Fig. 5.

Quasistatic compliance (Qst) from anesthetized 13-day-old WT and MMP-9 (−/−) pups after 8 days of hyperoxia or room air exposure measured by forced oscillation technique. The lungs of oxygen-exposed mice were less compliant than those of room air-exposed WT and MMP-9 (−/−) neonatal mice. This reduction was significantly less in MMP-9 (−/−) mice after hyperoxia (24% reduction compared with 47% reduction in WT after hyperoxia; n = 4 mouse pups per condition). *P < 0.03 compared with room air-exposed WT; bars are means ± SE. **P = 0.001 compared with room air-exposed MMP-9 (−/−).