Procollagen col1a1 propeptide

Staining was performed on 5-μm paraffin sections or cryosections. Slides were blocked with a blocking solution (3% BSA, and 0.2% Triton X-100 in PBS) for 2 h. Then, tissue sections were incubated at 4 °C overnight with primary antibodies: procollagen (COL1A1 propeptide, 1:50, Thermo Fisher Scientific) for the cryosections and rabbit anti-mouse FSP1 (1:100, Abcam, Cambridge, MA, USA) for the paraffin sections. Secondary antibodies conjugated with Alexa 594 (Thermo Fisher Scientific) were used. Coverslips were mounted by using Vectashield with 4′,6-diamidino-2-phenylindole (DAPI) (Vector Laboratories, Burlingame, CA, USA). Fluorescence images were recorded with FV10i fluorescence microscope (Olympus, Tokyo, Japan).