Lung Histological Assessment Protocol

The mouse lung (right) was perfused with 1 mL 10% (v/v) neutral-buffered formalin fixation solution through the trachea; then, the lungs were removed and submerged in formalin buffer. The tissue was paraffinized, cut to 5 μm thickness, and stained with Masson’s trichrome (MT) or hematoxylin and eosin (H&E) solution for the observation of inflammatory cell penetration and collagen fiber formation (Sigma-Aldrich, Seoul, Republic of Korea). The severity degree of inflammation was scored in a double-blind manner by two independent researchers and was determined using a subjective scale of 0–2 described by Lee et al. [8 (link)].