2.13 Hematoxylin and eosin staining
Skin tissues were fixed in 4% paraformaldehyde or 10% formalin overnight at 4°C. The tissues were dehydrated, paraffinized, embedded in paraffin and sliced into 4 μm thickness. The paraffin sections were rehydrated through xylene and graded ethanol series. The slides were incubated in hematoxylin for 5 minutes and eosin for 1 minute.