• Richard J Traub, Bin Tang, Yaping Ji, Sangeeta Pandya, Harris Yfantis, and Ying Sun.
• Department of Neural and Pain Sciences, University of Maryland Dental School, Baltimore, Maryland 21201, USA. rtraub@umaryland.edu
• Gastroenterology. 2008 Dec 1; 135 (6): 2075-83.

Background & AimsChronic visceral hyperalgesia is considered an important pathophysiologic symptom in irritable bowel syndrome (IBS); previous gastrointestinal inflammation is a potent etiologic factor for developing IBS. Although there are several animal models of adult visceral hypersensitivity after neonatal perturbation or acute colonic irritation/inflammation, current models of postinflammatory chronic visceral hyperalgesia are unsatisfactory. The aim of this study was to establish a model of chronic visceral hyperalgesia after colonic inflammation in the rat.MethodsDeoxycholic acid (DCA) was instilled into the rat colon daily for 3 days and animals were tested for up to 4 weeks.ResultsDCA induced mild, transient colonic inflammation within 3 days that resolved within 3 weeks. An exaggerated visceromotor response, referred pain to mechanical stimulation, increased spinal Fos expression, and colonic afferent and dorsal horn neuron activity were apparent by 1 week and persisted for at least 4 weeks, indicating chronic dorsal horn hyperexcitability and visceral hyperalgesia. There was no spontaneous pain, based on open field behavior. There was a significant increase in opioid-receptor activity.ConclusionsDCA induces mild, transient colitis, resulting in persistent visceral hyperalgesia and referred pain in rats, modeling some aspects of postinflammatory IBS.

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