In vivo neutralization of murine CXCR2 attenuates VILI. (a) VILI scores of H&E-stained histopathologic sections from mice placed on high–peak pressure/stretch ventilation protocol treated with neutralizing antibodies to CXCR2 or with control antibodies. A cumulative score was based on leukocyte infiltration, exudative edema, hemorrhage, and alveolar wall thickness (n = 15; three random sections per lung and five lungs per group). *P < 0.05. (b) Evans blue permeability index (n = 10 mice per group). *P < 0.05. (c) VILI scores of H&E-stained histopathologic sections from CXCR2^–/– mice placed on high–peak pressure/stretch ventilation protocol, as compared with CXCR2^+/+ mice (n = 15; three random sections per lung and five lungs per group). *P < 0.05. (d) Wet-to-dry weight ratio of lungs from CXCR2^–/– and CXCR2^+/+ mice placed on high–peak pressure/stretch ventilation protocol (n = 8 mice per group). *P < 0.05.