Pathological Observation of Intestinal Tissue

Paraffin-embedded sections of intestinal tissues were dewaxed with 5 µm sections, stained with hematoxylin-eosin (HE) (Sigma-Aldrich, USA), and examined under a microscope for assessment. The number of surviving crypts per circumference of the jejunum was assessed quantitatively by pathologists under blinded conditions. Ten circular transverse sections per mouse were stained with HE and blindly analyzed from the photographs to measure the length of small intestinal villi. The depth of small intestinal crypts were also measured. The ratio of villus length to crypt depth (V/C) was calculated as an index to determine the comprehensive function of the small intestine.^18,19