Colonic muscle enhances the production of interleukin-1 beta messenger RNA in experimental colitis.

Abstract

Inflammatory bowel diseases are accompanied by alterations in the contractile function of colonic muscle. Whether these changes are also accompanied by the production of interleukin-1 beta (IL-1 beta) mRNA remains unknown. To investigate the profile of IL-1 beta mRNA in the colonic muscle of rats with acetic acid induced colitis. Colitis was induced by intrarectal administration of 1 ml of 4% acetic acid 8 cm from anal margin. Myeloperoxidase activity was used as a marker of inflammation in the colon. RNA was extracted from colonic muscle and was used to amplify the level of IL-1 beta mRNA with a reverse transcription coupled polymerase chain reaction (RT-PCR) method developed in this study. Colonic muscle exhibited constitutive expression of IL-1 beta mRNA. The level was enhanced significantly, one, two, and five days after acetic acid administration. On day 7 after treatment, the level of IL-1 beta mRNA had returned baseline values. This profile of IL-1 beta mRNA was consistent with myeloperoxidase activity. IL-1 beta is a putative mediator of the changes in muscle function in this model of colitis.