Hematoxylin-Eosin (HE) staining

Paraffin sections (5-μm thick) were treated for deparaffinization and rehydration, stained with hematoxylin solution for 5 min, washed with water and dipped in 1% hydrochloric acid ethanol (1% HCl in 70% ethanol) for 5 s, and then washed in deionized water. Next, eosin solution was used to stain the sections. After 2 min of staining, the sections were washed with deionized water, 80% ethanol, 95% ethanol, 100% ethanol in turn to be dehydrated. After dehydration, the sections were cleared in xylene and mounted. Following observation and photographing were conducted using fluorescence microscope (Olympus, Tokyo, Japan).