title: TGF-betal transgenic mouse model of thoracic irradiation: modulation of MMP-2 and MMP-9 in the lung tissue.
abstract: To investigate the effects of TGF-beta1 on the two gelatinases (MMP-2 and MMP-9), and their roles in lung remodeling after irradiation-induced lung injury. Expressions of TGF-beta1 were measured with western blot, and expressions of MMP-2 and MMP-9 were analyzed with zymography in a -TGF-beta1 transgenic mouse model after thoracic irradiation with 12 Gy. We found expressions of TGF-beta1 in the lung from the transgenic mice were three folds as compared to those from control mice. With densitometrical analysis, we found a significant decrease in MMP-9 activity in lung homogenates from the transgenic mice as compared with those from non-transgenic control mice 8 weeks after sham-irradiation (relative MMP-9 activity: C: 1.000 0.1091; TG: 0.4772 +/- 0.470 (n = 8, P < 0.05). But MMP-2 was constitutively expressed in the lung homogenates from the transgenic mice as compared to those from control mice 8 weeks after sham-irradiation (relative MMP-2 activity 8 weeks after sham-irradiation: C: 1.000 +/- 0.1556, TG: 1.0075 +/- 0.1472). Eight weeks after thoracic irradiation with 12 Gy, we observed a significant increase of MMP-2 and MMP-9 activity in lung homogenates from both transgenic and normal mice. In TGF-beta1 transgenic mice relative MMP-9 activity was increased to 1.5321 +/- 0.2217 folds 8 weeks after thoracic irradiation with 12 Gy as compared to those after sham-irradiation (1.000 +/- 0.2153), and relative MMP-2 activity was increased to 1.7142 +/- 0.4231 folds. Our results show that TGF-beta1 itself down-regulates activity of MMP-9, thereby decreases ECM degradation in lungs of TGF-beta1 transgenic mice. Also we find that ionizing irradiation upregulates both MMP-2 and MMP-9 activity. Over-expressions of MMP-9 and MMP-2 after lung irradiation are involved in the inflammatory response associated with radiation-induced lung injury, and maybe further in radiation-induced lung fibrosis.
authors.affiliation: Union Hospital Cancer Center, Tongji Medical College, Huazhong Science and Technology University, Wuhan 430022, China.
authors.forename: Kunyu
authors.initials: K
authors.lastname: Yang
authors.forename: Li
authors.initials: L
authors.lastname: Liu
authors.forename: Tao
authors.initials: T
authors.lastname: Zhang
authors.forename: Gang
authors.initials: G
authors.lastname: Wu
authors.forename: Claudia
authors.initials: C
authors.lastname: Ruebe
authors.forename: Christian
authors.initials: C
authors.lastname: Ruebe
authors.forename: Yu
authors.initials: Y
authors.lastname: Hu
mesh_terms: D000818:Animals; D015153:Blotting, Western; D004797:Enzyme-Linked Immunosorbent Assay; D008168:Lung / Q000201:enzymology* / Q000473:pathology / Q000528:radiation effects; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism*; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D051379:Mice; D008822:Mice, Transgenic; D011658:Pulmonary Fibrosis / Q000201:enzymology / Q000235:genetics; D011833:Radiation Injuries, Experimental / Q000201:enzymology*; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000378:metabolism; D053773:Transforming Growth Factor beta1 / Q000097:blood / Q000235:genetics / Q000378:metabolism*
chemical_list: D019715:Tissue Inhibitor of Metalloproteinase-1; D053773:Transforming Growth Factor beta1; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9