Pathological changes of WT mice from different group. (A) (100X), H&E staining of lung tissue from CG. (B) (100X), H&E staining of lung tissue from NCM, exhibited enlarged alveolar space, thinner alveolar septum, and destroyed alveolar wall when compared with CG (A). (C) (100X), H&E staining of lung tissue from SCSE, also exhibited enlarged alveolar space, thinner alveolar septum, and destroyed alveolar wall when compared with CG (A) but lighter in than LCSE (E). (D) (100X), H&E staining of lung tissue from CSEII, also exhibited enlarged alveolar space, thinner alveolar septum, and destroyed alveolar wall when compared with CG (A) but lighter than LCSE (E). (E) (100X), H&E staining of lung tissue from LCSE, also exhibited enlarged alveolar space, thinner alveolar septum, and destroyed alveolar wall when compared with CG (A). (F) changes of mean alveolar septal thickness (MAST); (G) changes of mean linear intercept (MLI); (H) changes of destructive index (DI). *Compared with control group, p < 0.05; **compared with control group, p < 0.001; #compared with WT CS 6m group, p < 0.05; ##compared with WT CS 6m group, p < 0.001. Scale bars: 200 μm. Error bars: mean ± SEM. n = 5.