IL-1[beta] inhibits intestinal smooth muscle proliferation in an organ culture system: involvement of COX-2 and iNOS induction in muscularis resident macrophages

Intestinal inflammation causes hyperplasia of smooth muscle that leads to thickening of the smooth muscle layer, resulting in dysmotility. IL-1β is a proinflammatory cytokine that plays a central role in intestinal inflammation. In this study, to evaluate the effect of IL-β on proliferation of ileal...

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Published inAmerican journal of physiology: Gastrointestinal and liver physiology Vol. 292; no. 5; p. G1315
Main Authors Ohama, Takashi, Hori, Masatoshi, Momotani, Eiichi, Elorza, Margaret
Format Journal Article
LanguageEnglish
Published Bethesda American Physiological Society 01.05.2007
Subjects
Cytokines
Digestive system
Gastroenterology
Gastrointestinal diseases
Inflammatory diseases
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Summary:Intestinal inflammation causes hyperplasia of smooth muscle that leads to thickening of the smooth muscle layer, resulting in dysmotility. IL-1β is a proinflammatory cytokine that plays a central role in intestinal inflammation. In this study, to evaluate the effect of IL-β on proliferation of ileal smooth muscle cells in vivo, we utilized an organ culture system. When rat ileal smooth muscle tissue was cultured under serum-free conditions for 3 days, most smooth muscle cells maintained their arrangement and kept their contractile phenotype. When 10% FBS was added, an increased number of smooth muscle cells per unit area was observed. Moreover, immunohistochemical staining for PCNA demonstrated that FBS induced proliferation of smooth muscle cells. IL-1β inhibited the proliferative effect of FBS. Furthermore, IL-1β upregulated inducible nitric oxide (NO) synthase and cyclooxygenase-2 mRNA and protein and thus stimulated NO and ... productions. Moreover, exogenously applied NO and ... inhibited the increase of bromodeoxyuridine-positive cells stimulated with PBS. Immunostaining revealed that the majority of cyclooxygenase-2 and inducible NO synthase was located in the dense network of macrophages resident in the muscularis, which were immunoreactive to ED2. Based on these findings, IL-1β acts as an anti-proliferative mediator, which acts indirectly through the production of ... and NO from resident macrophage within ileal smooth muscle tissue. (ProQuest-CSA LLC: ... denotes formulae/symbols omitted.)
ISSN:0193-1857
1522-1547