Visceral and somatic hypersensitivity in a subset of rats following TNBS-induced colitis.
BACKGROUND
Chronic abdominal pain is one of the most common gastrointestinal symptoms experienced by patients. Visceral hypersensitivity has been shown to be a biological marker in many patients with chronic visceral pain. We have previously shown that IBS patients with visceral hypersensitivity also have evidence of thermal hyperalgesia of the hand/foot.


OBJECTIVE
The objective of the current study was to develop an animal model of chronic visceral and somatic hypersensitivity in rats treated with intracolonic trinitrobenzene sulfonic acid.


METHODS
Male Sprague-Dawley rats (200-250g) were treated with either 20mg/rat trinitrobenzene sulfonic acid (TNBS, Sigma Chemical Co.) in 50% ethanol (n=75), an equivalent volume of 50% ethanol (n=20) or an equivalent volume of saline (n=20). The agents were delivered with a 24-gauge catheter inserted into the lumen of the colon. Mechanical and thermal behavioral tests were performed using an automated von Frey and Hargreaves device to evaluate somatic hyperalgesia. Colonic distension was performed using an automated distension device to evaluate visceral pain thresholds. All animals were tested 16weeks after TNBS treatment following complete resolution of the colitis.


RESULTS
At 16weeks, 24% of the treated rats (18/75 rats) still exhibited evidence of visceral as well as somatic hypersensitivity compared to saline- and ethanol-treated rats.


CONCLUSIONS
Transient colonic inflammation leads to chronic visceral and somatic hypersensitivity in a subset of rats. These findings are similar to the subset of patients who develop chronic gastrointestinal symptoms following enteric infection.
Zhou
QiQi
Q
Department of Medicine, Division of Gasteroenterology, Hepatology, and Nutrition, University of Florida Colleges of Medicine and Dentistry, 1600 SW Archer Road, HD 602, PO Box 100214, Gainesville, FL 32610-0214, USA.
Price
Donald D
DD
Caudle
Robert M
RM
Verne
G Nicholas
GN
D000818:Animals; D003092:Colitis / Q000139:chemically induced / Q000503:physiopathology*; D006358:Hot Temperature / Q000009:adverse effects; D006930:Hyperalgesia / Q000139:chemically induced / Q000503:physiopathology*; D008297:Male; D010147:Pain Measurement / Q000379:methods; D017288:Pain Threshold; D051381:Rats; D017207:Rats, Sprague-Dawley; D020886:Somatosensory Disorders / Q000139:chemically induced / Q000503:physiopathology; D014110:Touch / Q000502:physiology*; D014302:Trinitrobenzenesulfonic Acid / Q000633:toxicity*; D017833:Visceral Afferents / Q000187:drug effects / Q000502:physiology*
D014302:Trinitrobenzenesulfonic Acid