OBJECTIVETo investigate the effect of balsalazide on intestinal mucosal permeability of experimental colitis induced by dextran sulfate sodium(DSS) in a mouse model and its possible mechanism.

METHODSForty-five C57BL/6J mice were randomly divided into five groups. Normal group was only fed with distilled water, DSS group and Balsalazide groups at doses of 42,141,423 mg/kg were fed with 5% DSS. Balsalazide was given by intragastric administration. DAI was evaluated daily. At the end of the experiment, colon tissue was collected for assessment of histological changes, MDA content, MPO, SOD and GSH-PX activity. Small intestinal mucosa was collected for assessment of transmission electron microscope(TEM), and detection of permeability by Evans blue.

RESULTSCompared with normal group, DSS group mice all manifested severe weight loss associated with hematochezia and diarrhea with significant increase of DAI and HI score(P<0.01). MDA content and MPO activity was increased with the reverse result of SOD and GSH-PX(P<0.01) in DSS group. Intestinal mucosa showed a focal reduction in thinning of microvillous carpet and even a total disarrangement of epithelial surface, with decurtated and broaden junctional complex and enlarged intercellular space under TEM observations in DSS group. The amount of Evans blue permeated into intestinal wall was obvious in DSS group. Compared with DSS group, balsalazide improved gross findings, decreased MPO activity and MDA content, but increased the activity of SOD and GSH-PX(P<0.05). The amount of Evans blue permeated into intestinal wall was less(P<0.05). Ileal microvillous carpet was ameliorated in dose-dependent manner by balsalazide.

CONCLUSIONSIntestinal mucosal permeability is increased in DSS group. Balsalazide can significantly ameliorate intestinal mucosal permeability in colitis model.