Histopathological examination

Colon sections were taken from the mice for histological examination. The length of the colon from the anus to appendix was measured by a ruler, then segments of colon were excised, fixed in 10% phosphate-buffered saline (PBS)-buffered formalin at room temperature for 24 h, then embedded in paraffin. Sections measuring 5–10 µm in thickness were cut, placed on glass slides and stained with hematoxylin and eosin (H&E). Histopathological changes were observed under a light microscope and graded semiquantitatively using a histological injury scale, as described by Wirtz et al (16). The scores for histological changes were as follows: 0, no evidence of inflammation; 1, low level inflammation with scattered mononuclear cells (1–2 foci); 2, moderate inflammation with multiple foci of mononuclear cells; 3, high level inflammation with increased vascular density and marked wall thickening; and 4, maximal inflammation with transmural leukocyte infiltration and loss of goblet cells.