Bleomycin induced lung fibrosis is more severe in MMP13 ^-/^- mice.

A–F: MMP-13^-/^- and WT mice were exposed to saline (control) or bleomycin and analyzed for extent of lung fibrosis 28 days later. Representative lung sections from WT (A, B, C) and MMP-13^-/^- (D, E, F) lungs were stained with haematoxylin and eosin (A, B, D, E, original magnification = 40X) and Mason-Trichrome (C, F, original magnification = 40X) stain for collagen.

G: Hydroxyproline content of WT and MMP-13^-/^- mice lungs 7, 14, and 28 days after saline (control) or bleomycin challenge. Duplicate analysis was undertaken per each lung sample. Data are presented as mean ± SEM out of 5 lungs per group. *p <0.05 compared with WT control; ^# p<0.05 compared with MMP-13^-/^- control. Differences in p-value between WT and MMP13^-/^- mice per each time point are directly indicated in the figure.

H: Representative gelatin substrate zymogram of BALF 7, 14 and 28 days after intra-tracheal administration of bleomycin or saline to MMP-13^-/- and WT mice. Lane1: molecular weight marker, lanes 2, 4, 6, 8: MMP-13 WT; lanes 3, 5, 7, 9: MMP-13^-/- ; Lane 10 recombinant MMP- 2 and -9.

J: Lung Compliance of saline-treated (control) and 28d bleomycin treated MMP-13^-/- and WT mice. The lung compliance of MMP-13^-/- mice on d28 after bleomycin challenge was significantly decreased as compared with d28 bleomycin challenged WT mice. n = 3 per group. Results are presented as mean ± SEM.