J Vet Sci.  2004 Dec;5(4):319-324.

Role of mucosal mast cells in visceral hypersensitivity in a rat model of irritable bowel syndrome

• La JH
• Kim TW
• Sung TS
• Kim HJ
• Kim JY
• Yang IS

Abstract

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.

Keyword

Irritable bowel syndrome; visceral hypersensitivity; mucosal mast cell

MeSH Terms

Acetic Acid/toxicity
Animals
Cell Count
Colitis/chemically induced/*pathology
Hypersensitivity/*pathology
Image Processing, Computer-Assisted
Intestinal Mucosa/*pathology
Irritable Bowel Syndrome/*pathology
Male
Mast Cells/drug effects/*pathology
Models, Theoretical
Phosphodiesterase Inhibitors/pharmacology
Rats
Rats, Sprague-Dawley
Thioxanthenes/pharmacology
Viscera/immunology
Xanthones/pharmacology