-
[show abstract]
[hide abstract]
ABSTRACT: In the present study a new method has been developed and validated for detecting free Microcystins (MCs) (MC-RR, MC-LR and MC-YR) by liquid chromatography-mass spectrometry (LC-MS) in the cyprinid Tinca tinca and in the crayfish Procambarus clarkii collected from three ponds in Extremadura (Spain) where the presence of the cyanobacteria species M. aeruginosa and A. spiroides has been confirmed. Once the method had been validated, free MCs were determined in fish (tench, Tinca tinca) and crayfish from different ponds in order to understand how they are bioaccumulated through the food web. MCs were not detected in any of the fish samples analyzed. It was confirmed that Procambarus clarkii accumulated MCs in their tissues without losing their organoleptic characteristics, with MC-LR (2.3-18.1 μg MC-LR/g body weight) being the predominant MC variant detected in all the crayfish samples. MC-RR was measured in 50% of the samples analyzed, ranging between 1.4-7.8 μg MC-RR/g body weight and no MC-YR was detected. The results indicated that crayfish can accumulate free MCs in higher quantities than tench that live in ponds contaminated by toxic cyanobacteria species, and emphasized the need for regular monitoring if the health risks associated with their consumption are to be avoided.
Food and chemical toxicology: an international journal published for the British Industrial Biological Research Association 03/2013; · 2.99 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Microcystins (MCs) and Cylindrospermopsin (CYN) are among the cyanotoxins which occur naturally, produced by different cyanobacteria species when they grow or proliferate under favorable environmental conditions. From a toxicological point of view, their relevance is due to the deleterious effects that they have been reported to induce in a wide range of organisms, including humans. Cyanotoxins intake from contaminated water and food is an important source of human exposure. Various edible aquatic organisms, plants, and food supplements based on algae, can bioaccumulate these toxins. A thorough review of the scientific data available on this topic is provided, the studies on MCs being much more numerous than those focused on CYN. The scientific literature suggests that these cyanotoxins can be accumulated at concentrations higher than their respective recommended Tolerable Daily Intake (TDI). Finally, the influence of different cooking procedures on their levels in food has been considered. In this regard, again studies on the matter dealing with CYN have been not yet raised. MCs contents have been reported to be reduced in muscle of fish after boiling, or cooking in a microwave-oven, although the effect of other traditional cooking processes such as frying, roasting or grilling have not been demonstrated.
Food and chemical toxicology: an international journal published for the British Industrial Biological Research Association 11/2012; · 2.99 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The occurrence of cyanobacterial blooms in aquatic environments is increasing in many regions of the world due to progressive eutrophication of water bodies. Because of the production of toxins such as Cylindrospermopsin (CYN), contamination of water with cyanobacteria is a serious health problem around the world. Therefore it is necessary to develop and validate analytical methods that allow us to quantify CYN in real samples in order to alert the public of this toxin. In this work, an analytical method has been developed an optimized for the determination of CYN from Aphanizomenon ovalisporum cultures. The analytical procedure is based on solvent extraction followed by a purification step with graphitized cartridges and CYN quantification by LC-MS/MS. The extraction and purification steps were optimized using a two-level full factorial design with replications. A suitable and practical procedure for assessing the trueness and precision of the proposed method has been applied by using validation standards. The method has been suitably validated: the regression equation was calculated from standards prepared in extracts from lyophilized M. aeruginosa PCC7820 (r(2)≥0.9999) and the linear range covered is from 5 to 500μg CYN/L, equivalent to 0.18-18.00μg CYN/g dry weight lyophilized cells. Limits of detection and quantification were 0.04 and 0.15μg CYN/g, respectively, the recovery range (%) oscillated between 83 and 94% and intermediate precision (RSD %) values from 5.6 to 11.0%. Moreover, the present method showed to be robust for the three factors considered: the batch of the graphitized carbon cartridges, the flow rate of the sample through the cartridge, and the final re-dissolved water volume after SPE treatment, which permits its validation. The validated method has been applied to different lyophilized cultures of A. ovalisporum (LEGE X-001) to evaluate CYN content. This procedure can be used for determining CYN in lyophilized natural blooms samples in environmental studies.
Talanta 10/2012; 100C:356-363. · 3.79 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Cylindrospermopsin is a cyanobacterial toxin frequently implicated in cyanobacterial blooms that is approaching an almost cosmopolitan distribution pattern. Moreover, the predominant extracellular availability of this cyanotoxin makes it particularly likely to be taken up by a variety of aquatic organisms including fish. Recently, Cylindrospermopsin has shown to alter the activity and gene expression of some of the glutathione related enzymes in tilapias (Oreochromis niloticus), but little is known about the influence of the route of exposure and the time of sacrifice after a single exposure to Cylindrospermopsin on these biomarkers. With this aim, tilapias were exposed by gavage or by intraperitoneal injection to a single dose of 200μgkg(-1) bw of pure Cylindrospermopsin and after 24h or 5d they were sacrificed. The activity and relative mRNA expression by real-time PCR of antioxidant enzymes glutathione peroxidase and soluble glutathione-S-transferases (sGST) and the sGST protein abundance by Western blot analysis were evaluated in liver and kidney. Results showed differential responses in dependence on the variables considered with a higher toxicity with the intraperitoneal exposure and with 5d as time of sacrifice.
Chemosphere 07/2012; · 3.21 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A new method for determining dissolved cylindrospermopsin (CYN) in waters using solid-phase extraction (SPE) with graphitized carbon cartridges and quantification by liquid chromatography coupled with tandem mass spectrometry is described and discussed. The method has been suitably validated: the linear range covered is from 0.900 to 125 µg CYN/L. Limits of detection and quantification were 0.5 and 0.9 µg CYN/L, respectively, and allow CYN determination at concentrations below the guideline proposed of 1 µg CYN/L in natural waters. The method exhibits mean recoveries from 83 to 95%, and intermediate precision (relative standard deviation (%)) values from 5 to 12%, ensuring adequacy against the Association of Official Analytical Chemists guidelines. The method is robust against the following three influential factors considered in the cleanup stage: the batch of the graphitized carbon cartridges, the flow rate of the water sample through the cartridge, and the final redissolved water volume after SPE treatment. The method has been successfully applied to detection and quantification of CYN in water samples from aquaria of a toxicological in vivo laboratory experiment. Environ. Toxicol. Chem. 2012; 31: 2233-2238. © 2012 SETAC.
Environmental Toxicology and Chemistry 07/2012; 31(10):2233-8. · 2.81 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Cylindrospermopsin (CYN) is a toxin produced by various cyanobacteria species. Fish can be exposed to this cyanotoxin in their natural environments and in aquaculture ponds, and toxic effects can be derived. The present study investigated the effects of dietary N-acetylcysteine (NAC) on the oxidative stress induced by pure CYN and CYN from lyophilized cells of Aphanizomenon ovalisporum in tilapia (Oreochromis niloticus). Fish were pretreated with 0, 22, and 45 mg NAC/fish/d for a week, and on day seven, they received a single dose of 200 µg/kg CYN and were killed after 24 h. Oxidative biomarkers evaluated included lipid peroxidation, protein oxidation, glutathione (GSH)/oxidized glutathione (GSSG) ratio, activity of the enzyme γ-glutamylcysteine synthetase, and activity and gene expression of glutathione-S-transferase and glutathione peroxidase. Results showed that CYN induced oxidative stress as evidenced by the increase of lipid peroxidation and protein oxidation, the decrease in GSH/GSSG, and the alteration of the enzymatic activities assayed. Moreover, exposure to cyanobacterial cells containing CYN induced higher toxic effects in comparison to pure CYN. N-acetylcysteine supplementation was effective at reducing the toxicity induced by CYN, particularly at the highest dose employed, with a recovery of some of the biomarkers assayed to basal levels. Therefore, NAC can be considered a useful chemoprotectant that reduces hepatic and renal oxidative stress in the prophylaxis and treatment of CYN-related intoxication in fish.
Environmental Toxicology and Chemistry 04/2012; 31(7):1548-55. · 2.81 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Carbon nanotubes (CNT) are among the more promising nanomaterials due to their potential applications. In this sense, the adverse effects that CNT can induce are of concern. In particular, carboxylic acid functionalized single wall carbon nanotubes (COOH-SWCNT) have shown to reduce cell viability and induce morphological effects on the human intestinal cell line Caco-2, but little is known about the toxic mechanisms involved. The aim of the present study was to investigate the oxidative stress responses of this cell line after 24h exposure to COOH-SWCNT. Biomarkers assayed included lipid peroxidation (LPO), reactive oxygen species (ROS) generation, and enzymatic and non-enzymatic antioxidant defences. Results showed an increase in ROS from 100μg/mL reaching 5.2-fold the basal value at the highest concentration assayed. An induction of catalase, superoxide dismutase and glutathione peroxidase activities was also observed, meanwhile glutathione reductase showed a reduced activity at 1000μg/mL. Glutathione (GSH) levels also decreased (2.5-fold) at the highest level of exposure. Therefore, the antioxidant defences could not overwhelm the oxidative insult caused by COOH-SWCNT and LPO products increased in a concentration-dependent manner. We can conclude that oxidative stress plays a role in the pathogenicity induced by COOH-SWCNT on Caco-2 cells at the concentrations assayed.
Toxicology in Vitro 03/2012; 26(5):672-7. · 2.78 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Cylindrospermopsin (CYN) is increasingly recognized as a potential threat to drinking water safety, due to its ubiquity. This cyanotoxin has been found to cause toxic effects in mammals, and although fish could be in contact with this toxin, acute toxicity studies on fish are nonexistent. This is the first study showing that single doses of CYN pure standard (200 or 400 μg CYN/kg fish bw) by oral route (gavage) generate histopathological effects in fish (Tilapia-Oreochromis niloticus) exposed to the toxin under laboratory condition. Among the morphological changes, disorganized parenchymal architecture in the liver, dilated Bowman's space in the kidney, fibrolysis in the heart, necrotic enteritis in the intestines, and hemorrhages in the gills, were observed. Moreover, some oxidative stress biomarkers in the liver and kidney of tilapias were altered. Thus, CYN exposure induced increased protein oxidation products in both organs, NADPH oxidase activity was significantly increased with the kidney being the most affected organ, and decreased GSH contents were also detected in both organs, at the higher dose assayed. © 2012 Wiley Periodicals, Inc. Environ Toxicol, 2012.
Environmental Toxicology 02/2012; · 2.41 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Although fish and aquatic organisms can be in contact with the cyanotoxin cylindrospermopsin (CYN), toxicological studies are practically nonexistent. CYN has a late and progressive acute toxicity in rodents, but no data have been reported in fish. In this work, tilapia (Oreochromis niloticus) were exposed for the first time to an acute dose of CYN (200 μg/kg fish) by intraperitoneal (i.p.) injection, and the effects were compared with the oral route (gavage). In both cases, fish were sacrificed after 24 h or 5 days of the toxin administration. CYN induced multiorganic damage, being the liver and kidney the main targets of toxicity. The histological findings were more pronounced after i.p. administration (in the liver, kidney, heart, gills) with the exception of the gastrointestinal tract. The time of sacrifice influenced the degree of histological damage in all organs studied, and was more severe after 5 d in comparison to 24 h. Moreover, CYN induced an increase in the average nuclear diameter of hepatocytes in the liver, and decreased cross sections of proximal and distal convoluted tubules in the kidney. The changes in these parameters were also more severe by i.p. route, and with the time of sacrifice, supporting the histopathological results obtained in these organs. Thus, both parameters could be useful for quantifying the extent of the damage in fish after CYN exposure.
Ecotoxicology and Environmental Safety 02/2012; 76(2):102-13. · 2.29 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The cyanobacterial toxin cylindrospermopsin (CYN) is a widely distributed contaminant of freshwater systems with the consequent risk for human and wildlife, particularly fish. However, CYN toxicity data on fish are still scarce. It is known that CYN inhibits glutathione synthesis and this could contribute to oxidative damage. In the present work tilapia (Oreochromis niloticus) were exposed by gavage to 200 and 400 μg/kg bw of pure CYN and sacrificed after 24 h. The activity and relative mRNA expression by real-time PCR of antioxidant enzymes glutathione peroxidase (GPx) and soluble glutathione-S-transferases (sGST) and the sGST protein abundance by Western blot analysis were evaluated in liver and kidney. Also the induction of lipid peroxidation (LPO) was assayed. Results show an increase of LPO products in both organs. Moreover, CYN altered the activity, gene expression and protein abundance of the enzymes, indicating the importance of GPx and sGST in CYN pathogenicity. This is the first time that CYN is reported to affect these enzymes in fish and they have shown to be responsive biomarkers of CYN toxicity.
Ecotoxicology 06/2011; 20(8):1852-60. · 2.36 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Cylindrospermopsin (CYN) is a toxin produced by various cyanobacterial species that are increasingly being found in freshwater systems. Although CYN can have toxic effects in humans, domestic animals and wildlife, it has been subject to very little investigation (particularly in fish). It has been reported to deplete the cellular glutathione content but the role of oxidative stress in the pathogenicity of CYN in fish is unknown. For this reason tilapia fish were exposed to 200 μg/kg pure CYN through two different exposure routes-gavage and intraperitoneal injection-and sacrificed after 24 h and 5 days. The results showed an increase in NADPH oxidase activity (a biomarker of reactive oxygen species formation), lipid peroxidation (LPO) and protein oxidation; no changes in DNA oxidation; and a reduction in glutathione levels (GSH) and γ-glutamylcysteine synthetase (GCS) activity, the limiting enzyme in glutathione synthesis. The time of sacrifice had a bigger influence on the results than the exposure route because after 5 days some of the biomarkers assayed had recovered their pre-intoxication levels, which was not the case after 24 h.
Aquatic toxicology (Amsterdam, Netherlands) 06/2011; 105(1-2):100-6. · 3.12 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The increasing occurrence of toxic cyanobacterial blooms in eutrophic water bodies is nowadays of worldwide concern due to their ability to produce toxins such as microcystins (MCs). These cyanobacterial toxins have been shown to affect aquatic organisms such as fish, resulting in oxidative stress. Among the antioxidant enzymes, glutathione peroxidase (GPx) and soluble glutathione-S-transferases (sGST) play an important role in the detoxification of MCs. In the present work tilapia (Oreochromis niloticus) were orally exposed to cyanobacterial cells containing MCs and non-containing MCs for 21 days. The activity and relative mRNA expression by real-time PCR of both enzymes and the GST protein abundance by Western blot analysis were evaluated in liver and kidney. Also the induction of lipid peroxidation (LPO) was assayed. MCs containing cyanobacterial cells induced an increase of LPO products in both organs, and MCs containing and MCs non-containing cyanobacterial cells altered the activity, gene expression and protein abundance of the enzymes, indicating the importance of GPx and sGST in MCs detoxification. Moreover, liver, the main organ involved in biodegradation and biotransformation, experienced an adaptative response to the toxic insult. These results show for the first time that the subchronic exposure to cyanobacterial cells causes changes in antioxidant and detoxification enzymes and that GPx and GST gene expression are good markers of these alterations in tilapia.
Ecotoxicology 03/2011; 20(2):479-90. · 2.36 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Titanium and its alloys have many applications in dentistry, being used in orthodontics, endodontics, prosthetics and implantology. But the use in the biomedical field depends on its biocompatibility, as the Council Directive 93/42/EEC of 14 June 1993 concerning medical devices has established. The aim of this study was to investigate the cytotoxicity and genotoxicity of a commercial titanium/aluminium/vanadium alloy (Ti-6Al-4V) developed by an innovative sand-blast process with aluminium oxide, and nitric-acid passivation. This procedure created a material with an average surface roughness of 1.73±0.16μm with applications in dental implants. International Organization for Standardization (ISO) procedures 7405:2008 and 10993-5:2009 were used to perform the cytotoxicity tests, and bacterial and cell-mutation assays to evaluate genotoxicity. The results show that this titanium alloy (Ti-6Al-4V) was neither cytotoxic nor genotoxic in any of the tests performed. It can be concluded that this new Ti-6Al-4V material with the roughness characteristics specified shows good biocompatibility and can be considered of choice in dental implantology.
Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis 09/2010; 702(1):17-23. · 2.85 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Cyanobacterial blooms are a worldwide problem due to the production of cyanotoxins such as microcystins (MCs), causing serious water pollution and public health hazard to humans and livestock. Oxidative stress plays a significant role in MCs toxicity. In the present work the differential oxidative stress responses to pure MCs, and Microcystin-containing and non-containing cyanobacterial crude extracts on the human colon carcinoma cell line Caco-2 has been studied for the first time. After exposure, cells were collected and the antioxidant enzymes activities superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione-S-transferase (GST) were measured. Moreover, lipid peroxidation (LPO) induction, reactive oxygen species (ROS) and reduced glutathione (GSH) content were also analyzed. The oxidative stress biomarkers that experienced higher alterations were ROS, CAT, SOD and GR activities. The MC containing cyanobacterial extract showed the higher toxic effects, followed by pure MC-LR. The non-MC containing cyanobacterial extract showed limited effects mainly in SOD activity, GSH content, and GP and GR activities only at the highest concentration used. These results suggest that MC-LR is the responsible of the oxidative stress responses observed in Caco-2 cells, but other compounds contained in the cyanobacterial extracts can contribute to the toxic effects.
Toxicon 10/2009; 55(2-3):514-22. · 2.51 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Increasing evidences suggest that oxidative stress may play a significant role in microcystins (MCs) toxicity not only in mammals, but also in fish. In this regard, many in vivo studies have been performed but little is still known about the alteration of oxidative stress biomarkers on fish cell lines so far. In this study, the toxic effects of MC-LR were investigated in the fish cell line PLHC-1, derived from a hepatocellular carninoma of the topminnow Poeciliosis lucida, after 48 h of exposure. The different response of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione-S-transferase (GST), as well as lipid peroxidation (LPO) as a biomarker of oxygen-mediated toxicity, were assessed in PLHC-1 cells. The increases in the antioxidant enzymatic activities (SOD, GPx, and GST) as well as in LPO values observed evidenced the oxidative stress induced by MC-LR exposure. Moreover, the enhancements of these enzymes could suggest an adaptative response to combat oxidative injure induced by MC-LR, confirming that this mechanism is involved in the damage induced by MCs on fish cells.
Toxicology in Vitro 09/2009; 23(8):1445-9. · 2.78 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The unique properties of carbon nanotubes (CNTs) have been explored for their use in biomedical sciences and in biotechnological fields; however, their possible toxic effects are of concern. The sources of human exposure to nanomaterials include inhalation, ingestion, dermal contact and injection. The pulmonary and dermal effects of CNTs in vitro have been previously studied with contradictory results, but data on intestinal cells are scarce. The aim of this study was to evaluate the cytotoxicity of single wall CNTs functionalized with carboxylic acid on differentiated and non-differentiated Caco-2 cells, derived from a human intestinal adenocarcinoma. Biomarkers assessed were neutral red uptake (NR), protein content (PT), a tetrazolium salt (MTS) metabolization, LDH leakage (LDH) and cell viability by means of the trypan blue exclusion test (TBET). Moreover, a morphological study was performed. Cells were exposed to concentrations between 5 and 1,000 microg/ml CNTs and toxic effects were studied after 24h of exposure. NR and MTS results showed a concentration-dependent trend with an inhibitory response from 100 microg/ml CNT, together with an increase in LDH leakage. TBET resulted in an 80% reduction at higher concentrations, and finally PT was only modified at higher concentrations. Overall, results indicated cytotoxic effects on the Caco-2 cells with differentiated cultures showing a higher sensitivity. Thus, a hazard assessment of CNTs is necessary as the nanotechnology industry grows, and more nanoscale wastes are released into the environment.
Toxicology in Vitro 08/2009; 23(8):1491-6. · 2.78 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Fish can be exposed to toxic cyanobacterial cells in natural waters and fish farms and suffer from oxidative damage. The present study investigates the effects of N-acetylcysteine (NAC), a glutathione (GSH) precursor, on the oxidative stress induced by Microcystis cyanobacterial cells containing microcystins (MCs) in tilapia fish (Oreochromis niloticus). Variation in lipid peroxidation (LPO) levels, carbonyl group content, reduced glutathione to oxidized glutathione ratio (GSH:GSSG), and catalase (Enzyme Commission [EC] 1.11.1.6), superoxide dismutase (SOD; EC 1.15.1.1), glutathione reductase (GR; EC 1.8.1.7), glutathione peroxidase (GPx; EC 1.11.1.9), and glutathione S-transferase (EC 2.5.1.18) activities in liver and kidney of tilapia exposed to a single oral dose of 120 microg MC-LR (with leucine [L] and arginine [R])/fish and killed in 24 h were investigated in the absence and presence of 20.0, 44.0, and 96.8 mg NAC/fish/d. Results showed a protective role of NAC, depending on the dose and the biomarker considered. The increase in LPO (1.9- and 1.4-fold in liver and kidney, respectively) and the decreased protein content and GSH: GSSG in the liver induced by MCs were recovered mainly by the lower doses of NAC employed. Antioxidant enzyme activities increased (range, 1.4- to 1.7-fold) by MCs also were ameliorated by NAC, although the highest level used induced significant alteration of some enzymatic activities, such as SOD, GPx, and GR. Thus, NAC can be considered to be a useful chemoprotectant that reduces hepatic and renal oxidative stress in the prophylaxis and treatment of MC-related intoxications in fish when careful attention is given to its application dose because of its own pro-oxidant activity, as shown in the present study at 96.8 mg NAC/fish/d.
Environmental Toxicology and Chemistry 04/2009; 28(8):1679-86. · 2.81 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The present study investigates the role of selenium (Se) supplementation (as sodium selenite) on the oxidative stress and histopathological changes induced by cyanobacterial cells containing microcystins (MCs) in tilapia fish (Oreochromis niloticus). Variation in lipid peroxidation (LPO) levels and carbonyl groups content, reduced glutathione/oxidized glutathione (GSH/GSSG) ratio, and catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GR), glutathione peroxidase (GPx) and glutathione S-transferase (GST) activities in liver and kidney of tilapia fish exposed to a single oral dose of 120 microg MC-LR/fish and sacrificed in 24 h, were investigated in the absence and presence of 1.5, 3.0 and 6.0 microg Se/g diet. Results showed a protective role of Se depending on the dose and the biomarker considered. Thus, the lower Se dose made CAT, liver GR and kidney SOD converged to basal values, whereas LPO and liver SOD and GST needed the higher dose. Kidney GR, however, was not protected at any Se dose. Moreover, Se has also shown to have a pro-oxidant effect with increased kidney LPO values and liver and kidney GPx activities in MC-free fish. The microscopic study revealed tissue alterations induced by cyanobacterial cells in the liver, kidney, heart and gastrointestinal tract that were ameliorated by the highest Se dose assayed. The level of Se supplementation must be therefore carefully selected to provide beneficial effects and to avoid potential negative consequences.
Toxicon 01/2009; 53(2):269-82. · 2.51 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Microcystins (MCs) are potent hepatotoxins produced by cyanobacteria in water systems that induce oxidative stress in fish. The present study investigated the effect of vitamin E pretreatment on MC-induced oxidative damage in the liver, kidneys, and gills of tilapia fish (Oreochromis niloticus). Groups of fish were fed vitamin E supplements (200 or 700 mg per kilogram of diet) for 7 d or received only commercial fish food and then were exposed to a single oral dose of cyanobacterial cells (120 microg of MC-LR [2:Leu, 4:Arg] per fish), and were sacrificed in 24 h. The potential benefits of vitamin E were evaluated based on lipid peroxidation (LPO), protein oxidation, catalase (CAT, Enzyme Commission [EC] 1.11.1.6), superoxide dismutase (EC 1.15.1.1), glutathione peroxidase (EC 1.11.1.9), glutathione reductase (EC 1.8.1.7), and the ratio of reduced glutathione to oxidized glutathione (GSH/GSSG). Microcystins induced a 1.6-fold increase in LPO values in liver, whereas vitamin E-pretreated fish showed no alteration on this biomarker. Enzyme activities levels were also ameliorated by the chemoprotectant, whereas protein oxidation and GSH/GSSG did not show any significant change. The higher vitamin E dose used proved to have the greater protective effects, particularly on the biomarkers LPO and CAT. The results show that vitamin E could have a potential use as a preventive or therapeutic measure in MC-exposed fish.
Environmental Toxicology and Chemistry 06/2008; 27(5):1152-9. · 2.81 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Microcystins (MC) are frequently present in cyanobacterial blooms in rivers and lakes, increasing the risk of toxicity to both animals and humans. There more than eighty reported microcystins, and the present study was undertaken to determine whether MC-LR and MC-RR can induce different enzyme alterations and histopathological changes in tilapia fish (Oreochromis sp.) exposed to a single intraperitoneal (i.p.) injection of the pure standards (MC-LR and MC-RR) at a dose of 500 mug/kg; the tilapia fish were then observed for seven days. The two MC variants caused significant changes in the activities of acid and alkaline phosphatases (ACP and ALP) in vital organs, showing a different response pattern. The livers and kidneys of fish injected with MC-LR were particularly affected. MC-RR induced a very pronounced increase of ACP in the kidney and a significant increase of ALP in the liver. Both MC variants caused pathological lesions in hepatic tissues, such as megalocytosis, necrotic process, and microvesicular steatosis, particularly in fish treated with MC-LR, and degenerative renal changes, glomerulopathy, were more severe in tilapias exposed to MC-RR. In addition, both microcystins also caused significant myopathy in the heart. In contrast, the gills did not show any change in enzyme activity or histopathological injury.
Toxicologic Pathology 02/2008; 36(3):449-58. · 1.91 Impact Factor
