the activity ( total A) of MMP-2 in supematant 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 6 h group. The highest value (Ahypoxia-Acontrol) ofthe 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 situation of hyperoxia for 12 h,the contonts (A450) of MMP-2 and TIMP-2 in supernatant were both higher then 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.``CONCLUSION HSC Js 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.