title: Evidence against a role for endotoxin in the hepatic encephalopathy of rats with thioacetamide-induced fulminant hepatic failure.
abstract: OBJECTIVE
  Endotoxin has been proposed to participate in the development of hepatic encephalopathy. However, there is no published data concerning the effects of endotoxin neutralization on the degree of hepatic encephalopathy. The present study investigated the effect of chronic intraperitoneal injection of polymyxin B, a neutralizing antagonist of endotoxin, on hepatic encephalopathy in rats with thioacetamide (TAA)-induced fulminant hepatic failure.
  
  
  METHODS
  Male Sprague-Dawley rats weighing 300-350 g were used. Fulminant hepatic failure was induced by intraperitoneal injection of TAA (350 mg/kg/day) for 3 days. Two series of rats were designed to compare the effects of low dose (0.1 mg) or high dose (0.2 mg) intraperitoneal polymyxin B administration versus normal saline (NS) on hepatic encephalopathy. The injection was twice daily started from 2 days prior to TAA administration and lasted for 5 days. Severity of encephalopathy was assessed by the counts of motor activity in an Opto-Varimex animal activity meter. Plasma levels of endotoxin and tumor necrosis factor-alpha (an index of liver injury) were measured by Limulus assay and the ELISA method, respectively.
  
  
  RESULTS
  Neutralization of endotoxin by either low dose or high dose polymyxin B administration did not significantly alleviate the degree of hepatic encephalopathy, as represented by the counts of motor activities (P > 0.05). Plasma levels of endotoxin and tumor necrosis factor-alpha were comparable between rats treated with polymyxin B or NS (P > 0.05).
  
  
  CONCLUSIONS
  Our findings do not support the notion that endotoxin plays a major role in the pathogenesis of hepatic encephalopathy in rats with TAA-induced fulminant hepatic failure.
authors.affiliation: Gastroenterology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan.
authors.forename: Chien-Ting
authors.initials: CT
authors.lastname: Chen
authors.forename: Chi-Jen
authors.initials: CJ
authors.lastname: Chu
authors.forename: Teh-Fang
authors.initials: TF
authors.lastname: Wang
authors.forename: Rei-Hwa
authors.initials: RH
authors.lastname: Lu
authors.forename: Fa-Yauh
authors.initials: FY
authors.lastname: Lee
authors.forename: Full-Young
authors.initials: FY
authors.lastname: Chang
authors.forename: Han-Chieh
authors.initials: HC
authors.lastname: Lin
authors.forename: Che-Chang
authors.initials: CC
authors.lastname: Chan
authors.forename: Sun-Sang
authors.initials: SS
authors.lastname: Wang
authors.forename: Hui-Chun
authors.initials: HC
authors.lastname: Huang
authors.forename: Shou-Dong
authors.initials: SD
authors.lastname: Lee
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage*; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D004731:Endotoxins / Q000037:antagonists & inhibitors / Q000097:blood*; D004797:Enzyme-Linked Immunosorbent Assay; D005500:Follow-Up Studies; D006501:Hepatic Encephalopathy / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control*; D007274:Injections, Intraperitoneal; D017114:Liver Failure, Acute / Q000097:blood / Q000139:chemically induced / Q000150:complications*; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D011112:Polymyxin B / Q000008:administration & dosage*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012720:Severity of Illness Index; D013853:Thioacetamide / Q000008:administration & dosage / Q000633:toxicity*; D013997:Time Factors; D016896:Treatment Outcome; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D004731:Endotoxins; D014409:Tumor Necrosis Factor-alpha; D013853:Thioacetamide; D011112:Polymyxin B