Effect of Adrenomedullin Administration in Two Rat Models of Experimental Inflammatory Bowel Disease

Adrenomedullin (AM) is a novel hypotensive peptide that also exerts powerful anti-inflammatory effects. We recently showed that AM significantly reduces the clinical severity of acetic acid-induced colitis, an experimental model of inflammatory bowel disease (IBD) in rats. In the present study, we examined the effect of AM in two alternative rat models of IBD. We found that 2,4,6-trinitrobenzenesulfonic acid (TNBS) induced megacolon development in the saline-treated group, but AM treatment reduced the macroscopic damage caused by TNBS. In the dextran sulfate sodium (DSS) model, treatment with AM reduced diarrhea and bloody stool scores, but did not reduce body weight. Histological analysis revealed that in both the TNBS and DSS models, colon inflammation was much more severe in the saline-treated group than in the AM-treated group. These findings indicate that the anti-inflammatory properties of AM make it an effective therapeutic agent for the treatment of IBD in rats.