[The establishment of TNBS-induced experimental colitis].

OBJECTIVE

To explore the pathogenesis of inflammatory bowel disease (IBD) and to establish some indices monitoring the activity and severity of IBD.

METHODS

A rat model of experimental colitis was induced by administration of the hapten 2, 4, 6-trinitrobenzenesulfonic acid (TNBS, 30 mg) in 50% ethanol 0.25 ml as the "barrier breaker". And it then recurs only after 10 mg TNBS administration. Inflammation was assessed by gross appearance using a grading scale and by histology. Myeloperoxidase(MPO) and superioxide dismutase(SOD) activities were also measured to evaluate the severity of inflammation.

RESULTS

An acute inflammation with ulcers and neutrophil infiltration developed that evolved into a chronic inflammation with luminol narrowing and abundant fibrous connective tissue hypertrophy at 21 days. Crypt abcess were observed in some rats killed in 1 week. MPO activity was significantly elevated, while SOD decreased, in mucosa from all treated groups at all time intervals when macroscopic and microscopic mucosal injury was evident.

CONCLUSIONS

These results indicate that this model affords an opportunity to study the pathogenesis of colonic inflammatory disease and may be used to evaluate new treatments potentially applicable to IBD in humans. In addition, MPO and SOD activities could be regarded as two markers which may evaluate the severity of colonic inflammation.