Molecular association of trinitrobenzenesulfonic acid and surface phospholipids in the development of colitis in rats.

BACKGROUND & AIMS: Mucosal hydrophobicity contributes to the barrier property of the stomach. This study examined the effect of 2,4,6-trinitrobenzenesulfonic acid (TNBS) on colonic mucosal hydrophobicity and its relationship with developing inflammation.

METHODS

After the initial study, which suggested that TNBS can chemically react with zwitterionic phospholipids, contact-angle analysis of the colonic mucosa was performed after the luminal exposure of everted sacs of rat colon to TNBS. In vivo, rats were given TNBS, TNBS in ethanol, or TNBS coupled with dipalmitoylphosphatidylcholine by enema. On the 11th day, mucosal hydrophobicity damage score, colon weight, and myeloperoxidase activity were measured.

RESULTS

TNBS acutely (5 minutes) reduced the contact angle of the rat colonic mucosa in vitro as well as in vivo when administered in 50% ethanol. Surface mucosal hydrophobicity was significantly reduced 11 days after intracolonic inoculation with TNBS in ethanol and appeared to be associated with colonic inflammation. The ability of TNBS to decrease mucosal hydrophobicity and induce colitis was attenuated if the hapten was coupled with dipalmitoylphosphatidylcholine.

CONCLUSIONS

TNBS may reduce mucosal hydrophobicity by reacting with the surface-active phospholipids of the colonic mucosa. Reduced hydrophobic integrity of the colonic mucosa may contribute to TNBS-induced colonic inflammation.