Lung histology analysis to assess the lung injury. (A) Haematoxylin–eosin staining of lung tissue section at 0, 2 and 4 h. Significantly increased congestion, oedema, inflammation and haemorrhage were found at 4 h. Haemorrhage in OLV is more serious than that of SV at 4 h. (I) congestion; (II) oedema; (III) inflammation; (IV) haemorrhage (arrowhead). Original magnification: ×200. (B) Lung injury score to assess the lung tissue injury. A significantly lower lung injury score was found in rabbits from SV group compared with the OLV group at 4 h, but not at 0 or 2 h. *P < 0.05 when compared with OLV group. SV: spontaneous ventilation; OLV: one-lung ventilation.