Synergistic Interaction of Light Alcohol Administration in the Presence of Mild Iron Overload in a Mouse Model of Liver Injury: Involvement of Triosephosphate Isomerase Nitration and Inactivation

PLoS One. 2017 Jan 19;12(1):e0170350. doi: 10.1371/journal.pone.0170350. eCollection 2017.

Abstract

It is well known that iron overload promotes alcoholic liver injury, but the doses of iron or alcohol used in studies are usually able to induce liver injury independently. Little attention has been paid to the coexistence of low alcohol consumption and mild iron overload when either of them is insufficient to cause obvious liver damage, although this situation is very common among some people. We studied the interactive effects and the underlining mechanism of mild doses of iron and alcohol on liver injury in a mouse model. Forty eight male Kunming mice were randomly divided into four groups: control, iron (300 mg/kg iron dextran, i.p.), alcohol (2 g/kg/day ethanol for four weeks i.g.), and iron plus alcohol group. After 4 weeks of treatment, mice were sacrificed and blood and livers were collected for biochemical analysis. Protein nitration level in liver tissue was determined by immunoprecipitation and Western blot analysis. Although neither iron overload nor alcohol consumption at our tested doses can cause severe liver injury, it was found that co-administration of the same doses of alcohol and iron resulted in liver injury and hepatic dysfunction, accompanied with elevated ratio of NADH/NAD+, reduced antioxidant ability, increased oxidative stress, and subsequent elevated protein nitration level. Further study revealed that triosephosphate isomerase, an important glycolytic enzyme, was one of the targets to be oxidized and nitrated, which was responsible for its inactivation. These data indicate that even under low alcohol intake, a certain amount of iron overload can cause significant liver oxidative damage, and the modification of triosephosphate isomerasemight be the important underlining mechanism of hepatic dysfunction.

MeSH terms

  • Animals
  • Disease Models, Animal
  • Ethanol / administration & dosage
  • Ethanol / toxicity*
  • Iron / administration & dosage
  • Iron Overload / complications*
  • Iron Overload / metabolism
  • Iron Overload / pathology
  • Liver / injuries*
  • Liver / metabolism
  • Liver / pathology
  • Liver Diseases, Alcoholic / complications*
  • Liver Diseases, Alcoholic / metabolism*
  • Liver Diseases, Alcoholic / pathology
  • Male
  • Mice
  • Nitro Compounds / metabolism
  • Oxidative Stress / drug effects
  • Triose-Phosphate Isomerase / antagonists & inhibitors
  • Triose-Phosphate Isomerase / metabolism*

Substances

  • Nitro Compounds
  • Ethanol
  • Iron
  • Triose-Phosphate Isomerase

Grants and funding

This work was supported by the National Natural Science Foundation of China Grant # 31170808, 31570810 (http://www.nsfc.gov.cn/). The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.