However, the PI3K/Akt/mTOR autophagy signalling pathway was blocked by ligustrazin, which increased autophagy, decreased Hh signalling (Figs.4, 5 and 6), downregulated Smo and Gli1 protein levels (Fig. 6), suppressed pro-Fibrin expression, and ameliorated PQ-induced lung fibrosis. Here, SMO is linked to pulmonary fibrosis.