摘要
To investigate the effects of TGF-β1 on the two gelatinases （MMP-2 and MMP-9）, and their roles in lung remodeling after irradiation-induced lung injury. Expressions of TGF-β1 were measured with western blot, and expressions of MMP-2 and MMP-9 were analyzed with zymography in a TGF-β1 transgenic mouse model after thoracic irradiation with 12 Gy. We found expressions of TGF-β1 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-β1 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-β1 itself down-regulates activity of MMP-9, thereby decreases ECM degradation in lungs of TGF-β1 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.
To investigate the effects of TGF-β1 on the two gelatinases （MMP-2 and MMP-9）, and their roles in lung remodeling after irradiation-induced lung injury. Expressions of TGF-β1 were measured with western blot, and expressions of MMP-2 and MMP-9 were analyzed with zymography in a TGF-β1 transgenic mouse model after thoracic irradiation with 12 Gy. We found expressions of TGF-β1 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-β1 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-β1 itself down-regulates activity of MMP-9, thereby decreases ECM degradation in lungs of TGF-β1 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.
