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D-galactose (d-gal) is an important physiological nutrient. According to the widely accepted aging metabolic theory d-gal at high levels can be converted into aldose and hydroperoxide, resulting in the overproduction of reactive oxygen species (ROS). Increased ROS levels may subsequently cause oxidative stress, inflammation, mitochondrial dysfunction, and apoptosis which are hallmarks of natural senescence as well as various pathological conditions. We investigated the effects of chronic oral d-gal intake (200 mg/kg and 500 mg/kg for 6 weeks) on physiological, neurological and toxicity parameters in 3 months old male Wistar rats. The obtained results indicate that body weight, food intake, serum glucose, neurological and toxicity status remained unaffected while urine proteins were significantly increased in d-gal treated rats. Although there was no effect on the general health status of the animals, our findings suggest that chronic oral d-gal administration may lead to renal dysfunction.

In the brain, three isoforms of nitric oxide synthase (NOS) regulate production of nitric oxide (NO), a signalling molecule with a role in cerebral blood flow regulation. Depending on the stimulus, NO exerts dual nature, from neuroprotective to neurodestructive. Given the scarcity of literature data on the involvement of nitrosative stress indicators in the rat hippocampal response to 7-day lasting progesterone (P4) treatment following permanent occlusion of both common carotid arteries, we assessed NO level and protein expressions of endothelial nitric oxide synthase (eNOS, including its total (t-eNOS) and phosphorylated at Ser1177 isoform (p-eNOS Ser1177)). According to obtained results, elevated NO levels occurred due to activity of other NOS forms since eNOS expressions were similar between experimental groups. Although NO level was downscaled it was still elevated in occluded animals treated with P4, showing modest anti-nitrosative effect of this potent steroid in the hippocampus.

Physical activity has been shown to increase the production of free radicals to a point that can exceed internal protective antioxidant system. The harmful effects of free radicals are neutralized by activity of antioxidant enzymes and numerous non-enzymatic antioxidants, including vitamins, glutathione, ubiquinone and flavonoids. Defence mechanisms against free radical-mediated oxidative damage also include the iron binding proteins such as transferrin and ferritin. Ferritin and trensferrin are able to restrict the availability of iron to participate in conversion of hydrogen peroxide to toxic hydroxyl radicals by Fenton reaction. Because the endogenous antioxidant system may not be sufficient to prevent exercise-induced free radical generation and consequent oxidative damage, supplementation of antioxidants may have important effect antioxidant status in athletes. The aim of the present work was to examine the association of physiological iron carriers with oxidative stress in elite athletes. One hundred and five elite athletes were divided into two groups: supplemented group which consisted of sixty-five athletes who regularly use antioxidant supplements and control group which consisted of forty athletes that were without antioxidants intake. Following parameters were measured: albumin, ferritin, transferrin, advanced oxidation protein products (AOPP), lipid hydroperoxides (LOOH), biological antioxidative potential (BAP), superoxide dismutase (SOD) and total sulphydryl group concentration (SH groups). Multivariate analysis of covariance (MANCOVA, Wilks' lambda) was performed to test the hypotheses that supplementation (fixed factor) and antioxidative proteins (indicated via albumin, ferritin and transferrin) (covariates) have a significant effect on the oxidative stress parameters (dependent variables). The SOD activity (P=0.024) and sulphydryl group concentration (P=0.042) were significantly higher in supplemented athletes. Multivariate analysis of covariance i

Aim. The objectives of this study were: 1) to evaluate pro-oxidant-antioxidant balance (PAB) associations with the commonly measured parameters of oxidative stress and antioxidative defence in elite female volleyball athletes; 2) to investigate changes in the parameters of oxidative stress during a period of intense training and dietary antioxidant supplementation. Methods. Twenty-seven female volleyball players participated in this study. Blood samples were collected the day before the pre-competitive mesocycle training period began. After the first blood sample donation and during the next six weeks fourteen players (supplemented group) received a cocktail of antioxidants while thirteen of them (control group) received no dietary supplementation. The following parameters were measured: reactive oxygen metabolites (ROMs), superoxide anion (O(2)(-)), malondialdehyde (AIDA), advanced oxidation protein products (AOPP), lipid hydroperoxides (LOOH), biological antioxidative potential (BAP), paraoxonase activity toward paraoxon (POase) and diazoxon (DZOase), superoxide dismutase (SOD), total sulphydryl group concentration (SH groups) and pro-oxidant-antioxidant balance. Results. Significant associations were observed between biomarkers of oxidative damage with PAB in multiple linear regression model in the supplemented and the control groups (82.3% vs. 83.1%) before training and in the control group (82.1%) after training. Significant associations between anti-oxidative defence parameters and PAB values were found in the supplemented group after six-weeks of training (57%). Conclusion. In the absence of antioxidant supplementation, PAB values were dependent on the association with biomarkers of oxidative damage before and after training. After a six-week training period and the applied antioxidant supplementation, PAB values were under the influence of nonenzymatic anti-oxidative defence.

The aim of this study was to determine the impact of long-term training on elite female volleyball players and to determine parameters that could discriminate them according to the level of oxidative stress-associated adaptation. Fifty-four elite female volleyball players were divided into 3 groups (1: below-average training experience lt 8.0 years, 2: average training experience between 8.0 and 10.5 years and 3: above-average training experience > 10.5 years). The measured parameters were reactive oxygen metabolites, biological anti-oxidative potential, superoxide anion, malondialdehyde, advanced oxidation protein products, lipid hydroperoxides, paraoxonase activity, superoxide-dismutase activity and sulphydryl groups. Multiple discriminant analysis of the oxidative stress status parameters between the three groups of athletes indicated a statistically significant difference (Wilks' lambda=0.458, X-2=35.898, p=0.031). The most important discriminant variables, superoxide-dismutase and superoxide anion, were the best indicators of differences between groups with different training experience. The significantly higher values were found in Group 3 compared with Group 1 in superoxide-dismutase activity (141 +/- 32 vs. 86 +/- 46; p=0.002), sulphydryl groups (p=0.031), and reactive oxygen metabolites (p = 0.042). The significantly lower superoxide anion was found between Group 3 and Group 1 (377 +/- 187 vs. 1183 +/- 905; p=0.001). Oxidative stress status parameters adequately discriminated 68.5% of athletes with different training experience.

The aim of the present study was to examine the association of proteins that regulate iron transport/storage content and acute phase response with oxidative stress in male and female athletes. Serum ferritin, transferrin, soluble transferrin receptor, C-reactive protein, interleukin-6 and oxidative stress parameters (reactive oxygen metabolites, superoxide anion, advanced oxidation protein products, lipid hydroperoxides, superoxide-dismutase and pro-oxidant-antioxidant balance) were determined in 138 athletes (73 females and 65 males). A general linear model indicated significant gender differences between athletes in terms of reactive oxygen metabolites (307.48 +/- 61.02 vs. 276.98 +/- 50.08; P = 0.030), superoxide-dismutase (114.60 +/- 41.64 vs. 101.42 +/- 38.76; P = 0.001), lipid hydroperoxides (149.84 +/- 38.95 vs. 101.43 +/- 39.26; P lt 0.001), pro-oxidant-antioxidant balance (512.40 +/- 148.67 vs. 413.09 +/- 120.30; P = 0.002), advanced oxidation protein products (1.49 +/- 0.30 vs. 0.91 +/- 0.25; P lt 0.001) and superoxide (2.61 +/- 0.36 vs. 2.22 +/- 0.35; P = 0.001), which were all significantly higher in females. Multivariate analysis of covariance indicated gender (P lt 0.001), training experience (P = 0.004), Creactive protein (P = 0.002), soluble transferrin receptor (P = 0.004) and transferrin (P lt 0.001) as significant covariates. Gender accounted for the largest proportion of variability for all oxidative stress parameters (46.3%) and female athletes were more susceptible to oxidative stress. Iron transport and storage proteins (transferrin and ferritin), but also acute phase reactants, were negatively related factors for oxidative stress. In conclusion, variation in the ferritin level may contribute to the different oxidative stress level between the sexes.