Visceral hypersensitivity and altered colonic motility after subsidence of inflammation in a rat model of colitis.
OBJECTIVE
Irritable bowel syndrome (IBS) is a functional bowel disorder characterized by visceral hypersensitivity and altered bowel motility. There is increasing evidence suggesting the role of inflammation in the pathogenesis of IBS, which addresses the possibility that formerly established rat model of colitis could be used as an IBS model after the inflammation subsided.


METHODS
Colitis was induced by intracolonic instillation of 4% acetic acid in male Sprague-Dawley rats. The extent of inflammation was assessed by histological examination and myeloperoxidase (MPO) activity assay. After subsidence of colitis, the rats were subjected to rectal distension and restraint stress, then the abdominal withdrawal reflex and the number of stress-induced fecal output were measured, respectively.


RESULTS
At 2 days post-induction of colitis, the colon showed characteristic inflammatory changes in histology and 8-fold increase in MPO activity. At 7 days post-induction of colitis, the histological features and MPO activity returned to normal. The rats at 7 days post-induction of colitis showed hypersensitive response to rectal distension without an accompanying change in rectal compliance, and defecated more stools than control animals when under stress.


CONCLUSIONS
These results concur largely with the characteristic features of IBS, visceral hypersensitivity and altered defecation pattern in the absence of detectable disease, suggesting that this animal model is a methodologically convenient and useful model for studying a subset of IBS.
La
Jun-Ho
JH
Department of Physiology, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea.
Kim
Tae-Wan
TW
Sung
Tae-Sik
TS
Kang
Jeoung-Woo
JW
Kim
Hyun-Ju
HJ
Yang
Il-Suk
IS
D019342:Acetic Acid / Q000633:toxicity; D000818:Animals; D015415:Biomarkers / Q000032:analysis; D003092:Colitis / Q000139:chemically induced / Q000473:pathology / Q000503:physiopathology*; D004195:Disease Models, Animal; D007249:Inflammation / Q000473:pathology; D043183:Irritable Bowel Syndrome / Q000139:chemically induced / Q000473:pathology / Q000503:physiopathology; D008297:Male; D010146:Pain / Q000503:physiopathology*; D009195:Peroxidase / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley
D015415:Biomarkers; D009195:Peroxidase; D019342:Acetic Acid