RESUMO
<p><b>OBJECTIVE</b>To study the relationship between the changes of intestinal mucosal tumor necrosis factor alpha (TNF-alpha), plasma diamine oxidase (DAO) values and the degree of mucosal injuries in young rat model of colitis and thereby to explore if plasma DAO could be used as a potential index for monitoring intestinal mucosal injury.</p><p><b>METHODS</b>One hundred and four healthy young male Sprague-Dawley (SD) rats aged 5-6 weeks were randomly divided into three groups: zero time group (n = 8), model group (n = 48) and control group (n = 48). The model and control groups were further divided into 24 h, 72 h, 1 week, 2 weeks, 3 weeks and 4 weeks subgroups, respectively, with 8 rats in each. The rats in model group were given 2, 4, 6-trinitrobenzene sulfonic acid (TNBSA) via enema to induce colitis, while the rats in the control group were given normal saline (NS) solution in the same way and those in zero time group were not treated. TNF-alpha and DAO were measured by immunohistochemical technique and spectrophotometry.</p><p><b>RESULTS</b>The most serious enteric mucosal injury was seen 24 hours after giving TNBSA. Plasma DAO and TNF-alpha decreased as the intestinal mucosal injury was alleviated.</p><p><b>CONCLUSIONS</b>Plasma DAO values may be used as a marker for intestinal mucosal injury. TNF-alpha is a factor for causing mucosal injury. Young rat colitis model can be used to study intestinal mucosal injury.</p>