Caffeine improves mitochondrial function in PINK1B9-null mutant Drosophila melanogaster.

Mitochondrial dysfunction plays a central role in Parkinson's disease (PD) and can be triggered by xenobiotics and mutations in mitochondrial quality control genes, such as the PINK1 gene. Caffeine has been proposed as a secondary treatment to relieve PD symptoms mainly by its antagonistic effects on adenosine receptors (ARs). Nonetheless, the potential protective effects of caffeine on mitochondrial dysfunction could be a strategy in PD treatment but need further investigation. In this study, we used high-resolution respirometry (HRR) to test caffeine's effects on mitochondrial dysfunction in PINK1B9-null mutants of Drosophila melanogaster. PINK1 loss-of-function induced mitochondrial dysfunction in PINK1B9-null flies observed by a decrease in O2 flux related to oxidative phosphorylation (OXPHOS) and electron transfer system (ETS), respiratory control ratio (RCR) and ATP synthesis compared to control flies. Caffeine treatment improved OXPHOS and ETS in PINKB9-null mutant flies, increasing the mitochondrial O2 flux compared to untreated PINKB9-null mutant flies. Moreover, caffeine treatment increased O2 flux coupled to ATP synthesis and mitochondrial respiratory control ratio (RCR) in PINK 1B9-null mutant flies. The effects of caffeine on respiratory parameters were abolished by rotenone co-treatment, suggesting that caffeine exerts its beneficial effects mainly by stimulating the mitochondrial complex I (CI). In conclusion, we demonstrate that caffeine may improve mitochondrial function by increasing mitochondrial OXPHOS and ETS respiration in the PD model using PINK1 loss-of-function mutant flies.

Toxicological evaluation of zidovudine and novel chalcogen derivatives in Drosophila melanogaster.

Zidovudine (AZT) is the most commonly prescribed antiviral drug for the treatment of human immunodeficiency virus (HIV) infection. However, its chronic administration causes toxic side effects limiting its use. This study aimed to evaluate the toxicity of different concentrations of AZT and novel chalcogen derivatives (7A, 7D, 7G, 7K, 7M) on locomotion, mitochondrial dysfunction, acetylcholinesterase (AChE) activity, and production of reactive oxygen species (ROS) in adult Drosophila melanogaster. Our results show that AZT and its derivative 7K at a concentration of 10 µM impaired flies' locomotor behavior. Furthermore, AZT and the derivatives 7K, 7A, and 7M induced mitochondrial dysfunction observed by a decrease in oxygen flux through mitochondrial complexes I and II. Neither of the compounds tested affected AChE activity or ROS production in flies. According to these data, AZT derivatives presented the following decreasing order of toxicity: 7K > AZT > 7G > 7A > 7M > 7D. Based on the chemical structure, it is possible to infer that the presence of the seleno-phenyl group in 7A and 7G increases their toxicity compared to compounds 7D and 7M. In addition, compounds 7G, 7M, and 7K with three carbon atoms as spacer were more toxic than analogs containing one carbon atom (7A and 7D). Finally, the insertion of a p-methoxyl group enhances toxicity (7K). Based on these results, excepting 7K, all other chalcogen derivatives presented lower toxicity than AZT and are potential drug candidates.

Toxicological evaluation of the herbicide Palace® in Drosophila melanogaster.

Drosophila melanogaster is a suitable model for toxicological studies of environmental pollutants including pesticides, which are known to produce adverse effects on the ecosystem. The aim of the present study was to investigate the adverse influence of the pesticide Palace®, a mixture of 2,4-dichlorophenoxyacetic acid (2,4-D) and picloram, using D. melanogaster as a model organism. D. melanogaster larvae were exposed to 0.011%, 0.022%, 0.112%, 0.224%, and 1.12% of Palace® and development examined. Adult flies were treated with 0.224%, 1.12%, 2.24%, 11.2%, and 22.4% of Palace® and the following analyzed survival, locomotor behavior, acetylcholinesterase (AchE) activity, reactive oxygen species (ROS) production, total and non-protein thiol levels, and mitochondrial function. Data demonstrated that exposure of flies during larval stage to Palace® significantly affected development of larvae to the adult stage. In adults, treatment with Palace® resulted in dose-dependent progressive adverse effects on survival and behavior with males more sensitive than females. In both males and females, ROS production and AchE activity were not markedly affected by Palace®. However, total thiol levels increased in female heads treated with highest dilution of Palace®, while decreased levels of non-protein thiols were detected in heads of male flies following Palace® exposure. In females and males flies exposed to Palace® reduced mitochondrial oxygen consumption related to oxidative phosphorylation (OXPHOS) state, mitochondrial capacity of excess (E-P) and respiratory control ratio (RCR) was noted, indicating that the pesticide mixture altered mitochondrial complexes functionality with consequences on bioenergetics. In summary, Palace® exposure produced adverse effects on D. melanogaster affecting survival, development, behavior and mitochondrial function, which may exert ecotoxicological consequences which poses risks to different organisms in the ecosystem.

Copper acutely impairs behavioral function and muscle acetylcholinesterase activity in zebrafish (Danio rerio).

Copper is a heavy metal found at relatively high concentrations in surface waters around the world. Copper is a micronutrient at low concentrations and is essential to several organisms. At higher concentrations copper can become toxic, which reveal the importance of studying the toxic effects of this metal on the aquatic life. Thus, the objective of this study was to evaluate the toxic effects of copper on the behavior and biochemical parameters of zebrafish (Danio rerio). Zebrafish were exposed for 24h at a concentration of 0.006 mg/L Cu. After the exposure period, behavioral profile of animals was recorded through 6 min using two different apparatuses tests: the Novel Tank and the Light-Dark test. After behavioral testing, animals were euthanized with a solution of 250 mg/L of tricaine (MS-222). Brain, muscle, liver and gills were extracted for analysis of parameters related to oxidative stress and accumulation of copper in these tissues. Acetylcholinesterase (AChE) activity was determined in brain and muscle. Results showed acute exposure to copper induces significant changes in behavioral profile of zebrafish by changing locomotion and natural tendency to avoid brightly lit area. On the other hand, there were no significant effects on parameters related to oxidative stress. AChE activity decreased significantly in zebrafish muscle, but there were no significant changes in cerebral AChE activity. Copper levels in tissues did not increase significantly compared to the controls. Taken together, these results indicate that a low concentration of copper can acutely affect behavioral profile of adult zebrafish which could be partially related to an inhibition on muscle AChE activity. These results reinforce the need of additional tests to establishment of safe copper concentrations to aquatic organisms and the importance of behavioral parameters in ecotoxicological studies.

N-Acetylcysteine does not protect behavioral and biochemical toxicological effect after acute exposure of diphenyl ditelluride.

Diphenyl ditelluride (PhTe)2 is a versatile molecule used in the organic synthesis and it is a potential prototype for the development of novel biologically active molecules. The mechanism(s) involved in (PhTe)2 toxicity is(are) elusive, but thiol oxidation of critical proteins are important targets. Consequently, the possible remedy of its toxicity by thiol-containing compounds is of experimental and clinical interest. The present study aimed to investigate putative mechanisms underlying the toxicity of (PhTe)2 in vivo. We assessed behavioral and oxidative stress parameters in mice, including the modulation of antioxidant enzymatic defense systems. In order to mitigate such toxicity, N-acetylcysteine (NAC) was administered before (3 d) and simultaneously with (PhTe)2 (7 d). Mice were separated into six groups receiving daily injections of (1) TFK (2.5 ml/kg, intraperitonealy (i.p.)) plus canola oil (10 ml/kg, subcutaneously (s.c.)), (2) NAC (100 mg/kg, i.p.) plus canola oil s.c., (3) TFK i.p. plus (PhTe)2 (10 µmol/kg, s.c.), (4) TFK i.p. plus (PhTe)2 (50 µmol/kg, s.c.), (5) NAC plus (PhTe)2 (10 µmol/kg, s.c.), and (6) NAC plus (PhTe)2 (50 µmol/kg, s.c.). (PhTe)2 treatment started on the fourth day of treatment with NAC. Results demonstrated that (PhTe)2 induced behavioral alterations and inhibited important selenoenzymes (thioredoxin reductase and glutathione peroxidase). Treatments produced no or minor effects on the activities of antioxidant enzymes catalase and glutathione reductase. Contrary to expected, NAC co-administration did not protect against the deleterious effects of (PhTe)2. Other low-molecular-thiol containing molecules should be investigated to determine whether or not they can be effective against ditellurides.

Analyzing Mitochondrial Function in a Drosophila melanogaster PINK1B9-Null Mutant Using High-resolution Respirometry.

Neurodegenerative diseases, including Parkinson's Disease (PD), and cellular disturbances such as cancer are some of the disorders that disrupt energy metabolism with impairment of mitochondrial functions. Mitochondria are organelles that control both energy metabolism and cellular processes involved in cell survival and death. For this reason, approaches to evaluate mitochondrial function can offer important insights into cellular conditions in pathological and physiological processes. In this regard, high-resolution respirometry (HRR) protocols allow evaluation of the whole mitochondrial respiratory chain function or the activity of specific mitochondrial complexes. Furthermore, studying mitochondrial physiology and bioenergetics requires genetically and experimentally tractable models such as Drosophila melanogaster. This model presents several advantages, such as its similarity to human physiology, its rapid life cycle, easy maintenance, cost-effectiveness, high throughput capabilities, and a minimized number of ethical concerns. These attributes collectively establish it as an invaluable tool for dissecting complex cellular processes. The present work explains how to analyze mitochondrial function using the Drosophila melanogaster PINK1B9-null mutant. The pink1 gene is responsible for encoding PTEN-induced putative kinase 1, through a process recognized as mitophagy, which is crucial for the removal of dysfunctional mitochondria from the mitochondrial network. Mutations in this gene have been associated with an autosomal recessive early-onset familial form of PD. This model can be used to study mitochondrial dysfunction involved in the pathophysiology of PD.

Mitochondrial function and cellular energy maintenance during aging in a Drosophila melanogaster model of Parkinson disease.

Parkinson's disease (PD) is a common neurodegenerative disease characterized by movement disorders as well as loss of dopaminergic neurons. Moreover, genes affecting mitochondrial function, such as SNCA, Parkin, PINK1, DJ-1 and LRRK2, were demonstrated to be associated with PD and other neurodegenerative disease. Additionally, mitochondrial dysfunction and cellular energy imbalance are common markers found in PD. In this study, we used the pink1 null mutants of Drosophila melanogaster as a Parkinson's disease model to investigate how the energetic pathways and mitochondrial functions change during aging in a PD model. In our study, the loss of the pink1 gene decreased the survival percent and the decreased climbing index during aging in pink1-/- flies. Furthermore, there was an impairment in mitochondrial function demonstrated by a decrease in OXPHOS CI&CII-Linked and ETS CI&CII-Linked in pink1-/- flies at 3, 15 and 30 days of life. Interestingly, OXPHOS CII-Linked and ETS CII-Linked presented decreases only at 15 days of life in pink1-/- flies. Moreover, there was an increase in peroxide (H2O2) levels in pink1-/- flies at 15 and 30 days of life. Loss of the pink1 gene also decreased the activity of citrate synthase (CS) and increased the activity of lactate dehydrogenase (LDH) in pink1-/- flies head. Our results demonstrate a metabolic shift in ATP production in pink1-/- flies, which changed from oxidative to glycolytic pathways from 15 days of age, and is apparently more pronounced in the central nervous system.

Effects of caffeine on brain antioxidant status and mitochondrial respiration in acetaminophen-intoxicated mice.

Hepatic encephalopathy is a pathophysiological complication of acute liver failure, which may be triggered by hepatotoxic drugs such as acetaminophen (APAP). Although APAP is safe in therapeutic concentration, APAP overdose may induce neurotoxicity, which is mainly associated with oxidative stress. Caffeine is a compound widely found in numerous natural beverages. However, the neuroprotective effect of caffeine remains unclear during APAP intoxication. The present study aimed to investigate the possible modulatory effects of caffeine on brain after APAP intoxication. Mice received intraperitoneal injections of APAP (250 mg/kg) and/or caffeine (20 mg/kg) and, 4 h after APAP administration, samples of brain and blood were collected for the biochemical analysis. APAP enhanced the transaminase activity levels in plasma, increased oxidative stress biomarkers (lipid peroxidation and reactive oxygen species), promoted an imbalance in endogenous antioxidant system in brain homogenate and increased the mortality. In contrast, APAP did not induce dysfunction of the mitochondrial bioenergetics. Co-treatment with caffeine modulated the biomarkers of oxidative stress as well as antioxidant system in brain. Besides, survival assays demonstrated that caffeine protective effects could be dose- and time-dependent. In addition, caffeine promoted an increase of mitochondrial bioenergetics response in brain by the enhancement of the oxidative phosphorylation, which could promote a better energy supply necessary for brain recovery. In conclusion, caffeine prevented APAP-induced biochemical alterations in brain and reduced lethality in APAP-intoxicated mice, these effects may relate to the preservation of the cellular antioxidant status, and these therapeutic properties could be useful in the treatment of hepatic encephalopathy induced by APAP intoxication.

Methyl and Ethylmercury elicit oxidative stress and unbalance the antioxidant system in Saccharomyces cerevisiae.

Methylmercury (MeHg) and Ethylmercury (EtHg) are toxic to the central nervous system. Human exposure to MeHg and EtHg results mainly from the consumption of contaminated fish and thimerosal-containing vaccines, respectively. The mechanisms underlying the toxicity of MeHg and EtHg are still elusive. Here, we compared the toxic effects of MeHg and EtHg in Saccharomyces cerevisiae (S. cerevisiae) emphasizing the involvement of oxidative stress and the identification of molecular targets from antioxidant pathways. Wild type and mutant strains with deleted genes for antioxidant defenses, namely: γ-glutamylcysteine synthetase, glutathione peroxidase, catalase, superoxide dismutase, mitochondrial peroxiredoxin, cytoplasmic thioredoxin, and redox transcription factor Yap1 were used to identify potential pathways and proteins from cell redox system targeted by MeHg and EtHg. MeHg and EtHg inhibited cell growth, decreased membrane integrity, and increased the granularity and production of reactive species (RS) in wild type yeast. The mutants were predominantly less tolerant of mercurial than wild type yeast. But, as the wild strain, mutants exhibited higher tolerance to MeHg than EtHg. Our results indicate the involvement of oxidative stress in the cytotoxicity of MeHg and EtHg and reinforce S. cerevisiae as a suitable model to explore the mechanisms of action of electrophilic toxicants.

6-Hydroxydopamine induces different mitochondrial bioenergetics response in brain regions of rat.

Mitochondrial dysfunction has been demonstrated to have a central role in Parkinson Disease (PD) pathophysiology. Some studies have indicated that PD causes an impairment in mitochondrial bioenergetics; however, the effects of PD on brain-region specific bioenergetics was never investigated before. This study aimed to evaluate mitochondrial bioenergetics in different rat brain structures in an in vitro model of PD using 6-OHDA. Rat brain slices of hippocampus, striatum, and cortex were exposed to 6-OHDA (100 µM) for 1 h and mitochondrial bioenergetic parameters, peroxide production, lactate dehydrogenase (LDH) and citrate synthase (CS) activities were analyzed. Hippocampus slices exposed to 6-OHDA presented increased peroxide production but, no mitochondrial adaptive response against 6-OHDA damage. Cortex slices exposed to 6-OHDA presented increased oxygen flux related to oxidative phosphorylation and energetic pathways exchange demonstrated by the increase in LDH activity, suggesting a mitochondrial compensatory response. Striatum slices exposed to 6-OHDA presented a decrease of oxidative phosphorylation and decrease of oxygen flux related to ATP-synthase indicating an impairment in the respiratory chain. The co-incubation of 6-OHDA with n-acetylcysteine (NAC) abolished the effects of 6-OHDA on mitochondrial function in all brain regions tested, indicating that the increased reactive oxygen species (ROS) production is responsible for the alterations observed in mitochondrial bioenergetics. The present results indicate a brain-region specific response against 6-OHDA, providing new insights into brain mitochondrial bioenergetic function in PD. These findings may contribute to the development of future therapies with a target on energy metabolism.

Methylmercury and diphenyl diselenide interactions in Drosophila melanogaster: effects on development, behavior, and Hg levels.

Methylmercury (MeHg) is a highly toxic environmental pollutant which binds with a high affinity to selenol groups. In view of this, seleno-compounds have been investigated as MeHg antidotes. In the present study, we evaluated the effects of the co-exposure to MeHg and the seleno-compound diphenyl diselenide (PhSe)2 on Drosophila melanogaster. We measured the survival rate, developmental survival, locomotor ability, reactive oxygen species (ROS) production, and Hg levels in D. melanogaster exposed to MeHg and/or (PhSe)2 in the food. Exposure to MeHg caused a reduction in the survival rate, developmental survival, and locomotion in D. melanogaster. In addition, MeHg increased the ROS production and mercury levels in flies. The co-exposure to MeHg and (PhSe)2 did not prevent the toxic effects of MeHg in D. melanogaster. On the contrary, the co-exposure enhanced the toxic effects on the locomotor ability and developmental survival. This effect may be explained by the fact that the co-exposure increased the Hg levels in body when compared to flies exposed only to MeHg, suggesting that MeHg and (PhSe)2 interaction may increase Hg body burden in D. melanogaster which could contribute for the increased toxicity observed in the co-exposure.

Caffeine and acetaminophen association: Effects on mitochondrial bioenergetics.

AIMS: Many studies have been demonstrating the role of mitochondrial function in acetaminophen (APAP) hepatotoxicity. Since APAP is commonly consumed with caffeine, this work evaluated the effects of the combination of APAP and caffeine on hepatic mitochondrial bioenergetic function in mice. MAIN METHODS: Mice were treated with caffeine (20mg/kg, intraperitoneal (i.p.)) or its vehicle and, after 30minutes, APAP (250mg/kg, i.p.) or its vehicle. Four hours later, livers were removed, and the parameters associated with mitochondrial function and oxidative stress were evaluated. Hepatic cellular oxygen consumption was evaluated by high-resolution respirometry (HRR). KEY FINDINGS: APAP treatment decreased cellular oxygen consumption and mitochondrial complex activities in the livers of mice. Additionally, treatment with APAP increased swelling of isolated mitochondria from mice livers. On the other hand, caffeine administered with APAP was able to improve hepatic mitochondrial bioenergetic function. Treatment with APAP increased lipid peroxidation and reactive oxygen species (ROS) production and decreased glutathione levels in the livers of mice. Caffeine administered with APAP was able to prevent lipid peroxidation and the ROS production in mice livers, which may be associated with the improvement of mitochondrial function caused by caffeine treatment. SIGNIFICANCE: We suggest that the antioxidant effects of caffeine and/or its interactions with mitochondrial bioenergetics may be involved in its beneficial effects against APAP hepatotoxicity.

Reversal of bioenergetics dysfunction by diphenyl diselenide is critical to protection against the acetaminophen-induced acute liver failure.

Physiopathological conditions such as acute liver failure (ALF) induced by acetaminophen (APAP) can often impair the mitochondrial bioenergetics. Diphenyl diselenide [(PhSe)2] has been shown protects against APAP-induced ALF. The present study aimed to clarify the signaling mechanism involved in the protection of bioenergetics dysfunction associated with ALF-induced by APAP overdose. Mice received APAP (600mg/kg) or (PhSe)2 (15.6mg/kg) alone, or APAP+(PhSe)2, all the solutions were administered by the intraperitoneal (i.p.). Samples of liver, blood and liver mitochondria were collected at 2 and 4h after APAP administration. APAP-induced ALF was able to induce ALF by means of alteration on liver injury biomarkers, increased Nitrite and Nitrate levels and the impairment of oxidative phosphorylation capacity (OXPHOS). In parallel, APAP overdose promoted activation of nuclear factor erythroid 2-related factor 2 (Nrf2) and Heat shock protein 70 (HSP70) expression. (PhSe)2 was able to abolish the APAP-induced decline of OXPHOS and changes on the Nrf2-ARE pathway. In addition, (PhSe)2 elevated the levels of peroxisome proliferator-activated receptor-γ coactivator (PGC-1α), helping to restore the levels of nuclear respiratory factor 1 (NRF1) associated with mitochondrial biogenesis. In summary, the treatment with (PhSe)2 maintained mitochondrial function, promoted genes related to mitochondrial dynamic and demonstrating to play critical role in the modulation of cellular protective responses during ALF.

Purple grape juice as a protector against acute x-irradiation induced alterations on mobility, anxiety, and feeding behaviour in mice.

The aim of this work was to test the hypothesis that a moderate intake of organic purple grape juice shows a positive radiomodifier effect over early behavioural damage following acute X-irradiation in mice. Anxiety-, locomotion-, and feeding-related responses to 6 Gy total body X-irradiation (TBI) were studied via open field, Rotarod, and feeding/drinking recording. Thirty-two male mice weighing 25-30 g were grouped according grape juice (J) or water (W) ad libitum drinking and either non-irradiated (N) or irradiated (R). 24 h post-TBI the access frequency to the center and corners of the open field was decreased, and the total stay in the corners increased, in RW vs. NW mice. Anxiety-related parameters decreased in RJ vs. RW mice. Rotarod latency times increased 72 h post-TBI in RJ vs RW mice. No overall changes in food and drink intake were observed along the experimental period. On the irradiation day, bout number was increased and bout duration was decreased in RW mice. The changes were reversed by purple grape juice intake. Grape juice intake before and after TBI can overcome several radiation-induced changes in behaviour within 24-72 hours after sub-lethal X-irradiation. This beneficial effect on short-term anxiety and mobilityrelated activities could probably be included in the list of flavonoid bio-effects. The present findings could be relevant in designing preventive interventions aimed to enhance body defense mechanisms against short-term irradiation damage.

El presente estudio tiene como objetivo comprobar la hipótesis de que una ingesta moderada de mosto ecológico de uva tinta presenta un efecto radiomodificador positivo sobre los daños comportamentales tempranos inducidos por la irradiación aguda con rayos X en el ratón. Se estudiaron respuestas relacionadas con el comportamiento ingestivo, ansiedad y locomoción frente a la irradiación aguda a cuerpo entero (TBI) con 6 Gy de rayos X, mediante registro directo de la ingestión de agua y alimento, rotarod y open field. Se utilizaron 32 ratones macho con un peso corporal entre 25 y 30 g, agrupados en función de haber sido sometidos a irradiación a cuerpo entero (R) o no (N) y de su ingesta de mosto (J) o agua (W) ad libitum. La frecuencia de acceso al centro y a las esquinas del open field disminuyó 24 horas después de la irradiación, mientras que aumentó la duración de la estancia en las esquinas en los ratones RW respecto a los NW. Los parámetros relacionados con ansiedad disminuyeron en ratones RJ respecto a los RW. No se observaron cambios significativos en la ingestión total de alimento y bebida durante los días analizados; sin embargo, en el día de la irradiación disminuyó el número total de episodios ingestivos al tiempo que aumentó el tamaño de los mismos. Estos cambios revirtieron en los animales que bebieron mosto. La ingesta de mosto antes y después de la irradiación puede revertir cambios comportamentales agudos inducidos por la irradiación subletal. El efecto beneficioso sobre la ansiedad y actividad motora a corto plazo podría ser relevante para diseñar intervenciones preventivas encaminadas a incrementar los mecanismos de defensa del cuerpo frente al daño por irradiación a corto plazo.

Brazilian nut consumption by healthy volunteers improves inflammatory parameters.

OBJECTIVE: The aim of this study was to investigate the effect of a single dose of Brazil nuts on the inflammatory markers of healthy individuals. METHOD: A randomized crossover study was conducted with 10 healthy individuals (mean age 24.7 ± 3.4 y). Each individual was tested four times regarding intake of different portions of Brazil nuts: 0, 5, 20 and 50 g. At each testing period, peripheral blood was collected before and at 1, 3, 6, 9, 24, and 48 h after intake of nuts, as well as at 5 and 30 d after intake of various Brazil nut portions. Blood samples were tested for high-sensitivity to C-reactive protein, interleukin (IL)-1, IL-6, IL-10, tumor necrosis factor (TNF)-α, and interferon (IFN)-γ, aspartate and alanine aminotransferases, albumin, total protein, alkaline phosphatase, gamma-glutamyltransferase, urea, and creatinine. RESULTS: Consumption of nuts did not affect biochemical parameters for liver and kidney function, indicating absence of hepatic and renal toxicity. A single intake of Brazil nuts (20 or 50 g) caused a significant decrease in serum IL-1, IL-6, TNF-α, and IFN-γ levels (P < 0.05), whereas serum levels of IL-10 were significantly increased (P < 0.05). CONCLUSION: The results indicate a long-term decrease in inflammatory markers after a single intake of large portions of Brazil nuts in healthy volunteers. Therefore, the long-term effect of regular Brazil nut consumption on inflammatory markers should be better investigated.

Effects of diphenyl diselenide on methylmercury toxicity in rats.

This study investigates the efficacy of diphenyl diselenide [(PhSe)2] in attenuating methylmercury- (MeHg-)induced toxicity in rats. Adult rats were treated with MeHg [5 mg/kg/day, intragastrically (i.g.)] and/ or (PhSe)2 [1 mg/kg/day, intraperitoneally (i.p.)] for 21 days. Body weight gain and motor deficits were evaluated prior to treatment, on treatment days 11 and 21. In addition, hepatic and cerebral mitochondrial function (reactive oxygen species (ROS) formation, total and nonprotein thiol levels, membrane potential (ΔΨm), metabolic function, and swelling), hepatic, cerebral, and muscular mercury levels, and hepatic, cerebral, and renal thioredoxin reductase (TrxR) activity were evaluated. MeHg caused hepatic and cerebral mitochondrial dysfunction and inhibited TrxR activity in liver (38,9%), brain (64,3%), and kidney (73,8%). Cotreatment with (PhSe)2 protected hepatic and cerebral mitochondrial thiols from depletion by MeHg but failed to completely reverse MeHg's effect on hepatic and cerebral mitochondrial dysfunction or hepatic, cerebral, and renal inhibition of TrxR activity. Additionally, the cotreatment with (PhSe)2 increased Hg accumulation in the liver (50,5%) and brain (49,4%) and increased the MeHg-induced motor deficits and body-weight loss. In conclusion, these results indicate that (PhSe)2 can increase Hg body burden as well as the neurotoxic effects induced by MeHg exposure in rats.

New therapeutic approach: diphenyl diselenide reduces mitochondrial dysfunction in acetaminophen-induced acute liver failure.

The acute liver failure (ALF) induced by acetaminophen (APAP) is closely related to oxidative damage and depletion of hepatic glutathione, consequently changes in cell energy metabolism and mitochondrial dysfunction have been observed after APAP overdose. Diphenyl diselenide [(PhSe)2], a simple organoselenium compound with antioxidant properties, previously demonstrated to confer hepatoprotection. However, little is known about the protective mechanism on mitochondria. The main objective of this study was to investigate the effects (PhSe)2 to reduce mitochondrial dysfunction and, secondly, compare in the liver homogenate the hepatoprotective effects of the (PhSe)2 to the N-acetylcysteine (NAC) during APAP-induced ALF to validate our model. Mice were injected intraperitoneal with APAP (600 mg/kg), (PhSe)2 (15.6 mg/kg), NAC (1200 mg/kg), APAP+(PhSe)2 or APAP+NAC, where the (PhSe)2 or NAC treatment were given 1 h following APAP. The liver was collected 4 h after overdose. The plasma alanine and aspartate aminotransferase activities increased after APAP administration. APAP caused a remarkable increase of oxidative stress markers (lipid peroxidation, reactive species and protein carbonylation) and decrease of the antioxidant defense in the liver homogenate and mitochondria. APAP caused a marked loss in the mitochondrial membrane potential, the mitochondrial ATPase activity, and the rate of mitochondrial oxygen consumption and increased the mitochondrial swelling. All these effects were significantly prevented by (PhSe)2. The effectiveness of (PhSe)2 was similar at a lower dose than NAC. In summary, (PhSe)2 provided a significant improvement to the mitochondrial redox homeostasis and the mitochondrial bioenergetics dysfunction caused by membrane permeability transition in the hepatotoxicity APAP-induced.

Antioxidant effect of organic purple grape juice on exhaustive exercise.

This study aimed to assess the potential protective effect of organic purple grape juice (PGJ) on oxidative stress produced by an exhaustive exercise bout in rats. To test this hypothesis, rats were acutely treated with organic PGJ (Vitis labrusca) and subsequently submitted to an exhaustive exercise bout. Parameters of oxidative stress, such as thiobarbituric acid reactive species (TBARS) levels, 2',7',-dichlorofluorescein diacetate (DCFH-DA) oxidation, and nonprotein sulfhydryl levels (NP-SH) in the brain, skeletal muscle, and blood, were evaluated. Enzyme activity of Na(+),K(+)-ATPase, Ca(2+)-ATPase, and δ-aminolevulinate dehydratase (δ-ALA-D) in the brain, skeletal muscle, and blood were also assayed. Statistical analysis showed that the exhaustive exercise bout increased TBARS levels and DCFH-DA oxidation, and decreased NP-SH levels in rat tissue. Ca(2+)-ATPase activity was increased in groups exposed to both exercise and PGJ treatment. The results indicate that organic PGJ intake was able to protect against the oxidative damage caused by an exhaustive exercise bout in different rat tissues.

The combination of organoselenium compounds and guanosine prevents glutamate-induced oxidative stress in different regions of rat brains.

This study was designed to investigate the protective effects of the combination of guanosine and 2 organoselenium compounds (ebselen and diphenyl diselenide) against glutamate-induced oxidative stress in different regions of rat brains. Glutamate caused an increase in reactive oxygen species (ROS) generation and a decrease in [(3)H]-glutamate uptake in striatal, cortical, and hippocampal slices. Guanosine, ebselen, and diphenyl diselenide prevented glutamate-induced ROS production in striatal, cortical and hippocampal slices. The combination of guanosine with organoselenium compounds was more effective against glutamate-induced ROS production than the individual compounds alone. Guanosine prevented [(3)H]-glutamate uptake inhibition in striatal, cortical, and hippocampal slices. Thus, protection against the harmful effects of glutamate is possibly due to the combination of the antioxidant properties of organoselenium compounds and the stimulatory effect of guanosine on glutamate uptake. In conclusion, the combination of antioxidants and glutamatergic system modulators could be considered a potential therapy against the prooxidant effects of glutamate.

Purple grape juice as a protector against acute x-irradiation induced alterations on mobility, anxiety, and feeding behaviour in mice / El mosto de uva tinta como protector frente a las alteraciones agudas de movilidad, ansiedad y comportamiento ingestivo inducidas por rayos x en ratones

The aim of this work was to test the hypothesis that a moderate intake of organic purple grape juice shows a positive radiomodifier effect over early behavioural damage following acute X-irradiation in mice. Anxiety-, locomotion-, and feeding-related responses to 6 Gy total body X-irradiation (TBI) were studied via open field, Rotarod, and feeding/drinking recording. Thirty-two male mice weighing 25-30 g were grouped according grape juice (J) or water (W) ad libitum drinking and either non-irradiated (N) or irradiated (R). 24 h post-TBI the access frequency to the center and corners of the open field was decreased, and the total stay in the corners increased, in RW vs. NW mice. Anxiety-related parameters decreased in RJ vs. RW mice. Rotarod latency times increased 72 h post-TBI in RJ vs RW mice. No overall changes in food and drink intake were observed along the experimental period. On the irradiation day, bout number was increased and bout duration was decreased in RW mice. The changes were reversed by purple grape juice intake. Grape juice intake before and after TBI can overcome several radiation-induced changes in behaviour within 24-72 hours after sub-lethal X-irradiation. This beneficial effect on short-term anxiety and mobilityrelated activities could probably be included in the list of flavonoid bio-effects. The present findings could be relevant in designing preventive interventions aimed to enhance body defense mechanisms against short-term irradiation damage (AU)

El presente estudio tiene como objetivo comprobar la hipótesis de que una ingesta moderada de mosto ecológico de uva tinta presenta un efecto radiomodificador positivo sobre los daños comportamentales tempranos inducidos por la irradiación aguda con rayos X en el ratón. Se estudiaron respuestas relacionadas con el comportamiento ingestivo, ansiedad y locomoción frente a la irradiación aguda a cuerpo entero (TBI) con 6 Gy de rayos X, mediante registro directo de la ingestión de agua y alimento, rotarod y open field. Se utilizaron 32 ratones macho con un peso corporal entre 25 y 30 g, agrupados en función de haber sido sometidos a irradiación a cuerpo entero (R) o no (N) y de su ingesta de mosto (J) o agua (W) ad libitum. La frecuencia de acceso al centro y a las esquinas del open field disminuyó 24 horas después de la irradiación, mientras que aumentó la duración de la estancia en las esquinas en los ratones RW respecto a los NW. Los parámetros relacionados con ansiedad disminuyeron en ratones RJ respecto a los RW. No se observaron cambios significativos en la ingestión total de alimento y bebida durante los días analizados; sin embargo, en el día de la irradiación disminuyó el número total de episodios ingestivos al tiempo que aumentó el tamaño de los mismos. Estos cambios revirtieron en los animales que bebieron mosto. La ingesta de mosto antes y después de la irradiación puede revertir cambios comportamentales agudos inducidos por la irradiación subletal. El efecto beneficioso sobre la ansiedad y actividad motora a corto plazo podría ser relevante para diseñar intervenciones preventivas encaminadas a incrementar los mecanismos de defensa del cuerpo frente al daño por irradiación a corto plazo (AU)