Changes in enteroendocrine and immune cells following colitis induction by TNBS in rats

Approximately 3.6 million individuals suffer from inflammatory bowel disease (IBD) in the western world, with an annual global incidence rate of 3–20 cases/100,000 individuals. The etiology of IBD is unknown, and the currently available treatment options are not satifactory for long-term treatment. Patients with inflammatory bowel disease present with abnormalities in multiple intestinal endocrine cell types, and a number of studies have suggested that interactions between gut hormones and immune cells may serve a pivotal role in the pathophysiology of IBD. The aim of the present study was to investigate alterations in colonic endocrine cells in a rat model of IBD. A total of 30 male Wistar rats were divided into control and trinitrobenzene sulfonic acid (TNBS)-induced colitis groups. Colonoscopies were performed in the control and TNBS groups at day 3 following the induction of colitis, and colonic tissues were collected from all animals. Colonic endocrine and immune cells in the obtained tissue samples were immunostained and their densities were quantified. The densities of chromogranin A, peptide YY, and pancreatic polypeptide-producing cells were significantly lower in the TNBS group compared with the control group, whereas the densities of serotonin, oxyntomodulin, and somatostatin-producing cells were significantly higher in the TNBS group. The densities of mucosal leukocytes, B/T-lymphocytes, T-lymphocytes, B-lymphocytes, macrophages/monocytes and mast cells were significantly higher in the TNBS group compared with the controls, and these differences were strongly correlated with alterations in all endocrine cell types. In conclusion, the results suggest the presence of interactions between intestinal hormones and immune cells.