Role of endoplasmic reticulum stress and oxidative stress in vinyl chloride-induced hepatic steatosis in mice

Toxicol Appl Pharmacol. 2019 Oct 15:381:114730. doi: 10.1016/j.taap.2019.114730. Epub 2019 Aug 22.

Abstract

Vinyl chloride (VC) is a common industrial organochlorine, shown to cause hepatic angiosarcoma and hepatic steatosis. However, the role of endoplasmic reticulum stress (ERS) and oxidative stress (OS) in hepatic steatosis after subchronic exposure to VC in mice, is unclear. Based on body weight, forty healthy SPF male C57BL/6 J mice were randomly divided into a control group and three VC exposure groups (57.3, 286.7, and 1433.6 ppm) (n = 10 each). VC was administered by static inhalation in a 50 L sealed plexiglass inhalation chamber for 2 h per day, five days per week for 16 weeks. Serum and liver tissues were analyzed for liver enzymes and lipids. Hepatic cytochrome P450 2E1 (CYP2E1) and OS related indicators malondialdehyde (MDA), glutathione (GSH), and superoxide dismutase (SOD) were measured. The mRNA expressions of ERS downstream genes, including glycoregulatory protein-78 (GRP-78), sterol regulatory element binding protein-1 (SREBP-1), Acetyl-CoA carboxylase (ACC), and fatty acid synthase (FAS) were detected by real-time PCR (RT-PCR) and their protein levels examined by western blotting. The CYP2E1 levels increased after VC administration in a dose-dependent manner. MDA levels increased (P < .05) and SOD and GSH levels decreased (P < .05) in the liver of each group with the increase in the dose of VC. ERS and expressions of downstream genes (GRP-78, SREBP-1, ACC, and FAS) were enhanced after VC administration. These results suggested that OS and ERS could be induced by VC, which may lead to an increase in fatty acid synthesis in the liver, further aggravating hepatic steatosis.

Keywords: Endoplasmic reticulum stress; Oxidative stress; Toxicant associated steatohepatitis; Vinyl chloride.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetyl-CoA Carboxylase / genetics
  • Acetyl-CoA Carboxylase / metabolism
  • Administration, Inhalation
  • Animals
  • Cytochrome P-450 CYP2E1 / metabolism
  • Endoplasmic Reticulum Chaperone BiP
  • Endoplasmic Reticulum Stress / drug effects*
  • Fatty Liver / chemically induced*
  • Fatty Liver / genetics
  • Fatty Liver / metabolism
  • Fatty Liver / pathology
  • Heat-Shock Proteins / genetics
  • Heat-Shock Proteins / metabolism
  • Liver / drug effects
  • Liver / metabolism
  • Liver / pathology
  • Male
  • Mice, Inbred C57BL
  • Oxidative Stress / drug effects*
  • Sterol Regulatory Element Binding Protein 1 / genetics
  • Sterol Regulatory Element Binding Protein 1 / metabolism
  • Vinyl Chloride / toxicity*
  • fas Receptor / genetics
  • fas Receptor / metabolism

Substances

  • Endoplasmic Reticulum Chaperone BiP
  • Fas protein, mouse
  • Heat-Shock Proteins
  • Srebf1 protein, mouse
  • Sterol Regulatory Element Binding Protein 1
  • fas Receptor
  • Cytochrome P-450 CYP2E1
  • cytochrome P-450 2E1, mouse
  • Acetyl-CoA Carboxylase
  • Vinyl Chloride