Different susceptibilities of spontaneous rhythmicity and myogenic contractility to intestinal muscularis inflammation in the hapten-induced colitis.
We examined the time-dependent changes in the immunoreactivity of the smooth muscle region and the accompanying motility disorder in a hapten-induced rat model of colitis. Histological analysis and myeloperoxidase (MPO) activity indicated that inflammatory cells infiltrated into the muscle layer at 2 days after 2,4,6-trinitrobenzenesulphonic acid (TNBS) treatment. The infiltrated immune cells then gradually decreased in number, but were still present at 14 days. The expression of proinflammatory cytokine mRNAs (TNF-alpha, IL-1beta and IL-6) and proteins in the muscle layer was increased at 2 days, then began to decrease, returning to control levels at 14 days. The frequency of spontaneous rhythmicity was suppressed at 2 and 7 days, and returned to control levels at 14 days. Consistent with these observations, the immunoreactivity of the interstitial cells of Cajal network was disrupted at 2 and 7 days, which then gradually reformed at 14 days. On the other hand, the myogenic contractions induced by high K(+) and carbachol were decreased at 2 days, and were still inhibited at 14 days. These results suggest that spontaneous rhythmicity dysfunction may improve more rapidly than myogenic contractility dysfunction in a hapten-induced rat model of colitis.
Kiyosue
M
M
Department of Veterinary Pharmacology, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Tokyo, Japan.
Fujisawa
M
M
Kinoshita
K
K
Hori
M
M
Ozaki
H
H
D000818:Animals; D003092:Colitis / Q000503:physiopathology*; D016207:Cytokines / Q000378:metabolism; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay; D005769:Gastrointestinal Motility / Q000502:physiology*; D015870:Gene Expression; D006241:Haptens; D007150:Immunohistochemistry; D007249:Inflammation / Q000139:chemically induced; D007413:Intestinal Mucosa / Q000502:physiology*; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D009130:Muscle, Smooth / Q000276:immunology / Q000503:physiopathology*; D009195:Peroxidase / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D014302:Trinitrobenzenesulfonic Acid / Q000633:toxicity
D016207:Cytokines; D006241:Haptens; D012333:RNA, Messenger; D014302:Trinitrobenzenesulfonic Acid; D009195:Peroxidase