Figure 7. Atg4b deficiency and impaired autophagy sensitizes mice to epithelial apoptosis and lung fibrosis. (A) Representative light microscopy images of H&E and Masson’s trichrome stained lung tissue sections from WT and Atg4b null mice at 21 days post-tunicamycin instillation. (B) Fibrosis extent percentage of damaged tissue area in the lung fields by quantitative image analysis and hydroxyproline content in lungs from tunicamycin-treated WT and Atg4b null mice. (C) Representative light microscopy images of NFκB and CAS3 positive stained lung tissue sections from WT and Atg4b null tunicamycin-treated mice at 21days (top panels). Total number of positive stained cells per high power field (40X) in lung tissue sections by quantitative image analysis (bottom panels). Results shown represent mean ± SD. Statistical significance was determined by Student’s t test (*p < 0.05).