Number of infiltrating cells recovered in the bronchoalveolar lavage fluid (BALF) obtained from the lungs with mechanical ventilation with higher tidal volume (30 mL/kg). (a) Administration of hydrogen had no effect on inflammatory cell accumulation in the BALF. N = 6 for each group. #P < 0.05 versus sham/N2 controls. (b) Protein concentration in BALF. Ventilator-induced lung injury (VILI) resulted in significant increases of protein contained in BALF. Hydrogen did not reduce leaked protein. N = 6 for each group. (c) Blood lactate concentration. VILI by mechanical ventilation for 2 hours was associated with hyperlactatemia. Mice subjected to ventilation with 2% hydrogen did not show significant increase of blood lactate levels compared with those of sham controls. N = 6 for each group. *P < 0.05 versus sham/N2 and sham/H2; #P < 0.05 versus VILI/N2.