['Protease-activated receptor-2 (PAR(2)) is highly expressed throughout the gut and regulates the inflammatory, mitogenic, fibroproliferative, and nociceptive responses to injury. PAR(2) is strikingly upregulated and exhibits increased activation in response to intestinal irradiation. We examined the mechanistic significance of radiation enteropathy development by assessing the effect of exogenous PAR(2) activation.', 'Rat small bowel was exposed to localized single-dose radiation (16.5 Gy). The PAR(2) agonist (2-furoyl-LIGRLO-NH(2)) or vehicle was injected intraperitoneally daily for 3 days before irradiation (before), for 7 days after irradiation (after), or both 3 days before and 7 days after irradiation (before-after). Early and delayed radiation enteropathy was assessed at 2 and 26 weeks after irradiation using quantitative histologic examination, morphometry, and immunohistochemical analysis.', 'The PAR(2) agonist did not elicit changes in the unirradiated (shielded) intestine. In contrast, in the irradiated intestine procured 2 weeks after irradiation, administration of the PAR(2) agonist was associated with more severe mucosal injury and increased intestinal wall thickness in all three treatment groups (p <.05) compared with the vehicle-treated controls. The PAR(2) agonist also exacerbated the radiation injury score, serosal thickening, and mucosal inflammation (p <.05) in the before and before-after groups. The short-term exogenous activation of PAR(2) did not affect radiation-induced intestinal injury at 26 weeks.'] Does activation of protease activated receptor 2 by exogenous agonist exacerbate early radiation injury in rat intestine?