title: Selective cyclooxygenase-1 inhibition improves collateral vascular reactivity in biliary cirrhotic rats.
abstract: BACKGROUND
  Evidence has demonstrated that overproduction of prostacyclin (PGI2) is critical in the pathogenesis of splanchnic hyposensitivity to vasoconstrictors in the cirrhotic state. The biosynthesis of PGI2 is through cyclooxygenase (COX). This study evaluated which isoform of COX is dominant in the mechanism of collateral vascular reactivity of biliary cirrhotic rats.
  
  
  METHODS
  Three groups of formalin-injected common bile duct-ligated (FBDL) induced cirrhotic rats received two doses of: (1) selective COX-1 inhibitor (SC-560 2 mg/kg); (2) COX-2 inhibitor (NS-398 2 mg/kg); (3) dimethyl sulfoxide (control). Subsequently, the rats were kept in metabolic cages for 24 hours to collect urine. Thereafter, the systemic and portal hemodynamics and renal function were measured. In another series, using in-situ collateral perfusion model, the collateral vascular responses to arginine vasopressin (AVP) were measured in the subject rats after preincubation of vehicle (Krebs solution), SC-560 (5 μM) or NS-398 (10 μM).
  
  
  RESULTS
  The mean arterial pressure, heart rate, and portal pressure were similar among SC-560-treated, NS-398-treated, and control groups. Additionally, there was no significant difference in the calculated creatinine clearance rates among these three groups. SC-560 preincubation significantly enhanced the pressor effect of AVP at the concentration of 3M × 10(-9) M (11.0 ± 1.0 mmHg vs. 6.4 ± 0.6 mmHg, p = 0.002) in the cirrhotic rats.
  
  
  CONCLUSIONS
  There was no significant hemodynamic change and renal toxicity after acute administration of COX inhibitor in the FBDL-induced cirrhotic rats. Preincubation of selective COX-1, but not COX-2, inhibitor could enhance collateral vascular response to AVP, indicating that COX-1 plays a major role in the collateral vascular reactivity.
authors.affiliation: Division of General Medicine, Taipei Veterans General Hospital, Taipei, Taiwan, ROC; National Yang-Ming University School of Medicine, Taipei, Taiwan, ROC.
authors.forename: Ching-Chih
authors.initials: CC
authors.lastname: Chang
authors.forename: Chiao-Lin
authors.initials: CL
authors.lastname: Chuang
authors.forename: Wen-Shin
authors.initials: WS
authors.lastname: Lee
authors.forename: Sun-Sang
authors.initials: SS
authors.lastname: Wang
authors.forename: Fa-Yauh
authors.initials: FY
authors.lastname: Lee
authors.forename: Han-Chieh
authors.initials: HC
authors.lastname: Lin
authors.forename: Hui-Chun
authors.initials: HC
authors.lastname: Huang
authors.forename: Shou-Dong
authors.initials: SD
authors.lastname: Lee
mesh_terms: D000818:Animals; D003097:Collateral Circulation / Q000187:drug effects; D051545:Cyclooxygenase 1 / Q000502:physiology*; D016861:Cyclooxygenase Inhibitors / Q000627:therapeutic use*; D006439:Hemodynamics / Q000187:drug effects; D007668:Kidney / Q000503:physiopathology; D008105:Liver Cirrhosis, Biliary / Q000188:drug therapy* / Q000503:physiopathology; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D016861:Cyclooxygenase Inhibitors; D051545:Cyclooxygenase 1
keywords: collateral vascular reactivity; cyclooxygenase; liver cirrhosis; portal-systemic collaterals; renal toxicity