Pulmonary microvascular permeability. Total protein levels were increased in all ventilated mice, compared to unventilated controls. Protein levels were highest in the groups Figure 5 . Cytokine levels. Cytokines were quantified in blood serum or BAL supernatant with commercial ELISA kits after six hours of ventilation and in unventilated mice. (Unventilated: n = 5, lowV T RM5 n = 6, highV T RM5 n = 6, lowV T noRM n = 4 in BAL and n = 5 in serum, highV T noRM n = 4, lowV T RM60 n = 5). * p,0.05, ** p,0.01, *** p,0.001, 1 *** p,0.001 versus all other groups). doi:10.1371/journal.pone.0024527.g005 without RM (Fig. 4A) . The BSA BAL/serum ratio confirmed that ventilation augmented microvascular permeability in the lung, particularly when inspiratory pressures were high, as in the groups ventilated without repetitive recruitment (Fig. 4B) .