Volume fraction of collagens in different groups. (A-D) Pathological images for (A) SH, (B) MI, (C) MG and (D) PDTC groups by Masson Trichrome Staining (scale bar, 200 µm). (E) Total collagen; (F) type I collagen; (G) type III collagen; (H) ratio of type I/III collagen. **P<0.01 vs. SH; ##P<0.01 as indicated. Groups: MI, myocardial infarction model group treated with saline for 28 days; SH, sham; MG, model group treated with MG-132 for 28 days; PDTC, model group treated with pyrrolidine dithiocarbamic acid for 28 days. NS, not significant.