Collagenases are upregulated in IPF lungs versus donor lungs.

<p>Peripheral lung tissue samples from IPF (n=16) and controls (n=6-8, 6 lung donors plus additional 2 control RNA) were analyzed for MMP and TIMP mRNA (quantitative PCR, A) and protein content (Western Blots, B, C) and for MMP13 immunohistochemistry (D). (A) mRNA content of each MMP/TIMP is indicated by target mRNA to human β-actin ratio. (B) Protein content of each MMP/TIMP is given as the mean normalized integrated density value (IDV) compared with that of actin as loading control. Mean value ± SEM is given. For each patient triplicate determination were undertaken. Data presented are from three independent experiments. Significance level is indicated by <i>*</i> (<i>p< 0.05</i>), <i>**</i> (<i>p<0.01</i>) and <i>***</i> (<i>p<0.001</i>) compared with normal lungs for mRNA and healthy donor lungs for protein expression. (C) Representative immunoblot demonstrating increased protein expression of both the latent and active form of MMP-13 in IPF (right lanes) versus controls (organ donors, left 3 lanes). (D) Immunohistochemistry for MMP-13 in controls (organ donors, D) versus IPF lungs (E, F). Whereas only weak MMP-13 immunoreactivity was observed in alveolar macrophages and bronchial epithelial cells in the control lungs, increased MMP-13 expression was easily detected in alveolar and bronchiolar epithelial cells (arrow), alveolar macrophages, but also in interstitial spaces of IPF lungs. Scale = 100µm. (F) Higher power view of E showing abundant MMP-13 immunoreactivity (arrows); scale = 50µm.