Fig. 3

Histological analysis, inflammatory scores and atelectasis. Sections of lungs from animals in the untreated group (Control a, a1), group treated with poractant alfa (b, b1) or rSP-C33Leu surfactant (c, c1); the quantification of inflammatory response in total lungs (d) and apical, medial and caudal regions of lungs (e); and atelectasis in total lungs (f). In control group, pulmonary parenchyma showed a diffuse intense inflammatory cell infiltrate and collapsed alveoli (a). Alveolar duct and alveoli displayed an acute cell reaction of polymorphs and low numbers of macrophages. Notice the thickened alveolar septa due to deposits of a eosinophilic amorphous material (arrows) probably fibrin, a precipitate of blood proteins, or another proteinaceous material (a1). In the poractant alfa group, the lung seemed normal at low power, but the alveolar septa displayed slightly increased leukocytes (b). There were increased polymorphs and macrophages in the septal capillaries. At sites, the leukocytes have migrated into the alveolar lumens (b1). The lungs from the rSP-C33Leu group showed inflammatory cell reaction with leukocytes in the alveoli. Notice the thickened alveolar septa with eosinophilic material (arrows) (c). Alveoli showed a mild inflammatory cell reaction of granulocytes and macrophages (c1). Br, bronchiole. The scale bar represent 100 μm in pictures a, b, c and 50 μm in a1, b1, c1. Data are presented as means ± SD. Statistical comparisons: for poractant alfa & rSP-C33Leu vs. Control ^*p < 0.05, ^**p < 0.01