animal tissue 8 controlled study 8 lung parenchyma 8 nonhuman 8 Animalia 6 Animals 6 article 6 female 6 Amphibia 4 Amphibian 4 Anura 4 Bufonidae 4 Electronic microscopic 4 Lung 4 Lung ultrastructure 4 Melanophryniscus stelzneri 4 Microscopy, Electron 4 Microscopy, Electron, Scanning 4 Respiratory epithelium 4 Toad 4 Vertebrata 4 animal cell 4 animal experiment 4 animal model 4 cell ultrastructure 4 comparative anatomy 4 interleukin 6 4 lung alveolus cell type 1 4 lung alveolus cell type 2 4 lung structure 4