Zebrafish exposure to diphenyl diselenide-loaded polymeric nanocapsules caused no behavioral impairments and brain oxidative stress.

Previous findings showed that the nanoencapsulation of diphenyl diselenide [(PhSe)2], an organoselenium compound, provided superior biological effects and lower toxicological potential than its free form in vitro. However, few studies reported the behavioral and biochemical effects of this nanocapsules formulation in vivo. Zebrafish (Danio rerio) has emerged as a useful animal model to determine the pharmacological and toxicological effects of nanoparticles. Here, we evaluated the behavioral and brain oxidative effects after zebrafish exposure to (PhSe)2-loaded nanocapsules. Formulations were prepared by interfacial deposition of preformed polymer method and later tested at concentrations ranging from 0.1 to 2.0 µM. Both locomotor and exploratory activities were assessed in the novel tank diving test. Moreover, brain oxidative status was determined by measuring thiobarbituric acid-reactive substance levels, glutathione peroxidase, glutathione redutase and glutathione S-transferase activities. (PhSe)2-loaded nanocapsules showed no alteration on travelled distance, immobility, and erratic swimming, suggesting the absence of behavioral impairments. Interestingly, the higher concentration tested had anxiolytic-like effects, since animals spent more time in the top area and showed a decreased thigmotaxis behavior. Biochemical analysis demonstrated that the concentrations used in this study did not affect oxidative stress-related parameters in brain samples, reinforcing the low toxicological potential of the formulation. In conclusion, the exposure to (PhSe)2-loaded nanocapsules caused no locomotor impairments as well as did not modify the oxidative status of zebrafish brain, indicating that this formulation is probably non-toxic and promising for future pharmacological studies.

Integrated biomarkers response confirm the antioxidant role of diphenyl diselenide against atrazine.

Atrazine (ATZ) is a herbicide worldwide used. That can cause oxidative damage in non-target organisms, such as fish. Furthermore, the threat of exposure to pesticides together with poor nutrition is hazardous to the normal development of fish, and supplementation of the fish diet with antioxidants compounds is an alternative approach to prevent the hazardous effects of pesticide exposure. Here we aimed to investigate the capacity of diphenyl diselenide (PhSe)2 diet supplementation to improve the antioxidant defense of Cyprinus carpio (carp) exposed to environmental concentrations of ATZ. To prove the efficiency of (PhSe)2, we used the Integrated Biomarkers Response (IBR) methodology. Therefore, carp were fed for 8 weeks diets either with or without (PhSe)2 and exposed to 2 or 10µg/L of ATZ for 96h, euthanized, and their liver, gills, and muscle tissues were removed for biochemical assays. ATZ was able to cause oxidative damage from reactive species production in all tissues of carp, as observed by the increase of lipid peroxidation and protein damage. The activity of some antioxidant enzymes was inhibited in carp exposed to ATZ. However, (PhSe)2 supplementation was able to prevent this ATZ-induced damage by improving the activities of antioxidant enzymes and through antioxidant competence of (PhSe)2per se. Furthermore, IBR was shown to be a useful tool to compare treatments, even at different concentrations, and identify the efficiently antioxidant behavior of the organoselenium compound.

Exposure to sublethal concentrations of copper changes biochemistry parameters in silver catfish, Rhamdia quelen, Quoy & Gaimard.

The effects of Cu exposure on catalase (CAT) and acetylcholinesterase (AChE) activity, formation of thiobarbituric acid-reactive species (TBARS) and metabolic parameters were evaluated in silver catfish (Rhamdia quelen). The fish were exposed for 45 days to 0, 16 and 29 µg/L Cu. The fish that were exposed to Cu exhibited lower TBARS levels in the muscle and higher TBARS levels in the liver. They also showed lower CAT activity in the liver and lower AChE activity in the brain and muscle. Higher glucose and lactate and lower protein plasma levels were observed in the fish exposed to Cu. The changes in the hepatic metabolic parameters were Cu concentration dependent. In the muscle, lower glycogen and higher lactate levels were observed in the fish exposed to Cu. Alterations in the metabolic parameters showed a preference for the anaerobic pathway of energy production and liver protein catabolism to supply the energy demand.

Toxicological responses of Cyprinus carpio exposed to a commercial formulation containing glyphosate.

The effects of commercial glyphosate herbicide formulation on the activity of acetylcholinesterase (AChE) enzyme and oxidative stress were studied in Cyprinus carpio exposed for 96 h to 0.0, 0.5, 2.5, 5.0 and 10.0 mg/L and then allowed to equal recovery period in water without herbicide. The activity of AChE was inhibited in the brain and in the muscle after exposure. However, after recovery period brain and muscle AChE activity increased. Brain thiobarbituric acid reactive species (TBARS) were measured as an indicator of oxidative stress. Increased TBARS levels were observed with all concentrations tested of the glyphosate formulation, and remained increased after the recovery period. The results recorded clearly indicate lipid peroxidation and anti-AChE action induced by Roundup(®) exposure.

Acute exposure to glyphosate herbicide affects oxidative parameters in piava (Leporinus obtusidens).

In recent years, commercial glyphosate herbicide formulations have been widely used in agriculture to control aquatic weeds. These pesticides may result in disruption of ecological balance, causing damage to nontarget organisms including fish. Teleostean fish (Leporinus obtusidens) were exposed to commercial glyphosate herbicide formulation at 0 (control), 3, 6, 10 or 20 mg L(-1) for 96 h. The effects of herbicide on plasmatic metabolic parameters, thiobarbituric acid reactive substances (TBARS), catalase activity, protein carbonyl, and mucus layer parameters were studied. Plasmatic glucose and lactate levels increased but protein levels showed reduction after herbicide exposure. TBARS levels in brain showed a reduction at all tested concentrations. However, liver demonstrated increased TBARS levels at all tested concentrations, whereas in white muscle TBARS production did not change after exposure to herbicide. Fish exposed to all concentrations of glyphosate showed increase in liver catalase activity and protein carbonyl. Herbicide exposure increased protein and carbohydrate levels of the mucus layer at all tested concentrations. The present results showed that, in 96 h, glyphosate changed toxicological parameters analyzed in piava. Parameters measured in this study may be useful in environmental biomonitoring.

Toxicological responses of Cyprinus carpio exposed to the herbicide penoxsulam in rice field conditions.

Cyprinus carpio fish were exposed to penoxsulam (Ricer) in field conditions. The experiment in the rice field was carried out for 7, 21 and 72 days. Oxidative stress parameters and antioxidant profile were studied. The acetylcholinesterase (AChE) enzyme activity in the brain was increased after 7 days and reduced after 21 and 72 days of the experiment in the rice field. The AChE activity in muscle was reduced only after 72 days of exposure. Thiobarbituric acid-reactive species were increased in the liver, brain and muscle at 7 days of the trial, reduced at 21 days in the brain and unaltered after 72 days of exposure in muscle. However, an increase in this parameter in the brain and liver was observed. Liver glutathione S-transferase was reduced at 7 days, unchanged at 21 days and increased after 72 days of exposure. Catalase of the liver changed only in the second experimental period, when it was reduced. Liver protein carbonyl was reduced at 7 days and increased at 21 and 72 days of exposure. This study shows long-term effects of rice herbicide at environmentally relevant concentrations on toxicological parameters in different tissues (brain, muscle and liver) of Cyprinus carpio.

Exposure to tebuconazol in rice field and laboratory conditions induces oxidative stress in carp (Cyprinus carpio).

Pesticides can have an effect on the biochemical and physiological functions of living organisms. The changes seen in fish and their response to pesticides can be used as an example for vertebrate toxicity. In this study, carp fish (Cyprinus carpio) were exposed to different concentrations of tebuconazol fungicide, by rice field (31.95 µg/L) and laboratory (33.47 and 36.23 µg/L) conditional testing, during a 7 day period. Parameters such thiobarbituric acid-reactive substance levels (TBARS), protein carbonyl, catalase, glutathione S-transferase and acetylcholinesterase activities were studied, using the liver, brain and white muscle of the fish. The field experiment showed that the TBARS levels were increased in all the analyzed tissues. Similarly, the protein carbonyl of the liver and the brain AChE activity increased after 7 days. The laboratory experiment demonstrated that the TBARS levels in the liver were increased in both of the concentration tests. TBARS levels in the muscle increased only by the lowest test concentration. On the other hand, the protein carbonyl was increased only by the highest concentration. The results indicate that the tebuconazol exposure from the field and laboratory conditions directly affected the health of the fish, showing the occurrence of oxidative stress.

Roundup effects on oxidative stress parameters and recovery pattern of Rhamdia quelen.

Antioxidant enzymes and oxidative stress indicators were evaluated in fish exposed to different concentrations of the herbicide Roundup 48% (Monsanto, St. Louis, MO): control (none), 0.45, or 0.95 mg/l. After exposure for 8 days to herbicide, fish were transferred to clean water for a recovery response period (also 8 days). Herbicide increased thiobarbituric acid reactive species in liver and muscle at the higher concentration and in the brain at both concentrations. Protein carbonyl in liver increased after exposure. Catalase (CAT) and superoxide dismutase (SOD) activities and ascorbic acid levels in liver did not change in fish exposed to both concentrations. Glutathione S-transferase (GST) levels decreased at both concentrations. The nonprotein thiol levels decreased at the 0.95 mg/l concentration. During the recovery period, some of the parameters that had altered, such as protein carbonyl content, later recovered. However, some enzymes reacted during this period, e.g., GST increased its activity, possibly indicating a compensatory response against the toxic conditions. In contrast, CAT and SOD activities decreased during the recovery period, indicating herbicide toxicity. Oxidative stress that occurred during the exposure period was likely due to the increased lipid peroxidation and protein carbonyl content. The results concerning oxidative and antioxidant profiles indicate that short-term exposure to herbicide is capable of causing oxidative stress in fish tissues.

Oxidative stress biomarkers in Cyprinus carpio exposed to commercial herbicide bispyribac-sodium.

Cyprinus carpio were exposed under field conditions to 20.87 microg l(-1) of commercial herbicide bispyribac-sodium (Nominee, SC), during 7, 21 and 72 days. Enzymatic parameters such as catalase (CAT), glutathione S-transferase (GST) and acetylcholinesterase (AChE) activities, as well as thiobarbituric acid-reactive substances (TBARS) and protein carbonyl contents were studied in different tissues. After 7 days of exposure, GST activity decreased. At the same period, brain AChE activity increased, but a reduction of activity was observed in muscle tissue. Brain TBARS levels increased at 7 days. After 21 days of exposure liver CAT levels and muscle AChE activities decreased. In the same period, liver protein carbonyl and muscle TBARS increased. After 72 days of exposure in the field, AChE activity was reduced in both brain and muscle. Protein carbonyl contents in liver and brain TBARS levels increased. Muscle AChE activity, TBARS and protein carbonyl can be used as biomarkers of exposure to the herbicide bispyribac-sodium. This study demonstrates effects of exposure to bispyribac-sodium under rice field conditions on oxidative stress parameters in tissues of Cyprinus carpio.

Herbicide formulation with glyphosate affects growth, acetylcholinesterase activity, and metabolic and hematological parameters in piava (Leporinus obtusidens).

The teleost fish Leporinus obtusidens (piava) was exposed to different concentrations of Roundup, a commercial herbicide formulation containing glyphosate (0, 1, or 5 mg L(-1)), for 90 days. Acetylcholinesterase (AChE) activity was verified in brain and muscle. Hepatic and muscular metabolic parameters as well as some hematological parameters were determined. The results showed that brain AChE activity was significantly decreased in fish exposed to 5 mg L(-1) Roundup, whereas muscular AChE activity was not altered. Both Roundup concentrations significantly decreased liver glycogen without altering the muscle glycogen content. Hepatic glucose levels were reduced only in fish exposed to 5 mg L(-1) Roundup. Lactate levels in the liver and muscle significantly increased in fish exposed to both Roundup concentrations. Hepatic protein content remained constant at 1 mg L(-1) but increased at 5 mg L(-1) Roundup. In the muscle however, protein content decreased with increasing exposure concentration. The herbicide exposure produced a decrease in hematological parameters at both concentrations tested. The majority of observed effects occur at environmental relevant concentrations, and in summary, the results show that Roundup affects brain AChE activity as well as metabolic and hematologic parameters of piavas. Thus, we can suggest that long-term exposure to Roundup causes metabolic disruption in Leporinus obtusidens.

Oxidative stress in cerebrospinal fluid of patients with aseptic and bacterial meningitis.

This study aimed to determine whether patients with aseptic and bacterial meningitis presented alterations in oxidative stress parameters of cerebrospinal fluid (CSF). A total of 30 patients were used in the research. The CSF oxidative stress status has been evaluated through many parameters, such as lipid peroxidation through thiobarbituric acid reactive substances (TBARS) and antioxidant defense systems such as superoxide dismutase (SOD), glutathione S-transferase (GST), reduced glutathione (GSH) and ascorbic acid. TBARS levels, SOD and GST activity increase in aseptic meningitis and in bacterial meningitis. The ascorbic acid concentration increased significantly in patients with both meningitis types. The reduced glutathione levels were reduced in CSF of patients with aseptic and bacterial meningitis. In present study we may conclude that oxidative stress contributes at least in part to the severe neurological dysfunction found in meningitis.

The 2,4-D herbicide effects on acetylcholinesterase activity and metabolic parameters of piava freshwater fish (Leporinus obtusidens).

The effects of 2,4-D (1 or 10 mg/L) on acetylcholinesterase (AChE) and metabolic parameters were evaluated in piava (Leporinus obtusidens) after 96 h. AChE activity was significantly reduced in the brain at a concentration of 10 mg/L and in the muscle at both concentrations tested. Muscle glycogen and lactate were significantly reduced for both 2,4-D concentrations but no significant change was observed in liver glycogen. Muscle protein levels were enhanced after exposure at 10 mg/L, but no significant changes were observed in muscle and liver glucose. Liver lactate and protein were significantly reduced after exposure to this herbicide. 2,4-D exposure produced a decrease in blood glucose at both concentrations and enhanced lactate levels at 10mg/L. Plasma protein increased at both concentrations tested. In conclusion, the results obtained indicate that 2,4-D affects brain and muscle AChE activity and some blood and tissue metabolic parameters of L. obtusidens. The stress generated by 2,4-D is the probable cause of alterations observed and measured parameters can be used to monitor 2,4-D fish toxicity.