Fig. 4.

Compliance, elastance, elastic recoil, and total lung volume. Mice were anesthetized and compliance (A), elastance (B), and pressure-volume relationships were (C) measured using the Flexivent system. Elastase- and elastase/LPS-treated mice showed an increase in compliance, a decrease in elastance, and a left shift of PV-loop compared with PBS- or LPS-treated mice (gray). Data are representative of at least 6 animals per group. B: with the chest closed, lungs were instilled with buffered formalin at 30 cmH₂O constant pressure for 30 min via a catheter inserted into the trachea, and total lung volume was measured by volume displacement. Elastase- and elastase/LPS-treated mice showed higher total lung volume than the PBS-treated mice. Data in A, B, and D represent means and SD calculated from 6–8 animals per group, *different from PBS group, P ≤ 0.05; †different from all other groups, P ≤ 0.05, 1-way ANOVA. A representative PV curve from 4 to 6 mice from each group is shown in C.