Bleomycin-induced pulmonary fibrosis in transgenic mice that either lack or overexpress the murine plasminogen activator inhibitor-1 gene.

DT Eitzman, RD McCoy, X Zheng… - The Journal of …, 1996 - Am Soc Clin Investig
DT Eitzman, RD McCoy, X Zheng, WP Fay, T Shen, D Ginsburg, RH Simon
The Journal of clinical investigation, 1996Am Soc Clin Investig
Impaired fibrinolytic activity within the lung is a common manifestation of acute and chronic
inflammatory lung diseases. Because the fibrinolytic system is active during repair
processes that restore injured tissues to normal, reduced fibrinolytic activity may contribute
to the subsequent development of pulmonary fibrosis. To examine the relationship between
the fibrinolytic system and pulmonary fibrosis, lung inflammation was induced by bleomycin
in transgenic mice that either overexpressed or were completely deficient in murine …
Impaired fibrinolytic activity within the lung is a common manifestation of acute and chronic inflammatory lung diseases. Because the fibrinolytic system is active during repair processes that restore injured tissues to normal, reduced fibrinolytic activity may contribute to the subsequent development of pulmonary fibrosis. To examine the relationship between the fibrinolytic system and pulmonary fibrosis, lung inflammation was induced by bleomycin in transgenic mice that either overexpressed or were completely deficient in murine plasminogen activator inhibitor-1 (PAI-1). 2 wk after 0.075 U of bleomycin, the lungs of transgenic mice overexpressing PAI-1 contained significantly more hydroxyproline (118 +/- 8 micrograms) than littermate controls (70.5 +/- 8 micrograms, P < 0.005). 3 wk after administration of a higher dose of bleomycin (0.15 U), the lung hydroxyproline content of mice completely deficient in PAI-1 (49 +/- 8 micrograms) was not significantly different (P = 0.63) than that of control animals receiving saline (37 +/- 1 micrograms), while hydroxyproline content was significantly increased in heterozygote (77 +/- 12 micrograms, P = 0.06) and wild-type (124 +/- 19 micrograms, P < 0.001) littermates. These data demonstrate a direct correlation between the genetically determined level of PAI-1 expression and the extent of collagen accumulation that follows inflammatory lung injury. These results strongly support the hypothesis that alterations in fibrinolytic activity influence the extent of pulmonary fibrosis that occurs after inflammatory injury.
The Journal of Clinical Investigation