Copper Deficiency Induces Oxidative Stress in Liver of Mice by Blocking the Nrf₂ Pathway

Copper (Cu) is an essential metal required for many physiological processes and biological reactions. Liver is the main organ of metabolism of Cu and is also the site where synthesis of some metalloproteins. The purpose of this study is to explore the effects of Cu deficiency on the liver and to evaluate the changes in liver oxidative stress levels to reveal its possible impact mechanisms. Mice were feed to a nutritional Cu-deficiency diet from weaning and injected with copper sulfate (CuSO₄) intraperitoneally to correct Cu deficiency. Cu deficiency resulted in reduced liver index, liver histological alteration, and oxidative stress; decreased the contents of Cu and ALB; elevated ALT and AST concentrations in serum together with decreased mRNA and protein expressions of Nrf₂ pathway related molecules (Nrf₂, HO-1, NQO1); and increased mRNA and protein expressions of Keap1. However, the supplement of copper sulfate (CuSO₄) significantly ameliorated the changes mentioned above. Our results indicate that Cu deficiency can cause hepatic damage in mice is associated with the activation of oxidative stress and inhibition of Nrf₂ pathway.