title: Inhibition of acrylamide genotoxicity in human liver-derived HepG2 cells by the antioxidant hydroxytyrosol.
abstract: The chemoprotective effect of hydroxytyrosol (HT), a strong antioxidant compound from extra virgin olive oil, against acrylamide (AA)-induced genotoxicity was investigated in a human hepatoma cell line, HepG2. The micronucleus test (MNT) assay was used to monitor genotoxicity. In MNT, we found that HT at all tested concentrations (12.5-50 microM) significantly reduced the micronuclei frequencies in a concentration-dependent manner caused by AA. In order to clarify the underlying mechanisms we measured the intracellular reactive oxygen species (ROS) formation using 2,7-dichlorofluorescein diacetate (DCFH-DA) as a fluorescent probe. Intracellular glutathione (GSH) level was estimated by fluorometric methods. The rate-limiting enzyme in GSH synthesis is gamma-glutamylcysteine synthetase (gamma-GCS) and gamma-GCS was measured using Western blotting. The results showed that HT significantly concentration-dependent reduced the genotoxicity caused by AA. Furthermore, HT was able to reduce intracellular ROS formation and attenuate GSH depletion caused by AA in a concentration-dependent manner. It was also found that HT enhanced the expression of gamma-GCS in HepG2 cells treated with 10 mM AA using immunoblotting in a concentration-dependent manner. The results showed that HT reduced the AA-induced genotoxicity by decreasing the ROS level and increasing the GSH level. The data strongly suggest that HT have significant protective ability against AA-induced genotoxicity in vitro.
authors.affiliation: Department of Toxicology, Dalian Medical University, 465 Zhongshan Road, Dalian 116027, Liaoning, China.
authors.forename: Xiaomei
authors.initials: X
authors.lastname: Zhang
authors.forename: Liping
authors.initials: L
authors.lastname: Jiang
authors.forename: Chenyan
authors.initials: C
authors.lastname: Geng
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Yoshimura
authors.forename: Laifu
authors.initials: L
authors.lastname: Zhong