Expression of α-SMA in mouse lung tissue after LPS challenge. Paraffin-embedded mouse lung tissue samples were deparaffinized, rehydrated, and processed to detect α-SMA using the avidin-biotin immunoperoxidase method. Representative images (×200) of samples are shown. BC: blank control group; NC: negative control group; PC: positive control group; TI: TLR4 inhibition group; TI+L: TLR4 inhibition group stimulated with LPS; 3d: specimens were collected 72 hours after LPS (or physiological saline) challenge. 4w: specimens were collected 28 days after LPS (or physiological saline) challenge. Each subgroup contains 6 specimens respectively (n = 6).