Radiation-induced acute intestinal inflammation differs following total-body versus abdominopelvic irradiation in the ferret

Purpose: The studies were designed to investigate the differences in the in testinal inflammatory response following abdominopelvic or total-body irrad iation in a ferret model. Materials and methods: Ferrets were exposed either to total-body or to abdo minopelvic gamma -radiation (5 Gy) and various parameters of inflammation s tudied in the jejunum, ileum and colon 2 and 7 days later. Results: Abdominopelvic and, to a greater extent, total-body irradiation ca used weight loss by 7 days. White blood cell counts were reduced in both gr oups, but more so following total-body irradiation, Myeloperoxidase activit y was significantly increased in the ileum 2 days after abdominopelvic irra diation, but it was reduced after total-body irradiation. Total-body irradi ation increased tissue prostaglandin E-2 levels in all regions at 2 days an d decreased jejunal leukotriene B-4 levels in the jejunum at both time poin ts. Ileal prostaglandin E-2 levels were increased 2 days after abdominopelv ic irradiation. Expression of inducible nitric oxide synthase was not alter ed by either irradiation protocol. Conclusions: The data show that there are regional differences in the intes tinal response to irradiation, depending on whether it was delivered to the whole body or locally to the abdominopelvic region. In particular, the ile um exhibited an acute increase in myeloperoxidase activity following abdomi nopelvic but not total-body irradiation.