TLR4-HMGB1-, MyD88- and TRIF-dependent signaling in mouse intestinal ischemia/reperfusion injury

Table 1 Histologic grading of intestinal ischemia-reperfusion injury

Grade	Features
0	Normal,villus to crypt ratio 5-6:1, minimal number of lymphocytes and plasma cells, tall columnar surface epithelial cells
1	Epithelial cell degenerative changes (cuboidal,vacuolated) but intact, mild increase of lymphocytes and plasma cells in lamina propria
2	Decreased villus height, yielding villus to crypt ratio ≤ 1, epithelial cell necrosis or erosions, more chronic inflammation in lamina propria ± neutrophils, glandular dilatation
3	Villi effaced (flat surface), epithelial cell necrosis or erosions, pseudomembrane may appear on surface, glandular destruction, inflammation extending deep to muscle layer
4	Transmural changes (all of above plus change in muscle layer)