title: Antagonism of the cannabinoid CB-1 receptor protects rat liver against ischaemia-reperfusion injury complicated by endotoxaemia.
abstract: OBJECTIVE
  Endotoxaemia can complicate hepatic ischaemia-reperfusion (IR) injury. Endocannabinoids appear to modulate the haemodynamic alterations and cytokine response induced by lipopolysaccharide (LPS). Thus, we aimed to determine the effect of the endocannabinoid CB1-receptor antagonist Rimonabant in a model of hepatic IR injury complicated by endotoxaemia.
  
  
  METHODS
  Sprague-Dawley rats pre-treated with Rimonabant 3 or 10 mg/kg or vehicle underwent partial hepatic IR and lipopolysaccharide (LPS) injection at reperfusion. Liver injury was evaluated by serum alanine aminotransferase (ALT) and necrotic-cell count. The inflammatory response was investigated by assessing hepatic neutrophil infiltration, tumour necrosis factor alpha (TNFalpha), interferon gamma (IFNgamma), interleukin 6 (IL6), and suppressor of cytokine signalling (SOCS) 1 and SOCS3 gene expression by real-time polymerase chain reaction (RT-PCR). Systolic blood pressure and hepatic blood flow were measured as haemodynamic parameters. Finally, lipid peroxidation, glutathione status, and immunoreactive CB1 receptor expression in the liver were also determined.
  
  
  RESULTS
  Liver injury and neutrophil infiltration occurring in the late-phase of LPS-enhanced IR were significantly reduced by CB1-receptor antagonism. Rimonabant-treated rats showed significantly higher gene expression of IFNgamma, IL6, SOCS1 and SOCS3 in "early" reperfusion, while that of TNFalpha was reduced. These findings were associated with increased STAT3 phosphorylation. Furthermore, CB1-receptor antagonism significantly improved the oxidative injury and haemodynamic alterations occurring during reperfusion in untreated rats. Finally, CB1-receptor immunoreactivity was upregulated early after reperfusion.
  
  
  CONCLUSIONS
  This study demonstrates that CB1-receptor antagonism protects the liver against LPS-enhanced IR injury by interfering with the inflammatory response that causes the late, neutrophil-dependent phase of reperfusion injury, although the prevention of the transient endotoxin-related hypotension occurring early during reperfusion may be also involved.
authors.affiliation: Department of Clinical Medicine, Alma Mater Studiorum, University of Bologna, Bologna, Italy. paolo.caraceni@unibo.it
authors.forename: P
authors.initials: P
authors.lastname: Caraceni
authors.forename: A M
authors.initials: AM
authors.lastname: Pertosa
authors.forename: F
authors.initials: F
authors.lastname: Giannone
authors.forename: M
authors.initials: M
authors.lastname: Domenicali
authors.forename: I
authors.initials: I
authors.lastname: Grattagliano
authors.forename: A
authors.initials: A
authors.lastname: Principe
authors.forename: C
authors.initials: C
authors.lastname: Mastroleo
authors.forename: M G
authors.initials: MG
authors.lastname: Perrelli
authors.forename: J
authors.initials: J
authors.lastname: Cutrin
authors.forename: F
authors.initials: F
authors.lastname: Trevisani
authors.forename: T
authors.initials: T
authors.lastname: Croci
authors.forename: M
authors.initials: M
authors.lastname: Bernardi
mesh_terms: D000410:Alanine Transaminase / Q000097:blood; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D004353:Drug Evaluation, Preclinical; D019446:Endotoxemia / Q000209:etiology*; D008070:Lipopolysaccharides; D008099:Liver / Q000098:blood supply* / Q000378:metabolism / Q000473:pathology; D008102:Liver Circulation / Q000187:drug effects; D008297:Male; D009336:Necrosis; D020556:Neutrophil Infiltration; D010880:Piperidines / Q000627:therapeutic use*; D011720:Pyrazoles / Q000627:therapeutic use*; D051381:Rats; D017207:Rats, Sprague-Dawley; D043884:Receptor, Cannabinoid, CB1 / Q000037:antagonists & inhibitors* / Q000378:metabolism; D015427:Reperfusion Injury / Q000150:complications / Q000378:metabolism / Q000517:prevention & control*; D000077285:Rimonabant
chemical_list: D008070:Lipopolysaccharides; D010880:Piperidines; D011720:Pyrazoles; D043884:Receptor, Cannabinoid, CB1; D000410:Alanine Transaminase; D000077285:Rimonabant