Extra virgin olive oil (EVOO) presents benefits against chronic liver injury induced by hepatotoxins such
as carbon tetrachloride (CCl4); however, the protective mechanisms remain unclear. In the present study,
a two-dimensional gel based proteomic approach was constructed to explore the mechanisms. Rats are
injected with CCl4 twice a week for 4 weeks to induce liver fibrosis, and were fed laboratory chow plus
20% (w/w) of either corn oil or EVOO over the entire experimental period. Histological staining, MDA
assay and fibrogenesis marker gene analysis illustrate that the CCl4-treated animals fed EVOO have a lower
fibrosis and lipid peroxidation level in the liver than the corn oil fed group. The proteomic study indicates
that the protein expression of thioredoxin domain-containing protein 12, peroxiredoxin-1, thiosulphate
sulphurtransferase, calcium-binding protein 1, Annexin A2 and heat shock cognate 71 kDa protein are
higher in livers from EVOO-fed rats with the CCl4 treatment compared with those from rats fed with corn
oil, whereas the expression of COQ9, cAMP-dependent protein kinase type I-alpha regulatory subunit,
phenylalanine hydroxylase and glycerate kinase are lower. Our findings confirmed the benefits of EVOO
against chronic liver injury, which may be attributable to the antioxidant effects, hepatocellular function
regulation and hepatic metabolism modification effects of EVOO.