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The effect of peroral administration of toxic cyanobacteria on laboratory rats (Rattus norvegicus var. alba).

Adamovsky O, Kopp R, Zikova A, Blaha L, Kohoutek J, Ondrackova P, Paskerova H, Mares J, Palikova M.

Evaluation Studies 2011; 32(Suppl 1): 35-45 PubMed PMID: 22167221 Keywords: Administration, Oral, Animals, Animals, Laboratory, Bacterial Toxins:pharmacology, Cyanobacteria:pathogenicity, Eating:physiology, Fish Products:toxicity, Food Contamination, Glutathione:metabolism, Lipid Peroxidation:drug effects, Male, Marine Toxins:pha.

OBJECTIVES: The toxic cyanobacteria are a serious problem for water supply systems, recreation, and agriculture. Cyanobacteria produce numerous bioactive compounds including microcystins - the most studied cyanobacterial hepatotoxins. Only rare studies addressed realistic situation, i.e. impact of MCs accumulated in the fish tissues on the overall physiology. The aim of the present study was to provide a model simulation of the simple food chain for evaluation of impacts of cyanobacteria on the rat physiology under different exposure scenario.

METHODS: Experimental rats were fed with food with fish meat, which contained external additions of isolated microcystins as well as toxic cyanobacteria Microcystis, nontoxic cyanobacteria Arthrospira and green alga Chlorella. Subgroups of the animals were also challenged with a model antigen KLH to investigated immune-related parameters. We studied parameters of oxidative stress in the liver as levels of lipid peroxidation and glutathion levels. Series of hematological, biochemical and immunological parameters were also investigated.

RESULTS: Although considerable amounts of microcystins were administered to rats, all levels of MCs were under the detection limit (1 ng/g fresh weight) in the rat tissues using tandem LC/MS. Only some conjugates of microcystins with cystein and glutathion were detected in the rat liver exposed to Microcystis biomass (values were around the detection limit). Statistically significant depletion of body and liver weight was observed in groups with microcystin addition in comparison with all other groups. Rats exposed to MCs had stimulated immune system (showed higher antibody answer on administered antigen). Also modulation of some lymphocyte subpopulations was recorded with the most interesting observation of stimulated NK cell numbers in groups exposed to isolated toxins (but not to biomass containing the same toxin amount).

CONCLUSIONS: Our study demonstrates that oral exposure to microcystins in the diet may induce some detoxification responses and modulation of some hematological and immunological parameters....

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Carnosine inhibits degradation of hyaluronan induced by free radical processes in vitro and improves the redox imbalance in adjuvant arthritis in vivo.

Drafi F, Bauerova K, Valachova K, Ponist S, Mihalova D, Juranek I, Boldyrev A, Hrabarova E, Soltes L.

Journal Article 2010; 31(Suppl 2): 96-100 PubMed PMID: 21187837 Keywords: Animals, Antioxidants:pharmacology, Antirheumatic Agents:pharmacology, Arthritis, Experimental:drug therapy, Carnosine:pharmacology, Disease Models, Animal, Free Radicals, Glutathione:metabolism, Hyaluronic Acid:metabolism, In Vitro Techniques, Male, Meth.

OBJECTIVE: New ways of supplementary or combinatory therapy of rheumatoid arthritis (RA) are of great importance. The aim is to find an additive to classical RA therapy with natural molecules without side effects possessing anti-inflammatory and anti-oxidative properties. In this study we investigated the anti-oxidative and anti-inflammatory properties of the endogenous natural compound carnosine (CARN) in vitro and in vivo. Moreover, we tested also the inhibitory properties of the drug methotrexate (MTX) on dynamic viscosity of hyaluronan (HA) solutions in the same manner.

METHODS: For in vitro testing of the inhibitory properties of CARN against degradation of HA solutions, we used the model of degradation of hyaluronan (HA) induced by free radicals. Both substances, CARN and MTX, were compared to glutathione (GSH). Rotational viscometry was used in evaluation of protective properties of compounds studied. The ability of CARN to restore the redox imbalance occurring in adjuvant arthritis (AA) of rats was also tested. We monitored the effect of CARN on hind paw volume (HPV) and on the levels of protein carbonyls, and thiobarbituric acid reacting substances (TBARS) in AA.

RESULTS: In the reaction system with the prevalence of •OH and/or peroxy-type radicals, CARN in 200 μmol/L concentration tested was shown to exert a protective action on HA degradation. MTX was less effective than CARN in preventing HA degradation. Its ability to protect HA against radical degradation was evident only at the highest concentration of 400 μmol/L. In AA, carnosine significantly reduced TBARS and protein carbonyls in plasma, and also decreased the HPV of animals most effectively on the day 14.

CONCLUSIONS: CARN proved its inhibitory properties against degradation of HA solutions at experimental conditions in vitro and showed its beneficial efficiency in vivo. Moreover, it reduced also HPV, the clinical marker of inflammation in AA....

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Effects of subchronic exposure to Spartakus (prochloraz) on common carp Cyprinus carpio.

Haluzova I, Modra H, Blahova J, Marsalek P, Siroka Z, Groch L, Svobodova Z.

Journal Article 2010; 31(Suppl 2): 105-113 PubMed PMID: 21187831 Keywords: Animals, Carps:metabolism, Ceruloplasmin:metabolism, Cytochrome P-450 CYP1A1:metabolism, Cytochrome P-450 Enzyme System:metabolism, Dose-Response Relationship, Drug, Fungicides, Industrial:pharmacology, Gills:drug effects, Glutathione:metabolism, Glutathi.

OBJECTIVES: The aim of the study was to investigate effects of the fungicide formulation Spartakus (prochloraz 450 g.L-1) on common carp Cyprinus carpio through biometric, biochemical, haematological and antioxidant indices, induction of xenobiotic metabolizing enzymes and histological examination of selected tissues.

DESIGN: The test was performed on juvenile fish, which was exposed to Spartakus (concentrations of prochloraz: 0.05; 0.15 and 0.38 mg.L-1) for 28 days. Haematological indices were assessed using unified methods of haematological examination in fish. Plasma biochemical indices were determined by biochemical analyzer. Concentration of total cytochrome P450 (CYP), glutathione (GSH) content and glutathione-S-transferase (GST) activity were determined spectrophotometrically in hepatopancreas. Activity of liver ethoxyresorufin-O-deethylase (EROD) activity was measured spectrofluorimetrically. Ferric reducing ability of plasma (FRAP) and ceruloplasmin activity were assessed spectrophotometrically. Histological changes in samples of hepatopancreas, skin, gills, spleen, head kidney and caudal kidney were examined by light microscopy.

RESULTS: There was a significant rise in hepatosomatic index (HSI) (p<0.01), CYP and EROD (p<0.05) of fish exposed to prochloraz of 0.15 and 0.38 mg.L-1 whereas GST was induced by all concentrations tested and GSH by 0.38 mg.L-1 (p<0.05). Red blood cell count decreased significantly (p<0.05) in prochloraz of 0.05 and 0.15 mg.L-1. Plasma potassium increased (p<0.01) in all Spartakus treated groups, a decline in total protein (p<0.05), ALT, Na+ and Ca (p<0.01) was found in fish exposed to prochloraz of 0.38 mg.L-1. Ceruloplasmin activity was elevated (p<0.05) in the highest concentration tested, FRAP declined (p<0.05) in the same group. Histopathological changes in gills were demonstrated in all pesticide treated groups, with a decreased activity of skin mucous cells in prochloraz of 0.38 mg.L-1.

CONCLUSION: The subchronic exposure to Spartakus influenced HSI, induced xenobitic metabolizing enzymes, initiated a disorder of selected plasma indices and a decline in red blood cell count, caused minor histological impairment, and affected antioxidant activities of the test fish....

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Effect of metals, with special attention of Cd, content of the Svitava and Svratka rivers on levels of thiol compounds in fish liver and their use as biochemical markers.

Kovarova J, Celechovska O, Kizek R, Adam V, Harustiakova D, Svobodova Z.

Journal Article 2009; 30(Suppl 1): 169-176 PubMed PMID: 20027166 Keywords: Animals, Biomarkers:analysis, Cadmium:analysis, Cyprinidae:metabolism, Cysteine:metabolism, Czech Republic, Glutathione:metabolism, Liver:chemistry, Metals:analysis, Rivers:chemistry, Spectrophotometry, Atomic, Sulfhydryl Compounds:analysis,.

OBJECTIVES: The aim of this study was to assess the effect of metals, with special attention of cadmium (Cd), content of the Svitava and Svratka rivers (Czech Republic) on levels of thiol compounds such as metallothioneins (MT), glutathione (GSH/GSSG), and cysteine (Cys) concentrations in chub (Leuciscus cephalus L.) liver and their use as biomarkers.

DESIGN: Levels of thiol compounds in fish liver were determined by the differential pulse voltammetry Brdicka reaction. Cadmium content in L. cephalus liver was measured by atomic absorption spectometry (AAS) with electrothermal atomization. The contents of thiols and Cd were correlated with the Cd and metals content of river bottom sediments.

RESULTS: Results were inconsistent with those of experimental studies. Correlations between liver Cd content and MT, Cys, GSSG were not significant in any locality (p > 0.05). Cd liver content was negatively (p< 0.05) correlated with GSH at one (Zidlochovice) of the seven tested sites. GSH and GSSG correlated negatively in five localities (p > 0.05). Correlations between Cd in sediment and Cys and GSSG (p > 0.05), and MT was negative (p< 0.05). The relationship between sum of metals value and MT was negative (p< 0.05), similarly with GSSG (p > 0.05).

CONCLUSION: Many factors influence content of MT, GSH, and GSSG, and data for Cd were equivocal. Monitoring the aquatic ecosystem to identify metal content using thiol compounds in fish liver as biomarkers is complex. More relevant data including laboratory experiments will be required to assess most of the factors influencing thiols and their relevance to Cd contamination....

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The effect of melatonin on glutathione and glutathione transferase and glutathione peroxidase activities in the mouse liver and kidney in vivo.

Swiderska-Kołacz G, Klusek J, Kołataj A.

Comparative Study 2006; 27(3): 365-368 PubMed PMID: 16816830 Keywords: Animals, Female, Glutathione:metabolism, Glutathione Peroxidase:metabolism, Glutathione Transferase:metabolism, Kidney:enzymology, Liver:enzymology, Male, Melatonin:physiology, Mice, Random Allocation,.

OBJECTIVES: The changes in reduced glutathione (GSH), activity of glutathione transferase (GST) and glutathione peroxidase (GSPx) after administration of exogenous melatonin (N-acetyl-5-methoxy-tryptamine) at a dose 20 mg/kg b.w. were investigated for five and ten days in the liver and kidney of male and female mice.

METHODS: The liver and kidney were homogenized in 0.1 M phosphate buffer. Glutathione level and activity of studied glutathione enzymes were determined in the supernatants.

RESULTS: Melatonin caused an increase in glutathione level, the activity of glutathione peroxidase as well as glutathione transferase in the examined organs.

CONCLUSION: Melatonin may exert some effects on the activity of enzymes engaged in the metabolism of thiol compounds in the cell. Glutathione may be useful for monitoring melatonin's protective role on cell damage....

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Pinealectomy inhibits antioxidant system in rats with hyperthyroidism.

Mogulkoc R, Baltaci A, Aydin L, Oztekin E, Sivrikaya A.

Comparative Study 2005; 26(6): 795-798 PubMed PMID: 16380688 Keywords: Animals, Antioxidants:metabolism, Brain:enzymology, Glutathione:metabolism, Hyperthyroidism:metabolism, Lipid Peroxidation:physiology, Liver:enzymology, Male, Malondialdehyde:metabolism, Myocardium:enzymology, Pineal Gland:physiology, Rats, Rats, Sprague-.

OBJECTIVE: Thyroid hormones regulate energy metabolism and act on the mitochondria, which is an important source of free radicals in the cell. Reactive oxygen types play a significant role in physiological mechanisms, but in excessive amounts they can cause oxidative damage in molecules. The aim of the present study was to determine levels of lipid peroxidation caused by induced hyperthyroidism in cerebral, hepatic and cardiac tissues of pinealectomized rats.

METHODS: Experimental animals used in the study were allocated to three groups as general control group, hyperthyroidism-sham pinealectomy group and hyperthyroidism-pinealectomy group. GSH and MDA levels in cerebral, hepatic and cardiac tissues were evaluated at the end of the 3-week study period.

RESULTS: It was found that MDA levels in cerebral, hepatic and cardiac tissues were the highest in hyperthyroidism and pinealectomy group and that these values were higher in hyperthyroidism-sham pinealectomy group than in the control group (p<0.001). It was seen that tissue GSH levels significantly increased in hyperthyroidism-sham pinealectomy group (p<0.001) and that the increase in hyperthyroidism and pinealectomy group was higher than the increase in the control group only (p<0.001).

CONCLUSION: Results of our study show that MDA and GSH levels in cerebral, hepatic and cardiac tissues increased due to hyperthyroidism and that the increase in MDA levels became more evident and GSH levels were significantly suppressed after pinealectomy....

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Hyperthyroidism causes lipid peroxidation in kidney and testis tissues of rats: protective role of melatonin.

Mogulkoc R, Baltaci A, Oztekin E, Aydin L, Tuncer I.

Comparative Study 2005; 26(6): 806-810 PubMed PMID: 16380687 Keywords: Animals, Glutathione:metabolism, Hyperthyroidism:chemically induced, Kidney:metabolism, Lipid Peroxidation, Male, Malondialdehyde:metabolism, Melatonin:metabolism, Oxidative Stress:physiology, Rats, Rats, Sprague-Dawley, Testis:metabolism, Thyroxine,.

OBJECTIVE: The present study aimed at determining how 3-week intraperitoneal melatonin administration affected oxidative stress caused by experimental hyperthyroidism.

MATERIALS AND METHODS: The study was conducted on 30 male rats of Sprague-Dawley species. The experimental animals were divided to 3 groups (control, hyperthyroidism and hyperthyroidism+melatonin). The supplementation was continued for 3 weeks after which the animals were sacrificed and tissue malondyaldehyde (MDA) and glutathione (GSH) levels were determined.

RESULTS: MDA levels in kidney and testis tissues in hyperthyroidism group were higher than those in control and hyperthyroidism+melatonin administered groups (p<0.001) and levels in hyperthyroidism+melatonin administered group were higher than those in the control group (p<0.001). The highest GSH levels were obtained in hyperthyroidism+melatonin-administered group (p<0.001) and GSH levels in hyperthyroidism group were higher than those in the control group (p<0.001).

CONCLUSION: Results of the study demonstrate that hyperthyroidism induced by 3-week L-thyroxine administration increased oxidative stress in kidney and testis tissues and that although melatonin administration inhibited this stress to a certain extent, it could not bring the stress down to the level in controls....

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Aflatoxin B1 induces apoptosis in rat liver: protective effect of melatonin.

Meki A, Abdel-Ghaffar S, El-Gibaly I.

Journal Article 2001; 22(6): 417-426 PubMed PMID: 11781538 Keywords: Aflatoxin B1:toxicity, Animals, Antioxidants:pharmacology, Apoptosis:drug effects, Caspase 3, Caspases:metabolism, Glutathione:metabolism, Glutathione Peroxidase:metabolism, Glutathione Reductase:metabolism, Glutathione Transferase:metabolism, Lipid Perox.

OBJECTIVES: A study of liver apoptosis after aflatoxin B1 (AFB1) administration and the effect of melatonin (MEL) was investigated in male rats.

METHODS: Five groups of 15 rats each were used: controls, MEL Soln-treated rats (MEL dose,5 mg/Kg body wt), AFB1-treated rats (50 microg/Kg body wt), MEL Soln+AFB1-treated rats, and MEL micro-capsules (MEL-MC)+ AFB1-treated rats. After 8 weeks of treatment, biochemical measurements in liver homogenates and histopathological examination of liver sections of different groups using light and transmission electron microscope were done. The caspase-3 enzyme activity, apoptotic marker, was determined in liver tissues. Because hepatic antioxidants represent the major defence against toxic liver injury, and they act as anti-apoptosis. So, the levels of glutathione (GSH) and zinc (Zn) and the enzyme activities of glutathione reductase (GR), glutathione peroxidase (GSPx) and glutathione-S-transferase (GST) were determined. In addition, the levels of malondialdehyde (MDA), a lipid peroxidation product, and nitric oxide (NO) levels were measured.

RESULTS: The levels of caspase-3 activities in AFB1 group were significantly higher than control group. The apoptosis was associated with degenerative and necrotic changes in the hepatocytes. Concomitantly, the levels of MDA and NO in liver tissues were significantly increased while the levels of GSH, Zn and enzyme activities of GSPx and GR in liver tissues were significantly decreased in AFB1 group compared to their levels in controls. Caspase-3 activity was positively correlated with MDA while negatively correlated with GSH, GSPx and GR in rat livers treated with AFB1. The apoptotic rate was significantly reduced when MEL co-administrated with AFB1. In rats which received MEL with AFB1, the levels of MDA and NO in liver tissues were significantly reduced while GSH and Zn levels and GSPx, GR and GST activities were significantly increased compared to AFB1 group. When MEL-MC co-administrated with AFB1 appeared more effective in reduction of apoptotic rate as detected by decline of caspase-3 activities (inhibition 66.82%) and confirmed by histopathology.

CONCLUSION: AFB1 can lead to direct or indirect caspase-3 activation and consequently to apoptosis in rat liver. MEL treatment of rats could enhance hepatic antioxidant/detoxification system which consequently reduce the apoptotic rate and the necrobiotic changes in the liver. MEL-MC exhibited an efficient protective effect against AFB1. Thus, clinical application of MEL as therapy should be considered in cases of aflatoxicosis....

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