Figure 1

Effects of adrenomedullin (AM) on bleomycin (BLM)-induced lung injury, body weight, and fluid content. Masson's trichrome staining of lung sections revealed significant tissue damage (B), when compared with sham-operated animals (A). AM administration caused a decrease of pulmonary lesion, consisting of moderate inflammation and slight fibrosis (C). The histological scoring of fibrosis severity in the lung samples showed in BLM-administered mice a severe degree of injury in relation to sham-operated mice (D); however, AM treatment significantly reduced the lung injury (D). BLM administration was associated with a marked loss in body weight (E), while AM significantly attenuated this weight loss (E). Moreover, BLM administration caused an increase of wet/dry lung weight ratio, when compared with sham-operated mice (F). On the contrary, AM significantly reduced this parameter (F). At 14 and 21 days after treatments, lung sections were subjected to Masson-trichrome staining for the presence of an intense fibrosis. This stain shows collagen in purple. Microphotographs of sections from (D and G) sham-operated animals, (E and H) BLEO (bleomycin-treated mice), and (F and I) AM treated animals show that abundant extracellular matrix (ECM) deposition, alveolar thickening, and severe distortion of lung structures observable in lung sections from BLEO was substantially reduced in AM-treated mice. Figures are representative of at least 3 experiments performed on different experimental days. Data are expressed as mean ± standard deviation from n = 10 mice for each group. *P < 0.01 vs. sham, °P < 0.01 vs. bleomycin + vehicle.