Different Lead- and Cadmium-Induced Oxidative Stress Profiles in the Liver and Kidneys of Subchronically-Exposed Mice

The aim of the present study was to determine the oxidative stress profiles in the liver and kidneys of mice subchronically exposed to lead (Pb) and cadmium (Cd). Four 45-day experiments were conducted using laboratory mice. A control group was compared to three groups exposed to 0.00250M Pb(NO3)2 and 0.00125M Cd(NO3)2 solutions, applied in drinking water separately or in combination. As biomarkers of oxidative stress, the levels of malondialdehyde (MDA) and total glutathione were evaluated, respectively, by using the thiobarbituric acid reactive substances test (TBARS) and a colorimetric assay for total glutathione. The results demonstrated approximately 2-fold higher induction of MDA in the liver of Pb-exposed mice in comparison with Cd-exposed mice, combined with a slow but not statistically significant depletion of total glutathione. In the kidneys of the Cd-exposed mice, the highest accumulation of MDA was detected, accompanied by 1.5-fold glutathione depletion. Nevertheless, in groups exposed to Pb and Pb/Cd intoxication, an inducible increase in total glutathione was observed. These findings confirmed that Pb induces higher levels of oxidative stress in the liver while the kidneys suffered more oxidative damage due to Cd intoxication, attributable to the bioaccumulation profiles of the two toxic metals.