A rat model of chronic postinflammatory visceral pain induced by deoxycholic acid.
OBJECTIVE
Chronic 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.


METHODS
Deoxycholic acid (DCA) was instilled into the rat colon daily for 3 days and animals were tested for up to 4 weeks.


RESULTS
DCA 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.


CONCLUSIONS
DCA induces mild, transient colitis, resulting in persistent visceral hyperalgesia and referred pain in rats, modeling some aspects of postinflammatory IBS.
Traub
Richard J
RJ
Department of Neural and Pain Sciences, University of Maryland Dental School, Baltimore, Maryland 21201, USA. rtraub@umaryland.edu
Tang
Bin
B
Ji
Yaping
Y
Pandya
Sangeeta
S
Yfantis
Harris
H
Sun
Ying
Y
D015746:Abdominal Pain / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology*; D000818:Animals; D002908:Chronic Disease; D003092:Colitis / Q000139:chemically induced / Q000150:complications* / Q000503:physiopathology; D003106:Colon / Q000294:innervation / Q000473:pathology / Q000503:physiopathology; D003840:Deoxycholic Acid / Q000633:toxicity; D004195:Disease Models, Animal; D004594:Electrophysiology / Q000379:methods; D005500:Follow-Up Studies; D017950:Ganglia, Sensory / Q000503:physiopathology; D007150:Immunohistochemistry; D008297:Male; D010147:Pain Measurement; D051381:Rats; D017207:Rats, Sprague-Dawley
D003840:Deoxycholic Acid