Figure 7. Pulmonary histology of injured and healthy lungs.

Histological comparison of lung tissue either exposed to bleomycin only (left column), bleomycin plus high cell dose (middle column), or representative healthy animal control (right column). Patchy areas of interstitial inflammation, edema, and fibrosis are similar in rat lungs treated with bleomycin (A) and bleomycin plus cells (B). Areas of airway dilation (bronchiectasis, b) are similarly rimmed with inflammation in rat lungs treated with bleomycin (D) and bleomycin plus cells (E). A small area of acute alveolar hemorrhage (h) is present in E. The inflammation consists of lymphocytes, histiocytes, and neutrophils (n) in G within an edematous (clear) interstitium in both lungs treated with bleomycin (G) and bleomycin plus cells (H). A small amount of acute hemorrhage (h) is present in E and H. Fibrosis (poorly cellular, eosinophilic, extracellular material, (f) is common and similar in inflamed areas of rat lungs treated with bleomycin (J) and bleomycin plus cells (K). Panels C, F, I, and L are form a healthy unmanipulated, non-study rat and are provided for comparison to normal rat lung.