Role of mucosal mast cells in visceral hypersensitivity in a rat model of irritable bowel syndrome.
The involvement of mucosal mast cells (MMC) in the pathophysiology of irritable bowel syndrome (IBS) is still controversial. We aimed to re-evaluate the role of MMC in visceral hypersensitivity associated with IBS using a rat IBS model that develops the IBS symptom after a subsidence of acetic acid-induced colitis. No significant difference in the number of MMC was observed between normal rat colon and IBS rat colon. (61.7 +/- 2.9/mm(2) in normal vs. 88.7 +/- 13.3/mm(2) in IBS, p > 0.29). However, the degranulation rate of MMC was significantly higher in IBS rat colon (49.5 +/- 2.4% in normal vs. 68.8 +/- 3.4% in IBS, p < 0.05). Pretreatment of a mast cell stabilizer, doxantrazole (5 mg/kg, i.p.), reduced the degranulation rate of MMC and significantly attenuated visceral hypersensitivity to rectal distension in IBS rat, whereas it had no effect on the visceral sensory responses in normal rat. These results suggest that, although the number of MMC is not significantly changed in IBS rat colon, the higher degranulation rate of MMC is responsible for visceral hypersensitivity in this model IBS.
La
Jun-Ho
JH
Department of Physiology, College of Veterinary Medicine, Seoul National University, Seoul 151-742, Korea.
Kim
Tae-Wan
TW
Sung
Tae-Sik
TS
Kim
Hyun-Ju
HJ
Kim
Jeom-Yong
JY
Yang
Il-Suk
IS
D019342:Acetic Acid / Q000633:toxicity; D000818:Animals; D002452:Cell Count; D003092:Colitis / Q000139:chemically induced / Q000473:pathology*; D006967:Hypersensitivity / Q000473:pathology*; D007091:Image Processing, Computer-Assisted; D007413:Intestinal Mucosa / Q000473:pathology*; D043183:Irritable Bowel Syndrome / Q000473:pathology*; D008297:Male; D008407:Mast Cells / Q000187:drug effects / Q000473:pathology*; D008962:Models, Theoretical; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013892:Thioxanthenes / Q000494:pharmacology; D014781:Viscera / Q000276:immunology; D044004:Xanthones / Q000494:pharmacology
D010726:Phosphodiesterase Inhibitors; D013892:Thioxanthenes; D044004:Xanthones; D019342:Acetic Acid; C010134:doxantrazole