Effect of zinc ions on the level of reduced glutathione and lipid peroxidation in nickel-treated mice

Introduction: The present study was devoted to evaluate whether zinc (Zn) as an antioxidant has any protective role against depletion of reduced glutathione (GSH) and lipid peroxidation (LPO) in the liver and blood of laboratory mice after 24 hours and 14 days of treatment by nickel (Ni). Material and methods: Experiments were done on 4-6 weeks old outbred mice. For acute intoxication (24 h) mice were once intraperitoneally injected with NiCl2 (95 mu mol elemental Ni per 1 kg of body mass) solution or/and ZnSO4 (24 mu mol elemental Zn per 1 kg of body mass) solution. For sub-acute intoxication mice were intraperitoneally injected for 14 days (once in a day) with NiCl2 (19 mu mol elemental Ni per 1 kg of body mass) solution or/and ZnSO4 (24 mu mol elemental Zn per 1 kg of body mass) solution. GSH was measured by reaction with DTNB to give a compound that absorbs at a wavelength of 412 nm. Product of LPO (MDA) was determined after reaction with thiobarbituric acid (TBA). Results: 24-h exposure to NiCl2 caused a decrease of GSH content in mice liver (by 22%) and in blood (by 23%). 14 days of mice exposure to Ni2+ didn't showed any significant changes on the level of GSH. Inhibitory ZnSO4 effect on GSH concentration (by 21%) was observed in the blood of mice after 24 hours of exposure as well as in the liver of mice (by 20%) after 14 days exposure period. 24 hours of exposure to both metals reduced GSH content by 41% (in liver) and 61% (in blood) as compared to the control. 14 days of mice pre-treatment with ZnSO4 reduced GSH content in mice liver by 15% compared to the control. According our results 24 hours of exposure to NiCl2 exceeded MBA concentration in liver and blood by 282% and 25% respectively. 14 day-long mice exposure to Ni2+ increased MDA concentrations in liver and blood by 28% and 89% respectively. Zn2+ decreased MDA content in liver and blood of mice after 24 hours of exposure by 32% and 28% respectively. 14 days exposure to ZnSO4 increased liver MDA contents by 42%. Zn pre-treatment raised liver MDA contents by 536% and 37% after 24 hours and 14 days of exposure, but provided protective effect on LPO in blood of mice in both exposure duration groups.