Modulatory effect of cadmium exposure on deltamethrin-induced oxidative stress in Channa punctata Bloch

Toxic effects of the synthetic pyrethroid permethrin on the hematological parameters and antioxidant enzyme systems of the freshwater fish Cyprinus carpio L

This study investigated changes in hematological and antioxidant parameters of carp exposed to two different doses of synthetic pyrethroid permethrin (control, vehicle, 10 ppm, and 20 ppm) for two different periods (4 days and 21 days). Hematological analyses were then performed on a veterinary Ms4 (Melet Schloesing, France) blood counter using commercially available kits (Cat. No. WD1153). Buege and Aust for MDA, Luck for CAT, McCord and Frivovich for SOD, Lawrence and Burk methods for GSH-Px were used to determine antioxidant parameters. Decreases in RBC count, Hb amount, Hct value, granulocyte ratios, and increases in total WBC and lymphocyte ratios were statistically significant in both dose groups treated with permethrin compared to the control group (p < 0.05). However, there was no statistically significant difference in monocyte ratios (p > 0.05). Overall, permethrin exposure caused an increase in MDA levels in the liver and gill tissues of carp in both dose and duration groups compared to the control group. Also, no statistically significant difference between the two dose groups in the liver tissue was observed in terms of duration (p > 0.05). Nonetheless, the increase in MDA levels in PERM10 and PERM20 dose groups in the gill tissues over 21 days was statistically significant (p < 0.05). Furthermore, permethrin exposure increased CAT, SOD, and GSH-Px enzyme activities in the gill tissue, while impacting in the opposite direction the liver tissue. Finally, regarding MDA, CAT, SOD, and GSH-Px levels, the control, and control acetone dose groups of all experimental groups were observed to be similar (p > 0.05). As a result, permethrin produced a toxic effect on Cyprinus carpio, triggering changes in blood parameters and inducing the antioxidant enzyme system.

Copper-induced Genotoxicity, Oxidative Stress, and Alteration in Transcriptional Level of Autophagy-associated Genes in Snakehead Fish Channa punctatus

Copper (Cu) is an essential and important trace element for some significant life processes for most organisms. However, an excessive amount of Cu can be highly toxic. The present study was conducted to elucidate the oxidative stress-induced alteration in transcriptional level of autophagy-related genes in the liver and kidney tissue of fish Channa punctatus after treatment with three different sublethal concentrations of CuSO₄ for 28 days. All the studied enzymatic and non-enzymatic oxidative stress markers viz. superoxide dismutase-SOD, catalase-CAT, glutathione peroxidase-GPx, glutathione reductase-GR, and glutathione-GSH showed an increase in their activity levels in the treated groups in a dose-dependent manner. Particularly SOD and CAT have shown a significant hike in activity levels. ROS levels in blood cells increased significantly (p < 0.05) in all the treated groups, i.e., Group II-1/20^th of 96 h-LC₅₀ (0.2 mg/L), Group III-1/10^th of 96 h-LC₅₀ (0.4 mg/L), and Group IV-1/5 ^h of 96 h-LC₅₀ (0.8 mg/L) of Cu²⁺ in a dose-dependent manner as compared to control (Group I). The upregulation in mRNA levels of autophagy-related genes Microtubule-associated protein 1 light chain 3 (LC3), Gamma-aminobutyric acid receptor-associated protein precursor (Gabarap), and Golgi-associated ATPase enhancer of 16 kDa (GATE16), autophagy-related 5 (ATG5) was observed while mammalian target of rapamycin (mTOR) showed downregulation in the liver and kidney tissue of fish. The decrease in mTOR and increase in ATG5 gene expression projects autophagic vesicle formation due to oxidative stress. There was significant induction in micronuclei (MN) frequency in all the treated groups. The highest frequency of MN induced by Cu²⁺ was recorded in Group IV after 28 days of the exposure period. Thus, it can be concluded that the available information about Cu²⁺-induced oxidative stress-mediated autophagy in the liver and kidney of fish C. punctatus remains largely unclear to date, so to fill the aforesaid gap, the present study was undertaken, which gives an insight for the mechanisms of autophagy induced by Cu²⁺ in fish.

Effects on Bioaccumulation, Growth Performance, Hematological Parameters, Plasma Components, and Antioxidant Responses in Starry Flounder (Platichthys stellatus) Exposed to Dietary Cadmium and Ascorbic Acid

This study evaluates the toxic effects of dietary Cd and mitigative effects of AsA supplementation by measuring the growth performance, bioaccumulation, hematological parameters, plasma components, and antioxidant responses of Starry flounder (Platichthys stellatus). Platichthys stellatus (mean weight, 69.5 ± 1.4 g; mean length, 18.2 ± 0.21 cm) was fed with dietary cadmium-ascorbic acid (Cd-AsA) composed of C₀A₀, C₀A₅₀₀, C₀A₁₀₀₀, C₄₀A₀, C₄₀A₅₀₀, C₄₀A₁₀₀₀, C₈₀A₀, C₈₀A₅₀₀, and C₈₀A₁₀₀₀ mg of Cd-AsA per kg diet for four weeks. Our results showed that Cd accumulation significantly increased in proportion to the Cd concentration, where the highest levels were observed in the intestine, followed by the kidney, liver, and gills. Dietary AsA significantly mitigated the Cd accumulation in all tissues, and the reduction in Cd accumulation was proportional to the increase in AsA concentration. Dietary Cd has adverse effects on growth performance (body weight gain, specific growth rate, feed conversion ratio, and hepatosomatic index) and can alter the hematological parameters (red blood cell count, hematocrit, and hemoglobin), plasma components (glucose, total protein, glutamic oxaloacetic transaminase, and glutamic pyruvic transaminase), and antioxidant responses (superoxide dismutase, catalase, glutathione S-transferase, and glutathione). Dietary AsA restored the decreased growth performance parameters and the altered hematological parameters, plasma components, and antioxidant responses caused by the dietary Cd exposure. The results of this study showed that dietary Cd is toxic to P. stellatus, while dietary AsA is effective in mitigating the toxic effects of Cd.

Histopathological, Immunohistochemical, And Molecular Alterations In Brain Tissue And Submandibular Salivary Gland Of Atrazine-Induced Toxicity In Male Rats

Atrazine (ATZ) is herbicide that has been widely used for different crops. This extensive use has resulted in severe deleterious effects in different species. In this work, we investigated the potentially harmful effect of atrazine herbicide on the brain and submandibular salivary gland. Our investigation was carried out on 20 adult male albino rats that were equally divided into two groups. The first group received distilled water as control, while the second group received ATZ at 200 mg/kg body weight/ day via stomach gavage for 30 successive days of the experiment; the oral LD50 for ATZ is 3090 mg/kg. Our findings revealed the ability of ATZ to cause damage to the cerebrum, hippocampus, and submandibular salivary gland. This damage resulted from the induced oxidative stress, which was indicated by a significant elevation in malondialdehyde (MDA) concentration, DNA fragmentation, tumor necrotic factor-alpha (TNF-α) expression, with a significant decrease in reduced glutathione (GSH) level and reduction of B cell lymphoma 2 (BCL2), dopamine receptor D1 (Drd1), cAMP-responsive element-binding protein 1 (Creb1) genes expression after ATZ exposure. Moreover, degeneration of cells, cytoplasmic vacuolation, congestion of blood vessels, a strong immune reaction to caspase 3, and negligible immune expression of a glial fibrillary acidic protein (GFAP) were also noticed in the ATZ-treated group. We concluded that ATZ induces oxidative stress and has a toxic and apoptotic effects on the cerebrum, hippocampus, and salivary gland of adult male albino rats.

Assessment of biochemical, hematological and behavioral biomarkers of Cyprinus carpio on exposure to a type-II pyrethroid insecticide Alpha-cypermethrin

This study assessed some important physiological biomarkers of freshwater edible fish Cyprinus carpio following exposure to 10 % (T1) and 20 % (T2) sublethal concentrations of Alpha-cypermethrin (A-cyp) over a total period of 45 days. Behavioral responses were noticed and Kaplan-Meier survival curves were prepared during acute toxicity study. Total serum protein concentration, total erythrocyte count, hemoglobin, packed cell volume, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, and total leukocytes count were decreased significantly (p < 0.05), while the blood glucose, total serum lipid concentration, and clotting time were increased significantly (p < 0.05) over control. The most affected fish group and most significantly altered biomarker under toxic stress of A-cyp were identified using integrated biomarker response (IBR). The biomarker response index (BRI) values measured the overall health status of the treated fish and indicated that moderate adverse effects were exerted on the fish group exposed to T2 for 45 days.

Effects of deltamethrin subacute exposure in snakehead fish, Channa argus: Biochemicals, antioxidants and immune responses

To evaluate the effects on biochemicals, antioxidants, immune responses and disease resistance of the snakehead fish, following exposure to deltamethrin at 0.061, 0.121, 0.242, 0.485 and 0.970 μg/L. After 28 d, the biochemical, the levels of antioxidant enzymes and immune enzymes in liver, spleen, kidney and intestine were negatively related to the concentrations of deltamethrin exposure. Likewise, the survival rates of the fish after 7 d challenge with Aeromonas veronii were negatively related. The levels of IL-1β, IL-8, TNF-α, Hsp70 and malondialdehyde in liver, spleen, kidney and intestine were positively connected to the concentrations of deltamethrin exposure. Results demonstrated that environmentally relevant concentrations (0.121, 0.242, 0.485 and 0.970 μg/L) inhibited the biochemicals, antioxidants and immune responses and disease resistance of snakehead fish.

Exposure to waterborne cadmium induce oxidative stress, autophagy and mitochondrial dysfunction in the liver of Procypris merus

The present study was performed to determine the effect of waterborne cadmium (Cd) exposure on oxidative stress, autophagy and mitochondrial dysfunction, and to explore the mechanism of Cd-induced liver damage in freshwater teleost Procypris merus. To this end, P. merus were exposed to waterborne 0, 0.25 and 0.5 mg/L Cd for 30 days (equal to 0, 2.22 and 4.45 μmol Cd/l). The waterborne Cd exposure significantly increased hepatic Cd accumulation and impaired histological structure of the liver of P. merus. both low and high-dose waterborne Cd exposure induced oxidative stress in the liver of P. merus, through increases Malondialdehyde (MDA) and reactive oxide species (ROS) accumulation in the liver. The Cd-induced oxidative stress in liver may result from reduction of enzyme activities (superoxide dismutases (SOD), catalases (CAT), GSH-S-transferases (GST)) and transcriptional expression of antioxidant related genes (gpx1, gpx2, cata, gsta1, sod1). Furthermore, the present study showed that waterborne Cd exposure decreased the transcriptional factor (nrf2) expression, which might lead to the down-regulation of antioxidant gene expression. Transmission electron microscopy (TEM) observations demonstrated that waterborne Cd exposure induced autophagy in the liver of P. merus. Gene expression analysis showed that waterborne Cd exposure also induced mRNA expression of a set of genes (beclin1, ulk1, atg5, lc3a, atg4b, atg9a, and p62) involved in the autophagy process, indicating that the influence of Cd on autophagy involved transcription regulation of autophagy gene expression. Waterborne Cd exposure induced a sharp decrease in ATP content in the liver of P. merus. In addition, the expression of mitochondrial function genes (sdha, cox4i1, cox1, atp5f1, and mt-cyb) are significantly decreased in the liver of P. merus in Cd treated groups, manifesting the suppression of Cd on mitochondrial energy metabolism. Taken together, our experiments demonstrate that waterborne Cd exposure induced oxidative stress, autophagy and mitochondrial dysfunction in the liver of P. merus. These results may contribute to the understanding of mechanisms that hepatotoxicity of Cd in teleost.

Mediation of oxidative stress toxicity induced by pyrethroid pesticides in fish

Organophosphate and organochlorine pesticides are banned in most countries because they cause high toxicity and bioaccumulation in non-target organisms. Pyrethroid pesticides have been applied to agriculture and aquaculture since the 1970s to replace traditional pesticides. However, pyrethroids are approximately 1000 times more toxic to fish than to mammals and birds. Fish-specific organs such as the gills and their late metabolic action against this type of pesticide make fish highly susceptible to the toxicity of pyrethroid pesticides. Oxidative stress plays an important role in the neurological, reproductive, and developmental toxicity caused by pyrethroids. Deltamethrin, cypermethrin, and lambda-cyhalothrin are representative pyrethroid pesticides that induce oxidative stress in tissues such as the gills, liver, and muscles of fish and cause histopathological changes. Although they are observed in low concentrations in aquatic environments such as rivers, lakes, and surface water they induce DNA damage and apoptosis in fish. Pyrethroid pesticides cause ROS-mediated oxidative stress in fish species including carp, tilapia, and trout. They also cause lipid peroxidation and alter the state of DNA, proteins, and lipids in the cells of fish. Moreover, changes in antioxidant enzyme activity following pyrethroid pesticide exposure make fish more susceptible to oxidative stress caused by environmental pollutants. In this review, we examine the occurrence of pyrethroid pesticides in the aquatic environment and oxidative stress-induced toxicity in fish exposed to pyrethroids.

Moringa Oleifera Leaf Extract Repairs the Oxidative Misbalance following Sub-Chronic Exposure to Sodium Fluoride in Nile Tilapia Oreochromis niloticus

The potential antioxidant property of Moringa oleifera (MO) has been the recent focus of an increased number of studies. However few studies investigated its antioxidative ability against sodium fluoride-induced redox balance breakdown in Oreochromis niloticus. Thus, this study evaluates the effects of MO against the oxidative stress induced by sub-chronic exposure to sodium fluoride (NaF). A total of 264 fish (40 ± 3 g BW) were used to calculate the 96 hr-LC50 of NaF and perform the sub-chronic exposure study. 96 hr-LC50 of NaF was calculated as (61 mg/L). The 1/10 dose of the calculated 96 hr-LC50 (6.1 mg/L) was used to complete the sub chronic exposure for eight weeks. Fish were divided into four groups (n = 51; three replicates each); control, non-treated group; NaF group (exposed to NaF 6.1 mg/L); MO group (treated with 1% MO of diet); and NaF+MO (exposed to NaF 6.1 mg/L and treated with 1% MO of diet). The results revealed that the sub-chronic exposure to NaF (6.1 mg/L) was substantially increased malondialdehyde (MDA) and decrease the activities of superoxide dismutase (SOD), catalase (CAT), glutathione reduced (GSH), glutathione peroxidase (GPx), and total antioxidant capacity (TAC) in the gills, liver, kidney, and muscle tissue in a time-dependent manner. In addition, a significant reduction in mRNA expression of GST in the liver was reported following NaF exposure. On the contrary, dietary supplementation of MO to NaF-exposed fish resulted in a significant reduction in MDA levels, and a significant elevation of SOD, CAT, GSH, GPx, and TAC activities in a time-dependent manner, in addition to significant elevation of GST mRNA expression in liver tissue. It could be concluded that a 1% MO (w/w) ration is a promising antioxidant plant that may successfully use to interfere with the oxidation processes induced by NaF in various tissues of Oreochromis niloticus.

Residual quantification and oxidative stress induced by malachite green after subacute and sublethal exposure in red tilapia

Background and Aim:

Malachite green (MG) is an effective antiparasitic and antifungal chemical for treatment of fish. However, MG is reported to be a potential carcinogen. Yet, it is widely used in aquaculture despite its prohibition for use in food-producing animals by the EU and USFDA. The present study quantified MG residues and evaluated the oxidative stress in red tilapia when exposed to subacute and sublethal concentrations of MG.

Materials and Methods:

Red tilapia exposed to subacute (0.105 mg/L for 20 days) and sublethal (0.053 mg/L for 60 days) concentrations were evaluated for total plasma protein, total immunoglobulin, nitroblue tetrazolium activity, malondialdehyde, reduced glutathione (GSH), and catalase (CAT) activity levels. The residues of MG and leuco-MG (LMG) were also quantified in the fish muscles using liquid chromatography–tandem mass spectrometry.

Results:

Fish exposed to subacute concentration showed higher CAT on day 10 in the liver and days 5 and 15 in the spleen, whereas in fish exposed to the sublethal concentration, higher levels of GSH were observed on day 1 in the kidney and day 50 in the spleen. Fish muscle was able to accumulate the sum of MG and LMG of 108.04 µg/kg for subacute (day 20) and 82.68 µg/kg for sublethal (day 60).

Conclusion:

This study showed that red tilapia was able to adapt to the stress caused by exposure to MG at sublethal concentration.

Toxicity and chronic effects of deltamethrin exposure on zebrafish (Danio rerio) as a reference model for freshwater fish community

In this study zebrafish specimens were exposed for 15 days to 0.25, 0.5, 1 and 2 μg L^-1 non-lethal concentrations of deltamethrin (DM) knowing that is the active compound in insecticides used on agricultural crops. They were investigated important issues resulted during the chronic exposure with DM: effects on aggressive behavior and swimming performances knowing that is a high neurotoxic compound; toxicity on nervous system investigated on telencephalon, optic tectum and cerebellum; activity of PCNA, p53 and TUNEL as toxicity markers in immunocytochemistry of the histological samples; changes of elements concentrations in the fish body and their role in detoxification of DM. This scenario investigated the harmful effects of this compound for freshwater fish communities. The aggressive behavior significantly increased and remained constant for the concentration 0.5 μg L^-1. They were not evidences in changing of anxiety level and swimming performances. The nervous system suffered significant damage for all studied concentrations and confirmed the changes in the behavior. Selenium concentration in the body decreased and may be involved in the detoxification processes.

Behavioral, molecular and physiological responses of embryo-larval zebrafish exposed to types I and II pyrethroids

Pyrethroids are potent neurotoxicants that may elicit multiple pathways of toxicity in non-target organisms. Comparative studies on the mechanistic and developmental effects of types I and II pyrethroids against non-target aquatic species are limited. This study assessed the effects of the two pyrethroid types against embryo-larval zebrafish (Danio rerio) at environmentally relevant and laboratory concentrations. Zebrafish embryos were exposed to type-I (permethrin, bifenthrin) and type-II (deltamethrin, λ-cyhalothrin, fenvalerate, esfenvalerate) pyrethroids at 1000, 10, 0.1, 0.01, 0.0 μg/L, starting at 5-h post-fertilization (hpf) through 5-d post-fertilization (dpf) under static exposure conditions. Swimming behavior (distance traveled and velocity) was assessed at 5-dpf. The relative expression of Nrf2a, GST, Casp-9 and p53 mRNA transcripts, carboxyl esterase (CES) activity and total reactive oxygen species (ROS) were measured. The stability of the pyrethroids across 5 days was analyzed. Bifenthrin-(10 μg/L) and esfenvalerate-(1000 μg/L) significantly (p < 0.05) reduced total distance traveled by larvae while 1000 μg/L deltamethrin and λ-cyhalothrin were lethal causing body axis curvature and pericardial edema. At environmentally relevant concentrations-(μg/L) compared to control, permethrin-(0.122) upregulated Nrf2a and Casp-9 expressions while λ-cyhalothrin-(0.053) downregulated Nrf2a and fenvalerate-0.037 downregulated GST. At laboratory concentrations-(μg/L), permethrin-(1000) upregulated Nrf2a, Casp-9 and p53 expressions, bifenthrin-(10) upregulated Casp-9 while fenvalerate-(0.1) and esfenvalerate-(1000) downregulated GST. There was concentration dependent increase in CES activity which correlated positively with total ROS. Pyrethroid concentrations decreased significantly by day 5. This study showed disparity in the mechanistic effects across the pyrethroids types and their instability in aqueous media may underestimate toxicity against non-target aquatic species when exposed in their natural environment.

Deltamethrin toxicity: A review of oxidative stress and metabolism

Deltamethrin is widely used worldwide due to its valuable insecticidal activity against pests and parasites. Increasing evidence has shown that deltamethrin causes varying degrees of toxicity. Moreover, oxidative stress and metabolism are highly correlated with toxicity. For the first time, this review systematically summarizes the deltamethrin toxicity mechanism from the perspective of oxidative stress, including deltamethrin-mediated oxidative damage, antioxidant status, oxidative signaling pathways and modulatory effects of antagonists, synergists and placebos on oxidative stress. Further, deltamethrin metabolism, including metabolites, metabolic enzymes and pathways and deltamethrin metabolite toxicity are discussed. This review will shed new light on deltamethrin toxicity mechanisms and provide effective strategies to ensure pest control and prevention of human and animal poisoning.

Development of an oxidative stress in vitro assay in zebrafish (Danio rerio) cell lines

The nuclear factor erythroid 2-related factor 2 (Nrf2) is a key regulator of cellular defense against oxidative stress and correlated with classical toxicological endpoints. In vitro methods using fish cell lines for the assessment of aquatic toxicity are needed for mechanistic studies and as an alternative to in vivo. We describe an in vitro assay to study oxidative stress using zebrafish cell lines. Transfection efficiency of twelve commercially available transfection reagents were tested in the zebrafish cell lines ZFL, ZF4, and Pac2. The most efficient reagent for each cell line was selected for further experiments. Cells were transiently transfected with an Nrf2-responsive luciferase plasmid. The assay was tested using the oxidative stress inducing chemicals tertbutylhydroquinone, hydrogen peroxide, and sulforaphane. Of the transfected cell lines, ZF4 and ZFL showed higher sensitivity. The latter were used to study potential oxidative stress induced by pesticides (diazinon, deltamethrin, atrazine, metazachlor, terbutylazine, diuron). Besides known inducers, Nrf2 activity was also significantly induced by diazinon, deltametrin, diuron, and metazachlor. Activation of Nrf2 by metazachlor is a novel finding. The described assay could be a valuable tool for research in toxicology to study the stress response of both pure chemicals and environmental water samples.

Effects of exposure to multiple heavy metals on biochemical and histopathological alterations in common carp, Cyprinus carpio L

Heavy metals are frequently encountered as mixtures of essential and non-essential elements. Therefore, evaluation of their toxic effects individually does not offer a realistic estimate of their impact on biological processes. We studied effects of exposure to mixtures of essential and toxic metals (Cr, Cd and Pb) on biochemical, immunotoxicity level and morphological characteristics of the various tissues of a biomarker freshwater fish common carp using environmentally relevant concentrations. Fish were exposed to metal mixture through tank water for 7, 15 and 30 days, under controlled laboratory conditions. Tissue accumulation of the metals was measured using Atomic Absorption Spectrophotometric techniques. Chromium, cadmium and lead accumulation in muscle, gills, liver, kidney and intestine, tissue of common carp exposed to mixture metals for 30 days increased significant compared with control group (p < 0.001). However, the activity of antioxidant enzymes such as catalase (CAT) and superoxide dismutase (SOD) levels was significant altered in various tissues of exposed fish. Besides, the lipid peroxidation (LPO) was significant (p < 0.001) increased. Moreover, the tumor necrosis factor - α (TNF-α), interleukin (IL-6), and interferon-γ (IFN-γ) contents in tissues of muscle, gills, liver, kidney and intestine were increased significant compared with control fish (p < 0.001). In addition, microscopic examination of the main alterations in general morphology of fish gills included spiking and fusion of secondary lamellae, formation of club-shaped filaments epithelium in the interlamellar regions and hepatocytes showed damage of central vein and rupture of irregular hepatic plate with more number of vacuoles in the fish exposed to metal mixture for a longer duration (30 days). These results of this study clearly demonstrate that concentration individual and mixtures of metals in aquatic systems will greatly influence the cytokine alterations may result in an immune suppression or excessive activation in the treated common carp as well as may cause immune dysfunction or reduced immunity. In conclusion, toxicity of multiple metal mixtures of Cr, Cd and Pb has antioxidant and immunotoxic effects on C. carpio.

Sublethal effects of the pyrethroid insecticide deltamethrin on oxidative stress parameters in green toad (Bufotes viridis L.)

Pyrethroids are synthetic insecticides widely used in agriculture, public health, and veterinary medicine. Deltamethrin, a type II pyrethroid insecticide, has attracted particular attention because of its frequent use. The mechanisms of the toxicity of most pesticides (including pyrethroids) in nontarget organisms is linked to the production of free radicals, oxidative stress induction, increased lipid peroxidation, and disruption of the total antioxidant potential. The aim of the present study was to investigate the effects of acute toxicity of 3 different concentrations (8, 16, and 32 mg/kg body wt) of orally applied deltamethrin after 96 h of treatment. Some of the front-line oxidative stress parameters as well as cholinesterase (ChE) activity and cytochrome P4501A (CYP1A) expression in the liver, muscle, skin, and gastrointestinal tissue of the adult green toad Bufotes viridis were determined. Compared with the control group, the activity of catalase and glutathione reductase was increased in the liver and skin, while the concentration of sulfhydryl groups was reduced. In the liver and muscle, concentrations of thiobarbituric reactive substances were increased, as well as liver CYP1A expression. In the muscle and skin, glutathione-S-transferase activity was higher in treated toads. The oxidative stress parameters examined were affected by different deltamethrin concentrations. We conclude that the assessed parameters represent good biomarkers of pesticide-induced oxidative stress. Environ Toxicol Chem 2017;36:2814-2822. © 2017 SETAC.

Subacute Toxicity Effects of Deltamethrin on Oxidative Stress Markers in Rainbow Trout

Deltamethrin is a pyrethroid insecticide that is considered extremely toxic to aquatic organisms. We evaluated the effect of subacute doses (0.033, 0.1, or 0.3 mg/kg) of deltamethrin on micronucleus frequency and oxidative stress markers in Rainbow Trout Oncorhynchus mykiss at 1, 2, 3, 4, and 8 d after intracoelomic injection. No genotoxic damage was recorded, as no specimen showed a micronucleus number above the physiological range. Deltamethrin exposure elicited a transient reduction in the levels of superoxide dismutase, catalase, glutathione peroxidase, and glutathione S-transferase and a persistent decrease in glutathione reductase activity. Overall, the lower antioxidant enzyme activity in the deltamethrin-treated fish was mainly dose-dependent. Received May 27, 2016 accepted June 18, 2017.

Variations in hepatic biomarkers in American alligators (Alligator mississippiensis) from three sites in Florida, USA

Sub-individual biomarkers are sub-lethal biological responses commonly used in the assessment of wildlife exposure to environmental contaminants. In this study, we examined the activity of glutathione-s-transferase (GST) and lactate dehydrogenase (LDH), and metallothionein (MT) concentrations among captive-raised alligator hatchlings, wild-caught juveniles, and wild-caught adults. Juveniles and adults were collected from three locations in Florida (USA) with varying degrees of contamination (i.e. Lake Apopka (organochlorine polluted site), Merritt Island National Wildlife Refuge (NWR) (metal polluted site), and Lake Woodruff NWR (reference site)). We examined whether changes in the response of these three biomarkers were age and sex dependent or reflected site-specific variations of environmental contaminants. Juvenile alligators from Merritt Island NWR had higher MT concentrations and lower GST activity compared to those from the other two sites. This outcome was consistent with higher metal pollution at this location. Sexually dimorphic patterns of MT and GST (F > M) were observed in juvenile alligators from all sites, although this pattern was not observed in adults. GST activity was lower in captive-raised alligators from Lake Apopka and Merritt Island NWR as compared to animals from Lake Woodruff NWR, suggesting a possible developmental modulator at these sites. No clear patterns were observed in LDH activity. We concluded that GST and MT demonstrate age and sex specific patterns in the alligators inhabiting these study sites and that the observed variation among sites could be due to differences in contaminant exposure.

Oxidative Stress Biomarkers in the Freshwater Fish, Heteropneustes fossilis (Bloch) Exposed to Sodium Fluoride: Antioxidant Defense and Role of Ascorbic Acid

The present study highlights fluoride -induced toxicity and the protective role of ascorbic acid in the liver and ovary of freshwater fish, Heteropneustis fossilis. The fish specimens were exposed to different concentrations (35 mg F/L and 70 mg F/L) of fluoride. Parameters related to oxidative stress were studied at the end of the experiment. The biomarkers selected for the study were thiobarbituric acid reactive substances for assessing the extent of lipid peroxidation (LPO) and antioxidant defense system such as reduced glutathione (GSH), superoxide dismutase (SOD) catalase (CAT) glutathione peroxidase (GPx), and glutathione S-transferase (GST) activities. The fluoride exposure significantly elevated the level of LPO, CAT, SOD, and GST in the tissues of treated group as well as modulated the activities of GSH and level of GPx after exposure as compared to the control. A significant decrease in GPx activity was found in these tissues suggesting that fluoride exposure increases the level of free radical, as well as CAT activity. Pre- and post treatment with ascorbic acid decreased the LPO, SOD, CAT, GST level, and increased GSH, GPx levels in the liver and ovary.

Neurotoxic effects of lambda-cyhalothrin modulated by piperonyl butoxide in the brain of Oreochromis niloticus

The objective of this research was to investigate the neurotoxic effects of pyrethroid pesticide lambda-cyhalothrin by the modulation of cytochrome P450 with piperonyl butoxide in the brain of juvenile Oreochromis niloticus. The fish were exposed to 0.48 μg L(-1) (1/6 of the 96-h LC50 ) lambda-cyhalothrin and 10 μg L(-1) piperonyl butoxide for 96 h and 15 days. tGSH, GSSG, TBARS contents, GPx, GR, GST, and AChE enzymes activities were determined by spectrophotometrical methods and Hsp70 content was analyzed by ELISA technique. Lambda-cyhalothrin had no significant effect on the components of GSH redox system, lipid peroxidation and Hsp70 levels but inhibited AChE activity. In the presence of piperonyl butoxide, lambda-cyhalothrin caused increases in tGSH, GSSG, TBARS and Hsp70 contents, GST activity, and decrease in AChE activity. Present results showed that in the presence of piperonyl butoxide, lambda-cyhalothrin caused neurotoxic effects by increasing oxidative stress. Adaptation to its oxidative stress effects may be supplied by GSH-related antioxidant system. Piperonyl butoxide revealed neurotoxic effect of lambda-cyhalothrin.

Biomarkers of type II synthetic pyrethroid pesticides in freshwater fish

Type II synthetic pyrethroids contain an alpha-cyano group which renders them more neurotoxic than their noncyano type I counterparts. A wide array of biomarkers have been employed to delineate the toxic responses of freshwater fish to various type II synthetic pyrethroids. These include hematological, enzymatic, cytological, genetic, omic and other types of biomarkers. This review puts together the applications of different biomarkers in freshwater fish species in response to the toxicity of the major type II pyrethroid pesticides and assesses their present status, while speculating on the possible future directions.

In vitro effect of cadmium and copper on separated blood leukocytes of Dicentrarchus labrax

The immunotoxic effects of heavy metals on blood leukocytes of sea bass (Dicentrarchus labrax) were examined. The cells, separated by a discontinuous Percoll-gradients, were exposed in vitro to various sublethal concentrations of cadmium and copper (10(-7)M, 10(-5)M, and 10(-3)M) and their immunotoxic effect was then evaluated by measuring neutral red uptake, MTT assay, DNA fragmentation and Hsp70 gene expression. First of all, we demonstrated that the cells treated in vitro could incorporate Cd and Cu. A relationship between heavy metal exposure and dose-time-dependent alterations in responses of leukocytes from blood was found for both metals, but copper was more immunotoxic than cadmium in all assays performed. A significant reduction in the cells׳ ability to uptake neutral red and viability by MTT assay was recorded, indicating that both cadmium and copper could change the membrane permeability, inducing cellular apoptosis when the concentration of metals reached 10(-3)M. The apoptotic effect may also explain the high level of cytotoxicity found when the leukocytes were exposed to higher concentration of metals. These results demonstrated that toxic effect of copper and cadmium affect on the mechanisms of cell-mediated immunity reducing the immune defences of the organism.

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.

Modulatory effects of deltamethrin-exposure on the immune status, metabolism and oxidative stress in gilthead seabream (Sparus aurata L.)

Deltamethrin, a sintetic pyrethroid, is the insecticide that has been replacing recently to others like organochlorines, organophosphates and carbamates which are less toxic for birds and mammals, although, unfortunately, all of them are highly toxic to various non-targeted aquatic organisms including fish. In the present study, the consequences of the exposition of gilthead seabream (Sparus aurata L.) specimens to sublethal bath dose of deltamethrin (0.1 ppb) on organo-somatic indexes, immunity, seric metabolic parameters, oxidative stress and liver histology were determined after 1, 3, 7 and 14 days of exposure. Deltamethrin alters gilthead seabream immune status, the hepato-somatic index and various seric metabolic parameters since the first exposure day while important progressive deleterious morphological changes in liver were also observed. However, no statistically significant deviation was detected in the expression of oxidative stress-related genes whilst the expression of cytochrome P450 gene was up-regulated in head-kidney and liver of exposed fish. Overall, the present results indicate severe immunotoxicological and metabolic effects of deltamethrin in gilthead seabream, the species with the highest rate of production in Mediterranean aquaculture. In general, the values obtained for the tested parameters during the trial seem to indicate that specimens try to adapt to this adverse situation although the continuous presence of the toxic impede the hypothetic recovery of homoeostasis. The use of deltamethrin in the proximities of seabream farms should be carefully considered.

Effects of deltamethrin on biometric parameters and liver biomarkers in common carp (Cyprinus carpio L.)

The present study is aimed to evaluate the effect of sublethal exposure to the pyrethroid pesticide deltamethrin, according to biometric parameters and important liver biomarkers in the common carp (Cyprinus carpio). Fish were exposed for 4, 15 and 30 days to deltamethrin mixed to the aquaria water at the concentrations of 0.08, 0.4 and 0.8μg/L. The exposure did not affect fish biometric parameters. Glutathione-S-transferase (GST) activity in liver (hepatopancreas) increased in fish exposed to the high concentration of pesticide only after 30 days when compared to controls. A significant increase of malondialdehyde (MDA) content (79.4% and 90.2% of control) was remarked after 15 and 30 days of exposure to the highest concentration of pesticide. Catalase activities (CAT) went up after 4 days of was to the concentration of 0.4μg/L and 0.8μg/L and at 15 days of exposure to 0.4μg/L. The most significant change of glutathione reductase (GR) activity was recorded at the fourth day, when GR activity was significantly increased after exposure to the concentrations of 0.4μg/L and 0.8μg/L of deltamethrin.

Oxidative and apoptotic effects of lambda-cyhalothrin modulated by piperonyl butoxide in the liver of Oreochromis niloticus

The aim of this study was to investigate the toxic effects of pyrethroid pesticide lambda-cyhalothrin in the presence of piperonyl butoxide as a modulator in the liver of juvenile Oreochromis niloticus. LC(50) (96h) value of lambda-cyhalothrin was determined as 2.901μg/L for O. niloticus. The fish were exposed to 0.48μg/L (1/6 of the 96-h LC(50)) lambda-cyhalothrin and 10μg/L piperonyl butoxide for 96-h and 15-d. tGSH, GSH, GSSG, Hsp70 and TBARS contents, GPx, GR, GST and caspase-3 enzymes activities were determined. Lambda-cyhalothrin caused increases in tGSH, GSH, TBARS contents, and GST activity. Piperonyl butoxide treatment with lambda-cyhalothrin caused significant increases in tGSH GSH, Hsp70, TBARS contents, and GPx and GST activities while caspase-3 activity was decreased. The results of the present study revealed that lambda-cyhalothrin caused oxidative stress which upregulated GSH and GSH-related enzymes. Piperonyl butoxide increased the oxidative stress potential and apoptotic effects of lambda-cyhalothrin.

Alterations in nitrogen metabolism in freshwater fishes, Channa punctatus and Clarias batrachus, exposed to a commercial-grade λ-cyhalothrin, REEVA-5

In the present study, two freshwater fishes Channa punctatus and Clarias batrachus were exposed to sub-acute concentrations of a commercial-grade λ-cyhalothrin, REEVA-5, for 96 h to observe the changes in amino acid catabolism under pyrethroid-induced stress and to investigate the comparative mechanisms of ammonia detoxification in both fishes. The experiments included the estimation of levels of free amino acid, urea, ammonia and the specific activities of aspartate aminotransferase (AAT), alanine aminotransferase (AlAT), glutamate dehydrogenase (GDH), glutamine synthetase (GS) and arginase in different vital organs of fishes. λ-cyhalothrin caused significant decline in the levels of amino acids along with simultaneous significant increase in the activity of AAT, AlAT and GDH, which indicated amino acid catabolism as one of the important mechanisms to meet out immediate energy demand of fishes. The level of ammonia was observed to be enhanced considerably at lower concentrations of λ-cyhalothrin while higher concentrations caused remarkable decline. The λ-cyhalothrin treatment resulted in significant increase in the activities of GDH and GS with concomitant increase in the activity of arginase and level of urea, indicating activation of two different mechanisms of ammonia detoxification. The mechanism of ammonia detoxification through its conversion into glutamate and glutamine was more prominent in C. punctatus, while C. batrachus demonstrated ureogenesis as the major route. In fishwise comparison, C. batrachus was observed to be more sensitive with respect to the above-mentioned parameters. Another important finding was that unlike the liver, the kidney appeared as one of the primary sites of ureogenesis in fishes.

Assessment of tissue-specific effect of cadmium on antioxidant defense system and lipid peroxidation in freshwater murrel, Channa punctatus

The effects of different concentrations of cadmium chloride on the extent of lipid peroxidation (LPO) and alterations in the antioxidant enzyme activities were studied in liver, kidney and gill tissues of freshwater murrel, Channa punctatus. The fish specimens were exposed to 6.7, 13.4 and 20.1 mg l(-1) sublethal concentrations of cadmium chloride and the oxidative stress was assessed after 24, 48, 72 and 96 h post-exposure. The biomarkers selected for the study were thiobarbituric acid reactive substances for assessing the extent of lipid peroxidation and antioxidant defense system such as reduced glutathione (GSH), glutathione reductase (GR), glutathione peroxidase (GP(X)), glutathione-S-transferase (GST), catalase (CAT) and superoxide dismutase (SOD) activities. In general, the cadmium exposure elevated the LPO in subject tissues of treated group and modulated the activities of GPx, GST, SOD, CAT, GR and level of GSH after given exposure as compared to the control. All enzymes activities, except CAT (in kidney and gills), and amount of LPO elevated significantly (P < 0.05) in treated group with respect to control in all tissues, while significant difference was not observed between the exposed concentrations and within exposure duration. The results indicated that increase in LPO level and the fluctuation in antioxidant defense system in fish could be due to cadmium-induced increase in the production of reactive oxygen species (ROS). The potential role of these parameters as biomarkers of heavy metal pollution in aquatic system is discussed.

Effects of carbofuran on the sea bass (Dicentrarchus labrax L.): study of biomarkers and behaviour alterations

The objective of this study was to investigate the acute effects of the pesticide carbofuran on the sea bass (Dicentrarchus labrax) using parameters at different levels of biological organisation (swimming behaviour and several biomarkers) and possible relationships between alterations found in different effect criteria. In a bioassay, sea bass juveniles were individually exposed to different doses of carbofuran (31, 63, 125 and 250 μg/L) for 96 h. At the end of the bioassay, the swimming performance and 11 biomarkers were determined. Biomarkers were: hepatosomatic index (HSI), lipid peroxidation (LPO), reduced glutathione and the activities of the enzymes ethoxyresorufin O-deethylase (EROD), glutathione S-transferases, superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, brain acetylcholinesterase (AChE) and muscle cholinesterases (ChE). After 96 h of exposure, carbofuran induced a decrease of the swimming velocity and inhibition of EROD activity at all concentrations tested, and inhibition of muscle ChE and brain AChE activities at 250 μg/L. No relevant alterations in any of the other tested parameters were found. These results show that carbofuran induced adverse effects on fish by interfering with neurofunction, capability of detoxication and swimming velocity. In addition, positive and significant correlations between the swimming velocity and (i) brain AChE activity, (ii) muscle ChE activity and (iii) EROD activity suggest that the inhibition of these enzymes may somehow be related to the behavioural changes observed. Since these functions are determinant for the survival and performance of the fish in the wild, the findings of the present study suggest that adverse effects may occur in populations exposed to carbofuran if a sufficient number of animals is affected.

Municipal landfill leachate induces hepatotoxicity and oxidative stress in rats

Human beings are more often exposed to complex mixtures of hazardous chemicals than single toxicant. The present study investigated the effects of Olushosun municipal landfill leachate (OMLL) from Ojota in Lagos State of Nigeria on hepatic function and some biomarkers of oxidative stress in adult rats. Physicochemical characteristic analysis of OMLL showed that while total alkalinity, total acidity, total hardness, biochemical oxygen demand and chemical oxygen demand were 3-fold, 2-fold, 4-fold and 1-fold, respectively, concentrations of heavy metals analysis showed that copper, lead, cadmium, arsenic, cobalt, chromium and mercury were 9-fold, 4-fold, 21-fold, 1320-fold, 7-fold, 5-fold and 4-fold, respectively, higher than acceptable limits by regulatory authorities. The OMLL was administered at 0, 10, 20, 30 and 40% concentrations to adult male rats for 14 days. Following exposure, serum was collected for serum biochemistry assays and liver was collected to determine the antioxidant status. Exposure of animals to 10, 20, 30 and 40% OMLL resulted in 3%, 31%, 52% and 83% increase in aspartate aminotransferase activity, whereas it elevated alanine aminotransferase activity by 10%, 25%, 30% and 49%, respectively, when compared with the control. While OMLL administration significantly increased catalase activity, a sequential decrease in reduced glutathione level and in superoxide dismutase and glutathione- S-transferase activities with concomitant increase in malondialdehyde level were observed, when compared with the control. Collectively, the hepatotoxicity of OMLL could be due to the induction of oxidative stress and may suggest possible health hazards in subjects with occupational or environmental exposure.

Ecotoxicoproteomics in gills of the sentinel fish species, Cottus gobio, exposed to perfluorooctane sulfonate (PFOS)

The environmental persistence, bioaccumulative tendency and potential toxicity of perfluorooctane sulfonate (PFOS) have generated great concern. This study aimed at evaluating the toxicity of short-term PFOS exposure in gills of the European bullhead Cottus gobio, a candidate sentinel species, by monitoring the response of some enzymes (citrate synthase CS, cytochrome c oxidase CCO, and lactate dehydrogenase LDH), and by undertaking a proteomic analysis using 2D-DIGE. First, a 96-h exposure to 1mg PFOS/L significantly altered the activity of mitochondrial CS and CCO. Second, 2D-DIGE gels were used to compare gills from the control fish group with tissues from fish exposed for 96h to either 0.1 or 1mg PFOS/L. From the 27 protein spots displaying significant changes in abundance following PFOS exposure, a total of 20 different proteins were identified using nano LC-MS/MS and the Peptide and Protein Prophet of Scaffold software. The differentially expressed proteins that were identified are involved in the general stress response, ubiquitin-proteasome system, energy metabolism, and actin cytoskeleton, which provide clues on the cellular pathways and components mainly affected by PFOS. Moreover, our results showed that most proteins were differentially expressed at the low but not at the high PFOS concentration. This work provides insights into the biochemical and molecular events in PFOS-induced toxicity in gill tissue, and suggests that further studies on the identified proteins could provide crucial information to better understand the mechanisms of PFOS toxicity in fish.

Toxicity of the herbicide atrazine: effects on lipid peroxidation and activities of antioxidant enzymes in the freshwater fish Channa punctatus (Bloch)

The present study was undertaken to evaluate the toxicity and effects of a commercial formulation of the herbicide atrazine (Rasayanzine) on lipid peroxidation and antioxidant enzyme system in the freshwater air breathing fish Channa punctatus. The 12, 24, 48, 72 and 96 h LC(50) of atrazine, calculated by probit analysis, were determined to be 77.091, 64.053, 49.100, 44.412 and 42.381 mg·L(-1), respectively, in a semi static system with significant difference (p < 0.05) in LC(10-90) values obtained for different times of exposure. In addition to concentration and time dependent decrease in mortality rate, stress signs in the form of behavioral changes were also observed in response to the test chemical. In fish exposed for 15 days to different sublethal concentrations of the herbicide (1/4 LC(50) = ∼10.600 mg·L(-1), 1/8 LC(50) = ∼5.300 mg·L(-1) and 1/10 LC(50) = ∼4.238 mg·L(-1)) induction of oxidative stress in the liver was evidence by increased lipid peroxidation levels. The antioxidants superoxide dismutase (SOD), catalase (CAT) and glutathione reductase (GR) responded positively in a concentration dependent pattern, thus, suggesting the use of these antioxidants as potential biomarkers of toxicity associated with contaminations exposure in freshwater fishes.

Deltamethrin attenuates antioxidant defense system and induces the expression of heat shock protein 70 in rainbow trout

The current research aims to determine alterations in gene expression and enzymatic activity of fish antioxidant metabolism in response to pesticide administration. To this end, three different deltamethrin concentrations (0.25, 1, 2.5mug/L) were administrated to rainbow trout (Oncorhynchus mykiss) at different time intervals (6, 12, 24, 48 and 72h) in order to observe the influences of the pesticide on the activity of glutathione reductase, glucose 6-phosphate dehydrogenase, 6-ghosphogluconate dehydrogenase, and the expression of Hsp70 gene. We observed that the activities of the enzymes decreased with increasing deltamethrin concentrations and exposure time. The pesticide had more inhibitory effects on gill enzymes than those of muscle, liver and kidney. In addition, we detected that deltamethrin increased the expression of the stress-related protein Hsp70 with significant fold-chance values. The efficiency rate was 96.4% which is equal to 1.96 calculated via conversion formula used to calculate fold-chance value. We conclude that deltamethrin causes oxidative stress in fish both at protein and mRNA levels.

Modulatory effects of deltamethrin on antioxidant defense mechanisms and lipid peroxidation in Carassius auratus gibelio liver and intestine

Pyrethroids, such as deltamethrin, are toxic substances that lead to generation of reactive oxygen species, which harm living organisms. We assessed the level and patterns of imbalance evolved by a single dose of 2 microg/L deltamethrin on the lipid peroxidation (LPO) and the antioxidant defense system of Carassius auratus gibelio liver and intestine, and monitored the recovery dynamics of these parameters during a 14-day post-exposure period. LPO and antioxidative defense mechanisms displayed different responses in the investigated tissues. Sudden increase of LPO in the liver, persisting at this elevated level throughout the test period, was observed on the third day post-exposure, while in the intestine significant enhancement of this parameter was recorded from the seventh day. Reduced glutathione (GSH) showed a transient increase in the liver, and was depleted in the intestine by the second day of exposure, with signs of recovery by the end of the experimental tenure. In the liver of fish a temporary inhibition of superoxide dismutase (SOD) and catalase (CAT) activity, and activation of glutathione peroxidase (GPX), glutathione transferase (GST), and glutathione reductase (GR) enzymes was observed, with maximum thresholds recorded on the third and second days, respectively. In the intestine a relevant increase in CAT and GST activity up to the second day and almost complete recovery by the end of the experiment was recorded, while for GR a continuous enhancement was apparent.

Influence of cypermethrin toxicity on ionic regulation and gill Na(+)/K(+)-ATPase activity of a freshwater teleost fish Cyprinus carpio

The effects of acute and sublethal toxicity of cypermethrin, a synthetic pyrethroid insecticide on plasma electrolytes (Na(+), K(+) and Cl(-)) levels and gill Na(+)/K(+)-ATPase activity in a common carp Cyprinus carpio were examined. The 24h LC(50) value of cypermethrin for C. carpio was 1.86ppm. During acute exposure, cypermethrin caused adverse effects in the form of hyponatreima, hypokalemia and hypochloremia and inhibition of gill Na(+)/K(+)-ATPase activity. In sublethal exposure to cypermethrin (0.186ppm for 35 days), plasma Na(+) was decreased throughout the exposure period except 7th day whereas plasma K(+) level was increased up to 28th day, then declined. However, plasma Cl(-) level was decreased. Likewise, gill Na(+)/K(+)-ATPase activity was decreased as the exposure period extended. The present study indicates that cypermethrin was highly toxic to freshwater fish and ion levels in blood as measured by specific ion concentrations (Na(+), K(+) and Cl(-)) and changes in gill Na(+)/K(+)-ATPase activity may represent a sensitive and useful nonspecific biomarkers of chemical exposure and effects.

Genotoxic and oxidative stress-inducing effects of deltamethrin in the erythrocytes of a freshwater biomarker fish species, Channa punctata Bloch

Deltamethrin, an alpha-cyano class of pyrethroid insecticide is used in insect pest control and antimalaria programs in several countries including India. Although various toxic manifestations of deltamethrin are reported in mammals, its ecotoxicologic dimensions are not adequately researched in ecologically and commercially important fishes. In this study, we report genotoxic effect of deltamethrin in a biomarker fish Channa punctata (Bloch). Adult fish were exposed to three concentrations of technical grade deltamethrin (0.4, 0.8, and 1.2 microg/L) for 48 and 72 h. Ethyl methane sulfonate was used as a positive control. Fish were analyzed for induction of micronucleus (MN), nuclear abnormalities (NAs), and oxidative stress biomarkers in erythrocytes. Deltamethrin significantly induced MN and NAs accompanied by increased lipid peroxidation. Activity of antioxidant enzyme superoxide dismutase was significantly decreased but an increase was observed in reduced glutathione level after 72 h of exposure. The NAs in exposed fish included blebbed, lobed and notched nuclei, and binucleated erythrocytes. Our findings suggest that oxidative stress may, in part, be contributing to deltamethrin-induced genotoxic damage to erythrocytes. Although MN induction is a nonspecific biomarker, it may provide an indication of pollution load of deltamethrin in the affected fish population when used as part of suite of other biomarkers.

Oxidative stress, protein carbonylation and heat shock proteins in the black tiger shrimp, Penaeus monodon, following exposure to endosulfan and deltamethrin

The impact of commonly used pesticides, endosulfan and deltamethrin, on the molecular stress level in black tiger shrimp Penaeus monodon, was assessed using classical oxidative stress biomarkers, protein carbonylation profiles, and levels of heat shock proteins. Results showed that 4 days exposure to 0.1 μg L(-1) deltamethrin significantly (p<0.05) increased lipid peroxidation (LPO) level in gills (64.3 ± 3.2 compared to 34.2 ± 5.3 nmol MDA equiv.g(-1) tissue at day 0). However, no pesticide treatment had significant effect on the activities of antioxidant enzymes catalase (CAT), glutathione peroxidase (GPx) and glutathione S-transferase (GST). Carbonylated protein profiles were determined on gills following 2,4-dinitrophenylhydrazine derivatization and 2D-PAGE along with Western blotting. Immunoblotting with dinitrophenol-specific antibody revealed 17 protein spots carbonylated in response to 4 days exposure to 0.1 μg L(-1) deltamethrin while 24 protein spots specifically oxidized at day 0 were no longer detected after deltamethrin treatment. On the other hand, endosulfan exposure at 0.1 and 1 μg L(-1) induced up to 2.1-fold increase of HSP90 level in muscle. This approach is providing new insights into the molecular impacts of deltamethrin and endosulfan on an economically important crustacean. While deltamethrin has shown a pro-oxidant effect in gills, endosulfan exposure rather induced proteotoxic effects in muscles. This argues that LPO level, protein carbonylation specificities, and HSP90 levels may be potential discriminating biomarkers to assess the chemical stress level in farm shrimp.

Contamination assessment of a coastal lagoon (Ria de Aveiro, Portugal) using defence and damage biochemical indicators in gill of Liza aurata--an integrated biomarker approach

Fish gill importance in toxicants uptake, bioconcentration and excretion allied to meagre knowledge on branchial damage/protection responses substantiate this study. Five critical sites in Ria de Aveiro (Portugal) were assessed in comparison with a reference site (Torreira), focusing on Liza aurata gill antioxidant defences versus damage (oxidative and genetic). Only in Barra fish displayed damage (lipid peroxidation) though no differences were found in antioxidants. In all other sites, except Rio, antioxidant alterations were found. Thus, fish from Gafanha, Laranjo and Vagos showed higher total glutathione, glutathione peroxidase and catalase. Higher glutathione reductase and glutathione S-transferase activity was also found in the first and the last sites, respectively. In Laranjo, metallothionein levels were higher though lower in Gafanha and Vagos. In general, damage was not accompanied by defences weakening confirming that predicting damage based on antioxidants depletion is not straightforward. The integrated biomarker response index ranked sites as: Gafanha>Barra>Laranjo>Vagos>Rio>Torreira.

Effect of binary combination of deltamethrin+MGK-264 on the levels of phospholipid and lipid peroxidation in the snail Lymnaea acuminata

Effect of sublethal treatment of (40% and 60% of 48 h LC50) of deltamethrin+MGK on phospholipid level and rate of lipid peroxidation in nervous and foot tissue of Lymnaea acuminata were studied. Maximum reduction in phospholipid (24.10%) level and increase in rate of lipid peroxidation (586.8%) were observed in foot tissue of snail exposed to 60% of 48 h LC50 of deltamethrin+MGK 264 for 96 h. Alterations in the levels of phospholipids and rate of lipid peroxidation were time and concentration dependent. Use of MGK-264 with deltamethrin increases the toxicity of deltamethrin and their action on membrane phospholipids and rate of lipid peroxidation.

Effects of cypermethrin, propetamphos, and combination involving cypermethrin and propetamphos on lipid peroxidation in mice

Insecticides are the chemicals widely used in agriculture, environmental health, human-and animal-health fields. Exposure to insecticides has been associated with many hazardous effects, including antioxidative metabolism. In the current study, the effect of cypermethrin (CYP), propetamphos (PRO) and their mixtures on oxidative stress in mice to understand the possible health effects to animals and human beings was investigated. In the present study, 245 male Albino mice weighing 35-40 g were used. The mice were divided into seven groups. The first group served as the control group. The second and third groups were administered CYP at doses of 5 mg/kg/bw and 10 mg/kg/bw, respectively, and the fourth and fifth groups were given PRO at doses of 2.5 mg/kg/bw and 5.0 mg/kg/bw, respectively. The sixth and seventh groups received combination regimens containing 5 mg/kg/bw CYP plus 2.5 mg/kg/bw PRO and 10 mg/kg/bw CYP plus 5 mg/kg/bw PRO, respectively, in feed for 60 days. Blood samples were collected by cardiac puncture on the 15th, 45th and 60th days. Serum nitric oxide (NO) and plasma malondialdehyde (MDA) levels and erythrocyte superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) activities were measured. In conclusion, the alterations observed in the MDA and NO levels and SOD, CAT, and GSH-Px activities of the trial groups, demonstrate the administration of certain doses of CYP and PRO, either alone or combined, to mice for a period of 60 days to produce oxidative stress. The degree of oxidative stress was found to be related to the dose administered, the duration of exposure and the administration of the indicated compounds either alone or as a combination.

Joint effects of dietary cadmium and polychlorinated biphenyls on metallothionein induction, lipid peroxidation and histopathology in the kidneys and liver of bank voles

Free-living bank voles have been shown to be more sensitive to cadmium (Cd) toxicity than the rodents exposed to Cd under laboratory conditions. The present study was designed to find out whether polychlorinated biphenyls (PCBs), common environmental co-contaminants, increase susceptibility to Cd toxicity through inhibition of metallothionein (MT) synthesis-a low molecular weight protein that is considered to be a primary intracellular component of the protective mechanism. For 12 weeks, the male bank voles were provided with diets containing Cd (0.05 microg/g (control) and 10 microg/g dry wt) and PCBs (0, 10 and 50 microg/g dry wt) alone or in combination under long (16 h) and short (8 h) photoperiods. At the end of exposure period, histological examinations and analyses of MT, Cd, Fe and lipid peroxidation in the kidneys and liver were carried out. Dietary PCBs did not affect Cd inducibility of renal MT, but decreased it significantly in the liver; however, no signs of Cd toxicity (measured by histopathology) occurred in both organs. On the contrary, PCBs at the highest dose increased significantly lipid peroxidation in the kidneys and liver (4-fold) only in the bank voles raised under a long photoperiod; the PCB-induced hepatic lipid peroxidation was accompanied by extensive histopathological changes including hepatocyte enlargement, necrosis and steatosis. Co-treatment with dietary Cd significantly suppressed the increase in lipid peroxidation and apparently reduced hepatic damage. These data indicate that (1) dietary PCBs do not enhance Cd toxicity in the kidneys and liver of bank voles and (2) dietary Cd suppresses PCB-induced hepatotoxicity that appears to be photoperiod-dependent.

Responses of metallothionein and reduced glutathione in a freshwater fish Oreochromis niloticus following metal exposures

In this study, levels of reduced glutathione (GSH) and metallothionein (MT) which are known to be biomarker of metal exposures were measured in a freshwater fish Oreochromis niloticus following exposure to 0, 5, 10 and 20μM concentrations of Cu, Zn, Cd and Pb for 14 days. Metals and GSH were measured in the liver, gill, intestine, muscle and blood, and MT in the liver. Copper accumulation occurred only in the gill, while Zn accumulation occurred only in the muscle. Lead accumulated in the liver and gill, whereas Cd accumulated in all the tissues. Metal exposures did not alter GSH levels in the blood, muscle and gill, but its levels increased in the liver following Cd, Zn and Cu exposures. MT levels in the liver increased only in Cd-exposed fish. The results showed that there was no significant change in tissue GSH levels following metal exposures, except in the liver. The levels of liver GSH increased significantly by all the metals, except lead. Data indicated that only the liver may be suitable indicator tissue to determine the response of GSH and MTs to metal exposure in environmental monitoring studies.

In vitro free radical scavenging activity of hepatic metallothionein induced in an Indian freshwater fish, Channa punctata Bloch

Mammalian metallothioneins (MT) have been reported to scavenge free radicals. There is no experimental evidence to show that fish MT has a similar property. In the present study cadmium-induced MT (Cd-MT) from the liver of an Indian freshwater fish Channa punctata Bloch was investigated for its free radical scavenging activity using three different in vitro assays. Exposure to cadmium chloride (0.2 mg/kg body weight; three doses on alternate days) resulted in a marked induction of Cd-MT in liver. Only a single isoform of Cd-MT was found to be induced. Molecular weight of Cd-MT was found to be 14 kDa as deduced by SDS-PAGE analysis. The purified Cd-MT effectively scavenged the following free radicals: superoxide radical (O2*-), 2,2'-azinobis 3-ethylbenzothiazoline-6-sulfonic acid (ABTS*+) and 1,1-diphenyl-picrylhydrazyl radical (DPPH*). The radical scavenging effect was found to be concentration-dependent. Also, the purified MT exhibited an inhibitory effect on ferric nitrilotriacetate (Fe-NTA) induced oxidative DNA damage in vitro. The cysteine residues of MT are proposed to be the main candidate for its radical scavenging activity. Findings of the present study strongly suggest a free radical scavenging role for fish MT. Present study adds to the little existing knowledge about fish MT and its possible biological functions.