Histological images of the distal small intestine of sham and IO rats. (Panels A-D) Sections of intestinal tissues were stained with H & E. (Panels E and F) The apoptotic level of intestinal tissues was examined by TUNEL assay. (A) Normal villous structure was seen in the distal small intestine of sham rats. (B) Following IO, villi were edematous and blunted. Severe shedding of epithelial cells was observed in the intestinal lumen of IO rats (asterisk). (C) Higher magnification of the epithelial layer in the distal small intestine of IO rats showing epithelial shedding without villous denudation. (D) A positive control displaying epithelial discontinuity in an ischemic gut model. (E) No sign of TUNEL(+) cells was observed in the intestine of sham controls. (F) A high number of apoptotic cells was seen in the gut lumen following IO (arrows). (G) Quantification of TUNEL(+) cells. *p < 0.05 vs. respective sham groups. #p < 0.05 vs. IO+v rats. Panels A, B, E and F: 100× magnification. Panels C and D: 400× magnification.