Reduced neurons in the ileum of proctocolectomized rat models

Ileal pouch-anal anastomosis (IPAA) is the operation of choice following proctocolectomy for patients who suffer from ulcerative colitis and familial adenomatous polyposis. The aim of this study was to morphologically examine the neurons, endocrine cells and mast cells in the ileum of rats subjected to proctocolectomy followed by three different types of ileoanal anastomosis. Rats were subjected to either sham operation or proctocolectomy followed by ileoanal anastomosis end-to-end, side-to-end or IPAA (J-pouch). In comparison to sham-operated rats, the body weight was reduced in rats that underwent proctocolectomy with end-to-end or side-to-end, but not IPAA procedure. In all three models of ileoanal anastomosis, the ileum displayed crypt hyperplasia with a chronic inflammatory infiltrate located in the interstitium, hyperplasia of goblet cells, but reduced protein gene product 9.5 (PGP 9.5)-immunoreactive neurons in the mucosa as well as submucosa. Numbers of endocrine cells in the mucosa (chromogranin A immunostaining) and mast cells in the mucosa and submucosa (Astra blue staining) were unchanged after proctocolectomy. In conclusion, neurons, but neither endocrine cells nor mast cells, were reduced in the ileum of proctocolectomized rats followed by either of three different types of ileoanal anastomosis.