The pathophysiologies of neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS), Parkinson’s disease (PD), and Alzheimer’s disease (AD), are far from being fully explained. Oxidative stress (OS) has been proposed as one factor that plays a potential role in the pathogenesis of neurodegenerative disorders. Clinical and preclinical studies indicate that neurodegenerative diseases are characterized by higher levels of OS biomarkers and by lower levels of antioxidant defense biomarkers in the brain and peripheral tissues. In this article, we review the current knowledge regarding the involvement of OS in neurodegenerative diseases, based on clinical trials and animal studies. In addition, we analyze the effects of the drug-induced modulation of oxidative balance, and we explore pharmacotherapeutic strategies for OS reduction.

The pathophysiology of psychiatric diseases, including depression, anxiety, schizophrenia and autism, is far from being fully elucidated. In recent years, a potential role of the oxidative stress has been highlighted in the pathogenesis of neuropsychiatric disorders. A body of clinical and preclinical evidence indicates that psychiatric diseases are characterized by higher levels of oxidative biomarkers and with lower levels of antioxidant defense biomarkers in the brain and peripheral tissues. In this article, we review current knowledge on the role of the oxidative stress in psychiatric diseases, based on clinical trials and animal studies, in addition, we analyze the effects of drug-induced modulation of oxidative balance and explore pharmacotherapeutic strategies for oxidative stress reduction.

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Oxidative stress plays an important role as a mediator of damage produced by fructose metabolism. This work was designed to investigate the effect of diet supplemented with quinoa seeds on oxidative stress in plasma, heart, kidney, liver, spleen, lung, testis and pancreas of fructose administered rats. Fructose administration (310 g/kg fodder for 5 weeks) caused oxidative stress that was manifested by the increase in plasma malondialdehyde (MDA) (p<0.05), and by the non-significant changes in the enzymatic antioxidant potential in plasma and most of tissues. Co-administration of quinoa seeds (310 g/kg fodder) maintained normal activities of some enzymes. It also influenced the oxidative stress as was evidenced by decreasing MDA in plasma, and decreasing the activities of antioxidant enzymes (erythrocyte superoxide dismutase - eSOD, catalase -CAT, plasma glutathione peroxidase - pGPX). These findings demonstrate that quinoa seeds can act as a moderate protective agent against potential of fructose-induced changes in rats by reducing lipid peroxidation and by enhancing the antioxidant capacity of blood (plasma) and heart, kidney, testis, lung and pancreas.

Oxidative stress is a dysfunctional state of living cells, caused by the disturbance of the pro-/antioxidative equilibrium. This dynamic equilibrium, constitutive for all aerobic organisms, is an inevitable necessity of maintaining the level of oxidative factors on non-destructive value to the cell. Among these factors reactive oxygen species (ROS) and reactive nitrogen species (RNS) are the best known molecules. This review article shows the current state of knowledge on the chemical specificity, relative reactivity and main sources of ROS and RNS in biological systems. As a Part 1 to the report about the role of oxidative stress in psychiatric disorders (see Smaga et al., Pharmacological Reports, this issue), special emphasis is placed on biochemical determinants in nervous tissue, which predisposed it to oxidative damage. Oxidative stress can be identified based on the analysis of various biochemical indicators showing the status of antioxidant barrier or size of the damage. In our article, we have compiled the most commonly used biomarkers of oxidative stress described in the literature with special regard to potentially effective in the early diagnosis of neurodegenerative processes.

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Summary.A high-performance liquid chromatography (HPLC) method was used to assess the concentration of reduced and oxidized glutathione (GSH and GSSG) in rat striatum. Following decapitation, striatum was isolated from the male Wistar rat brain and immediately homogenized with double distilled water. GSH level was determined after pre-column derivatization with o-phthalaldehyde (OPA). The optimal incubation time with OPA was tested. The concentration of GSSG was determined after blockage the thiol groups of GSH by N-ethylmaleimide (NEM). The useful time for incubation with NEM was optimized. Next, disulfide bounds of GSSG were reduced by dithiothreitol (DTT), and released GSH is derivatized with OPA. The total glutathione, tGSH (sum of free and bound GSH, GSSG, and other low-molecular-mass aminothiols), was determined after reduction with DTT and then derivatization with OPA. The level of GSSG was calculated of the difference in concentrations of tGSH and GSH, but we showed that the calculated concentration of GSSG was within the range of standard deviation of the mean concentration of tGSH or GSH. Finally, the concentration of GSH was determined after 5-min incubation with OPA and the concentration of GSSG after 30-s incubation with NEM and 5-min incubation with DTT and OPA. The relative standard deviation (RSD) values obtained for the assay of GSH and GSSG were lower than 10%. The values obtained for accuracy for GSH (50-500 nM) and GSSG (0.5-5 nM) were within limits regarded as acceptable for analysis of biological samples (percent of recovery: 95-105%). Mean absolute recovery of GSH and GSSG was ranged from 97.1% to 99%. Limit of detection for GSH was 2.7 nM, and limit of quantification was 8.2 nM. Limit of detection (LOD) for GSSG is twice the value for GSH. Described method allows to determine GSH and GSSG levels in isolated rat brain structures with high level of reliability.