Inflammatory bowel disease in rats: Bacterial and chemical interaction

Table 1 Criteria for macroscopic grading of the experimental colitis

	Macroscopic grading
Feature	0	1	2	3
Stool	Normal	Loose stool	Diarrhea	Diarrhea with blood
Hyperemia	None	Focal	Focal and thickening of bowel wall	Extensive thickening of bowel wall
Adhesions	None	Mild	Moderate	Extensive
Megacolon	None	Mild	Moderate	Toxic megacolon
Ulcerations	None	Mild ulceration on one side < 1 cm	Moderate ulceration > 1 cm	Severe damage extending > 2 cm

Table 2 Criteria for microscopic grading of experimental chronic colitis

	Histologic grading
Feature	0	1	2	3
Abnormalities of mucosal architecture	None (Normal)	Mild or focal, not exceeding lamina propria	Moderate, not exceeding the submucosa	Severe & diffuse, exceeding the submucosa
Crypt abnormalities	None	Mild atrophy	Moderate atrophy, Branched crypts	Severe atrophy, branched crypts, cryptitis, crypt abscess
Inflammatory cell infiltration	Normal	Scattered cells	Moderate or confluent cells	Massive infiltration of cells
Vascular dilatation	Normal blood vessels	Mild dilatation (localized)	Moderate dilatation of several blood vessels	Severe generalized dilatation of blood vessels
Edema	None	Low level limited to villi	In the submucosa	All over the section
Mast cells	Normal scattered cells	Three cells clustered in submucosa	Clusters of > 3 cells in the submucosa	Clusters in submucosa and serosa