title: Reduction of endotoxin attenuates liver fibrosis through suppression of hepatic stellate cell activation and remission of intestinal permeability in a rat non-alcoholic steatohepatitis model.
abstract: Previous clinical studies have demonstrated that endotoxin/toll‑like receptor 4 (TLR4) signaling is critical in the inflammatory pathways associated with non‑alcoholic steatohepatitis (NASH). In human and animal studies, NASH was associated with portal lipopolysaccharide (LPS) and the plasma LPS level was hypothesized to be associated with small intestinal bacterial overgrowth, change in composition of the microbiota and increased intestinal permeability. The aim of the present study was to investigate the roles of endogenous endotoxin and TLR4 in the pathogenesis of NASH. The effects of antibiotics were assessed in vivo using a choline deficiency amino acid (CDAA)‑induced experimental liver fibrosis model. Antibiotics, including polymyxins and neomycins, were orally administered in drinking water. Antibiotics attenuated hepatic stellate cell (HSC) activation and liver fibrosis via TGF‑β and collagen in an experimental hepatic fibrosis model. The mechanism by which antibiotics attenuated LPS‑TLR4 signaling and liver fibrosis was assessed. Notably, TLR4 mRNA level in the liver was elevated in the CDAA group and the CDAA‑induced increase was significantly reduced by antibiotics. However, no significant differences were observed in the intestine among all groups. Elevated mRNA levels of LPS binding protein, which was correlated with serum endotoxin levels, were recognized in the CDAA group and the CDAA‑induced increase was significantly reduced by antibiotics. The intestinal permeability of the CDAA group was increased compared with the choline‑supplemented amino acid group. The tight junction protein (TJP) in the intestine, determined by immunohistochemical analysis was inversely associated with intestinal permeability. Antibiotics improved the intestinal permeability and enhanced TJP expression. Inhibition of LPS‑TLR4 signaling with antibiotics attenuated liver fibrosis development associated with NASH via the inhibition of HSC activation. These results indicated that reduction of LPS and restoration of intestinal TJP may be a novel therapeutic strategy for treatment of liver fibrosis development in NASH.
authors.affiliation: Third Department of Internal Medicine, Nara Medical University, Kashihara, Nara 634‑8521, Japan.
authors.forename: Akitoshi
authors.initials: A
authors.lastname: Douhara
authors.affiliation: Third Department of Internal Medicine, Nara Medical University, Kashihara, Nara 634‑8521, Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Moriya
authors.affiliation: Third Department of Internal Medicine, Nara Medical University, Kashihara, Nara 634‑8521, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Yoshiji
authors.affiliation: Third Department of Internal Medicine, Nara Medical University, Kashihara, Nara 634‑8521, Japan.
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Noguchi
authors.affiliation: Third Department of Internal Medicine, Nara Medical University, Kashihara, Nara 634‑8521, Japan.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Namisaki
authors.affiliation: Third Department of Internal Medicine, Nara Medical University, Kashihara, Nara 634‑8521, Japan.
authors.forename: Mitsuteru
authors.initials: M
authors.lastname: Kitade
authors.affiliation: Third Department of Internal Medicine, Nara Medical University, Kashihara, Nara 634‑8521, Japan.
authors.forename: Kosuke
authors.initials: K
authors.lastname: Kaji
authors.affiliation: Third Department of Internal Medicine, Nara Medical University, Kashihara, Nara 634‑8521, Japan.
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Aihara
authors.affiliation: Third Department of Internal Medicine, Nara Medical University, Kashihara, Nara 634‑8521, Japan.
authors.forename: Norihisa
authors.initials: N
authors.lastname: Nishimura
authors.affiliation: Third Department of Internal Medicine, Nara Medical University, Kashihara, Nara 634‑8521, Japan.
authors.forename: Kosuke
authors.initials: K
authors.lastname: Takeda
authors.affiliation: Third Department of Internal Medicine, Nara Medical University, Kashihara, Nara 634‑8521, Japan.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Okura
authors.affiliation: Third Department of Internal Medicine, Nara Medical University, Kashihara, Nara 634‑8521, Japan.
authors.forename: Hideto
authors.initials: H
authors.lastname: Kawaratani
authors.affiliation: Third Department of Internal Medicine, Nara Medical University, Kashihara, Nara 634‑8521, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Fukui
mesh_terms: D000821:Animal Feed; D000818:Animals; D000900:Anti-Bacterial Agents / Q000378:metabolism / Q000493:pharmacokinetics; D004731:Endotoxins / Q000378:metabolism*; D055166:Hepatic Stellate Cells / Q000187:drug effects / Q000378:metabolism*; D007413:Intestinal Mucosa / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000378:metabolism; D008103:Liver Cirrhosis / Q000209:etiology*; D008297:Male; D065626:Non-alcoholic Fatty Liver Disease / Q000150:complications* / Q000378:metabolism*; D010539:Permeability; D051381:Rats; D015398:Signal Transduction; D062725:Tight Junction Proteins / Q000378:metabolism; D051197:Toll-Like Receptor 4 / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D004731:Endotoxins; D008070:Lipopolysaccharides; D062725:Tight Junction Proteins; D051197:Toll-Like Receptor 4