Histopathology of lungs is associated with mechanical ventilation. Representative photomicrographs (×400) with H&E staining of the lung histopathology. (a) Mice placed on high–peak pressure/stretch mechanical ventilation treated with anti–murine CXCR2 or with control antibodies. (b) CXCR2–/– mice placed on high–peak pressure/stretch mechanical ventilation, as compared with CXCR2+/+ mice.