Diazoxide attenuates DOX-induced cardiotoxicity in cultured rat myocytes.

Doxorubicin (DOX)-induced cardiotoxicity is a well known clinical problem, and many investigations have been made of its possible amelioration. We have investigated whether diazoxide (DIA), an agonist at mitochondrial ATP-sensitive potassium channels (mitoKATP), could reverse DOX-induced apoptotic myocardial cell loss, in cultured rat cardiomyocytes. The role of certain proteins in this pathway was also studied. The rat cardiomyocyte cell line (H9c2) was treated with DOX, and also co-treated with DOX and DIA, for 24 h. Distribution of actin filaments, mitochondrial membrane potential, superoxide dismutase (SOD) activity, total oxidant and antioxidant status (TOS and TAS, respectively), and some protein expressions, were assessed. DOX significantly decreased SOD activity, increased ERK1/2 protein levels, and depolarised the mitochondrial membrane, while DIA co-treatment inhibited such changes. DIA co-treatment ameliorated DOX-induced cytoskeletal changes via F-actin distribution and mitoKATP structure. Co-treatment also decreased ERK1/2 and cytochrome c protein levels. Cardiomyocyte loss due to oxidative stress-mediated apoptosis is a key event in DOX-induced cytotoxicity. DIA had protective effects on DOX-induced cardiotoxicity, via mitoKATP integrity, especially with elevated SUR2A levels; but also by a cascade including SOD/AMPK/ERK1/2. Therefore, DIA may be considered a candidate agent for protecting cardiomyocytes against DOX chemotherapy.

Binary effects of fluoxetine and zinc on the biomarker responses of the non-target model organism Daphnia magna.

The antidepressant effect of zinc on mammals has been documented in recent decades, and the concentration of the antidepressant fluoxetine (FLX) in aquatic environments has been rising constantly. The aim of the present study is to evaluate the combined toxicity of a serotonin reuptake inhibitor (FLX) and Zn2+ on a non-target aquatic model organism Daphnia magna. Animals were exposed to single and binary combinations of FLX (20.5 and 41 µg/L for subchronic and 41 and 82 µg/L for acute exposures) and Zn2+ (40 µg/L for subchronic and 80 µg/L for acute exposures). In vivo experiments were done for 7 days subchronic and 48 h acute exposure, while subcellular supernatants of whole Daphnia lysate (WDL) were directly treated with the same concentrations used in the acute experiments. Morphological characteristics, Ca2+-ATPase, antioxidant enzyme activities, and lipid peroxidation were examined. There was antioxidant system suppression and Ca2+-ATPase inhibition despite the diverse response patterns due to duration, concentration, and toxicant type. After acute exposure, biomarkers showed a diminishing trend compared to subchronic exposure. According to integrated biomarker response index (IBR) analysis, in vivo Zn2+ exposure was reasonably effective on the health of D. magna, whereas exposure of WDL to Zn2+ had a lesser impact. FLX toxicity increased in a concentration-dependent manner, reversed by the combined exposure. We concluded that potential pro-oxidative and adverse Ca2+-ATPase effects of FLX and Zn2+ in D. magna may also have harmful impact on ecosystem levels. Pharmaceutical exposure (FLX) should be considered along with their potential to interact with other toxicants in aquatic biota.

Oxidative and osmoregulatory effects of imidacloprid, cadmium, and their combinations on Daphnia magna.

Oxidative stress and osmoregulatory system damage-inducing potential of binary mixtures of neonicotinoid insecticide imidacloprid (IMI) and Cd2+ in Daphnia magna were evaluated. Animals were subjected to subchronic (7 days) and acute (48 h) of IMI and Cd2+ effects with single and binary mixtures. ATPase and antioxidant enzyme activities with lipid peroxidation were measured. Morphometric characteristics were also evaluated. Response patterns showed variability due to the duration, concentration, and toxicant type. While the enzyme activities mostly showed a decreasing trend upon the subchronic IMI effect, there was an increasing trend after the Cd2+. Declined enzyme activities were more pronounced with the acute higher IMI+Cd2+ exposure. Ca2+-ATPase and CAT were the most sensitive biomarkers in the toxicity response. IMI+Cd2+ exposures are appeared to increase their toxic effects due to their oxidative potential. ATPase inhibition and antioxidant enzyme alterations with a decrease in morphometric characteristics in Daphnia even at their low concentrations of IMI and Cd2+ show evidence of their toxicities on aquatic life. It was emphasized that investigating the combined effects of toxicants at their environmental level based on the multi-biomarker approach is essential in toxicity evaluation.

Sulfoxaflor, Zn2+ and their combinations disrupt the antioxidant and osmoregulatory (Ca2+-ATPase) system in Daphnia magna.

BACKGROUND: The oxidative- and osmoregulatory stress-inducing potential of binary mixtures of sulfoxaflor (SUL), a recently developed sulfoximine insecticide, and Zn2+ was aimed to evaluate in Daphnia magna with different exposure regimes. METHODS: Animals were exposed to different SUL concentrations (1.25, 2.5, 10, and 25 mg/L) for 7 days. In vivo 48 h and in vitro effects of single and binary mixtures of SUL (25 and 50 mg/L) and Zn2+ (40 µg/L) were also determined. Furthermore, Ca2+-ATPase, oxidative stress biomarkers (catalase, CAT; superoxide dismutase, SOD; glutathione peroxidase, GPX; glutathione S-transferase, GST; reduced glutathione, GSH; thiobarbituric acid reactive substances, TBARS), and morphometric characteristics were measured. RESULTS: Variable response patterns were observed due to exposure duration and regime, toxicant type, and concentration. Marked effects of SUL were observed, especially in subacute exposure, and 25 mg/L SUL concentration can be considered as a threshold level. Stimulation of GST activity was the most typical response, followed by declined SOD activity and GSH levels. GPX activity and TBARS levels responded differently depending upon the exposure type. Subacute and in vitro effects of SUL and Zn2+ produced similar responses except for some cases. Ca2+-ATPase activity was altered differently upon subchronic duration, though inhibited by in vitro SUL+Zn effect. Subchronic SUL exposure increased body weight and length up to 25 mg/L, contrary to the observed decrease at higher concentrations. CONCLUSIONS: Single and binary mixtures of SUL and Zn2+ caused damage to the antioxidant and osmoregulatory system due to their oxidative potential on cellular targets (biomarkers). The current data emphasized that investigating the SUL toxicity with the Zn2+ combination based on the multi-biomarker approach is essential in the realistic evaluation of SUL toxicity in toxicological research.

Effects of Different Ammonia Levels on Tribenuron Methyl Toxicity in Daphnia magna.

The present study investigates the toxicity of the herbicide tribenuron methyl (TBM) as an anthropogenic agent and ammonia as an abiotic factor on Daphnia magna at environmentally relevant concentrations. These stressors may coexist in surface waters in agricultural regions. To achieve this objective, D. magna were exposed to TBM at a nominal concentration of 0.81 µg/L in association with a low ammonia (LA) concentration of 0.65 mg/L and a high ammonia (HA) concentration of 1.61 mg/L in acute toxicity tests of 96-h duration and chronic toxicity tests of 21-day duration. The D. magna also were exposed to TBM, HA, and LA singly. The D. magna were analysed for various biomarkers of sublethal toxicity. Glutathione peroxidase (GPx), glutathione S-transferase (GST), cholinesterase (ChE) enzyme activities, and levels of thiobarbituric acid reactive substances (TBARS) and total protein were determined spectrophotometrically. Mitochondrial membrane potential (MMP) was analysed by microscopy with fluorescence staining. Cytochrome c and 5' AMP-activated protein kinase (AMPK) were analysed by Western blotting. Morphometric properties were examined microscopically. This is the first study in which AMPK, an indicator of intracellular energy, was measured in D. magna. GST and ChE enzyme activities and TBARS and total protein levels did not change during acute exposures (i.e., 96 h) in all treatments. GPx activity increased in D. magna from the HA + TBM treatment compared with single-exposure groups. The level of cytochrome c protein was elevated in D. magna from the LA and LA + TBM treatments. AMPK protein levels increased in all treatments with daphnids, except in the LA group. MMP was depolarised in D. magna from all treatments, whereas the most notable change was observed in HA + TBM mixture group in chronic exposures. The results show that GST and ChE may not be sensitive biomarkers for evaluating the sublethal toxic effects to D. magna exposed to environmentally relevant concentrations of ammonia and TBM. Acute and chronic exposure to ammonia and TBM probably caused an energetic crisis in D. magna. Therefore, AMPK and MMP are promising biomarkers for these toxicants.

Chemical and biological characteristics of propolis from Apis mellifera caucasica from the Ardahan and Erzurum provinces of Turkey: a comparative study.

The aim of this study was to compare the biological activities of ethanolic propolis extracts of Apis mellifera caucasica obtained from Ardahan and Erzurum provinces of Turkey. Samples were tested for antioxidant, anticytotoxic, anticarcinogenic, antibacterial, and antifungal potentials using different techniques. Propolis samples from the two provinces had different mineral and organic compositions related to their geographical origin. The ferric reducing antioxidant power (FRAP) test showed superiority of Ardahan propolis over the Erzurum. Regardless of origin and the presence of mitomycin C in the culture medium, propolis enhanced human peripheral lymphocyte viability, which depended on the duration and propolis concentration. Antiperoxidative activity on MCF-7 breast cancer cells was concentration-dependent. Erzurum propolis showed the highest anticarcinogenic activity at the concentrations of 62.5 µg/mL and 125 µg/ mL, which dropped at higher concentrations. All propolis samples also showed antibacterial activity against the tested human pathogens similar to ampicillin and penicillin controls, except for Pseudomonas aeruginosa. However, they did not exert any antifungal activity against Candida albicans and Yarrowia lipolytica. In conclusion, propolis samples from both provinces showed promising biological activities, but further research should focus on finding the right concentrations for optimal effect and include the cell necrosis pathway to get a better idea of the anticarcinogenic effects.

Oxidative and apoptotic effects of fluoxetine and its metabolite norfluoxetine in Daphnia magna.

The aim of this study was to investigate the oxidative and apoptotic potential of fluoxetine, a widely used antidepressant in Turkey and the world, and of its metabolite norfluoxetine on a model non-target organism, Daphnia magna to see how exposure to this group of antidepressants (specific serotonin reuptake inhibitors) could affect the aquatic environment in which they end up. Juvenile D. magna specimens were chronically exposed to fluoxetine and norfluoxetine alone and in combination at concentrations found in the aquatic environment (0.091 and 0.011 µg/L, respectively) and to their 10-fold environmental concentrations for 21 days. Another group of 17-day-old animals were subacutely exposed to 100-fold environmental concentrations for four days. After exposure, we measured their glutathione peroxidase (GPx) and cholinesterase (ChE) activities, thiobarbituric acid-reactive substances (TBARS), and total protein content spectrophotometrically, while mitochondrial membrane potential (MMP) was analysed by fluorescence staining, and cytochrome c and ERK1/2 protein content by Western blotting. This is the first-time cytochrome c and ERK1/2 were determined at the protein level in D. magna. We also measured their carapace length, width, and caudal spine length microscopically. At environmental concentrations fluoxetine and norfluoxetine caused an increase in ChE activity and brood production. They also caused a decrease in juvenile carapace length, width, and caudal spine length and depolarised the mitochondrial membrane. At 10-fold environmental concentrations, GPx activity, lipid peroxidation levels, cytochrome c, and ERK1/2 protein levels rose. The most pronounced effect was observed in D. magna exposed to norfluoxetine. Norfluoxetine also decreased brood production. Similar effects were observed with subacute exposure to 100-fold environmental concentrations. However, total protein content decreased. All this confirms that fluoxetine and norfluoxetine have oxidative and apoptotic potential in D. magna. Daphnia spp. have a great potential to give us precious insight into the mechanisms of environmental toxicants, but there is still a long way to go before they are clarified in these organisms.

Silencing HMGB1 expression inhibits adriamycin's heart toxicity via TLR4 dependent manner through MAPK signal transduction.

PURPOSE: Adriamycin (ADR) is a commonly used anti-cancer drug. ADR has toxic effects on cardiomyocytes and leads to heart failure. However, the underlying mechanism(s) by which ADR causes heart failure is still not clarified exactly. The aim of present study is to investigate whether ADR-induced heart failure is mediated via HMGB1/TLR4 to initiate the apoptosis through MAPK/AMPK pathways. METHODS: H9c2 cell line was used to create four groups as a control, HMGB1 inhibition, ADR, ADR+HMGB1 inhibition. Silencing HMGB1 was performed with specific small interfering RNA. ADR was used at 2 µM concentration for 36 and 48 hours. Protein and genes expressions, apoptosis was measured. RESULTS: Although ADR decreased AMPK, pAMPK, ERK1/2, pERK1/2, p38, JNK protein expression, ADR+HMGB1 inhibition led to change those protein expressions. The effect of silencing of HMGB1 prevented apoptosis induced by ADR in the cells. HMGB1 caused changes a kind of posttranscriptional modification on the TLR4 receptor. This posttranscriptional modification of TLR4 receptor led to decreased AMPK protein level, but phosphorylated-AMPK. This alternation of AMPK protein caused enhancing of JNK protein, resulting from the decline of p38 and ERK protein levels. Eventually, JNK triggered apoptosis by a caspase-dependent pathway. The number of TUNEL positive and active caspase 8 cells at ADR was high, although HMGB1 silencing could decrease the cell numbers. CONCLUSIONS: Inhibition of HMGB1 might prevent the lose of the cardiac cell by inhibition of apoptotic pathway, therefore HMGB1 plays an essential role as amplifying on ADR toxicity on the heart by TLR4.

Concentrations of some heavy metal and macroelements in sediment, water, macrophyte species, and leech (Hirudo sulukii n. sp.) from the Kara Lake, Adiyaman, Turkey.

Content of some heavy metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) and macroelements (Ca, Mg, Na, and K) were determined in samples of water, sediment, macrophytes (Potamogeton crispus, Potamogeton perfoliatus, Myriophyllum spicatum, and Chara vulgaris), and leech (Hirudo sulukii n. sp.) collected from Kara Lake Adiyaman, Turkey at four distinct seasons using inductively coupled plasma optical emission spectrometer (ICP-OES). It was found that the studied heavy metals were completely below the detection limit of ICP-OES for water samples. The results showed that most heavy metals (Ni, Cr, Zn, Fe, and Pb) and macroelements (Mg and Na) had their highest values in sediment samples in August. Increases of heavy metals and macroelements may be due to evaporation because of summer stagnation at this period. The average content of studied elements was in the order of Mn>Ni>Cr>Zn>Fe>Pb>Cu in sediment samples. As a non-essential heavy metal, Cr was the most accumulated in all the macrophytes studied. The average Cr concentration was in the order of P. crispus > P. perfoliatus > M. spicatum > C. vulgaris. In C. vulgaris, the accumulation of Ca was the highest compared with other macrophytes. The accumulation of heavy metal was in the order of Fe>Zn>Cu>Pb>Mn>Cr>Ni>Cd in H. sulukii n. sp. The obtained results showed that the heavy metal and macroelement (Na, Ca, Mg, and K) concentrations in water, sediment, macrophytes, and leech are below the risk values according to the aquatic life pollutant data provided by the U.S. Environmental Protection Agency. Overall, the element contents can be attributable to the geological sources because of the general absence of serious pollution in Kara Lake, Adiyaman, Turkey.

The role of toll-like receptors in the protective effect of melatonin against doxorubicin-induced pancreatic beta cell toxicity.

AIMS: Doxorubicin, an anticancer drug, has a toxic effect on many tissues such as heart, pancreas, liver, kidney, and testis. The aim of current study is to investigate whether melatonin would be protective in doxorubicin-induced beta (ß) cell toxicity via HMGB1/TLR2/TLR4/MAPK/NF-қB signaling pathway. MAIN METHODS: Human pancreatic ß cell (1.1B4) was used in the present study. Four experimental groups were created as control, melatonin (10 µM), doxorubicin (2 µM) and the combination of melatonin with doxorubicin. Following 24-h treatment, Mitogen-activated protein kinase (MAPKs), Toll like receptors (TLRs) including TLR2 and TLR4, pro-and anti-apoptotic protein expression levels were determined by western blotting. Total antioxidant (TAS), oxidant status (TOS) and oxidative stress index (OSI) of the cells as well as superoxide dismutase (SOD) levels were determined. Active caspase-8 activity was measured and TUNEL staining was performed to study apoptotic pathways. Mitochondrial membrane potential (MMP), some protein expressions and F-actin distribution were analyzed. KEY FINDINGS: Doxorubicin caused to depolarize MMP, resulting in enhancing apoptosis by activation of caspase-8 via MAPKs/NF-кB pathway via elevation of TOS and decreasing TAS. Also, doxorubicin destroyed F-actin distribution and elevated TLR2 and some apoptotic proteins, including Bax. However, co-treatment of melatonin with doxorubicin could reverse depolarization of MMP and inhibition of apoptosis through MAPK/NF-кB signaling by decreasing TOS and increasing TAS. The co-treatment reversed the alternations of TLR2, TLR4, MAPKs and apoptotic protein expressions induced by doxorubicin. SIGNIFICANCE: Melatonin could be a good candidate against pancreatic ß cell toxicity-induced by doxorubicin through TLR2/TLR4/MAPK/NF-кB pathways.

Sex-related effects of imidacloprid modulated by piperonyl butoxide and menadione in rats. Part II: genotoxic and cytotoxic potential.

Despite its intended use, imidacloprid causes genotoxic and cytotoxic effects in mammals, especially in the presence of metabolic activation systems. The aim of this study was to determine to which extent these effects are sex related and how its metabolism modulators piperonyl butoxide and menadione affect its toxicity. Male and female Sprague-Dawley rats were injected with the intraperitoneal LD50 dose of imidacloprid alone (170 mg/kg) or pretreated with piperonyl butoxide (100 mg/kg) and menadione (25 mg/kg) for 12 and 24 h. Structural chromosome aberrations, abnormal cells and mitotic index were determined microscopically in bone marrow cells. Male rats showed susceptibility to the genotoxic effects of imidacloprid. Piperonyl butoxide was effective in countering this effect only at 24 h, whereas menadione exacerbated imidacloprid-induced genotoxicity. Piperonyl butoxide and menadione pretreatments increased the percentage of structural chromosome aberrations and abnormal cells in females. Imidacloprid decreased the mitotic index, whereas pretreatment with piperonyl butoxide and menadione showed improvement in both sexes. We believe that CYP450-mediated metabolism of imidacloprid is under the hormonal control and therefore that its genotoxicity is sex related. Piperonyl butoxide pretreatment also showed sex-related modulation. The hormonal effects on imidacloprid biotransformation require further investigation.

A functional HOTAIR rs920778 polymorphism does not contributes to gastric cancer in a Turkish population: a case-control study.

An aberrant up-regulation of HOX transcript antisense intergenic RNA (HOTAIR), a long non-coding RNA (lncRNA), is associated with human cancers including gastric cancer (GC) and worse clinicopathological features. A naturally occurring functional single nucleotide polymorphism (SNP) rs920,778 (C→T) in the intronic enhancer of HOTAIR gene has been demonstrated to affect HOTAIR expression and cancer susceptibility. To investigate the association of the HOTAIR rs920778 polymorphism on the risk of GC susceptibility in Turkish population, a hospital-based case-control study was carried out consisting of 104 GC and 209 healthy control subjects matched on age and gender. The genotype frequency of HOTAIR rs920778 polymorphism was determined by using TaqMan Real-Time Polymerase Chain Reaction. No statistically significant differences were found in the allele or genotype distributions of the HOTAIR rs920778 polymorphism among GC and healthy control subjects (P > 0.05). Our results demonstrate that the HOTAIR rs920778 polymorphism has not been in any major role in genetic susceptibility to gastric carcinogenesis, at least in the population studied here. Independent studies are needed to validate our findings in a larger series, as well as in patients of different ethnic origins.

Comparison of the protective effects of antioxidant compounds in the liver and kidney of Cd- and Cr-exposed common carp.

The aim of this study was to see whether the taurine (TAU), alpha-lipoic acid (LA), curcumin (CUR), and N-acetylcysteine (NAC) protection against oxidative stress caused by heavy metals is owed to the metal-decreasing or antioxidative effect. In this context, liver and kidney tissues of common carp (Cyprinus carpio carpio L.) were exposed in vivo to model toxicants cadmium (Cd) and chromium (Cr). The tissues were dissected 96 h after intraperitoneal injection of the metals and antioxidant substances. Cd and Cr levels were determined in the liver using the ICP-OES, but we could not obtain enough kidney tissue to make the same measurements in the kidney. The enzymatic activities of SOD, CAT, and GPx, and the GSH redox status and lipid peroxidation levels were analyzed using spectrophotometric methods. Of all investigated antioxidants, only NAC decreased metal levels in the liver. Cd had little effect on oxidative stress parameters, while Cr showed a weak prooxidative effect. Cotreatment with TAU/LA/CUR/NAC and Cr significantly increased liver SOD activity. Chromium induced kidney SOD and CAT, but all antioxidants lowered CAT activity. Cadmium reduced liver and increased kidney GSSG. NAC increased liver GSH, but the increase did not correlate with decrease in Cd. Curcumin given with Cd increased kidney and decreased liver lipid peroxidation, whereas TAU with Cr increased lipid peroxidation in both tissues. N-Acetylcysteine was the most effective antioxidative agent, owing to its metal-decreasing function as well as to its effects on the GSH redox status. We believe that the investigated antioxidant substances which may have been involved in the reduction of Cr caused an increase in SOD activity and a decrease in CAT activity. Changes in the GSSG levels in both tissues might be an adaptive response to the prooxidative potential of Cd. Because of their respective tissue- and metal-dependent prooxidative effects, CUR and TAU deserve particular attention in regard to their use against metal toxicity, Cr in particular.

Sex-, tissue-, and exposure duration-dependent effects of imidacloprid modulated by piperonyl butoxide and menadione in rats. Part I: oxidative and neurotoxic potentials.

Earlier research has evidenced the oxidative and neurotoxic potential of imidacloprid, a neonicotinoid insecticide, in different animal species. The primary aim of this study was to determine how metabolic modulators piperonyl butoxide and menadione affect imidacloprid's adverse action in the liver and kidney of Sprague-Dawley rats of both sexes. The animals were exposed to imidacloprid alone (170 mg kg⁻¹) or in combination with piperonyl butoxide (100 mg kg⁻¹) or menadione (25 mg kg⁻¹) for 12 and 24 h. Their liver and kidney homogenates were analysed spectrophotometrically for glutathione peroxidase, glutathione S-transferase, catalase, total cholinesterase specific activities, total glutathione, total protein content, and lipid peroxidation levels. Imidacloprid displayed its prooxidative and neurotoxic effects predominantly in the kidney of male rats after 24 h of exposure. Our findings suggest that the observed differences in prooxidative and neurotoxic potential of imidacloprid could be related to differences in its metabolism between the sexes. Co-exposure (90-min pre-treatment) with piperonyl butoxide or menadione revealed tissue-specific effect of imidacloprid on total cholinesterase activity. Increased cholinesterase activity in the kidney could be an adaptive response to imidacloprid-induced oxidative stress. In the male rat liver, co-exposure with piperonyl butoxide or menadione exacerbated imidacloprid toxicity. In female rats, imidacloprid+menadione co-exposure caused prooxidative effects, while no such effects were observed with imidacloprid alone or menadione alone. In conclusion, sex-, tissue-, and duration-specific effects of imidacloprid are remarkable points in its toxicity.

Prevalence of beta-thalassemia trait and abnormal hemoglobins in the province of Adiyaman, Turkey.

BACKGROUND/AIMS: Thalassemia is one of the most common hereditary disorders in Turkey. The aim of this study was to determine the prevalence of the beta-thalassemia trait and abnormal hemoglobins in the province of Adiyaman in Turkey. METHODS: The study included 3571 high school students of both sexes; aged 12-22 (mean 16.59 ± 1.34). After they received information about thalassemia, they were screened for beta-thalassemia and abnormal hemoglobin using complete blood count (CBC) and quantification of hemoglobin. Hemoglobin was fractionated using HPLC. RESULTS: The beta-thalassemia trait was found in 38 students (1.06%), and abnormal hemoglobin in seven students (0.20%). Of the latter, four carried HbD Los Angeles, two HbS, and one HbE-Saskatoon. CONCLUSION: The prevalence of the beta-thalassemia trait and abnormal hemoglobin in the province of Adiyaman is low, compared to the rest of Turkey. Our results seem to reflect the heterogeneity of beta-thalassemia in the province of Adiyaman and may be of value for genetic counseling and premarital screening.

Antioxidative effects of N-acetylcysteine, lipoic acid, taurine, and curcumin in the muscle of Cyprinus carpio L. exposed to cadmium.

We investigated the muscle tissue of a teleost Cyprinus carpio L. to find out whether N-acetylcysteine (NAC), alpha-lipoic acid (LA), taurine (TAU), and curcumin (CUR) were able to counteract oxidative stress induced by acute exposure to cadmium (Cd). The muscle tissue was dissected 96 h after a single intraperitoneal injection of Cd (5 mg kg(-1)) and of antioxidant substances (50 mg kg(-1)). Using spectrophotometry, we determined the glutathione redox status, lipid peroxidation levels and the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione disulphide reductase (GR). Accumulation of Cd in the muscle was analysed using inductively coupled plasma - optical emission spectrometry (ICP-OES).All substances lowered Cd levels in the following order of efficiency; LA=NAC>TAU=CUR. Cadmium increased SOD activity, but CAT activity declined, regardless of antioxidant treatment. Treatment with CUR induced GPx activity. Treatment with TAU lowered Cd due to higher total glutathione (tGSH). The most effective substances on lipid peroxidation were LA and NAC due to a greater Cd-lowering potential. It seems that the protective role of TAU, LA, and NAC is not necessarily associated with antioxidant enzymes, but rather with their own activity.

Tissue-specific effects of fenthion on glutathione metabolism modulated by NAC and BSO in Oreochromis niloticus.

INTRODUCTION: The present study was designed to understand the effects of organophosphate (OP) insecticide and avicide fenthion on cellular redox status and the role of reduced glutathione (GSH) on fenthion toxicity in the liver and kidney of Oreochromis niloticus as a model organism. N-acetylcysteine (NAC) and buthionine sulfoximine (BSO) were injected intraperitoneally to fenthion-exposed fish as modulators of GSH metabolism. GSH redox status, GSH-related enzyme activities, and thiobarbituric acid reactive substances (TBARS) contents were then measured spectrophotometrically at 24, 48, and 96 hours. To assess recovery from fenthion exposure, similar analyses were performed on fish transferred to non-treated water for 24, 48, and 96 hours. RESULTS: Fenthion increased glutathione S-transferase (GST; EC 2.5.1.18) activity and caused changes in total GSH (tGSH), GSH and oxidized glutathione (GSSG) contents and glutathione peroxidase (GPx; EC 1.11.1.9) specific activity in the liver tissue over time. Increases observed in tGSH and GSSG contents at 24 hours were decreased by fenthion treatment at 96 hours. BSO caused a sharp decline in liver tGSH, GSH, and GSSG contents and an elevation in GST and gamma-glutamyl transpeptidase (gamma-GT; EC 2.3.2.2) enzyme activities. A significant decrease was observed in tGSH and GSH contents and, also, GST enzyme activities in the kidney at 48-hour fenthion treatment. On the contrary to the liver, a significant increase was observed in tGSH and GSH contents in the kidney by BSO injection. NAC application eliminated the decreasing effects of fenthion on GST activity in this tissue. NAC injection caused decreases in lipid peroxidation (LPO) levels. Decline in tGSH and GSH contents were maintained in the liver during the recovery period, and elevations in LPO levels in the kidney were observed during the same period. CONCLUSIONS: In conclusion, tissue-specific and time-dependent GSH redox status disturbance of fenthion were observed. BSO revealed the significance of GST-mediated GSH conjugation on the detoxification process of fenthion. NAC seemed useful to avoid the fenthion-related oxidative toxicity.

Tissue-specific in vivo inhibition of cholinesterases by the organophosphate fenthion in Oreochromis niloticus.

This study was designed to elucidate the effect of the organophosphate fenthion exposure on cholinesterase-specific activities in brain, liver, and kidney tissues of juvenile Oreochromis niloticus, and to define the best indicator tissue to fenthion exposure. The 96-h LC(50) value was determined as 2.27 mg/L and fish were exposed to 20% of this concentration for 24-, 48-, and 96-h. Recovery periods in similar durations were provided to evaluate the ChE activities. AChE and BChE activities were determined spectrophotometrically. The activities of these enzymes were significantly inhibited in all the tissues tested, liver was the most and kidney was the least affected tissues. The inhibition percentages of AChE and BChE were at similar levels in the liver while BChE was more affected in kidney. BChE was not detected in the brain. A significant positive correlation in ChE inhibitions was found among tissues, and the effect of fenthion on ChE activities was tissue specific. In general enzymes activities were not significantly recovered in 96-h recovery period; however, an elevation in AChE inhibition was observed in brain. Based on the data of this study, the liver may be suggested as the best indicator tissue especially for phosphorothioate exposure.

N-Acetylcysteine provides dose-dependent protection against fenthion toxicity in the brain of Cyprinus carpio L.

N-Acetyl-L-cysteine, a low-molecular weight thiol compound, with two different doses was used to prevent fenthion, an organophosphorus insecticide and acaricide, related oxidative stress in the brain of a model organism, Cyprinus carpio. Fish were exposed to sub-lethal and nominal concentration of fenthion after intraperitoneal injection of 0.5 or 400 mg/kg NAC. Brain tissues were then dissected and homogenized to analyse GSH, GSSG, TBARS, and protein contents. Enzymes that constitute the first line antioxidant defence, namely SOD and CAT, GSH-related enzymes, GR and GST, together with AChE activities were also determined spectrophotometrically. Fenthion did not cause any alteration in SOD and CAT activities while increasing GSH content, GSH/GSSG ratio and GST specific enzyme activity and decreasing GSSG, TBARS, and protein contents. Although, the highest induction in SOD and GST enzymes activities and the highest increase in GSH content were observed in the 0.5 mg/kg NAC-injected fish, their protein contents showed a decrease. 400 mg/kg NAC impeded the activation of the GST enzyme and a higher decrease in lipid peroxidation was observed. Fish were also protected against protein depletion by the higher dose NAC application. AChE activity was not influenced by fenthion exposure. Xenobiotic and GSH transporters may cause mild oxidative stress conditions in brain. Cellular redox status could trigger a series of reactions that result in an increase in SOD activity and a decrease in protein content. Based on the present results, it was suggested that the usefulness of NAC against fenthion depends on applied dose and tissue characteristics. Species-specifity and concentration selection should be taken into consideration in studies dealing with anticholinesterases.

Modulation of fenthion-induced oxidative effects by BSO in the liver of Cyprinus carpio L.

The objective of the present study was to evaluate the oxidative stress potential of low-level organophosphate fenthion exposure with the modulatory effect of buthionine sulfoximine in the liver of Cyprinus carpio L. The fish were exposed to 20% of 96-hour LC(50) of fenthion for 24 and 96 hours. Total and oxidized glutathione, thiobarbituric acid reactive substances, protein levels, glutathione peroxidase, glutathione reductase, glutathione-S-transferase, superoxide dismutase, and catalase-specific enzyme activities were measured spectrophotometrically. There was a 15-day depuration period to evaluate the changes in the studied parameters. Fenthion caused a time-dependent depletion of the total and reduced glutathione levels. The oxidized/reduced glutathione ratio and catalase specific enzyme activity were reduced while the glutathione-S-transferase activity was elevated. Intraperitonal buthionine sulfoximine application disclosed the inhibitory effect of fenthion on superoxide dismutase and glutathione peroxidase activities, whereas glutathione-S-transferase activity was increased. There was no change in lipid peroxidation levels during the experiments. No amelioration was observed in the affected parameters except the glutathione-S-transferase activity in the 15-day depuration period. In conclusion, glutathione-S-transferase and catalase enzyme activities and total and reduced glutathione levels were better estimators to monitor the effects of fenthion in low concentration in the liver of C. carpio. The depuration period was not adequate to recover the antioxidant capacity.