The following primary antibodies were independently used to detect specific proteins: collagen I (1:500 dilution, Bioworld, USA), collagen III (1:500 dilution, Bioworld, USA), MPO (1:200 dilution, Santa Cruz, USA), matrix metalloproteinase (MMP)-2 (1:500 dilution, ProteinTech, USA), MMP-9 (1:500 dilution, ProteinTech, USA), and tissue inhibitors of metalloproteinase (TIMP)-1 (1:1000 dilution, Abcam, USA). An antibody against β-actin (1:1000 dilution, ProteinTech, USA) was used as an internal control.
Horseradish peroxidase-conjugated anti-goat (1:10000 dilution, Beyotime, China) or anti-mouse (1:10000 dilution, ZSGB Biological Company, China) IgGs were used to bind the primary antibodies. Protein bands on Western blots were visualized using an enhanced chemiluminescence detection system (Santa Cruz, USA). Relative band densities of proteins in Western blots were normalized against β-actin.