Figure 2

Histologic analysis of lungs. (A and a) NV group; (B and b) NC group; (C and c) MHA group; (D and d) SHA group and (E) lung injury scores in the four groups. NV = normal-pressure ventilation with normocapnia; NC = high-pressure ventilation with normocapnia; MHA = moderate hypercapnic acidosis; SHA = severe hypercapnic acidosis. The A, B, C and D panels represent 100x magnification, and the a, b, c and d panels represent 400x magnification. Severe edema in the alveolar septum and spaces with hyaline membrane formation (red arrow) were seen in the NC group, and rare neutrophil infiltration, moderate interstitial edema and less hyaline membrane formation were observed in both hypercapnic acidosis groups. Horizontal bars represent the median. n = 12 for each group.^ap <0.05 versus the NV group; ^bp <0.05 versus the NC group; ^cp < 0.001 in the SHA group versus the MHA group.