Abstract
We previously demonstrated an increase in gene expression of MMP-8 and MMP-13 since the first hours of the induction of emphysema in mice by porcine pancreatic elastase (PPE) and a posterior reduction in the volume ratio of collagen type I (3 days) that returned to similar values of control groups at the 21th day of the protocol. Such results suggested the importance of collagenases in emphysema progression. Objectives: To describe the importance of MMP-12, as well as the repair process of elastin and fibrillin at the beginning of the emphysema development and correlated it with previous findings. Methods: C57BL/6 mice were submitted to intranasal instillation of PPE (0,667 IU) and were euthanized at different times after that: 1 hour, 3 hours, 6 hours, 3 days and 21 days. Control groups (S) received the same treatment with saline (NaCl 0.9%). We used the Real-time RT-PCR to assess the gene expression of MMP-12 and immunohistochemistry to quantify the volume ratio of elastin and fibrillin in lungs. Results: The MMP-12 gene expression was increased since 3 hs of emphysema induction until 6 hs. Fibrillin analyses showed no difference in its parenchyma percentage at any of the PPE groups comparing to S groups. Elastin instead, presented a decrease at 3rd day after PPE instillation and a increase at 21st day compared to respective S groups. Conclusions: We attested the importance of the MMP-12 together with MMP-8 and MMP-13 activity since the first hours after the emphysema induction. Also we verified a repair process characterized by a prior reduction in quantified parenchymal fibers followed by an increase at 21th day.
- © 2014 ERS