In vitro genotoxic effects of the insecticide deltamethrin in human peripheral blood leukocytes: DNA damage ('comet' assay) in relation to the induction of sister-chromatid exchanges and micronuclei

New insight on some selected nanoparticles as an effective adsorbent toward diminishing the health risk of deltamethrin contaminated water

Deltamethrin is a widely used insecticide that kills a wide variety of insects and ticks. Deltamethrin resistance develops as a result of intensive, repeated use, as well as increased environmental contamination and a negative impact on public health. Its negative impact on aquatic ecology and human health necessitated the development of a new technique for environmental remediation and wastewater treatment, such as the use of nanotechnology. The co-precipitation method was used to create Zn-Fe/LDH, Zn-AL-GA/LDH, and Fe-oxide nanoparticles (NPs), which were then characterized using XRD, FT-IR, FE-SEM, and HR-TEM. The kinetic study of adsorption test revealed that these NPs were effective at removing deltamethrin from wastewater. The larval packet test, which involved applying freshly adsorbed deltamethrin nanocomposites (48 hours after adsorption), and the comet assay test were used to confirm that deltamethrin had lost its acaricidal efficacy. The kinetics of the deltamethrin adsorption process was investigated using several kinetic models at pH 7, initial concentration of deltamethrin 40 ppm and temperature 25°C. Within the first 60 min, the results indicated efficient adsorption performance in deltamethrin removal, the maximum adsorption capacity was 27.56 mg/L, 17.60 mg/L, and 3.06 mg/L with the Zn-Al LDH/GA, Zn-Fe LDH, and Fe Oxide, respectively. On tick larvae, the results of the freshly adsorbed DNC bioassay revealed larval mortality. This suggests that deltamethrin's acaricidal activity is still active. However, applying DNCs to tick larvae 48 hours after adsorption had no lethal effect, indicating that deltamethrin had lost its acaricidal activity. The latter result corroborated the results of the adsorption test's kinetic study. Furthermore, the comet assay revealed that commercial deltamethrin caused 28.51% DNA damage in tick cells, which was significantly higher than any DNC. In conclusion, the NPs used play an important role in deltamethrin decontamination in water, resulting in reduced public health risk. As a result, these NPs could be used as a method of environmental remediation.

Effects of deltamethrin and thiacloprid on cell viability, colony formation and DNA double-strand breaks in human bronchial epithelial cells

Deltamethrin (DEL) and thiacloprid (THIA) are commonly used insecticides applied either separately or as a mixture. We aimed to investigate the effects of DEL and THIA on cell viability, proliferation and DNA damage in human bronchial epithelial cells (BEAS-2B) because their effects in lung cells are not known. Our results indicate that all concentrations of DEL and THIA statistically decreased colony formation, plating efficiency and survival fraction in a concentration-dependent manner in BEAS-2B cells expect the lowest concentration for 24 h. MTT assay showed that treatment of DEL + THIA increased the cytotoxicity at higher concentrations. DEL + THIA significantly induced the foci formation of phosphorylated H2AX protein and p53 binding protein 1 at the highest concentration (44 μM DEL+666 μM THIA) for 120 h. Because gH2AX foci number was still higher in the recovery group given an additional 24 h after 120 h, the recovery period was not sufficient for DNA double-strand breaks repair.

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.

Microplastics enhance Daphnia magna sensitivity to the pyrethroid insecticide deltamethrin: Effects on life history traits

The aim of the study was to investigate the influence of microplastics (MPs) on the ecotoxicity of common contaminants of aquatic ecosystems. As a model contaminant, the hydrophobic pesticide deltamethrin (DM) was chosen, and its effects on life history traits of Daphnia magna were studied in the presence or absence of polyethylene MPs. Commercialized DM and MPs obtained as dry powder were used in the experiment. According the manufacturer (Cospheric, Santa Barbara, CA, USA) MPs were spherical (1-4 μm in diameter), had a density of 0.96 g/cm^-3 and were without any solvent. Three concentrations of polyethylene MPs were tested (0, 1, 10 mg/L) with two realistic concentrations of DM (0 and 40 ng/L) and a solvent control (acetone). During the 21 d experiment, D. magna neonates were individually exposed to the treatments, and the effects of MPs and DM alone and together were evaluated by assessing survival, number of cumulative molts, days to first brood, number of broods, number of neonates per surviving adult, and body length. Significant detrimental effects on survival were only observed for the two mixture treatments. DM alone (40 ng/L) delayed the days to first brood and reduced the number of neonates per surviving adult, whereas MPs alone (10 mg/L) induced significant reduction in the number of juveniles by surviving adults. The combined exposure to DM and MPs clearly had a synergistic effect on survival, brood number, and number of neonates per surviving female. For example, compared to exposure to 40 ng/L of DM alone, the addition of 1 mg/L of MPs resulted in a 51.1% reduction in number of neonates per surviving female and a 46% reduction in brood number. These results suggest the potential drastic effects of this kind of mixed exposure on daphnid populations, which are key components of freshwater food webs.

Assessment of the genotoxic potential of a migraine-specific drug by comet and cytokinesis-block micronucleus assays

Background: Eletriptan is a migraine-specific drug-containing the triptan group. In terms of drug safety, the present study aimed to investigate the genotoxic potential of eletriptan.Research design & methods: We conducted our study by using the cytokinesis-block micronucleus cytome (CBMN) assay, a comprehensive method for measuring micronucleus formation, and a sensitive method for detecting DNA-strand breaks. In the assay, cytokinesis-block proliferation index and the frequency of micronuclei were evaluated in lymphocytes treated with three different concentrations (1, 10 and 25 µg/ml) of eletriptan for 48 hours. In comet assays, DNA damage was evaluated in leucocytes treated with three different concentrations (1, 10 and 25 µg/ml) of eletriptan for an hour.Results: Eletriptan did not induce cytotoxicity nor any increased micronuclei frequencies. While the comet parameters % DNA in tail, tail moment, and the olive moment was found to be significantly increased at 10 and 25 µg/ml, the cytokinesis-block proliferation index values were not.Conclusion: These findings suggest that eletriptan is non-cytotoxic but potentially weakly genotoxic at higher concentrations (10 and 25 µg/ml).

Biochemical and endocrine-disrupting effects in Clarias gariepinus exposed to the synthetic pyrethroids, cypermethrin and deltamethrin

In the present study, we investigated plasma biochemical and steroid hormone responses, together with gonado-histopathological alterations in Clarias gariepinus exposed to sublethal concentrations of two synthetic pyrethroids (cypermethrin and deltamethrin). Fish were exposed to environmentally-relevant concentrations of cypermethrin at 0 (ethanol solvent control), 0.07, 0.014, 0.028, 0.056) and deltamethrin at 0.22, 0.44, 0.88 and 1.76 μg/L, for 7, 14, 21 and 28 days. Plasma enzyme (aspartate transaminase: AST, alanine transaminase: ALT and alkaline phosphatase: ALP) and steroid hormones (estradiol-17β: E2, testosterone: T) levels were analyzed. Gonado-histopathological evaluation shows the presence of ovo-testis (intersex), oocytes atresia, cytoplasmic degeneration and clumping of vitellogenic oocytes in females, while male fish displayed enlargement and degeneration of testicular seminiferous tubules after 28 days exposure to cypermethrin and deltamethrin. Plasma biochemical analysis in pesticides exposed fish revealed that AST, ALT and ALP were significantly increased in a concentration-dependent manner. In addition, we observed respective and apparent concentration- and time-dependent increase and decrease of plasma E2 and T levels, compared to control. Interestingly, the significant increase in E2 levels paralleled gonadal ovo-testis (intersex) condition in exposed fish, indicating endocrine disruptive effects of cypermethrin and deltamethrin that favor the estrogenic pathway, in addition to overt negative consequences on reproductive, biochemical and physiological health of the exposed fish.

Pyrethroid pesticide exposure and hematological cancer: epidemiological, biological and molecular evidence

Pyrethroid insecticides are commonly used worldwide. The chronic effects of these compounds are of concern given that epidemiological studies have suggested an association with hematological cancer, particularly in children. However, the biological evidence at molecular and cellular levels is limited. A review on the molecular and cellular effects of pyrethroids is helpful to guide the study of the biological plausibility of the association of pyrethroids with hematological cancer. We reviewed studies suggesting that pyrethroids are genotoxic, induce genetic rearrangements, alter gene expression and modify DNA. All of these biological modifications could potentially contribute to the carcinogenic process in hematopoietic cells.

Zebrafish embryos exposed to deltamethrin exhibit abnormalities despite induced expression of related genes ( you, you-too, momo and u-boot)

Evaluation of the toxic effects of a widely used synthetic pyrethroid, deltamethrin (DM), was carried out in this study. This pesticide is preferred for pest control because of its low environmental persistence and toxicity. We investigated the expression pattern of four genes, namely, you ( you), yot ( you-too), momo ( mom) and ubo ( u-boot) during early development of zebrafish, that is, from 12 hpf to 48 hpf stages. These stages are selected as most of the important developmental aspects take place during this period. All four genes are known to play a vital role in development of notochord and somites. To understand the effect of DM on development, embryos of 4 hpf stage were exposed to two concentrations (100 and 200 µg/L) of DM, and observations were made at 12, 24 and 48 hpf stages. Our earlier studies have shown phenotypic abnormalities such as notochord bending, tail deformation, yolk sac and pericardial edema, lightening of body and eye pigmentation and interfered in somite patterning, during these stages of development. Understanding the relationship of phenotypic abnormalities with these four genes has been our primary objective. These four genes were analyzed by Reverse transcription (RT)-polymerase chain reaction and intensity of the bands has shown induction in their expression after exposure to the toxicant. In spite of the expression of genes, it was noticed that DM caused abnormalities. It can be said from the results that translational pathway could have been affected.

Neurophysiological responses in the brain tissues of rainbow trout (Oncorhynchus mykiss) treated with bio-pesticide

The aim of this study was to investigate neurophysiological responses in rainbow trout brain tissue exposed to natural/botanical pesticides. Fish were exposed to botanical and synthetic pesticides over a 21-day period. At the end of the treatment period, oxidative DNA damage (indicated by 8-OHdG (8-hydroxy-2'-deoxyguanosine), AChE activity (acetylcholinesterase) and transcriptional parameters (gpx (glutathione peroxidase), sod (superoxide dismutase), cat (catalase), HSP70 (heat shock protein 70) and CYP1A (cytochromes P450)) was investigated in control and application groups. Our results indicated that brain AChE activities decreased very significantly in fish treated with both insecticide types when compared with control (p < 0.05). 8-OHdG activity increased in a dose/time-dependent situation in the brain tissues of Oncorhynchus mykiss (p < 0.05). In addition, with regards to gene expression, gpx sod and, cat expressions were down-regulated, whereas CYP1A and HSP70 gene expression were up-regulated in fish treated with both insecticides when compared to the control group (p < 0.05). The data for this study suggests that bio-pesticides can cause neurophysiological changes in fish brain tissue.

Evaluation of acute toxicity of triazophos and deltamethrin and their inhibitory effect on AChE activity in Channa punctatus

Pesticides are applied to control the pests indoor and outdoor; however, their remarkable amount reaches to the aquatic system through various routes like run-off, leaching, spray-drift, effluent from factories. These are reported to have negative metabolic impact on different non-target aquatic organisms like fishes. Thus, present study is aimed to evaluate the acute toxicity of two groups of pesticides, organophosphate and pyrethroid, namely triazophos and deltamethrin, respectively. The test was conducted for 96 h period in a freshwater teleost, Channa punctatus. The LC₅₀ values for triazophos and deltamethrin after 96 h treatment was found to be 0.069 mg/L and 7.33 μg/L. The deltamethrin was found to be about ten times more toxic than triazophos to the fish. In treated fish, alterations in various behavioural patterns were observed with increasing concentrations of both the pesticides as compared to control. Further, tissue specific as well as dose dependent inhibition in the acetylcholinesterase (AChE, EC 3.1.1.7) activity was found in brain, muscle and gills in Channa punctatus exposed to both the insecticides. However, the effect was more pronounced in triazophos treated fishes than the deltamethrin. A futuristic approach on biochemical and molecular studies may throw light on the mechanism of action of these pesticides.

Deciphering the toxic effects of organochlorine pesticide, dicofol on human RBCs and lymphocytes

Organochlorine pesticides have generated growing concern owing to their diverse toxicities. In this connection, we have evaluated toxic potential of an acaricide, dicofol (DCF) and its harmful effects on human RBCs and lymphocytes. DCF caused hemolysis and rupture of human erythrocytes as confirmed by scanning electron microscopy (SEM). Significant increase in protein oxidation, lipid peroxidation, ROS production, methemoglobin formation with enhanced activities of superoxide dismutase and catalase but decreased level of reduced glutathione were observed as a result of DCF exposure to human erythrocytes. SEM showed significant DCF induced alterations in RBCs from normal discoid shape to echinocytes. Similarly, lymphocytes showed membrane damage, formation of membrane blebs and distorted cell morphology. In vitro comet assay indicated a significant DNA fragmentation in human lymphocytes upon DCF exposure. These results strongly suggest that DCF induces oxidative stress in RBCs via generation of ROS and alters the cellular architecture directly and indirectly.

Transcriptional responses in the hepatopancreas of Eriocheir sinensis exposed to deltamethrin

Deltamethrin is an important pesticide widely used against ectoparasites. Deltamethrin contamination has resulted in a threat to the healthy breeding of the Chinese mitten crab, Eriocheir sinensis. In this study, we investigated transcriptional responses in the hepatopancreas of E. sinensis exposed to deltamethrin. We obtained 99,087,448, 89,086,478, and 100,117,958 raw sequence reads from control 1, control 2, and control 3 groups, and 92,094,972, 92,883,894, and 92,500,828 raw sequence reads from test 1, test 2, and test 3 groups, respectively. After filtering and quality checking of the raw sequence reads, our analysis yielded 79,228,354, 72,336,470, 81,859,826, 77,649,400, 77,194,276, and 75,697,016 clean reads with a mean length of 150 bp from the control and test groups. After deltamethrin treatment, a total of 160 and 167 genes were significantly upregulated and downregulated, respectively. Gene ontology terms "biological process," "cellular component," and "molecular function" were enriched with respect to cell killing, cellular process, other organism part, cell part, binding, and catalytic. Pathway analysis using the Kyoto Encyclopedia of Genes and Genomes showed that the metabolic pathways were significantly enriched. We found that the CYP450 enzyme system, carboxylesterase, glutathione-S-transferase, and material (including carbohydrate, lipid, protein, and other substances) metabolism played important roles in the metabolism of deltamethrin in the hepatopancreas of E. sinensis. This study revealed differentially expressed genes related to insecticide metabolism and detoxification in E. sinensis for the first time and will help in understanding the toxicity and molecular metabolic mechanisms of deltamethrin in E. sinensis.

In vitro genotoxic and cytotoxic effects of doxepin and escitalopram on human peripheral lymphocytes

Antidepressants are drugs used for the treatment of many psychiatric conditions including depression. There are findings suggesting that these drugs might have genotoxic, carcinogenic, and/or mutagenic effects. Therefore, the present in vitro study is intended to investigate potential genotoxic and cytotoxic effects of the antidepressants escitalopram (selective serotonin reuptake inhibitor) and doxepin (Tricyclic antidepressant) on human peripheral lymphocytes cytokinesis-block micronucleus (CBMN), sister chromatid exchange (SCE), and single cell gel electrophoresis (alkaline comet assay) were used for the purpose of the study. In the study, four different concentrations of both drugs (1, 2.5, 5, and 10 µg/mL) were administered to human peripheral lymphocytes for 24 h. The tested concentrations of both drugs were found to exhibit no cytotoxic and mitotic inhibitory effects. SCE increase caused by 5 and 10 µg/mL of escitalopram was found statistically significant, while no statistically significant increase was observed in DNA damage and micronucleus (MN) formation. Moreover, the increase caused by doxepin in MN formation was not found statistically significant. Besides, 10 µg/mL of doxepin was demonstrated to significantly increase arbitrary unit and SCE formation. These findings suggest that the investigated concentrations of escitalopram and doxepin were non-cytotoxic but potentially genotoxic at higher concentrations.

Assessment of Genotoxic Effects of Pendimethalin in Chinese Hamster Over Cells by the Single Cell Gel Electrophoresis (Comet) Assay

Objectives

Pendimethalin (N-(1-ethylpropyl)-3,4-dimethyl-2,6-dinitrobenzeneamine) is a dinitroaniline herbicide compound which selectively controls weeds. It is a cell division and growth inhibitor. It descends plants in a short time after seedling. It is a soil and water pollutant due to the widespread use of formulations in Turkey and around the world. Pendimethalin is manufactured in and imported by Turkey. Pendimethalin is a slightly toxic compound that is classified in toxicity class 3 by the United States Environmental Protection Agency (USEPA). Even though it is classified as group C (human possible carcinogen) compound by the USEPA, there are limited number of studies about its genotoxic effects. The aim of this study was to evaluate in vitro genotoxic effects of different concentrations of pendimethalin in Chinese hamster over (CHO) cells by the single cell gel electrophoresis (comet) assay.

Materials and Methods

The cells are incubated with 1, 10, 100, 1000 and 10000 µM concentrations of pendimethalin for 30 min at 37°C and DNA damage was compared with CHO cells untreated with pendimethalin. 50 µM hydrogen peroxide was used as positive control.

Results

No significant cytotoxic effects were observed within the concentration ranges studied. The DNA damage in CHO cells was significantly increased in the pendimethalin concentrations of 1, 100, 1000 and 10000 µM, however, a significant decrease was observed in 10 µM pendimethalin concentration.

Conclusion

Our results show that 1-10000 µM concentrations of pendimethalin induce DNA damage in CHO cells, which was assessed by comet assay.

Genotoxicity of commercial fungicide Cabrio Plus on human cell

Cabrio Plus, a commercial fungicide, is used in agriculture as the control agent for a broad spectrum of diseases including black dot, early blight, late blight and powdery mildew. This study aimed to evaluate the genotoxicity of commercial formulation of Cabrio Plus which has been inadequately evaluated. The genotoxic potential of Cabrio Plus in isolated human peripheral blood lymphocytes was measured by means of an alkaline version of the comet assay (pH > 13) and in whole blood by use of the in vitro micronucleus test. Cabrio Plus induced a statistically significant increase in DNA damage assessed with the in vitro micronucleus assay and the comet assay. Cabrio Plus also induced cytotoxicity in a dose-dependent manner with the in vitro micronucleus assay. It can be concluded that a commercially available pesticide formulation, Cabrio Plus, has the ability to cause DNA damage and cytotoxicity.

Determination of genotoxic effects of methidathion alkaline hydrolysis in human lymphocytes using the micronucleus assay and square-wave voltammetry

The interaction of pesticides with environmental factors, such as pH, may result in alterations of their physicochemical properties and should be taken into consideration in regard to their classification. This study investigates the genotoxicity of methidathion and its alkaline hydrolysis by-products in cultured human lymphocytes, using the square-wave voltammetry (square wave-adsorptive cathodic stripping voltammetry (SW-AdCSV) technique) and the cytokinesis block micronucleus assay (CBMN assay). According to the SW-AdCSV data the alkaline hydrolysis of methidathion results in two new molecules, one non-electro-active and a second electro-active which is more genotoxic than methidathion itself in cultured human lymphocytes, inducing higher micronuclei frequencies. The present study confirms the SW-AdCSV technique as a voltammetric method which can successfully simulates the electrodynamics of the cellular membrane.

Surface Water Impacted by Rural Activities Induces Genetic Toxicity Related to Recombinagenic Events in Vivo

This investigation assessed the interaction of surface water samples with DNA to quantitatively and qualitatively characterize their mutagenic and/or recombinagenic activity. Samples were obtained at three different sites along the Tocantins River (Tocantins State, Brazil). The area has withstood the impact mainly of rural activities, which release different chemical compounds in the environment. The Drosophila melanogaster Somatic Mutation and Recombination Test (SMART) was performed in standard (ST) and high bioactivation (HB) crosses. SMART is useful for the detection of mutational and recombinational events induced by genotoxins of direct and indirect action. Results demonstrated that samples collected in both seasons were able to induce increments on the mutant spot frequencies in the larvae of the HB cross. Genotoxicity was related to a massive recombinagenic activity. The positive responses ascribed to only the HB cross means that it is linked to pro-genotoxins requiring metabolic activation. The SMART wing test in Drosophila melanogaster was shown to be highly sensitive to detect genotoxic agents present in the aquatic environment impacted by agriculture.

Genotoxic evaluation of Halfenprox using the human peripheral lymphocyte micronucleus assay and the Ames test

The genotoxicity and mutagenicity of Halfenprox, a synthetic pyrethroid insecticide and acaricide, was assessed using two standard genotoxicity assays of the Salmonella typhimurium mutagenicity assay (Ames test) and in vitro micronucleus (MN) assay in human peripheral lymphocytes. In the Ames test, Salmonella strains TA98 and TA100 were treated with or without S9 fraction. The doses of Halfenprox were 6.25, 12.5, 25, 50, and 100 μg/plate and test materials were dissolved in DMSO. The concentrations of Halfenprox did not show mutagenic activity on both strains with and without S9 fraction. The MN assay was used to investigate the genotoxic effects of Halfenprox in human peripheral lymphocytes treated with 250, 500, 750, and 1000 μg/ml concentrations of Halfenprox for 24 and 48 h, and at 1000 μg/ml the concentration was significantly increased and the MN formation was compared with the negative control for both treatment periods. In addition, a significant decrease of the nuclear devision index (NDI) values at the higher concentrations of Halfenprox and at both treatment periods was observed.

Long-term exposure to cypermethrin and piperonyl butoxide cause liver and kidney inflammation and induce genotoxicity in New Zealand white male rabbits

Cypermethrin (CY) is a frequently used class II pyrethroid pesticide, while piperonyl butoxide (PBO) plays a major role in the pesticide formulation of synthetic pyrethroids. Synthetic pyrethroids are metabolized in mammals via oxidation and ester hydrolysis. PBO can prevent the metabolism of CY and enhances its pesticide effect. While this potentiation effect reduces the amount of pesticide required to eliminate insects, it is not clear how this mixture affects mammals. In our in vivo experiment, New Zealand white male rabbits were exposed to low and high doses of CY, PBO, and their combinations, for 4 months. Genotoxicity and cytotoxicity were monitored by measuring binucleated cells with micronuclei (BNMN), micronuclei (MN) and the cytokinesis block proliferation index (CBPI) in lymphocytes. After two months of exposure, a statistically significant increase in the frequency of BNMN was observed for all exposed animals (p < 0.001) in a dose-dependent way. MN were significantly elevated compared to controls (p < 0.001), with high dose groups reaching a 442% increase when co-exposed. BNMN and MN continued to increase after four months. Histopathological examination of lesions showed damage involving inflammation, attaining lymphoplasmatocytic infiltration in the high dose groups. Both CY and PBO cause liver and kidney inflammation and induce genotoxicity.

The toxic effects of deltamethrin on Danio rerio: the correlation among behavior response, physiological damage and AChE

In this work we comprehensively evaluated the effects of deltamethrin, a pyrethroid pesticide, on the behavior, physiology and acetylcholinesterase (AChE) activity of fish.

The effects of cyfluthrin on some biomarkers in the liver and kidney of Wistar rats

Pesticides can cause oxidative stress resulting to deleterious effects in animal metabolisms. Cyfluthrin is a synthetic pyrethroid used worldwide to protect crops and to eliminate pests. Thus, the aim of this study was to investigate the effects of the cyfluthrin on the level of malondialdehyde (MDA) and activities of catalase (CAT), glutathione peroxidase (GPx), and acetylcholinesterase (AChE) in the liver and kidney of Wistar Albino Sprague Dawley rats (Rattus norvegicus var. albinos) following intraperitoneal treatment of cyfluthrin (1.2, 12, and 120 mg/kg b.w./day) for 21 days. Comparisons were made with two control solutions named as serum physiologic and solvent in which cyfluthrin was dissolved. CAT activity in the liver and kidney of rats did not change after the lowest cyfluthrin treatment, while its activity significantly decreased at the higher doses. In general, cyfluthrin significantly decreased the activity of GPx in the liver and kidney at all doses, while MDA levels in the liver increased at all doses. Cyfluthrin significantly decreased AChE activity in the liver of rats at all doses, while this was true at the highest dose for the kidney. This study showed that the studied biomarkers were effective in determining the toxic effects of cyfluthrin. Thus, they should be used to monitor pesticide-affected areas before untargeted animals, including humans who suffer from the use of pesticides.

Is acetylcholinesterase a biomarker of susceptibility in Daphnia magna (Crustacea, Cladocera) after deltamethrin exposure?

In the present study, we explored the possibility of using the acetylcholinesterase (AChE) as a biomarker after deltamethrin (pyrethroid insecticide) exposure with three strains of the cladoceran Daphnia magna. Four calculated time-weighted deltamethrin concentrations (20.1, 40.3, 80.6 and 161.3 ng L(-1)) were compared against control acetylcholinesterase activity. Our results showed that after 48 h of deltamethrin exposure, all treatments induced a significant decrease of AChE activities whatever the three considered strains. However, diverse responses were registered in terms of lowest observed effect concentrations (LOEC: 80.6 ng L(-1) for strain 1 and 20.1 ng L(-1) for strains 2 and 3) revealing differences in sensitivity among the three tested strains of D. magna. Our results suggest that after deltamethrin exposure, the AChE activity responses can be also used as a biomarker of susceptibility (i.e., variation of strain specific response). Moreover, our results show that strain 1 is the less sensitive in terms of IC50-48 h of AChE, whereas it became the most sensitive when considering the EC50-48 h estimated in the standard ecotoxicity test.

Proposed model for binding of permethrin and deltamethrin insecticides with ct-DNA, a structural comparative study

In this work, the interaction of two synthetic pyrethroid insecticides, permethrin (PER) and deltamethrin (DEL), with ct-DNA has been studied by cyclic voltammetry (CV), circular dichroism (CD), competitive fluorescence, atomic force microscopy (AFM), UV-vis spectroscopy, thermodynamic measurements, Fourier-transform infra-red (FT-IR), high performance liquid chromatography (HPLC) and two-layered ONIOM (our N-layered integrated molecular orbital+molecular mechanics) (DFT B3LYP, 6-31++G(d, p):UFF) molecular modeling methods. The last four methods were also utilized to study the binding of DEL with DNA. The results revealed that the PER may interact through partial intercalation and groove binding process while the PER only interacts through groove binding. Finally, the insecticides structure effect on interaction is discussed.

Micronucleus assay in human lymphocytes after exposure to alloxydim sodium herbicide in vitro

This study evaluates the cytotoxic and genotoxic potential of alloxydim sodium using micronucleus (MN) assay, in human peripheral lymphocytes. MN assay was used to investigate the genotoxic effects of alloxydim sodium in human peripheral lymphocytes treated with 250, 500, 750, 1,000 µg/ml concentrations of alloxydim sodium for 24 and 48 h. Solvent, negative and positive controls were also used in the experiments in parallel. The obtained results were evaluated in statistical analyses by using Dunnett-t test (two sided) and p < 0.05 was accepted as significant. Alloxydim sodium significantly increased the MN formation compared with the negative control, at both 750 and 1,000 µg/ml concentrations and treatment periods. We also evaluated the nuclear division index (NDI) for cytotoxicity of this pesticide in the experiment, and finally observed a significant decrease of the NDI values at all concentrations of alloxydim sodium and at both treatment periods.

A novel toxicokinetic modeling of cypermethrin and permethrin and their metabolites in humans for dose reconstruction from biomarker data

To assess exposure to pyrethroids in the general population, one of most widely used method nowadays consists of measuring urinary metabolites. Unfortunately, interpretation of data is limited by the unspecified relation between dose and levels in biological tissues and excreta. The objective of this study was to develop a common multi-compartment toxicokinetic model to predict the time courses of two mainly used pyrethroid pesticides, permethrin and cypermethrin, and their metabolites (cis-DCCA, trans-DCCA and 3-PBA) in the human body and in accessible biological matrices following different exposure scenarios. Toxicokinetics was described mathematically by systems of differential equations to yield the time courses of these pyrethroids and their metabolites in the different compartments. Unknown transfer rate values between compartments were determined from best fits to available human data on the urinary excretion time courses of metabolites following an oral and dermal exposure to cypermethrin in volunteers. Since values for these coefficients have not yet been determined, a mathematical routine was programmed in MathCad to establish the possible range of values on the basis of physiological and mathematical considerations. The best combination of parameter values was then selected using a statistic measure (reliability factor) along with a statistically acceptable range of values for each parameter. With this approach, simulations provided a close approximation to published time course data. This model allows to predict urinary time courses of trans-DCCA, cis-DCCA and 3-PBA, whatever the exposure route. It can also serve to reconstruct absorbed doses of permethrin or cypermethrin in the population using measured biomarker data.

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.

Cytogenetic effects of commercial formulations of deltamethrin and/or thiacloprid on Wistar rat bone marrow cells

Deltamethrin (DEL) and thiacloprid (THIA) are two insecticides that are widely used in agriculture either separately or in combination. Studies on genotoxicity and cytotoxicity of TIA and the mixture of DEL and THIA insecticides have not been reported so far. Therefore, we investigated the cytotoxic and genotoxic effects of commercial formulations DEL and/or THIA in rat bone marrow cells, using mitotic index (MI), micronucleus (MN) and chromosome aberrations (CA) assay. In vivo cytokinesis-block micronucleus (CBMN) assay using cytochalasin-B in bone marrow cells was performed for the first time in this study. Rats were orally gavaged with a single dose of DEL (15 mg/kg), THIA (112.5 mg/kg) or DEL + THIA (15 + 112.5 mg/kg) for 24 h (acute treatments), or DEL (3 mg/kg/day), THIA (22.5 mg/kg/day) or DEL + THIA (3 + 22.5 mg/kg/day) for 30 days (subacute treatments). A corn oil vehicle control group and cyclophosphamide (50 mg/kg) positive control group were also included. All DEL and/or THIA treatments significantly decreased MI and binucleated (BN) cell numbers, and significantly increased CA, as compared to the vehicle control group. The results of CBMN assay indicated that the combination of DEL and THIA for both treatment times and the 30-day treatment with THIA alone caused a significant increase in micronucleus formation in BN cells. The present findings indicated the combined exposure of DEL and THIA showed genotoxic and cytotoxic effects more than those of individual exposure of DEL or THIA in rat bone marrow cells.

In utero exposure to dicyclohexyl and di-n-hexyl phthalate possess genotoxic effects on testicular cells of male rats after birth in the comet and TUNEL assays

Phthalates are diester derivatives of phthalic acid widely used in many commercial applications. The aim of this study is therefore to evaluate possible genotoxicity of di- n-hexyl phthalate (DHP) and dicyclohexyl phthalate (DCHP) at different concentrations using single-cell gel electrophoresis (comet) and terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick end-labeling (TUNEL) assays in testes samples of male rat pups. DCHP and DHP in corn oil were administered to the pregnant rats by gavage at the doses of 0 (vehicle), 20, 100, and 500 mg kg−1 day−1 from gestational day 6 (GD6) to GD19. After delivery, male rats were allowed to grow until prepubertal, pubertal, and adulthood. At necropsy, the blood samples were collected from heart and were excised immediately. The apoptotic cells of prepubertal, pubertal, and adult testis were detected using TUNEL assay. The comet assay was performed on blood lymphocytes and testes samples of adult male rats. The comet assay results showed that tail length, tail intensity, olive tail moment (OTM), and percentage of DNA present in tail were higher when DHP content was increased. Judging from the values of OTM and percentage of DNA, DHP could significantly induce DNA breakage at doses of 100 and 500 mg kg−1 day−1 compared with the control group. An increase in TUNEL-positive cells of prepubertal, pubertal, and adult testicular cells was observed in the treated groups. In conclusion, prenatal exposure to DHP and DCHP may possess genotoxic risk to testicular cells of rats at all stages of development, even at adulthood.

Exposure to lambda-cyhalothrin, a synthetic pyrethroid, increases reactive oxygen species production and induces genotoxicity in rat peripheral blood

Lambda-cyhalothrin (LTC) is a synthetic pyrethroid with a broad spectrum of insecticidal and acaricidal activities used to control a wide range of insect pests in a variety of applications. However, there is little known about its adverse effects, in particular those related to its genotoxicity in humans. To elucidate the genotoxicity mechanisms of LTC, the micronuclei (MN) frequencies, the levels of reactive oxygen species (ROS), erythrocyte osmotic fragility, nitrite (NO) formation, protein carbonyl (PCO) levels and malondialdehyde (MDA) production were evaluated for a period of 7, 14 and 21 days. Our results show that exposure rat to LTC (1/10DL50 = 6.23 mg/kg) for a period of 7, 14 and 21 days induced a noticeable genotoxic effect in rat peripheral blood evidenced by a significant increase in the frequency of MN only at day 21 of treatment. Significant differences between the two groups were observed in erythrocyte osmotic fragility. Further, a significant (p < 0.01) increase in ROS contents, NO formation, PCO levels and lipid peroxidation in erythrocytes were observed at different times of treatments, suggesting the implication of oxidative stress in its toxicity. These results confirm the genotoxic and the pro-oxidant effects of LTC in rat peripheral blood.

Ecohealth interventions limit triatomine reinfestation following insecticide spraying in La Brea, Guatemala

In this study, we evaluate the effect of participatory Ecohealth interventions on domestic reinfestation of the Chagas disease vector Triatoma dimidiata after village-wide suppression of the vector population using a residual insecticide. The study was conducted in the rural community of La Brea, Guatemala between 2002 and 2009 where vector infestation was analyzed within a spatial data framework based on entomological and socio-economic surveys of homesteads within the village. Participatory interventions focused on community awareness and low-cost home improvements using local materials to limit areas of refuge and alternative blood meals for the vector within the home, and potential shelter for the vector outside the home. As a result, domestic infestation was maintained at ≤ 3% and peridomestic infestation at ≤ 2% for 5 years beyond the last insecticide spraying, in sharp contrast to the rapid reinfestation experienced in earlier insecticide only interventions.

Effects of commercial formulations of deltamethrin and/or thiacloprid on thyroid hormone levels in rat serum

Deltamethrin (DEL) and thiacloprid (THIA) are the two commonly used synthetic insecticides applied either separately or as a mixture. The aim of this study was to assess thyroid stimulating hormone (TSH) and the serum levels of thyroid hormones exposure to these compounds in rats. The animals were orally gavaged with a single dose of DEL (15 mg/kg), THIA (112.5 mg/kg) or DEL + THIA (15 + 112.5 mg/kg) for 24 h (acute treatments) or DEL (3 mg/kg per day), THIA (22.5 mg/kg per day) or DEL + THIA (3 + 22.5 mg/kg per day) for 30 days (subacute treatments). Although all independent and combined treatments with DEL and THIA changed the levels of TSH, these alterations were not significant. Statistically significant increases in free triiodothyronine (FT3) and free thyroxine (FT4) serum hormone levels were observed in the independent treatment with THIA and the combined treatment with DEL and THIA for 30 days. The results of this study suggest that in vivo exposure to subacute treatments of commercial formulations of THI and mixture of DEL + THIA increased serum FT3 and FT4 levels in rats. Further studies are required to determine the effects of endocrine disruptors and potential health risks of these insecticides in human, especially in children because of the importance of these hormones during growth and development.

Veterinary Pesticides

Veterinary pesticides are used to treat a range of parasitic conditions in companion and farm animals. These products are based on a number of different compounds with different modes of action and different spectra of toxicity. The older agents include the synthetic pyrethroids and organophosphorus compounds, while the newer examples include, for example, representatives of the insect growth promoters, the neonicotinoids, and the oxadiazones. For many of these compounds, toxicity is associated with their pharmacological activity or mode of action. Thus the synthetic pyrethroids and the organophosphorus compounds exert neurotoxic effects. For others, toxicity may be associated with mechanisms that are independent of their mode of action. When used according to the manufacturer's instructions, these products are generally safe and efficacious. However, accidental contamination and misuse can lead to toxicity in operators and treated animals. These compounds are important in the treatment of parasitic disease in animals and their regulation and uses are based on favourable risk-benefit outcomes.

Evaluation of toxicity and genotoxic effects of spinosad and deltamethrin in Drosophila melanogaster and Bactrocera oleae

BACKGROUND

The insecticides spinosad and deltamethrin are being increasingly used in pest management programmes. In order to assess further their toxic effects to target and non-target insect species, an evaluation was made of their insecticidal profile on Bactrocera oleae (Rossi) and Drosophila melanogaster (Meig.). Moreover, possible genotoxic effects of the two pesticides were investigated using the somatic mutation and recombination test (SMART) in D. melanogaster.

RESULTS

Both insecticides were highly effective against B. oleae, exhibiting similar LC(50) values. Moreover, they were found to be more effective against Bactrocera than against Drosophila adults. However, spinosad was significantly more toxic than deltamethrin to D. melanogaster. The results showed a lack of genotoxic activity of both insecticides under the in vivo experimental procedure employed, at least at applied doses.

CONCLUSION

The present study provides information for lethal and sublethal effects of spinosad and deltamethrin against a target and a non-target species. Both insecticides can exert high toxicity to B. oleae when adults are exposed even to very low doses for long periods of time. The results contribute to the database on the genotoxic potential of spinosad and deltamethrin, suggesting a safety profile for both insecticides.

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.

The in vitro genotoxic effects of a commercial formulation of alpha-cypermethrin in human peripheral blood lymphocytes

alpha-Cypermethrin, a highly active pyrethroid insecticide, is effective against a wide range of insects encountered in agriculture and animal husbandry. The potential genotoxicity of a commercial formulation of alpha-cypermethrin (Fastac 100 EC, containing 10% alpha-cypermethrin as the active ingredient) on human peripheral lymphocytes was examined in vitro by sister chromatid exchange (SCE), chromosomal aberrations (CAs), and micronucleus (MN) tests. The human lymphocytes were treated with 5, 10, 15, and 20 microg/ml of alpha-cypermethrin for 24- and 48-hr. alpha-Cypermethrin induced SCEs and CAs significantly at all concentrations and treatment times and MN formation was significantly induced at 5 and 10 microg/ml of alpha-cypermethrin when compared with both the control and solvent control. Binuclear cells could not be detected sufficiently in the highest two concentration of alpha-cypermethrin (15 and 20 microg/ml) for both the 24- and 48-hr treatment times. alpha-Cypermethrin decreased the proliferation index (PI) at three high concentrations (10, 15, and 20 microg/ml) for both treatment periods as compared with the control groups. In addition, alpha-cypermethrin reduced both the mitotic index (MI) and nuclear division index (NDI) significantly at all concentrations for two treatment periods. The PI and MI were reduced by alpha-cypermethrin in a concentration-dependent manner during both treatment times. In general, alpha-cypermethrin showed higher cytotoxic and cytostatic effects than positive control (MMC) at the two highest concentrations for the 24- and 48-hr treatment periods. The present study is the first to report the genotoxic and cytotoxic effects of commercial formulation of alpha-cypermethrin in peripheral blood lymphocytes.

Efficacy of different treatment regimes against setariosis (Setaria tundra, Nematoda: Filarioidea) and associated peritonitis in reindeer

Background

When a severe peritonitis outbreak in semi-domesticated reindeer was noticed in 2003 in Finland, the concerned industry urged immediate preventive actions in order to avoid detrimental effects of S. tundra and further economical losses. A research programme was swiftly initiated to study S. tundra and its impact on the health and wellbeing of reindeer.

Methods

The ultimate aim of this study was to test the efficacy of different treatment regimes against S. tundra and associated peritonitis in reindeer. The timing of the trials was planned to be compatible with the annual rhythm of the reindeer management; (1) the treatment of calves in midsummer, during routine calf ear marking, with ivermectin injection prophylaxis and deltamethrin pour-on solution as a repellent against insect vectors, (2) the treatment of infected calves in early autumn with ivermectin injection, and (3) ivermectin treatment of breeding reindeer in winter. The results were assessed using the post mortem inspection data and S. tundra detection. Finally, to evaluate on the population level the influence of the annual (late autumn-winter) ivermectin treatment of breeding reindeer on the transmission dynamics of S. tundra, a questionnaire survey was conducted.

Results

In autumn, ivermectin treatment was efficient against peritonitis and in midsummer had a slight negative impact on the degree of peritonitis and positive on the fat layer, but deltamethrin had none. Ivermectin was efficient against adult S. tundra and its smf. All the reindeer herding cooperatives answered the questionnaire and it appeared that antiparasitic treatment of reindeer population was intense during the study period, when 64–90% of the animals were treated. In the southern part of the Finnish reindeer husbandry area, oral administration of ivermectin was commonly used.

Conclusion

Autumn, and to a lesser degree summer, treatment of reindeer calves with injectable ivermectin resulted in decreased severity of peritonitis and perihepatitis in reindeer calves due to setariosis. In the case of necessity for animal welfare reasons, treatment during early autumn round ups should be considered. On the population level, massive and routinely applied antiparasitic treatments can improve the health of breeding reindeer and decrease the mortality and the number of carriers but during the outbreak could not prevent its movement and expansion to the North.

Characterization of Anopheles minimus CYP6AA3 expressed in a recombinant baculovirus system

Metabolism by cytochrome P450 monooxygenases is a major mechanism implicated in resistance of insects to insecticides, including pyrethroids. We previously isolated the cytochrome P450 CYP6AA3 from deltamethrin-selected resistant strain of Anopheles minimus mosquito, a major malaria vector in Thailand. In the present study, we further investigated the role of CYP6AA3 enzyme in deltamethrin metabolism in vitro. The CYP6AA3 was expressed in Spodoptera frugiperda (Sf9) insect cells via baculovirus-mediated expression system. The enzymatic activity of CYP6AA3 in deltamethrin metabolism was characterized after being reconstituted with An. minimus NADPH-cytochrome P450 reductase and a NADPH-regenerating system. The contribution of CYP6AA3 responsible for deltamethrin metabolism was determined by measurement of deltamethrin disappearance following the incubation period and deltamethrin-derived compounds were detected using combined gas chromatography mass spectrometry analysis. 3-Phenoxybenzaldehyde was a major product of CYP6AA3-mediated deltamethrin metabolism. Deltamethrin degradation and formation of metabolites were NADPH-dependent and inhibited by piperonyl butoxide. Deltamethrin was catalyzed by CYP6AA3 with an apparent K(m) of 80.0 +/- 2.0 and V(max) of 60.2 +/- 3.6 pmol/min/pmol P450. Furthermore, deltamethrin cytotoxicity assays by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and trypan blue dye exclusion were examined in Sf9 insect cells, with and without expression of CYP6AA3. Results revealed that CYP6AA3 could play a role in detoxifying deltamethrin in the cells. Thus, the results of this study support the role of CYP6AA3 in deltamethrin metabolism.

Assessment of the genotoxicity of imidacloprid and metalaxyl in cultured human lymphocytes and rat bone-marrow

Imidacloprid and metalaxyl are two pesticides that are widely used in agriculture, either separately, or in combination. These agents were studied for their possible genotoxic effects with respect to the following cytogenetic end-points: (1) in vitro micronucleus (MN) formation and sister-chromatid exchange (SCE) induction in human lymphocytes and (2) in vivo micronucleus induction in polychromatic erythrocytes (PCEs) of the rat bone-marrow. The results of the MN analysis indicate that MN frequencies after treatment with both pesticides, separately or as a mixture, do not significantly differ from those in the controls except after treatment with metalaxyl alone at 50 microg/ml (p<0.05). The results of the SCE analysis show that SCE frequencies after treatment with imidacloprid do not differ significantly from those in the controls. A statistically significant increase (p<0.05) in SCE frequency resulted from treatments with metalaxyl at 5, 10 and 100 microg/ml and with the combination of imidacloprid and metalaxyl at 100 and 200 microg/ml. Finally, the in vivo micronucleus assay with rat bone-marrow polychromatic erythrocytes showed a statistically significant effect upon separate treatments with imidacloprid and metalaxyl at doses of 300 mg/kg body weight (b.w.) (p<0.01) or upon combined treatment with 200 mg/Kg b.w. (p<0.001) and 400 mg/kg b.w. (p<0.05).

Cytogenetic effects of commercial formulations of deltamethrin and/or isoproturon on human peripheral lymphocytes and mouse bone marrow cells

The cytogenetic effects of deltamethrin (DEL) and/or isoproturon (ISO) were examined in human lymphocytes and mouse bone marrow cells. Peripheral lymphocytes were exposed to DEL (2.5, 5, 10, or 20 microM), ISO (25, 50, 100, or 200 microM), or DEL + ISO (2.5 + 25, 5 + 50, 10 + 100, or 20 + 200 microM) and cytogenic effects were evaluated via chromosomal aberrations (CA) and the cytokinesis-block micronucleus assay (CBMN). Mice were orally gavaged to single dose of DEL (6.6 mg/kg), ISO (670 mg/kg), or DEL+ISO (6.6 + 670 mg/kg) for 24 hr or to DEL (3.3 mg/kg/day), ISO (330 mg/kg/day), or DEL + ISO (3.3 + 330 mg/kg/day) for 30 days and analyzed for CA. DEL induced a significant frequency of CA at 10 microM whereas ISO (25-100 microM) alone, or in combination with DEL, did not show any significant effect. Micronucleus (MN) induction was observed to be concentration-dependent though significant frequencies were observed at 5 microM DEL, 100 microM ISO, or 5 + 50 microM DEL + ISO. In mice, DEL inhibited the mitotic index (MI) significantly (P < 0.001) at 24 hr while ISO alone, or in combination with DEL, did not cause any statistically significant effect. Following a 24 hr exposure, DEL and ISO alone induced significant (P < 0.01) frequencies of CA, whereas DEL + ISO in combination did not. Furthermore, 30 days exposure of ISO significantly inhibited the MI (P < 0.02 or < 0.01) and induced CA while DEL alone, or in combination with ISO, resulted in no significant effect on CA or the MI. The present findings indicate that the in vitro and in vivo exposure of a commercial formulation of DEL can cause genotoxic effects in mammals. However, the coexposure of DEL and ISO did not show additive effects, but instead demonstrated somewhat reduced genotoxicity.

Primary DNA damage and genetic polymorphisms for CYP1A1, EPHX and GSTM1 in workers at a graphite electrode manufacturing plant

Background

The results of a cross-sectional study aimed to evaluate whether genetic polymorphisms (biomarkers of susceptibility) for CYP1A1, EPHX and GSTM1 genes that affect polycyclic aromatic hydrocarbons (PAH) activation and detoxification might influence the extent of primary DNA damage (biomarker of biologically effective dose) in PAH exposed workers are presented. PAH-exposure of the study populations was assessed by determining the concentration of 1-hydroxypyrene (1OHP) in urine samples (biomarker of exposure dose).

Methods

The exposed group consisted of workers (n = 109) at a graphite electrode manufacturing plant, occupationally exposed to PAH. Urinary 1OHP was measured by HPLC. Primary DNA damage was evaluated by the alkaline comet assay in peripheral blood leukocytes. Genetic polymorphisms for CYP1A1, EPHX and GSTM1 were determined by PCR or PCR/RFLP analysis.

Results

1OHP and primary DNA damage were significantly higher in electrode workers compared to reference subjects. Moreover, categorization of subjects as normal or outlier highlighted an increased genotoxic risk OR = 2.59 (CI95% 1.32–5.05) associated to exposure to PAH. Polymorphisms in EPHX exons 3 and 4 was associated to higher urinary concentrations of 1OHP, whereas none of the genotypes analyzed (CYP1A1, EPHX, and GSTM1) had any significant influence on primary DNA damage as evaluated by the comet assay.

Conclusion

The outcomes of the present study show that molecular epidemiology approaches (i.e. cross-sectional studies of genotoxicity biomarkers) can play a role in identifying common genetic risk factors, also attempting to associate the effects with measured exposure data. Moreover, categorization of subjects as normal or outlier allowed the evaluation of the association between occupational exposure to PAH and DNA damage highlighting an increased genotoxic risk.

The antioxidative response system in Glycine max (L.) Merr. exposed to Deltamethrin, a synthetic pyrethroid insecticide

Forty-five-day-old plants of Glycine max (soybean) were exposed to several Deltamethrin (synthetic pyrethroid insecticide) concentrations (0.00%, 0.05%, 0.10%, 0.15% and 0.20%) through foliar spray in the field conditions. In the treated plants, as observed at the pre-flowering (10 DAT), flowering (45 DAT) and post-flowering (70 DAT) stages, lipid peroxidation, proline content and total glutathione content increased, whereas the total ascorbate content decreased, as compared with the control. Among the enzymatic antioxidants, activity of superoxide dismutase, ascorbate peroxidase and glutathione reductase increased significantly whereas that of catalase declined markedly in relation to increasing concentration of Deltamethrin applied. The changes observed were dose-dependent, showing a strong correlation with the degree of treatment.

Effects of co-exposure to extremely low frequency (50 Hz) magnetic fields and xenobiotics determined in vitro by the alkaline comet assay

In the present study, we used human peripheral blood leukocytes from 4 different donors, to investigate in vitro the possible genotoxic and/or co-genotoxic activity of extremely low frequency magnetic fields (ELF-MF) at 3 mT intensity. Two model mutagens were used to study the possible interaction between ELF-MF and xenobiotics: N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and 4-nitroquinoline N-oxide (4NQO). Primary DNA damage was evaluated by the alkaline single-cell microgel-electrophoresis ("comet") assay. Control cells (leukocytes not exposed to ELF-MF, nor treated with genotoxins) from the different blood donors showed a comparable level of basal DNA damage, whereas the contribution of individual susceptibility toward ELF-MF and the tested genotoxic compounds led to differences in the extent of DNA damage observed following exposure to the genotoxins, both in the presence and in the absence of an applied ELF-MF. A 3 mT ELF-MF alone was unable to cause direct primary DNA damage. In leukocytes exposed to ELF-MF and genotoxins, the extent of MNNG-induced DNA damage increased with exposure duration compared to sham-exposed cells. The opposite was observed in cells treated with 4NQO. In this case the extent of 4NQO-induced DNA damage was somewhat reduced in leukocytes exposed to ELF-MF compared to sham-exposed cells. Moreover, in cells exposed to ELF-MF an increased concentration of GSH was always observed, compared to sham-exposed cells. Since following GSH conjugation the genotoxic pattern of MNNG and 4NQO is quite different, an influence of ELF-MF on the activity of the enzyme involved in the synthesis of GSH leading to different activation/deactivation of the model mutagens used was hypothesized to explain the different trends observed in MNNG and 4NQO genotoxic activity in the presence of an applied ELF-MF. The possibility that ELF-MF might interfere with the genotoxic activity of xenobiotics has important implications, since human populations are likely to be exposed to a variety of genotoxic agents concomitantly with exposure to this type of physical agent.