Microscopic presentation of TNBS-induced colitis in rats (hematoxylin and eosin staining; original magnification 10×). (A) Normal group: mucus layer and crypts are normal; (B) TNBS-control group: epithelial distortion, crypt damage and inflammatory cell infiltrates; (C & D) Dexamethasone and tropisetron groups respectively: mild to moderate mucosal and submucosal inflammation and mucosal inflammatory cell infiltrates; (E & F): mCPBG and mCPBG + tropisetron, respectively: infiltration of neutrophils and destruction of mucosal architecture.