The molecular events leading to radiation-induced intestinal barrier failure are not well known. The influence of the expression of claudin proteins in the presence and absence of neurotensin was investigated in radiation-exposed rat intestinal epithelium. Wistar rats were randomly divided into control, irradiation, and irradiation + neurotensin groups, and bacterial translocation to the mesenteric lymph node and expression of claudins were determined. Irradiation led to intestinal barrier failure as demonstrated by significant bacterial translocation. In irradiated terminal ilea, expression of claudin-3 and claudin-4 was significantly decreased, and claudin-2 expression was increased. Administration of neurotensin significantly reduced bacterial translocation and restored the structure of the villi as seen by histologic examination. Among the three subtype of claudins, only claudin-3 expression was restored. These results suggest that the therapeutic effect of neurotensin on the disruption of the intestinal barrier is associated with claudin-3 alteration and that claudin-3 could be used as a marker in evaluating radiation-induced intestinal injury. (C) 2014 Published by Elsevier Inc.