Effects of <i>P</i>. <i>aeruginosa</i> (PA) instillation on mechanical ventilation-induced lung injury.

<p>(A) WT mice were intranasally instilled with live PA (1 × 10⁴ or 1 × 10⁶ CFU) or normal saline at 2 days before receiving mechanical ventilation (MV) for 3 h and lung tissues were harvested and assayed. (B) Positive bacterial cultures of lung tissues shown as CFU counted on the LB plates. (C) PA instillation before ventilation increased MPO activity of the lung. (D) PA instillation before MV increased nitrite concentration in BALF. Nitrite in BALF was assayed by Griess reagent. PA, <i>P</i>. <i>aeruginosa</i>; MPO, myeloperoxidase; BALF, bronchoalveolar lavage fluid; NS, normal saline. *P<0.05, **P<0.01, ***P<0.001. n = 6/group.