title: Intrahepatic microcirculatory disorder, parenchymal hypoxia and NOX4 upregulation result in zonal differences in hepatocyte apoptosis following lipopolysaccharide- and D-galactosamine-induced acute liver failure in rats.
abstract: Although the mechanisms responsible for acute liver failure (ALF) have not yet been fully elucidated, studies have indicated that intrahepatic macrophage activation plays an important role in the pathogenesis of ALF through intrahepatic microcirculatory disorder and consequent parenchymal cell death. Intrahepatic microcirculatory disorder has been demonstrated in animal models using intravital microscopy; however, the limitations of this method include simultaneously evaluating blood flow and the surrounding pathological changes. Therefore, in this study, we devised a novel method involving tetramethylrhodamine isothiocyanate (TRITC)-dextran administration for the pathological assessment of hepatic microcirculation. In addition, we aimed to elucidate the mechanisms through which intrahepatic microcirculatory disorder progresses with relation to activated macrophages. ALF was induced in Wistar rats by exposure to lipopolysaccharide and D-galactosamine. Intrahepatic microcirculation and microcirculatory disorder in zone 3 (pericentral zone) of the livers of rats with ALF was observed. Immunohistochemical examinations in conjunction with TRITC-dextran images revealed that the macrophages were mainly distributed in zone 2 (intermediate zone), while cleaved caspase-3-positive hepatocytes, pimonidazole and hypoxia-inducible factor 1-α were abundant in zone 3. We also found that 4-hydroxy-2-nonenal and nicotinamide adenine dinucleotide phosphate oxidase (NOX)4-positive cells were predominantly located in the zone 3 parenchyma. The majority of apoptotic hepatocytes in zone 3 were co-localized with NOX4. Our results revealed that the apoptotic cells in zone 3 were a result of hypoxic conditions induced by intrahepatic microcirculatory disorder, and were not induced by activated macrophages. The increased levels of oxidative stress in zone 3 may contribute to the progression of hepatocyte apoptosis.
authors: Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812‑8582, Japan.
authors: Masatake
authors: M
authors: Tanaka
authors: Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812‑8582, Japan.
authors: Kosuke
authors: K
authors: Tanaka
authors: Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812‑8582, Japan.
authors: Yuko
authors: Y
authors: Masaki
authors: Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812‑8582, Japan.
authors: Masayuki
authors: M
authors: Miyazaki
authors: Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812‑8582, Japan.
authors: Masaki
authors: M
authors: Kato
authors: Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812‑8582, Japan.
authors: Kazuhiro
authors: K
authors: Kotoh
authors: Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka 814-0180, Japan.
authors: Munechika
authors: M
authors: Enjoji
authors: Department of Gastroenterology, Kyushu Medical Center, National Hospital Organization, Fukuoka 810-8563, Japan.
authors: Makoto
authors: M
authors: Nakamuta
authors: Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812‑8582, Japan.
authors: Ryoichi
authors: R
authors: Takayanagi
mesh_terms: D000447:Aldehydes / Q000378:metabolism; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3 / Q000235:genetics / Q000378:metabolism; D004195:Disease Models, Animal; D015725:Fluconazole / Q000008:administration & dosage / Q000009:adverse effects; D005688:Galactosamine; D022781:Hepatocytes / Q000187:drug effects / Q000378:metabolism; D051793:Hypoxia-Inducible Factor 1 / Q000378:metabolism; D008070:Lipopolysaccharides; D008099:Liver / Q000166:cytology* / Q000187:drug effects / Q000473:pathology; D017114:Liver Failure, Acute / Q000139:chemically induced / Q000473:pathology*; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism; D008297:Male; D008833:Microcirculation / Q000187:drug effects*; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases / Q000235:genetics / Q000378:metabolism*; D009593:Nitroimidazoles / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D012235:Rhodamines / Q000008:administration & dosage; D015854:Up-Regulation
chemical_list: D000447:Aldehydes; D051793:Hypoxia-Inducible Factor 1; D008070:Lipopolysaccharides; D009593:Nitroimidazoles; D012235:Rhodamines; C009434:tetramethylrhodamine isothiocyanate; C033815:pimonidazole; D005688:Galactosamine; D015725:Fluconazole; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases; C498911:Nox4 protein, rat; C505410:Casp3 protein, rat; D053148:Caspase 3; C027576:4-hydroxy-2-nonenal