Enhanced expressions and activations of leukotriene C4 synthesis enzymes in D-galactosamine/lipopolysaccharide-induced rat fulminant hepatic failure model

AIM: To investigate the expression and activity of leukotriene C4 (LTC4) synthesis enzymes and their underlying relationship with cysteinyl leukotriene (cys-LT) generation in a rat fulminant hepatic failure (FHF) model induced by D-galactosamine/lipopolysaccharide (D-GaIN/ LPS). METHODS: Rats were treated with D-GaIN (300 mg/kg) plus LPS (0.1 mg/kg) for 1, 3, 6, and 12 h. Enzyme immunoassay was used to determine the hepatic cys-LT content. Reverse transcription-polymerase chain reaction (RT-PCR), Western blot or immunohistochemical assay were employed to assess the expression or location of LTC4 synthesis enzymes, which belong to membrane associated proteins in eicosanoid and glutathione (MAPEG) metabolism superfamily. Activity of LTC4 synthesis enzymes was evaluated by determination of the products of LTA4 after incubation with liver microsomes using high performance liquid chromatography (HPLC). RESULTS: Livers were injured after treatment with D-GaIN/LPS, accompanied by cys-LT accumulation at the prophase of liver injury. Both LTC4 synthase (LTC4S) and microsomal glutathione-S-transferase (mGST) 2 were expressed in the rat liver, while the latter was specifically located in hepatocytes. Their mRNA and protein expressions were up-regulated at an earlier phase after treatment with D-GaIN/LPS. Meantime, a higher activity of LTC4 synthesis enzymes was detected, although the activity of LTC4S played the main role in this case. CONCLUSION: The expression and activity of both LTC4S and mGST2 are up regulated in a rat FHF model, which are, at least, partly responsible for cys-LT hepatic accumulation. (C) 2008 WJG. All rights reserved.