title: The dual effect of cannabinoid receptor-1 deficiency on the murine postoperative ileus.
abstract: BACKGROUND
  Intestinal inflammatory responses play a critical role in the pathogenesis of postoperative ileus (POI). As cannabinoid receptor-1 (CB1) is involved in inhibiting gastrointestinal (GI) motility and anti-inflammation, we aimed to explore its contribution to POI.
  
  
  METHODS
  Experimental POI was induced in adult female CB1-deficient (CB1-/-) mice and wild-type littermates (C57BL/6N) by standardized small bowel manipulation. Twenty-four hours after surgery, GI transit was assessed by charcoal transport. FITC avidin, F4/80, and myeloperoxidase immunohistochemistry techniques were used to evaluate the inflammatory response in the muscularis of ileum and colon. Expressions of p38MAPK and its phosphorylated form (pp38) in the intestine were determined. Plasma levels of proinflammatory cytokines and chemokines were measured by ELISA as well.
  
  
  RESULTS
  POI was characterized by decreased GI transit (p<0.01) and accompanied by a marked intestinal and systematic inflammatory response in wild-type and CB1-/- mice. Increased numbers of inflammatory cells, including macrophages, neutrophils, and mast cells were observed in the muscularis of ileum and colon (p<0.01, or p<0.05). Plasma levels of interleukin-6 (IL-6), cytokine-induced neutrophil chemoattractant-1 (CINC-1/KC), and monocyte chemoattractant protein-1 (MCP-1) were elevated (p<0.01, or p<0.05). Expression of p38 and pp38 increased in the intestine (p<0.01, or p<0.05). CB1-/- mice showed an increased inflammatory response during POI, especially the systemic inflammatory markers, such as IL-6, KC, CINC1, and pp38 expression were increased as compared to those in WT mice (p<0.05).
  
  
  CONCLUSIONS
  Intestinal motility was inhibited during POI. In this condition, inhibition of motility did not seem to be altered by the absence of CB1 receptors, however, an increased inflammatory response was observed in CB1-/- mice. Hence, CB1 receptor activation rather than inhibition may reduce the inflammatory response in POI, which has a remote potential to relate into reduced inhibition of intestinal motility during POI.
authors.affiliation: Department of Pathophysiology, Institute of Digestive Disease, Tongji University School of Medicine, Shanghai, China. liyongyu@tongji.edu.cn
authors.forename: Yong-yu
authors.initials: YY
authors.lastname: Li
authors.forename: Ming-hua
authors.initials: MH
authors.lastname: Cao
authors.forename: Brigitte
authors.initials: B
authors.lastname: Goetz
authors.forename: Chun-qiu
authors.initials: CQ
authors.lastname: Chen
authors.forename: Ya-jing
authors.initials: YJ
authors.lastname: Feng
authors.forename: Chang-Jie
authors.initials: CJ
authors.lastname: Chen
authors.forename: Michael S
authors.initials: MS
authors.lastname: Kasparek
authors.forename: Andrej
authors.initials: A
authors.lastname: Sibaev
authors.forename: Martin
authors.initials: M
authors.lastname: Storr
authors.forename: Martin E
authors.initials: ME
authors.lastname: Kreis
mesh_terms: D000818:Animals; D018932:Chemokine CCL2 / Q000097:blood; D003106:Colon / Q000378:metabolism / Q000473:pathology; D004195:Disease Models, Animal; D005260:Female; D005769:Gastrointestinal Motility / Q000235:genetics; D007082:Ileum / Q000378:metabolism / Q000473:pathology; D045823:Ileus / Q000235:genetics* / Q000378:metabolism; D015850:Interleukin-6 / Q000097:blood; D008264:Macrophages / Q000378:metabolism / Q000473:pathology; D051379:Mice; D018345:Mice, Knockout; D009130:Muscle, Smooth / Q000378:metabolism / Q000473:pathology; D011183:Postoperative Complications / Q000235:genetics* / Q000378:metabolism; D011184:Postoperative Period; D043884:Receptor, Cannabinoid, CB1 / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000097:blood; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D018932:Chemokine CCL2; D015850:Interleukin-6; D043884:Receptor, Cannabinoid, CB1; D014409:Tumor Necrosis Factor-alpha; D048051:p38 Mitogen-Activated Protein Kinases