Masson's trichrome stain

Cardiac fibrosis was determined using Masson's trichrome staining. Mice were transfected with lentivirus expressing miR-93 or scr-miR 7 days before induction of MI. Subsequently, 3 weeks after MI, hearts were harvested, post-fixed with 4% paraformaldehyde for 12 h at 4°C, and sliced horizontally. Sections (5 µm) were stained using Masson's trichrome staining kit (cat. no. G1340; Beijing Solarbio Science & Technology Co., Ltd.) at room temperature for 1 h according to the manufacturer's protocol (concentrations not commercially available). Stained sections were examined using light microscope (magnification, ×12.5) and analyzed using ImageJ software (NIH; version 1.48; http://rsb.info.nih.gov/ij/).