For H&E staining, the major organ of mice was collected, fixed
in 4% paraformaldehyde overnight, and embedded in paraffin according
to standard histological protocols. Next, the tissue was cut into
5 μm-thick cross-sectional slices. The paraffin sections in
each group were dewaxed, stained with hematoxylin for 3–5 min,
and differentiated with ethanolic hydrochloric acid. The paraffin
sections were washed and stained with eosin for 5 min. Images were
photographed under a microscope (Eclipse C1, Nikon, Japan).
For TUNEL staining, the harvested tumor tissues were first fixed
with 4% paraformaldehyde. Then, they were embedded in an optimal cutting
temperature compound followed by cutting into 5 μm-thick sections.
The sections were treated using Triton X-100 at room temperature for
10 min and then blocked with 5% bovine serum albumin. The apoptotic
cells were measured with a TUNEL apoptosis assay kit in accordance
with the manufacturer’s instruction. DAPI was selected for
nuclear staining. The image was photographed under a microscope (Eclipse
C1, Nikon, Japan).