Simvastatin ameliorates liver fibrosis via mediating nitric oxide synthase in rats with non-alcoholic steatohepatitis-related liver fibrosis

PLoS One. 2013 Oct 2;8(10):e76538. doi: 10.1371/journal.pone.0076538. eCollection 2013.

Abstract

Background: Simvastatin exerts pleiotropic effects on cardiovascular system. However, its effect on non-alcoholic fatty liver disease, especially the liver fibrosis, remains obscure. We aimed to clarify the relationship between simvastatin and liver fibrosis both in vivo and in vitro.

Methods: A High-fat diet was given to establish rat models with non-alcoholic steatohepatitis (NASH)-related liver fibrosis and simvastatin (4mg·kg(-1)·d(-1)) was administrated intragastrically until hepatic histological findings confirmed the appearance of fibrosis. Human hepatic stellate cell (HSC) line lx-2 cells were cultured in an adipogenic differentiating mixture (ADM) and then were treated with transforming growth factorβ1 (TGF-β1), served as a positive control, simvastatin, TGF-β1 plus simvastatin, Nω-nitro-L-arginine methyl ester hydrochloride (L-NAME, a inhibitor of nitric oxide synthase), and L-NAME plus simvastatin, respectively. The expressions of endothelial nitric oxide synthase (eNOS), inducible nitric oxide synthase (iNOS), and Collagen І as well as cellular α-smooth muscle actin (α-SMA) were measured by real-time reverse transcriptase-polymerase chain reaction (qRT-PCR) and Western blot in liver tissue and HSC.

Results: With the progress of NASH-related fibrosis, hepatic mRNA and protein expressions of iNOS, α-SMA, and Collagen І were increased while those of eNOS were decreased. Compared with model rats in 24(th) week group, rats in simvastatin group had less expressions of iNOS, α-SMA, and Collagen І and more expressions of eNOS. In vitro, LX-2 cells acquired quiescent phenotype when cultured in ADM, and TGF-β1 could activate the quiescent HSC. Simvastatin inhibited LX-2 cells activation due to TGF-β1 or L-NAME by increasing the expression of eNOS and decreasing the expression of iNOS.

Conclusions: Simvastatin improves the prognosis of NASH-related fibrosis by increasing the expression of eNOS, decreasing the expression of iNOS, and inhibiting the activation of HSC.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / antagonists & inhibitors
  • Actins / genetics
  • Actins / metabolism
  • Animals
  • Cells, Cultured
  • Collagen Type I / antagonists & inhibitors
  • Collagen Type I / genetics
  • Collagen Type I / metabolism
  • Diet, High-Fat / adverse effects
  • Enzyme Inhibitors / pharmacology
  • Fatty Liver / drug therapy*
  • Fatty Liver / enzymology
  • Fatty Liver / etiology
  • Fatty Liver / pathology
  • Gene Expression / drug effects
  • Hepatic Stellate Cells / drug effects
  • Hepatic Stellate Cells / enzymology
  • Hepatic Stellate Cells / pathology
  • Humans
  • Hypolipidemic Agents / pharmacology*
  • Liver / drug effects*
  • Liver / enzymology
  • Liver / pathology
  • Liver Cirrhosis / enzymology
  • Liver Cirrhosis / etiology
  • Liver Cirrhosis / pathology
  • Liver Cirrhosis / prevention & control*
  • Male
  • NG-Nitroarginine Methyl Ester / pharmacology
  • Nitric Oxide Synthase Type II / antagonists & inhibitors
  • Nitric Oxide Synthase Type II / genetics
  • Nitric Oxide Synthase Type II / metabolism*
  • Nitric Oxide Synthase Type III / genetics
  • Nitric Oxide Synthase Type III / metabolism*
  • Non-alcoholic Fatty Liver Disease
  • Rats
  • Rats, Wistar
  • Simvastatin / pharmacology*
  • Transforming Growth Factor beta1 / pharmacology

Substances

  • Actins
  • Collagen Type I
  • Enzyme Inhibitors
  • Hypolipidemic Agents
  • Transforming Growth Factor beta1
  • smooth muscle actin, rat
  • Simvastatin
  • Nitric Oxide Synthase Type II
  • Nitric Oxide Synthase Type III
  • Nos2 protein, rat
  • Nos3 protein, rat
  • NG-Nitroarginine Methyl Ester

Grant support

This study was supported by a grant from the Ministry of Education in Hebei Province as a major project of science and technology, number ZD2010225. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of manuscript.