Ameliorative effect of lycopene against 2,3,7,8-tetrachlorodibenzo- p -dioxin-induced rat liver microsomal toxicity

Abstract

The objective of the current study was to investigate the potential oxidative damage of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in hepatic microsomal fractions in vitro and to further elucidate the potential modulatory effect of lycopene. Rat liver microsomes were divided into four groups. Group I served as a control and is incubated with vehicle (toluene). Groups II and IV were incubated with 20 µM lycopene for 1 h before further incubating; groups III and IV with 15 nM of TCDD for further 1 h. Hydrogen peroxide (H₂O₂) production, lipid peroxidation (LPO), protein carbonyl content and activities of uridine 5′-diphospho-glucuronyltransferase (UDPGT) and P450 were significantly increased. Moreover, the activity of antioxidant enzymes superoxide dismutase, glutathione peroxidase, catalse, glutathione-S-transferase and glutathione reductase as well as the microsomal thiol content were significantly decreased. Incubation with lycopene (group IV) maintained near normal activities of the enzymes, normalized thiol and carbonyl content and significantly reduced LPO and H₂O₂ production. In conclusion, the findings of the study indicate that TCDD induces a significant oxidative stress in liver microsomes as manifested by increased LPO, H₂O₂ production, protein carbonyl content and activities of UDPGT and P450 and decreased antioxidant enzymes activities and thiol content. By the reversal of biochemical and oxidative markers toward normalcy, the protective role of lycopene is illuminated in rat liver microsomal toxicity.