Particles generated from numerous anthropogenic and/or natural sources, such as crystalline α-Fe2O3 nanoparticles, have the potential to damage lung cells. In our study we investigated the effects of these nanoparticles (12.5 µg/ml) on lipid peroxidation and the antioxidative system in MRC-5 lung fibroblast cells following exposure for 24, 48 or 72 h. Exposure to α-Fe2O3 nanoparticles increased lipid peroxidation by 81 %, 189 % and 110 % after 24, 48 and 72 h, respectively. Conversely, the reduced glutathione concentration decreased by 23.2 % and 51.4 % after 48 and 72 h of treatment, respectively. In addition, an augmentation of the activities of superoxide dismutase, catalase, glutathione peroxidase, glutathione transferase and glutathione reductase within the interval between 48-72 h was noticed. Taking into account that the reduced glutathione level decreased and the malondialdehyde level, a lipid peroxidation product, remained highly increased up to 72 h of exposure, it would appear that the MRC-5 antioxidant defense mechanisms did not efficiently counteract the oxidative stress induced by exposure to hematite nanoparticles.
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The present work was aimed to obtain information about age-dependent changes of γ-glutamyltransferase (GGT) activity and the levels of non-protein sulfhydryl compounds (NPSH) in rat kidneys. In addition, protein-bound cysteine (PB-Cys), sulfane sulfur compounds and reactive oxygen species (ROS) were estimated. The results indicate that the activity of GGT and NPSH levels in the kidneys are reduced with age. At the same time, a significant increase in the level of protein-bound cysteine was observed. Simultaneously, the content of sulfane sulfur compounds was increased in the group of the oldest animals. These findings indicate that the capacity for extracellular glutathione degradation and, in consequence, the availability of cysteine for intracellular glutathione biosynthesis may be impaired. The increased PB-Cys level indicates potentiation of the thiolation reaction, i.e. development of protein-mixed disulfides. These results reveal age dependent disturbances in the thiol-disulfide equilibrium in the kidneys which leads to an imbalance between pro- and antioxidatory processes.
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