Hydroxyproline content in lungs 14 days after saline (n = 3 for each genotype) or bleomycin treatment of WT (n = 4), Pg+/− (n = 5), Pg−/− (n = 5), u-PA−/− (n = 5), u-PAR−/− (n = 7), and t-PA−/− (n = 4) mice. Values are means ± SE of 4 to 7 mice, performed in duplicate.