TBBPA induces developmental toxicity,oxidative stress,and apoptosis in embryos and zebrafish larvae (Danio rerio)

Tetrabromobisphenol A (TBBPA) is currently one of the most frequently used brominated flame retardants and can be considered as a high production volume chemical. In this study, zebrafish embryos and larvae served as a biological model to evaluate TBBPA‐induced developmental toxicity, oxidative stress, oxidant‐associated gene expression, and cell apoptosis. Abnormalities, including hyperemia and pericardial edema, were induced in zebrafish larvae. The results showed that toxicity endpoints such as hatching rate, survival rate, malformation rate, and growth rate had a significant dose–response relationship with TBBPA. Further studies revealed that TBBPA did not alter the enzyme activities of Copper/Zinc Superoxide dismutase (Cu/Zn‐SOD), catalase (CAT), and glutathioneperoxidase (GPx) at 0.10 mg/L, but decreased activities following exposure to 0.40, 0.70, and 1.00 mg/L. Despite the significantly decreased gene expression of Cu/Zn‐SOD, CAT, and GPx1a in the 1.00 mg/L treatment group, other treatments (0.10, 0.40, 0.70 mg/L) did not alter gene expression. Moreover, Acridine orange staining results showed that apoptotic cells mainly accumulated in the brain, heart, and tail, indicating possible TBBPA‐induced brain, cardiac, and blood circulation system impairment in zebrafish embryos and larvae. Histological analysis also showed evidence of obvious heart impairment in TBBPA‐treated groups. This study provides new evidence on the developmental toxicity, oxidative stress, and apoptosis of embryos and zebrafish larvae, which is important for the evaluation of environmental toxicity and chemical risk. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1241–1249, 2016.     

Developmental toxicity and DNA damage to zebrafish induced by perfluorooctane sulfonate in the presence of ZnO nanoparticles

Perfluorooctane sulfonate (PFOS) and ZnO nanoparticles (ZnO–NPs) are frequently detected in the environment, but few studies have assessed their joint toxicity. In this study, the acute toxicity and chronic toxicity to zebrafish (Danio rerio) induced by PFOS in the presence of ZnO–NPs were investigated, including developmental toxicity and DNA damage. The embryos were exposed to PFOS (only) (0.4, 0.8, and 1.6 mg/L) and PFOS plus ZnO–NPs (0.4 + 50, 0.8 + 50, and 1.6 + 50 mg/L) solutions to evaluate mortality (96 h), body length (96 h), hatch rate (72 h), heart rate (48 h),and malformation rate (96 h). The results revealed that the co‐treatment could cause more severe developmental toxicity compared with the control and single‐treatments, and the toxic effects generally increased in a dose–response manner. In addition, adult zebrafish were exposed to single and mixed solutions of PFOS and ZnO–NPs (at the concentrations mentioned above) for 30 days. DNA damage to zebrafish was evaluated by the comet assay and micronucleus test. We found that the PFOS single‐treatment at all doses (0.4, 0.8, and 1.6 mg/L) could strongly induce DNA damage to peripheral blood cells and that ZnO–NPs could aggravate the formation of DNA damage in co‐treatments. Histological examination of liver, testicle, and ovary showed that the presence of ZnO–NPs (50 mg/L) could also cause more serious histological damage to adult zebrafish than PFOS alone. As a result, the synergistic effects played an important role during joint exposure. Our observations provide a basic understanding of the joint toxicity of PFOS and ZnO–NPs to aquatic organisms. © 2014 Wiley Periodicals, Inc. Environ Toxicol 31: 360–371, 2016.     

斑马鱼胚胎发育毒性评价方法的建立

目的以致胚胎毒性阳性药物全反式维甲酸（ATRA）及丙戊酸钠进行斑马鱼胚胎发育毒性试验,建立有效的斑马鱼胚胎发育毒性评价方法。方法采用水浴染毒法,将受精后2h（2hpf）的斑马鱼胚胎暴露于不同浓度梯度的阳性约物。分别在24、48、72和144hpf观察并记录畸形及死亡的胚胎数目。统计阳性药物的EC50和LG50,计算致畸指数（TI=LC50／EG50）。结果两种阳性药物所致斑马鱼胚胎发育早期（24～48hpf）与发育后期（72～144hpf）的畸形表现不同。在72hpf,两种阳性药物对胚胎孵化率均有明显抑制作甩144hpf可见ATRA（≥1．6×10^-3mg／L）和丙戊酸钠（≥1．25×10^2mg／L）严晕致畸作用,T1分别为10.35和5．72。两种阳性药物胚胎敛畸率及死亡率均呈明显的浓度依赖关系,且与已有动物试验及体外试验结果相符。结论以两种阳性药物建立有效的斑马鱼胚胎发育毒性评价方法,可进行进一步的验证。     

Prochloraz effects on biomarkers activity in zebrafish early life stages and adults

Zebrafish early life stages (ELS) assays have been increasingly used to assess the toxicity of chemicals and waste waters, showing a great potential due to the wide variety of endpoints that can be incorporated in the test. Moreover, zebrafish ELS test have been proposed, mainly for ethical reasons, as a surrogate for tests with adults. In this work, the fungicide Prochloraz (PCZ) was used as a chemical model to compare sensitivities of embryos/larvae and adult zebrafish focusing on lethality and biomarkers as endpoints. Effects on embryo development were also assessed. Organization for economic cooperation and development (OECD) guidelines were followed and adapted to include the analyses of the biomarkers cholinesterase, glutathione S‐transferase, and lactate dehydrogenase. The acute toxicity of PCZ for zebrafish ELS and adults seemed to be similar with 96h‐LC₅₀ values of 8.5 and 4.6 mg/L, respectively. However, biomarkers were only responsive in larvae indicating a higher sensitivity of this life stage at sublethal level. PCZ also proved to be teratogenic: at intermediate concentrations effects on embryo development could be noticed, including spine deformations, edemas, lack of pigmentation, slower heart rate, and complete hatching failure. At the lowest concentrations, the more relevant effects (edemas and abnormal absorption of the yolk sac) were observed after hatching. The measurement of biomarkers in the zebrafish ELS assay seems to a useful tool in the detection of chemical effects showing higher sensitivity than adults. Further research should focus on the link between biomarkers responses in larvae and effects at later life stages of zebrafish. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2013.     

Protective effects of puerarin against tetrabromobisphenol a‐induced apoptosis and cardiac developmental toxicity in zebrafish embryo‐larvae

Tetrabromobisphenol A (TBBPA), a brominated flame retardant, is detected commonly in aquatic environments, where it is thought to be highly toxic to the development of aquatic life. In this study, zebrafish embryos and larvae were used to investigate the protective effects of puerarin after exposure to TBBPA. Malformation, blood flow disorders, pericardial edema, and spawn coagulation rates increased, whereas survival decreased significantly after exposure to 0.5 and 1.0 mg L^?1 TBBPA. The measured indices of morphological toxicity improved after treatment with puerarin. TBBPA also induced reactive oxygen species (ROS) production in a dose‐dependent manner. Acridine orange staining results revealed that TBBPA exposure caused cardiomyocyte apoptosis and induced the expression of three proapoptotic genes: P53, Bax, and Caspase9. In contrast, the expression of the antiapoptotic gene Bcl2 was down‐regulated. When genes related to cardiac development were assessed, the expression of Tbx1, Raldh2, and Bmp2b changed after exposure to the combination of TBBPA and puerarin. These results suggest that TBBPA induces cardiomyocyte apoptosis and ROS production, resulting in cardiac developmental toxicity in zebrafish embryos or larvae. Therefore, puerarin regulates the expression of cardiac developmental genes, such as Tbx1, Bmp2b, and Raldh2 by inhibiting ROS production, and subsequently modulates cardiac development after the exposure of zebrafish larvae to TBBPA. © 2014 Wiley Periodicals, Inc. Environ Toxicol 30: 1014–1023, 2015.     

Developmental toxicity of brominated flame retardants,tetrabromobisphenol A and 1,2,5,6,9,10-hexabromocyclododecane,in rat offspring after maternal exposure from mid-gestation through lactation

To evaluate developmental exposure effects of two brominated flame retardants, tetrabromobisphenol A (TBBPA) and 1,2,5,6,9,10-hexabromocyclododecane (HBCD), pregnant Sprague–Dawley rats were administered either chemical at doses of 100, 1000 or 10,000 ppm in a soy-free diet from gestation day 10 until the day 20 after delivery. Offspring exposed to TBBPA showed dose-unrelated slight decreases of serum triiodothyronine (T₃) concentration at postnatal day 20, and there was no evidence of hypothyroidism-related neuronal mismigration and impaired oligodendroglial development as judged by morphometric analyses of NeuN-immunoreactive neuronal distribution in the hippocampal CA1, and area of corpus callosum as well as density of 2′,3′-cyclic nucleotide 3′-phosphodiesterase (CNPase)-immunoreactive oligodendrocytes in the cingulate deep cortex at the adult stage. On the other hand, HBCD exerted a weak hypothyroidism evident with increases in thyroid weight, thyroid follicular cell hypertrophy and serum concentrations of thyroid-stimulating hormone as well as decreases of serum T₃ concentrations in offspring at 10,000 ppm at weaning. Increased thyroid weights and decreased serum T₃ concentrations were also observed in the adult stage from 1000 ppm. With regard to the effect on brain development, HBCD reduced density of CNPase-positive oligodendrocytes at 10,000 ppm, suggesting an impaired oligodendroglial development. Results thus suggest that TBBPA did not exert developmental brain effects, while HBCD did, and 100 ppm was determined to be the no-observed-adverse-effect level of HBCD from changes in thyroid parameters at the adult stage by maternal exposure, translating into 8.1–21.3 mg/kg-d.     

Role of reactive oxygen species in organophosphate insecticide phosalone toxicity in erythrocytes in vitro.

Reactive oxygen species (ROS) caused by organophosphates may be involved in the toxicity of various pesticides. Therefore, in this study we aimed to investigate how an organophosphate insecticide, phosalone, affects lipid peroxidation (LPO) and the antioxidant defence system in vitro. For this purpose, the effects of various doses of phosalone on LPO and the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) in erythrocytes were studied. Each phosalone dose was incubated with a previously prepared erythrocyte sample at +4 degrees C for 0, 60 and 180 min. After incubation, the levels of malondialdehyde (MDA) and the activities of SOD, GSH-Px and CAT were determined. Phosalone caused an increase in MDA formation and a decrease in the activities of SOD, GSH-Px and CAT. However, these effects were seen only at extremely high concentrations of phosalone and these concentrations were in the lethal range. Therefore, we suggest that ROS may not involve in the toxic effects of the pesticidal use of phosalone in low concentrations.     

Single and combined effects of carbamazepine and copper on nervous and antioxidant systems of zebrafish (Danio rerio)

Various pollutants co‐exist in the aquatic environment such as carbamazepine (CBZ) and copper (Cu), which can cause complex effects on inhabiting organisms. The toxic impacts of the single substance have been studied extensively. However, the studies about their combined adverse impacts are not enough. In the present study, zebrafish were exposed to environmental relevant concentrations of CBZ (1, 10, and 100 μg/L), Cu (0.5, 5, and 10 μg/L) and the mixtures (1 μg/L CBZ + 0.5 μg/L Cu, 10 μg/L CBZ + 5 μg/L Cu, 100 μg/L CBZ + 10 μg/L Cu) for 45 days, the effects on nervous and antioxidant systems of zebrafish were investigated. The results demonstrated that, in comparison with single exposure group, the combined presence of CBZ and Cu exacerbated the effect of antioxidant system (the ability of inhibition of hydroxyl radicals (IHR), superoxide dismutase (SOD), catalase (CAT) and glutathione S‐transferase (GST)) but not nervous system (Acetylcholinesterase [AChE]). The qPCR results supported the changes of corresponding enzymes activities. Hepatic histopathological analysis verified the results of biomarkers. Our work illustrated that the toxicity of mixed pollutants is very complicated, which cannot simply be inferred from the toxicity of single pollutant, and calls for more co‐exposure experiments to better understanding of the co‐effects of pollutants on aquatic organisms.     

Single and 14-day repeated dose inhalation toxicity studies of hexabromocyclododecane in rats

Limited toxicological information is available for hexabromocyclododecane (HBCD),a widely used additive brominated flame retardant. Inhalation is a major route of human exposure to HBCD. The aim of this study was to determine the acute inhalation toxicity and potential subchronic inhalation toxicity of HBCD in Sprague-Dawley rats exposed to HBCD only through inhalation. The acute inhalation toxicity of HBCD was determined using the limit test method on five male and five female Sprague-Dawley rats at a HBCD concentration of 5000 mg/m³. Repeated-dose toxicity tests were also performed, with 20 males and 20 females randomly assigned to four experimental groups (five rats of each sex in each group). There were three treatment groups (exposed to HBCD concentrations of 125,500, and 2000 mg/m³) and a blank control group (exposed to fresh air). In the acute inhalation toxicity study, no significant clinical signs were observed either immediately after exposure or during the recovery period. Gross pathology examination revealed no evidence of organ-specific toxicity in any rat. The inhalation LC_50(4 h) for HBCD was higher than 5312 ± 278 mg/m3 for both males and females. In the repeated dose inhalation study, daily head/nose-only exposure to HBCD at 132 ± 8.8, 545.8 ± 35.3, and 2166.0 ± 235.9 mg/m³ for 14 days caused no adverse effects. No treatment-related clinical signs were observed at any of the test doses. The NOAEL for 14-day repeated dose inhalation toxicity study of HBCD is 2000 mg/m³.     

Effects of 3,4-dichloroaniline and diazinon on different biological organisation levels of zebrafish (Danio rerio) embryos and larvae

In this study the effects of 3,4-dichloroaniline (3,4-DCA), a decomposition product of the herbicides propanil and diuron (and other pesticides), and diazinon, a neurotoxic insecticide, on early life stages of zebrafish Danio rerio were assessed. The toxicity of these substances with different modes of action (acetylcholine esterase inhibitor vs. polar narcosis) was tested for single substances as well as in binary mixtures. To study effects on different biological organisation levels (from the molecular up to the whole organism level) the molecular stress response regarding Hsp70, the embryonic and larval development and the locomotor activity were investigated as integrative biomarkers. In single substance tests 3,4-dichloroaniline elicited deformations at ≥0.25 mg/l during the 11 days subchronic test, whereas locomotor activity and mortality were impaired at ≥0.5 mg/l. Diazinon effects on those parameters were obvious at ≥2 mg/l, except for the deformation rate (11 days:1 mg/l). In equitoxic mixtures of both substances concentration additivity was observed for deformation rate and mortality (11 days). An increase in the Hsp70 content occurred in zebrafish exposed to 0.25 mg 3,4-DCA/l as well as to 0.05 mg diazinon/l; in mixtures concentration additivity could be shown. The investigated endpoints varied in respect to their sensitivity, with deformations and Hsp70 levels as most sensitive parameters concerning 3,4-DCA and Hsp70 as most sensitive parameter concerning diazinon. Accordingly, for an integrated understanding of the effects of chemicals and their mixtures on fish, a battery of different test methods should be applied. Volker Scheil and Cornelia Kienle contributed equally to this paper and share first authorship.     

Developmental toxicity and alteration of gene expression in zebrafish embryos exposed to PFOS

Perfluorooctanesulfonate (PFOS) is a persistent organic pollutant, the potential toxicity of which is causing great concern. In the present study, we employed zebrafish embryos to investigate the developmental toxicity of this compound. Four-hour post-fertilization (hpf) zebrafish embryos were exposed to 0.1, 0.5, 1, 3 and 5 mg/L PFOS. Hatching was delayed and hatching rates as well as larval survivorship were significantly reduced after the embryos were exposed to 1, 3 and 5 mg/L PFOS until 132 hpf. The fry displayed gross developmental malformations, including epiboly deformities, hypopigmentation, yolk sac edema, tail and heart malformations and spinal curvature upon exposure to PFOS concentrations of 1 mg/L or greater. Growth (body length) was significantly reduced in the 3 and 5 mg/L PFOS-treated groups. To test whether developmental malformation was mediated via apoptosis, flow cytometry analysis of DNA content, acridine orange staining and TUNEL assay was used. These techniques indicated that more apoptotic cells were present in the PFOS-treated embryos than in the control embryos. Certain genes related to cell apoptosis, p53 and Bax, were both significantly up-regulated upon exposure to all the concentrations tested. In addition, we investigated the effects of PFOS on marker genes related to early thyroid development (hhex and pax8) and genes regulating the balance of androgens and estrogens (cyp19a and cyp19b). For thyroid development, the expression of hhex was significantly up-regulated at all concentrations tested, whereas pax8 expression was significantly up-regulated only upon exposure to lower concentrations of PFOS (0.1, 0.5, 1 mg/L). The expression of cyp19a and of cyp19b was significantly down-regulated at all exposure concentrations. The overall results indicated that zebrafish embryos constitute a reliable model for testing the developmental toxicity of PFOS, and the gene expression patterns in the embryos were able to reveal some potential mechanisms of developmental toxicity.     

Ecotoxicological effects of a veterinary food additive,copper sulphate,on antioxidant enzymes and mRNA expression in earthworms

The present study was aimed to investigate the effect of the veterinary food additive copper sulphate (CuSO₄) on the eco-toxicological responses of earthworms Eisenia fetida (E. fetida). The following biomarkers were measured: catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione-S-transferase (GST) activities. Gene expression analyses such as metallothionein (MT) and heat shock protein 70 (Hsp70) were also examined. A time-dependent increase of CAT activity was found at 400 mg/kg and SOD activity at 200 and 400 mg/kg. The highest expression of Hsp70 (4.4-fold) was observed at day 15 at 400 mg/kg. Our results indicated that the measured antioxidant enzymes (except GST) had the ability to provide antioxidant defenses against the stressor; and compared to expression of MT, expression of Hsp70 could be more reliable molecular tools with predictive possibilities to monitor the eco-toxicity of stressors such as feed additive CuSO₄.     

Melatonin protects against lead-induced hepatic and renal toxicity in male rats

The present study was designed to investigate the potential protective effect of melatonin against the hepatic and renal toxicity of lead in male rats. Three groups of animals were used in this study (control, lead acetate-treated (100 mg/kg), and lead acetate plus melatonin (10 mg/kg) for 30 days. Levels of lipid peroxidation (LPO) products, superoxide dismutase (SOD) activity, total glutathione (GSH), histopathological changes in the liver and kidneys were investigated. In addition, nuclear area (NA), nuclear volume (NV) and the ratio of nuclear volume/cellular volume (N/C) were measured in the liver. The results revealed increased LPO and decreased SOD, GSH, NA, NV and N/C in the studied organs of lead-treated rats. Histopathological observations showed severe damage in the liver and kidneys. Melatonin co-treatment to the lead-administered rats attenuated the increase of LPO and restored the activity of SOD and levels of GSH as well as the mean values of NA, NV and N/C. Also, the morphological damage in the liver and kidneys was reduced and the tissues appeared like those of controls. The present study suggests that melatonin may be useful in combating free radical-induced damage due to lead toxicity.     

Piperine as an adjuvant increases the efficacy of curcumin in mitigating benzo(a)pyrene toxicity

In the present study, the antioxidative and anticlastogenic effects of curcumin and piperine separately and in combination have been investigated against benzo(a)pyrene (BaP)-mediated toxicity in mice. Male Swiss albino mice were pretreated with curcumin (100 mg kg(-1) body weight) and piperine (20 mg kg(-1) body weight) separately as well as in combination orally in corn oil for 7 days; and subsequently, after 2 h of pretreatment, BaP was administered orally in corn oil (125 mg kg(-1) body weight). A single dose of BaP in normal mice increased the levels of lipid peroxidation (LPO), protein carbonyl content (PCC), and frequency of bone marrow micronucleated polychromatic erythrocytes (MNPCEs) but decreased significantly the levels of endogenous antioxidants such as superoxide dismutases (SODs), glutathione peroxidase (GPx), glutathione reductase (GR), catalase (CAT) and reduced glutathione (GSH) in the liver. Pretreatments with curcumin and curcumin plus piperine before administration of single dose of BaP significantly decreased the levels of LPO, PCC, and incidence of MNPCEs but elevated the level of GSH and enzyme activities of GPx, GR, SOD, CAT, and glutathione-S-transferase (GST) when compared to the BaP-treated group. The effect of curcumin plus piperine is more pronounced as compared to curcumin in attenuating BaP-induced oxidative insult and clastogenicity.     

Toxicity evaluation of β‐diketone antibiotics on the development of embryo‐larval zebrafish (Danio rerio)

This study evaluated the effects of β‐diketone antibiotics (DKAs) on the development of embryo‐larval zebrafish (Danio rerio). When exposure to DKAs, developmental malformations, such as hatching delay, curved body axis, pericardial edema, uninflated swim bladder and yolk sac edema, were observed at 120 h postfertilization (hpf). The estimated 120 hpf nominal concentrations of no observed effect concentration and lowest observed effect concentration for DKAs were 18.75 and 37.50 mg/L, respectively, suggesting that DKAs have much lower toxicity than other persistent pollutants. Following DKA exposure, embryonic heart rates were significantly reduced as compared to the controls at 48 and 60 hpf. The peak bending motion frequency appeared 1 h earlier than in control embryos. The 2.34 and 9.38‐mg/L treatment groups had a higher basal swim rate than control groups at 120 hpf in both light and light‐to‐dark photoperiod experiments. The occurrence of high speed swim rates was enhanced approximately threefold to sevenfold in the 2.34 and 9.38 mg/L treatments compared to the control. Glutathione (GSH) concentrations in the 2.34 and 9.38‐mg/L treatments were significantly higher than the control at 72 hpf, suggesting that GSH production was induced at the end of the hatching period. When exposed to DKAs, zebrafish superoxide dismutase enzyme (SOD) activities were significantly inhibited in the early embryonic period, demonstrating that the clearing ability in zebrafish was lower than the generation rate of free radicals. In summary, the combined DKAs were developmentally toxic to zebrafish in their early life stages and had the ability to impair individual behaviors that are of great importance in the assessment of their ecological fitness. © 2013 Wiley Periodicals, Inc. Environ Toxicol 29: 1134–1146, 2014.     

In situ evaluation of sediment toxicity in Guadalete Estuary (SW Spain) after exposure of caged Arenicola marina

A 7 day in situ assay to assess sediment toxicity was carried out per replicate in two sites from Guadalete Estuary (Guad1 and Guad2) (South-West, Spain) using the polychaete Arenicola marina (n = 20) in benthic cages. After the exposure period, a battery of biomarkers were determined to asses the sediment toxicity. Five of them were exposure biomarkers [ethoxyresorufin O-deethylase (EROD), dibenzylfluorescein (DBF) dependant CytP450, gluthation reductase (GR), and gluthation-S-transferase (GST) activities] and one of them was an effect biomarker [lipid peroxidation (LPO)]. Toxicity due to metals bound to the sediment was found in Guad2. Metals provoke the inhibition of EROD, DBF, and GR and the induction of GST, which is showed to carry out antioxidative stress defense. Toxicity caused by metals and also PAH was detected in Guad1. The presence of these chemicals leads to GST induction in and presumably in consequence, to LPO inhibition. GST activity resulted to be the main protection mechanism against oxidative stress in Arenicola marina. We suggest further research in Guadalete Estuary focusing on the detection and toxicity assessment of pharmaceutical and personal care products.     

Feasibility study of the zebrafish assay as an alternative method to screen for developmental toxicity and embryotoxicity using a training set of 27 compounds

To anticipate to increased testing needs for reproductive toxicity and 3R approaches, we studied zebrafish embryo/larva as an alternative for animal testing for developmental toxicity and embryotoxicity and evaluated a training set of 27 compounds with a standardized protocol. The classification of compounds in the zebrafish embryo/larva assay, based on a prediction model using a TI (teratogenic index) cut-off value of 2, was compared to available animal and human data. When comparing the classification of compounds in the zebrafish embryo/larva assay to available animal classification, a sensitivity of 72% and specificity of 100% were obtained. The predictive values obtained in comparison to a limited set of human data were 50, 60% respectively for teratogens, non-teratogens. Overall, we demonstrated that the zebrafish embryo/larva assay, may be used as screening tool for prioritization of compounds and could contribute to reduction of animal experiments in the field of developmental toxicology.     

Assessing lethal and sub-lethal effects of trichlorfon on different trophic levels

Trichlorfon (TCF) is one of the most used veterinary pharmaceuticals not only to fight infestations but also as a preventive measure worldwide. The high concentrations used generate concerns about environmental and human health. In this work we assessed the acute toxicity of this compound to non-target organisms belonging to different trophic levels: Danio rerio (early life stages and adults), Daphnia magna and algae (Pseudokirchneriella subcapitata and Chlorella vulgaris), and studied the potential of the biomarkers cholinesterase (ChE), glutathione-S-transferase (GST), lactate dehydrogenase (LDH) and catalase (CAT) to assess sub-lethal effects of trichlorfon in zebrafish and daphnids. The fish embryo test followed the OECD draft guideline FET and was based on the exposure of newly fertilized eggs to 0, 2.5, 5.0, 10, 20, 40, 80 and 160 mg/L of TCF for 5 days; the fish acute test followed the OECD guideline 203 and was based on the exposure of adult fish to 0, 2.5, 5, 10, 20, 40, 60 and 80 mg/L of TCF for 4 days; Daphnia sp. immobilization assay followed the OECD guideline 202 and was based on the exposure of juvenile daphnids to 0, 0.1, 0.3, 0.5, 0.7, 0.9, 1 and 2 μg/L of TCF for 2 days and the algae growth inhibition assay followed the OECD guideline 201 and was based on the exposure of the two species to 0, 1, 3.2, 10, 32, 100 and 300 mg/L of TCF for 4 days. Biomarker levels were measured after 96 h exposure to TCF in zebrafish early life stages and adults and after 48 h exposure in D. magna. Tested organisms seem to have dissimilar sensitivities towards TCF exposure. D. magna (48 h-LC(50)=0.29 μg/L) was the most sensitive organism, followed by early life stages and adults of zebrafish (96 h-LC(50)=25.4 and 28.8 mg/L, respectively) and finally by the algae P. subcapitata (96 h-LC(50)=274.5 mg/L) and C. vulgaris (no effect observed). As daphnids are a source of food for organisms of higher trophic levels, the impairment on its population is prone to have consequences in the entire ecosystem. The biomarker activities measured in daphnids and fish seemed to be useful tools in the assessment of trichlorfon effects, especially ChE activity which was the most sensitive biomarker tested for all organisms. Trichlorfon was teratogenic for zebrafish embryos leading to anomalies in the absorption of the yolk sac, spine bending and pericardial oedemas. The present research suggests that further work is urgently needed in order to monitor environmental concentrations of trichlorfon and to test the long term effects of environmentally realistic concentrations of this compound.     

氟砷联合染毒对大鼠子代大脑氧化性损伤的研究

目的 揭示氟砷共存时对子代健康的影响。方法 采用两代一窝繁殖实验的方法,测定Ｗｉｓｔａｒ大鼠暴露于氟砷后其子代大脑中氟砷蓄积情况、脂质过氧化水平。结果 随着暴露剂量的增加,大脑氟砷含量显著增加,ＳＯＤ和ＧＳＨ－Ｐｘ活性随之降低,而ＬＰＯ含量却逐渐增加,同代不同剂量组间比较,差异均有非常显著意义（Ｐ〈０．０１）,并出出明显的病理性变化;停止氟砷暴露８周后,大脑氟砷含量显著降低,酶的生有所恢复,而ＬＰ     

Role of vitamin E in mitigating methomyl induced acute toxicity in blood of male Wistar rats

The present study was designed to evaluate the protective potential of vitamin E, if any, in attenuating the toxic effects induced by acute methomyl treatment in rats. Male Wistar rats, weighing between 230 and 250 g, received either a single oral dose of 9 mg/kg of methomyl, vitamin E alone injected intraperitoneally on alternate days (4 injections) at 50 mg/kg body for 1 week prior to methomyl treatment, or both methomyl plus vitamin E given in a similar manner. The effects of different treatments were studied on lipid peroxidation (LPO), reduced glutathione (GSH) and antioxidant enzymes, which included superoxide dismutase (SOD), glutathione-s-transferase (GST), glutathione reductase (GR), glutathione peroxidase (GSHPx) and catalase and various hematological parameters, including total leucocytes count (TLC), differential leukocyte count (DLC), hemoglobin, platelets counts, red cell counts, and scanning electron microscopy (SEM). Acute 24-h treatment to rats resulted in a significant increase in the LPO. GSH levels and the activities of catalase, GST, and GSHPx were found to be significantly decreased following methomyl treatment. A significant elevation in the activity of SOD and in TLC was also observed after 24 h of methomyl treatment. Further, a significant increase in the neutrophils and eosinophil counts was also observed. However, lymphocytes showed a significant decrease following methomyl treatment. SEMs showed significant morphological changes following methomyl treatment. Vitamin E pretreatment to methomyl-treated rats effectively normalized the levels of LPO and GSH. Vitamin E could also significantly elevate the activity of catalase, increase platelets counts and TLC, and normalized the activities of SOD and GSHPx. Vitamin E pretreatment improved the morphology of the red blood cells. The study concludes that vitamin E affords protection in methomyl-induced toxicity in the rat.