Fig. 2.

Increased lung proteolytic activity elicited by MV-O₂ is suppressed in elafin-expressing mice. Elastase activity (A) and matrix metalloproteinase (MMP)-9 (B) activity measured in the lungs of 6-day-old wild-type mice after MV-O₂ for 24 h is increased when compared with unventilated controls that breathed 40% O₂ for 24 h. In contrast, neither lung elastase activity nor MMP-9 activity increased in response to MV-O₂ in lungs of elafin-expressing mice. *Significant difference between groups, P < 0.05. Values are means and SD; n = 4–5/group for elastase activity, n = 3/group for MMP-9 activity.