Lung slides from WT and p66 Shc−/− mice scored at 5 months for active caspase-3, TUNEL and p16INK4a. Immunohistochemical evaluation of active caspase-3 on lungs of air control (A) and smoking WT (B) mice at 5 months. Note in (B) a positive staining on alveolar macrophages and epithelial lung cells. The positivity on lung epithelial cells is more evident at higher magnification (see the arrowheads in the inset). Active caspase-3 staining on tissue slides from air-control (C) and smoking p66 Shc−/− mice (D). DNA strand-break extremities labeling (TUNEL) on lung tissues from air-control (E) and smoking (F) WT at 5 months. In (G) and (H) TUNEL labeling on air-control and smoking p66 Shc−/− mice, respectively. Immunohistochemical staining for the cyclin-dependent kinase inhibitor p16INK4a on lung slides from WT (I) and p66 Shc−/− (J) mice after 5 months of CS exposure. (A-J): Scale bars = 40 μm.
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