MMP9 and pulmonary fibrosis: In our study, based on network pharmacology, we found that PFD alleviated silica-induced pulmonary fibrosis by modulating key genes (e.g., TNF, MMP9 and NF-κB1) and engaging in immune-inflammatory processes through the following thematically grouped signaling pathways: (1) inflammatory responses (Toll-like receptor, IL-17, NF-κB, and TNF pathways), (2) cellular survival/apoptosis regulation (PI3K-Akt and MAPK pathways), and (3) hypoxia/stress responses (HIF-1 pathway).