Figure 2. BN^m rats develop inflammatory bowel disease.

(A) Small intestine and colon from 12 week-old BN and BN^m rats. (B, C) Length of small intestine and colon (B) and thickness of the duodenum, jejunum, ileum and colon (C) of BN (n = 10) and BN^m rats with macroscopic signs of intestinal lesions (n = 7). (D) Hematoxylin-eosin staining of duodenum, jejunum and colon from 8 to 10 week-old BN and BN^m rats. Images are representative of microscopic lesions observed in all affected BN^m rats (original magnification: 100 X). Stars indicate granulomas; arrows point to infiltration and double head arrows indicate the thickness of the intestinal wall. (E) CD68, CD3 and B220 immunoperoxydase staining on sections of jejunum from 8 week-old BN^m rats. Positive staining results in a brown reaction product. HE: hematoxylin-eosin staining showing the presence of polymorphonuclear leucocytes (original magnification: 400 X). (F) Myeloperoxidase (MPO) activity in the duodenum, jejunum, ileum and colon tissue samples from BN (n = 30) and BN^m rats with macroscopic lesions (n = 21). (G) Cytokine and chemokine protein expression in duodenum from BN (n = 7) and BN^m rats with macroscopic lesions (n = 7). (H) Relative mRNA expression of IL-2 and IL-17A in duodenum from BN (n = 4) and BN^m rats exhibiting intestinal macroscopic lesions (n = 7). (BN: black columns, BN^m: white columns).