Hematoxylin and eosin staining of skin sections

P20 mice were perfused with 4% paraformaldehyde before PBS washes and dehydration. Skin tissue was flash-frozen in liquid nitrogen using Cryomatrix (ThermoFisher Scientific) cryoprotectant [39] and sectioned at 8µm (Leica CM 3050S). H&E staining was performed as follows: CAT hematoxylin (Biocare Medical) for 2 minutes, wash for 30 seconds, Tasha’s bluing solution (Biocare Medical) for 30 seconds, wash for 10 minutes, eosin Y (Biocare Medical) for 2 minutes, 70% ethanol for 1 minute, 90% ethanol for 1 min, 100% ethanol for 4 min, Xylene for 15 minutes. Slides were mounted with permount (Fisher Scientific).