MMP9 and chronic obstructive pulmonary disease: Figure B represents the analysis of the hub genes for the action of the seven compounds and COPD, and it was found that the main hub genes for DBP were PTGS2, ESR1, and CASP3; the main hub genes for DEHP were CASP3, MMP9, BCL2, BCL2L1, MTOR, and PPARG; the main hub genes for DEP were CASP3, BCL2, MMP9, and CCND1; the major hub genes of DIBP are EGFR, CASP3, STAT3; the major hub genes of DINP are EGFR, CASP3, PTGS2, and MAPK14; the major hub genes of DMP are CASP3, EGFR, and TLR4; and the major hub genes of DOP are CASP3, BCL2, IL 10, and HIF1A.