Developmental neurotoxic effects of two pesticides: Behavior and neuroprotein studies on endosulfan and cypermethrin

Residue levels, processing factors and risk assessment of pesticides in ginger from market to table

Ginger is consumed as a spice and medicine globally. However, pesticide residues in ginger and their residue changes during processing remain poorly understood. Our results demonstrate that clothianidin, carbendazim and imidacloprid were the top detected pesticides in 152 ginger samples with detection rates of 17.11-27.63%, and these pesticides had higher average residues of 44.07-97.63 μg/kg. Although most samples contained low levels of pesticides, 66.45% of the samples were detected with pesticides, and 38.82% were contaminated with 2-5 pesticides. Peeling, washing, boiling and pickling removed different amounts of pesticides from ginger (processing factor range: 0.06-1.56, most <1). By contrast, pesticide residues were concentrated by stir-frying and drying (0.50-6.45, most >1). Pesticide residues were influenced by pesticide physico-chemical parameters involving molecular weight, melting point, degradation point and octanol-water partition coefficient by different ginger processing methods. Chronic and acute dietary risk assessments suggest that dietary exposure to pesticides from ginger consumption was within acceptable levels for the general population. This study sheds light on pesticide residues in ginger from market to processing and is of theoretical and practical value for ensuring ginger quality and safety.

Effects of acute insecticide exposure on neuronal activity in vitro in rat cortical cultures

Exposure to pesticides, such as carbamates, organophosphates, organochlorines and pyrethroids, has been linked to various health problems, including neurotoxicity. Although most in vivo studies use only male rodents, some studies have shown in vivo sex-specific effects after acute exposure. Since in vivo studies are costly and require a large number of animals, in vitro assays that take sex-specific effects into account are urgently needed. We therefore assessed the acute effects of exposure to different carbamates (methomyl, aldicarb and carbaryl), organophosphates (chlorpyrifos (CPF), chlorpyrifos-oxon (CPO) and 3,5,6-trichloropyridinol), organochlorines (endosulfan, dieldrin and lindane) and pyrethroids (permethrin, alpha-cypermethrin and 3-phenoxy-benzoic acid (3-PBA)) on neuronal network function in sex-separated rat primary cortical cultures using micro-electrode array (MEA) recordings. Our results indicate that exposure to the carbamate carbaryl and the organophosphates CPF and CPO decreased neuronal activity, with CPO being the most potent. Notably, (network) burst patterns differed between CPF and CPO, with CPO inducing fewer, but more intense (network) bursts. Exposure to low micromolar levels of endosulfan induced a hyperexcitation, most likely due to the antagonistic effects on GABA receptors. Interestingly, females were more sensitive to endosulfan than males. Exposure to dieldrin and lindane also increased neuronal activity, albeit less than endosulfan and without sex-specific effects. Exposure to type I pyrethroid permethrin increased neuronal activity, while exposure to type II pyrethroid alpha-cypermethrin strongly decreased neuronal activity. The increase seen after permethrin exposure was more pronounced in males than in females. Together, these results show that acute exposure to different classes of pesticides exerts differential effects on neuronal activity. Moreover, it shows that MEA recordings are suited to detect sex-specific neurotoxic effects in vitro.

Delayed in sensorimotor reflex ontogeny, slow physical growth, and impairments in behaviour as well as dopaminergic neuronal death in mice offspring following prenatally rotenone administration

The environment is varying day by day with the introduction of chemicals such as pesticides, most of which have not been effectively studied for their influence on a susceptible group of population involving infants and pregnant females. Rotenone is an organic pesticide used to prepare Parkinson's disease models. A lot of literature is available on the toxicity of rotenone on the adult brain, but to the best of our knowledge, effect of rotenone on prenatally exposed mice has never been investigated yet. Therefore, the recent work aims to evaluate the toxic effect of rotenone on mice, exposed prenatally. We exposed female mice to rotenone at the dose of 5 mg/Kg b.w. throughout the gestational period with oral gavage. We then investigated the effects of rotenone on neonate's central nervous systems as well as on postnatal day (PD) 35 offspring. In the rotenone group, we observed slow physical growth, delays in physical milestones and sensorimotor reflex in neonates and induction of anxiety and impairment in cognitive performances of offspring at PD-35. Additionally, immunohistochemical analysis revealed a marked reduction in TH-positive neurons in substantia nigra. Histological examination of the cerebellum revealed a decrease in Purkinje neurons in the rotenone exposed group as compared to the control. The data from the study showed that prenatally exposure to rotenone affects growth, physical milestones, neuronal population and behaviour of mice when indirectly exposed to the offspring through their mother. This study could provide a great contribution to researchers to find out the molecular mechanism and participating signalling pathway behind these outcomes.

Multiomics implicate gut microbiota in low cypermethrin (CP) exposure induced multiorgan toxicological effects in pubertal male rats

Cypermethrin (CP), widely used as a broad-spectrum pesticide, has raised concerns over its frequent presence in the environment and potential health risks. The present study focused on incorporating the gut-organ axis theory to reinterpret the toxicological effects and mechanisms following CP exposure at environmentally relevant concentrations (0.1 mg/kg/d and 0.5 mg/kg/d) in pubertal male rats. The results showed alterations in histopathological and organosomatic indices in the liver, brain, and epididymis. Through multiomics network analysis, it was found that Lachnospiraceae and Ruminococcaceae may contribute to the alteration in serum L-carnitine and trigonelline, leading to hepatic lipid accumulation following CP exposure. Additionally, Ruminococcaceae, Lachnospiraceae, and Porphyromonadaceae were associated with CP-induced glutamatergic hypofunction and overproduction of TNF-α, potentially contributing to the brain neurotoxicity. Overall, the study provides important insights into the potential mechanisms underlying CP-induced toxicity and highlights the need for continued research to fully understand the implications for CP-induced health risks. The incorporation of the gut-organ axis theory in the study provides a promising avenue for future research into the potential interactions between gut microbiota and organ toxicity, and the potential for targeted interventions to mitigate the adverse effects of environmental toxins.

Endosulfan affects embryonic development synergistically under elevated ambient temperature

In the present study, we determined the developmental toxicity of endosulfan at an elevated ambient temperature using the zebrafish animal model. Zebrafish embryos of various developmental stages were exposed to endosulfan through E3 medium, raised under two selected temperature conditions (28.5 °C and an elevated temperature of 35 °C), and monitored under the microscope. Zebrafish embryos of very early developmental stages (cellular cleavage stages, such as the 64-cell stage) were highly sensitive to the elevated temperature as 37.5% died and 47.5% developed into amorphous type, while only 15.0% of embryos developed as normal embryos without malformation. Zebrafish embryos that were exposed concurrently to endosulfan and an elevated temperature showed stronger developmental defects (arrested epiboly progress, shortened body length, curved trunk) compared to the embryos exposed to either endosulfan or an elevated temperature. The brain structure of the embryos that concurrently were exposed to the elevated temperature and endosulfan was either incompletely developed or malformed. Furthermore, the stress-implicated genes hsp70, p16, and smp30 regulations were synergistically affected by endosulfan treatment under the elevated thermal condition. Overall, the elevated ambient temperature synergistically enhanced the developmental toxicity of endosulfan in zebrafish embryos.

Esculin protects human blood cells from bioallethrin-induced toxicity: An ex vivo study

Bioallethrin, a household insecticide, is a member of the pyrethroid family and is known for its adverse effects on human health. Human exposure to pyrethroids is unavoidable due to their widespread use in controlling several fatal vector-borne diseases, mostly in developing nations. Bioallethrin is known to induce oxidative stress in target cells, including erythrocytes. Here we have studied the protective effect of dietary antioxidant esculin on bioallethrin-induced damage in isolated human erythrocytes. The cells were incubated with 200 μM bioallethrin, without or with different concentrations of esculin (200, 400 and 600 μM), and the results compared to the untreated control samples. Bioallethrin-treated erythrocytes showed a significant increase in oxidative stress markers, like protein and lipid oxidation, accompanied by decrease in free amino groups and ratio of reduced to oxidized glutathione. There was enhanced generation of reactive oxygen and nitrogen species with changes in plasma membrane integrity. Bioallethrin oxidized hemoglobin to methemoglobin, which cannot transport oxygen. It altered the activities of antioxidant enzymes and lowered the electron donating and free radical quenching ability of erythrocytes. The cell morphology and redox system of erythrocyte membrane were also altered by bioallethrin. Treatment with esculin, prior to incubation with bioallethrin, led to significant restoration in all these parameters in an esculin concentration-dependent manner. Thus esculin attenuated the biolletherin-induced oxidative damage to erythrocytes. Esculin can, therefore, be an effective chemoprotectant against xenobiotic-induced toxicity in human erythrocytes.

Effects of pyrethroids on the cerebellum and related mechanisms: a narrative review

Pyrethroids (PYRs) are a group of synthetic organic chemicals that mimic natural pyrethrins. Due to their low toxicity and persistence in mammals, they are widely used today. PYRs exhibit higher lipophilicity than other insecticides, which allows them to easily penetrate the blood-brain barrier and directly induce toxic effects on the central nervous system. Several studies have shown that the cerebellum appears to be one of the regions with the largest changes in biomarkers. The cerebellum, which is extremely responsive to PYRs, functions as a crucial region for storing motor learning memories. Exposure to low doses of various types of PYRs during rat development resulted in diverse long-term effects on motor activity and coordination functions. Reduced motor activity may result from developmental exposure to PYRs in rats, as indicated by delayed cerebellar morphogenesis and maturation. PYRs also caused adverse histopathological and biochemical changes in the cerebellum of mothers and their offspring. By some studies, PYRs may affect granule cells and Purkinje cells, causing damage to cerebellar structures. Destruction of cerebellar structures and morphological defects in Purkinje cells are known to be directly related to functional impairment of motor coordination. Although numerous data support that PYRs cause damage to cerebellar structures, function and development, the mechanisms are not completely understood and require further in-depth studies. This paper reviews the available evidence on the relationship between the use of PYRs and cerebellar damage and discusses the mechanisms of PYRs.

Maternal exposure to glyphosate-based herbicide promotes changes in the muscle structure of C57BL/6 mice offspring

Glyphosate (GBH) is a worldwide consumption pesticide and is used in the formulation of Roundup®, one of the most commercialized herbicides in the world. Maternal exposure to this herbicide can promote changes and adaptations in the offspring; however, the effects on skeletal muscle are poorly understood. In this sense, the present study sought to evaluate the effect of exposure to GBH on the characteristics of the soleus (SOL) and extensor digitorum longus (EDL) muscles. C57BL/6 pregnant female mice were divided into two groups: control (CTL) receiving water and glyphosate (GBH; n = 6) receiving 0.5% glyphosate. Male puppies were designated according to the group to which the mothers belonged, such as CTL-F1 and GBH-F1 and then euthanized at 150 days of age. There was a reduction in body weight and nasoanal length of animals exposed to GBH, while there was an increase in EDL weight, reduction in the proportion of fibers and number of nuclei, and an increase in the connective tissue of the SOL. The animals exposed to GBH presented higher values of body characteristics, mainly adiposity gain, while they presented a reduction in neuromuscular junctions (NMJ), and an increase in fibrosis in the SOL muscle, while there was a reduction in the number of nuclei, and an increase in the weight of the EDL muscle. These findings indicate that glyphosate can promote changes in the offspring's body growth, the deposition of adipose panicles and its effects on muscle can lead to changes in the structure and functioning of this tissue.

Aberrant Hoxa10 gene methylation as a mechanism for endosulfan-induced implantation failures in rats

DNA methylation is a well-established epigenetic mechanism controlling gene expression. Environmental chemicals, such as pesticides have been shown to alter DNA methylation. We have previously shown that the insecticide endosulfan impairs female fertility in rats by increasing the rate of preimplantation embryo losses. In this study, we evaluated whether early postnatal exposure to endosulfan affects long-term transcriptional regulation of Homeobox A10 (Hoxa10) gene, which is a key marker of endometrial receptivity. Female rats were neonatally exposed to 6 or 600 μg/kg/day (ENDO6 and ENDO600, respectively) of endosulfan and uterine samples collected on gestational day (GD) 5. Hoxa10 protein and mRNA levels were assessed by immunohistochemistry and quantitative real-time PCR (qRT-PCR), respectively. In silico analysis of enzyme-specific restriction sites and predicted transcription factors were performed to investigate the methylation status of the regulatory regions of Hoxa10 gene by methylation-sensitive restriction enzymes-PCR technique. The expression of the DNA methyltransferases (Dnmts) was also evaluated. ENDO600 showed a decreased uterine Hoxa10 expression at protein and transcript level, while ENDO6 decreased only the level of transcripts, during the receptive stage. In addition, endosulfan increased levels of Dnmt3a and Dnmt3b. Dysregulation of DNA methylation patterns of Hoxa10 regulatory regions was detected in ENDO6- and ENDO600-treated rats. All these results suggest that aberrant DNA methylation in Hoxa10 gene could be an underlining mechanism contributing to explain endosulfan-induced preimplantation losses.

Association between pesticide and polychlorinated biphenyl exposure during pregnancy and autism spectrum disorder among children: a meta-analysis

BACKGROUND

The effect of exposure to environmental factors on autism spectrum disorders (ASD), especially during pregnancy, is unclear.

PURPOSE

This meta-analysis investigated the association between exposure to pesticides and polychlorinated biphenyls (PCBs) during pregnancy and ASD risk among children.

METHODS

We searched Scopus, PubMed, Web of Science, and ProQuest for articles published through September 2019. Random-effects models were used to examine the association among studies using pooled odds ratios (ORs) and their 95% confidence intervals (CI). I2 tests were used to measure interstudy heterogeneity.

RESULTS

The pooled OR indicated a significant association between PCB and pesticide exposure during pregnancy and ASD risk among children (OR, 1.80; 95% CI, 1.26-2.34; and OR, 1.20; 95% CI, 1.02-1.39), respectively.

CONCLUSION

Findings of the present study indicate that exposure to pesticides and PCBs during pregnancy may affect the risk of ASD among children.

Maternal Exposure to Pesticides and Risk of Autism Spectrum Disorders in Offspring: A Meta-analysis

This meta-analysis was conducted to estimate the overall association between maternal exposure to pesticides and risk of ASD in offspring. PubMed, EMBASE, Web of Science, and the PsycINFO were searched until December 30, 2020 to include eligible studies. Eight studies with 50,426 participants, 5810 of whom had ASD, were involved in the study. Overall, the summary OR (95% confidence interval) of ASDs in offspring for maternal exposure to pesticide estimated by residential proximity measures and self-report was 1.88 (1.10-3.20). However, maternal exposure to pesticide measured by biomarkers was not associated with an increased risk of ASDs (pooled OR 1.13; 95% CI 0.83-1.54). Further well-designed studies are needed to confirm our findings.

Characterization, mechanism of cypermethrin biosorption by Saccharomyces cerevisiae strains YS81 and HP and removal of cypermethrin from apple and cucumber juices by inactive cells

Cypermethrin is a common food contaminant and environmental pollutant that cause health threats to animals and humans. In this study, the characterization, mechanism, and application of cypermethrin removal by Saccharomyces cerevisiae were investigated. The binding of cypermethrin by the strains S. cerevisiae YS81 and HP was rapid and reached equilibrium at 2-8 h. The removal efficiency was dependent on incubation temperature and yeast concentration, whereas cypermethrin binding was not affected by pH. Heat and acid treatments enhanced the binding ability. Both strains survived in simulated digestion juices and removed cypermethrin effectively under simulated gastrointestinal conditions. Among the strains tested, the YS81 strain was the better candidate for cypermethrin concentration reduction. For the two S. cerevisiae strains, the biosorption kinetics and isotherm followed the pseudo-second-order model and Langmuir model well. The cell walls and the protoplasts were the main yeast cell components involved in cypermethrin binding. Fourier transformed infrared spectroscopy analysis revealed that -OH, -NH, -C-N, -COO^-, and -C-O played a major role in binding cypermethrin. Inactive cells effectively removed cypermethrin from apple and cucumber juices and did not affect the physico-chemical properties. Therefore, S. cerevisiae strains YS81 and HP may be used for cypermethrin reduction in food or feed.

Effect of environmental toxicants on neuronal functions

In the last few years, neurodegenerative diseases like Alzheimer's disease (AD) and Parkinson's disease (PD) have attracted attention due to their high prevalence worldwide. Environmental factors may be one of the biggest reasons for these diseases related to neuronal dysfunctions. Most of neuronal disorders are strongly associated with pre- and postnatal exposure to environmental toxins released from industries. Some of the neurotoxic metals such as lead, aluminum, mercury, manganese, cadmium, and arsenic as well as some pesticides and metal-based nanoparticles have been involved in AD and PD due to their ability to produce senile/amyloid plaques and NFTs which are the main feature of these neuronal dysfunctions. Exposure to solvents is also majorly responsible for neurodegenerative disorders. The present review highlights the impact of omnipresent heavy metals with some other neurotoxins on human health and how they give rise to neuronal dysfunctions which in turn causes socio-economic consequences due to increasing pollution worldwide. Graphical abstract.

Amino acid, fatty acid, and carbohydrate metabolomic profiles with ginsenoside-induced insecticidal efficacy against Ostrinia furnacalis (Guenee)

Background

Previous studies have shown the insecticidal efficacy of ginsenosides. In the present study, we aimed to investigate the metabolic mechanism related to the inhibitory effect of panaxadiol saponins (PDSs) against the Asian corn borer Ostrinia furnacalis (Guenee).

Methods

Third instar larvae of O. furnacalis were fed normal diets with different concentrations of PDSs for 4 days. The consumption index, relative growth rate, approximate digestibility, and conversion of ingested and digested food were recorded. A targeted gas chromatography–mass spectrometry assay was performed to detect the profiles of amino acids, fatty acids, and carbohydrates in larvae of O. furnacalis. In addition, the activity of detoxification-related enzymes was determined.

Results and Conclusions

PDSs decreased the consumption index, relative growth rate, approximate digestibility, and conversion of ingested and digested food in the 3rd instar larvae of O. furnacalis in a dose-dependent manner. PDSs decreased 15 free amino acids, 16 free fatty acids, and 5 carbohydrates and increased the levels of palmitoleic acid, palmitic acid, and 9-octadecenoic acid in the 3rd instar larvae. The activity of detoxification-related enzymes, such as acetylcholinesterase, glutathione S-transferase, cytochrome P450, carboxylesterase, trehalase, acid phosphatase, and alkaline phosphatase, was reduced in a dose-dependent manner in the 3rd instar larvae exposed to PDSs. These data confirmed the inhibitory effect of PDSs against growth, food utilization, and detoxification in the 3rd instar larvae of O. furnacalis and the potential for using PDSs as an efficient tool for insect pest management for O. furnacalis larvae.

•

Panaxadiol saponins (PDSs) reduced larval growth and food consumption and utilization in Ostrinia furnacalis.

•

PDSs reduced the levels of free amino acids, fatty acids, and sugar in larvae.

•

PDSs inhibited the activity of acetylcholinesterase, glutathione S-transferase, cytochrome P450, carboxylesterase, trehalase, acid phosphatase, and alkaline phosphatase.

•

All the inhibitory effects of PDSs against O. furnacalis larvae were dose dependent.

Endosulfan exposure alters transcription of genes involved in the detoxification and stress responses in Physella acuta

Endosulfan is a persistent pesticide that has been in use for more than five decades. During this time, it has contaminated soil, air, and water reservoirs worldwide. It is extremely toxic and harmful to beneficial non-target invertebrates, aquatic life, and even humans upon consumption, which is one of the many dangers of this pesticide since it biomagnifies in the food chain. The effects of three endosulfan concentrations (1, 10, and 100 µg/L) on the freshwater snail Physella acuta, an invasive cosmopolitan species, were examined over a week-long exposure period. Alterations in the expression of ten genes related to stress and xenobiotic detoxification were measured against the endogenous controls rpL10 and GAPDH by Real-Time polymerase chain reaction. Four genes are described here for the first time in this species, namely Hsp60, Grp78, GSTk1, and GSTm1. The rest of genes were Hsp90, sHsp16.6, cyp2u1, cyp3a7, cyp4f22, and MRP1. cyp2u1, sHsp16.6, and Grp78 expression were all altered by endosulfan. These results suggest a low pesticide concentration activates the acute response in P. acuta by affecting detoxification and stress responses and alter endoplasmic reticulum function and lipid metabolism. Furthermore, the newly identified genes extend the number of processes and cellular locations that can be analyzed in this organism.

Evaluation of Chemical Effects on Network Formation in Cortical Neurons Grown on Microelectrode Arrays

Thousands of chemicals to which humans are potentially exposed have not been evaluated for potential developmental neurotoxicity (DNT), driving efforts to develop a battery of in vitro screening approaches for DNT hazard. Here, 136 unique chemicals were evaluated for potential DNT hazard using a network formation assay (NFA) in cortical cells grown on microelectrode arrays. The effects of chemical exposure from 2 h postplating through 12 days in vitro (DIV) on network formation were evaluated at DIV 5, 7, 9, and 12, with cell viability assessed at DIV 12. Only 82 chemicals altered at least 1 network development parameter. Assay results were reproducible; 10 chemicals tested as biological replicates yielded qualitative results that were 100% concordant, with consistent potency values. Toxicological tipping points were determined for 58 chemicals and were similar to or lower than the lowest 50% effect concentrations (EC50) for all parameters. When EC50 and tipping point values from the NFA were compared to the range of potencies observed in ToxCast assays, the NFA EC50 values were less than the lower quartile for ToxCast assay potencies for a subset of chemicals, many of which are acutely neurotoxic in vivo. For 13 chemicals with available in vivo DNT data, estimated administered equivalent doses based on NFA results were similar to or lower than administered doses in vivo. Collectively, these results indicate that the NFA is sensitive to chemicals acting on nervous system function and will be a valuable contribution to an in vitro DNT screening battery.

Mechanistic Interplay Between Autophagy and Apoptotic Signaling in Endosulfan-Induced Dopaminergic Neurotoxicity: Relevance to the Adverse Outcome Pathway in Pesticide Neurotoxicity

Chronic exposure to pesticides is implicated in the etiopathogenesis of Parkinson's disease (PD). Previously, we showed that dieldrin induces dopaminergic neurotoxicity by activating a cascade of apoptotic signaling pathways in experimental models of PD. Here, we systematically investigated endosulfan's effect on the interplay between apoptosis and autophagy in dopaminergic neuronal cell models of PD. Exposing N27 dopaminergic neuronal cells to endosulfan rapidly induced autophagy, indicated by an increased number of autophagosomes and LC3-II accumulation. Prolonged endosulfan exposure (>9 h) triggered apoptotic signaling, including caspase-2 and -3 activation and protein kinase C delta (PKCδ) proteolytic activation, ultimately leading to cell death, thus demonstrating that autophagy precedes apoptosis during endosulfan neurotoxicity. Furthermore, inhibiting autophagy with wortmannin, a phosphoinositide 3-kinase inhibitor, potentiated endosulfan-induced apoptosis, suggesting that autophagy is an early protective response against endosulfan. Additionally, Beclin-1, a major regulator of autophagy, was cleaved during the initiation of apoptotic cell death, and the cleavage was predominantly mediated by caspase-2. Also, caspase-2 and caspase-3 inhibitors effectively blocked endosulfan-induced apoptotic cell death. CRISPR/Cas9-based stable knockdown of PKCδ significantly attenuated endosulfan-induced caspase-3 activation, indicating that the kinase serves as a regulatory switch for apoptosis. Additional studies in primary mesencephalic neuronal cultures confirmed endosulfan's effect on autophagy and neuronal degeneration. Collectively, our results demonstrate that a functional interplay between autophagy and apoptosis dictate pesticide-induced neurodegenerative processes in dopaminergic neuronal cells. Our study provides insight into cell death mechanisms in environmentally linked neurodegenerative diseases.

Endosulfan promotes cell migration via PTP4A3-mediated signaling pathways in HUVECs

Endosulfan is a persistent organic pollutant and can cause endothelial dysfunction, closely related to cardiovascular diseases. Endothelial cell migration plays a critical role in atherosclerosis and angiogenesis. This study was aimed to investigate the effect of environmentally relevant doses of endosulfan and underlying molecular mechanism on endothelial cell migration. Human umbilical vein endothelial cells (HUVECs) were treated with DMSO (control) or endosulfan (0.1, 1, 10 and 20 μM) in the presence or absence of inhibitors. Wound healing and Transwell assay were employed to explore the effect of endosulfan on endothelial cell migration. The expression of genes or proteins was assayed by real-time PCR or immunoblotting. The results showed that endosulfan at relative low concentration (0.1, 1, 10 and 20 μM) increased cell migration ability horizontally and vertically at 12 h after exposure. In line with this cellular effect, Protein-tyrosine Phosphatase 4A3 (PTP4A3) expression was significantly increased in endosulfan-exposed endothelial cells. Specific inhibitor of PTP4A3 significantly inhibited 20 μM endosulfan-induced cell migration, the expression and phosphorylation of Src and phosphorylation of focal adhesion kinase (FAK). Exposure to endosulfan resulted in activation of various signaling pathways including phosphoinositide 3-kinase (PI3K)/AKT, mitogen-activated protein kinase (MAPK) and nuclear factor kappa B (NF-κB), which were suppressed by PTP4A3 inhibitor or specific inhibitor for each signaling pathway. Exposure to endosulfan significantly reduced nitric oxide production and caused oxidative stress in HUVECs. These findings suggest that endosulfan promoted cell migration through PTP4A3-mediated various signaling pathways in endothelial cells.

A Multiomics Study To Unravel the Effects of Developmental Exposure to Endosulfan in Rats: Molecular Explanation for Sex-Dependent Effects

Exposure to low levels of environmental contaminants, including pesticides, induces neurodevelopmental toxicity. Environmental and food contaminants can reach the brain of the fetus, affecting brain development and leading to neurological dysfunction. The pesticide endosulfan is a persistent pollutant, and significant levels still remain detectable in the environment although its use is banned in some countries. In rats, endosulfan exposure during brain development alters motor activity, coordination, learning, and memory, even several months after uptake, and does so in a sex-dependent way. However, the molecular mechanisms driving these effects have not been studied in detail. In this work, we performed a multiomics study in cerebellum from rats exposed to endosulfan during embryonic development. Pregnant rats were orally exposed to a low dose (0.5 mg/kg) of endosulfan, daily, from gestational day 7 to postnatal day 21. The progeny was evaluated for cognitive and motor functions at adulthood. Expression of messenger RNA and microRNA genes, as well as protein and metabolite levels, were measured on cerebellar samples from males and females. An integrative analysis was conducted to identify altered processes under endosulfan effect. Effects between males and females were compared. Pathways significantly altered by endosulfan exposure included the phosphatidylinositol signaling system, calcium signaling, the cGMP-PKG pathway, the inflammatory and immune system, protein processing in the endoplasmic reticulum, and GABA and taurine metabolism. Sex-dependent effects of endosulfan in the omics results that matched sex differences in cognitive and motor tests were found. These results shed light on the molecular basis of impaired neurodevelopment and contribute to the identification of new biomarkers of neurotoxicity.

Intracerebroventricular injection of deltamethrin increases locomotion activity and causes spatial working memory and dopaminergic pathway impairment in rats

Deltamethrin (DM) is widely used in agriculture, veterinary medicine and control of domestic pests. Epidemiological studies suggest that DM exposure is a risk factor for neurodegenerative disorders such as Parkinson's (PD) and Alzheimer diseases; however the mechanisms are elusive. In the present study we evaluated the effects of intracerebroventricular (i.c.v.) administration of DM on locomotion activity, spatial working memory and dopaminergic pathway in the rat. Middle-aged male Wistar rats received three i.c.v. injections of DM 0.5 μg, DM 5 μg or vehicle, every other day. Across the treatment, the animals were submitted to behavioral evaluation in the catalepsy test, open field test, and spontaneous alternation task. Following completion of behavioral tests, rats were perfused and their brains were processed to tyrosine hydroxylase (TH) immunohistochemistry. We observed that i.c.v. administration of DM 5 μg increased locomotion activity (open field) and caused spatial working memory impairment (spontaneous alternation task). These alterations were accompanied by reduction TH immunoreactivity in the substantia nigra pars compacta (SNpc), ventral tegmental area (VTA) and dorsal striatum. Conversely, no motor change was observed in the catalepsy test. These results indicate that i.c.v. administration of DM can cause hyperactivity and cognitive alteration which may be related to disruption of the dopaminergic pathway.

Neurotoxicity of pesticides

Pesticides are unique environmental contaminants that are specifically introduced into the environment to control pests, often by killing them. Although pesticide application serves many important purposes, including protection against crop loss and against vector-borne diseases, there are significant concerns over the potential toxic effects of pesticides to non-target organisms, including humans. In many cases, the molecular target of a pesticide is shared by non-target species, leading to the potential for untoward effects. Here, we review the history of pesticide usage and the neurotoxicity of selected classes of pesticides, including insecticides, herbicides, and fungicides, to humans and experimental animals. Specific emphasis is given to linkages between exposure to pesticides and risk of neurological disease and dysfunction in humans coupled with mechanistic findings in humans and animal models. Finally, we discuss emerging techniques and strategies to improve translation from animal models to humans.

Maternal Exposures Associated with Autism Spectrum Disorder in Jamaican Children

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder with poorly understood etiology. Many maternal exposures during pregnancy and breastfeeding potentially interfere with neurodevelopment. Using data from two age- and sex-matched case-control studies in Jamaica (n = 298 pairs), results of conditional logistic regression analyses suggest that maternal exposures to fever or infection (matched odds ratio (MOR) = 3.12, 95% CI 1.74-5.60), physical trauma (MOR 2.02, 95% CI 1.01-4.05), and oil-based paints (MOR 1.99, 95% CI 1.14-3.46) may be associated with ASD. Additionally, maternal exposure to oil-based paints may modify the relationship between maternal exposure to pesticides and ASD, which deepens our understanding of the association between pesticides and ASD.

Cypermethrin Promotes Lung Cancer Metastasis via Modulation of Macrophage Polarization by Targeting MicroRNA-155/Bcl6

Cypermethrin (CYM), a type II pyrethroid, is widely used as an insecticide for agriculture and household. Cumulative evidence indicates that acute and chronic exposure to CYM might cause a number of health problems, such as cancer and neuronal system diseases. However, the molecular mechanism underlying this pathology is not known. The main objective of this study was to define the effects of CYM on macrophages and the implication of such effects in cancer metastasis and the potential mechanism involved. The effects of CYM on the macrophages were evaluated by detecting the expression of M1 and M2 macrophage polarization markers through ELISA, quantitative RT-PCR, and Western blot assay. Transwell and wound healing assays were used to test the migration of lung cancer cells after exposure to CYM in vitro and a metastasis animal model in vivo. Treatment with CYM significantly suppressed lipopolysaccharide (LPS)-induced M1 macrophage polarization and promoted a shift toward M2 macrophage status. Mechanistically, CYM downregulated miR-155 significantly, leading to enhanced expression of its target gene Bcl6, thereby reducing the expression of mitogen-activated protein kinase 4 (MKK4), an upstream kinase of c-Jun N-terminal kinases (JNK), and inhibiting JNK activation. Impaired JNK activation thus promoted a shift in macrophage polarization from the M1 to the M2 phenotype. Finally, CYM-treated macrophages promoted metastasis of Lewis lung cancer cells in both in vitro and in vivo models. Taken together, our findings show that CYM is able to inhibit the M1 polarization and promote the macrophages to the M2 phenotype, which plays an important role in tumor metastasis.

Prenatal and infant exposure to ambient pesticides and autism spectrum disorder in children: population based case-control study

OBJECTIVE

To examine associations between early developmental exposure to ambient pesticides and autism spectrum disorder.

DESIGN

Population based case-control study.

SETTING

California's main agricultural region, Central Valley, using 1998-2010 birth data from the Office of Vital Statistics.

POPULATION

2961 individuals with a diagnosis of autism spectrum disorder based on the Diagnostic and Statistical Manual of Mental Disorders, fourth edition, revised (up to 31 December 2013), including 445 with intellectual disability comorbidity, were identified through records maintained at the California Department of Developmental Services and linked to their birth records. Controls derived from birth records were matched to cases 10:1 by sex and birth year.

EXPOSURE

Data from California state mandated Pesticide Use Reporting were integrated into a geographic information system tool to estimate prenatal and infant exposures to pesticides (measured as pounds of pesticides applied per acre/month within 2000 m from the maternal residence). 11 high use pesticides were selected for examination a priori according to previous evidence of neurodevelopmental toxicity in vivo or in vitro (exposure defined as ever v never for each pesticide during specific developmental periods).

MAIN OUTCOME MEASURE

Odds ratios and 95% confidence intervals using multivariable logistic regression were used to assess associations between pesticide exposure and autism spectrum disorder (with or without intellectual disabilities) in offspring, adjusting for confounders.

RESULTS

Risk of autism spectrum disorder was associated with prenatal exposure to glyphosate (odds ratio 1.16, 95% confidence interval 1.06 to 1.27), chlorpyrifos (1.13, 1.05 to 1.23), diazinon (1.11, 1.01 to 1.21), malathion (1.11, 1.01 to 1.22), avermectin (1.12, 1.04 to 1.22), and permethrin (1.10, 1.01 to 1.20). For autism spectrum disorder with intellectual disability, estimated odds ratios were higher (by about 30%) for prenatal exposure to glyphosate (1.33, 1.05 to 1.69), chlorpyrifos (1.27, 1.04 to 1.56), diazinon (1.41, 1.15 to 1.73), permethrin (1.46, 1.20 to 1.78), methyl bromide (1.33, 1.07 to 1.64), and myclobutanil (1.32, 1.09 to 1.60); exposure in the first year of life increased the odds for the disorder with comorbid intellectual disability by up to 50% for some pesticide substances.

CONCLUSION

Findings suggest that an offspring's risk of autism spectrum disorder increases following prenatal exposure to ambient pesticides within 2000 m of their mother's residence during pregnancy, compared with offspring of women from the same agricultural region without such exposure. Infant exposure could further increase risks for autism spectrum disorder with comorbid intellectual disability.

Endosulfan-Induced Prolonged Super-Refractory Status Epilepticus

Endosulfan is a highly toxic pesticide that causes hyperstimulation of the central nervous system by antagonizing gamma aminobutyric acid-mediated inhibition. Seizure is the most important manifestation of endosulfan poisoning, frequently progressing to status epilepticus and refractory status epilepticus. Here, we report a recent case of a 64-year-old man with endosulfan-induced super-refractory status epilepticus, which persisted for a remarkably longer period than has been described in previous reports. The patient arrived at the emergency room with continuous generalized tonic-clonic seizures. Electroencephalogram-recorded seizures that persisted even after intravenous administration of lorazepam and antiepileptic drugs. Intravenous anesthetic agents were administered for 9 days to confront the persistently recurring seizures. Immediately after this treatment period, the seizures subsided, and the patient showed marked neurological improvement. After 2 months however, he died of multiple systemic complications. This case report elucidates the importance of aggressive evaluation and management including continuous EEG monitoring in cases of endosulfan-related status epilepticus.

Mechanisms of synergistic neurotoxicity induced by two high risk pesticide residues - Chlorpyrifos and Carbofuran via oxidative stress

Multi-component pesticide residues, especially pesticide residues with synergistic toxicity, are a serious threat to food safety. With risk assessment, we found that Chlorpyrifos (CPF) and Carbofuran (CBF) are 2 pesticide residues with highest risk for Actinidia chinensis planch. The results showed CPF and CBF have a synergistic neurotoxicity on neural cell SK-N-SH. The toxicity was partly depending on oxidative stress (OS) and had effects on cell apoptosis and cell cycle arrest. Furthermore, the toxicity remained on long-term low-dose condition.

Prenatal Deltamethrin Exposure-Induced Cognitive Impairment in Offspring Is Ameliorated by Memantine Through NMDAR/BDNF Signaling in Hippocampus

Background: Pyrethroids have been widely used in residential and agricultural areas. However, little is known about the effects of prenatal exposure to deltamethrin on cognition in early development of offspring. In this study, the effects of prenatal exposure to deltamethrin on learning and memory abilities, N-methyl-D-aspartate receptor (NMDAR) subunits, brain derived neurotrophic factor (BDNF), Tyrosine kinase B (TrkB) receptor, and phosphorylated cAMP response element binding protein (pCREB) in the hippocampus of offspring rats were investigated.

Experimental Approaches: Groups each of six female SD rats, as F0-generation, were administered with deltamethrin (0, 0.54, 1.35, and 2.7, 9 mg/kg), or memantine (10 mg/kg), or co-administered with deltamethrin (9 mg/kg) and memantine (10 mg/kg) daily by gavage during pregnancy. The learning and memory ability was evaluated using Morris water maze (MWM) task on postnatal day 21. The expression of NMDAR (GluN1, GluN2A, and GluN2B), BDNF, pTrkB/TrkB, and pCREB/CREB in hippocampus were assessed with western blotting.

Results: Prenatal exposure to a relatively low dose of deltamethrin (2.7, 1.35, and 0.54 mg/kg) had no impact on learning and memory abilities or the expression of NMDAR, BDNF, pTrkB, and pCREB in the hippocampus of the exposed offspring. The group treated with 9 mg/kg deltamethrin showed impaired cognitive abilities and decreased expression levels of GluN1, GluN2A, GluN2B, BDNF, pCREB/CREB, and pTrkB/TrkB in the hippocampus. However, the declined cognitive ability were ameliorated by memantine treatment with increased GluN1, GluN2A, GluN2B, BDNF, pCREB/CREB, and pTrkB/TrkB expression in the hippocampus.

Conclusion and Implications: Prenatal exposure to a relatively high does of deltamethrin (9 mg/kg) alters cognition in offsprings and that this cognitive dysfunction can be ameliorated by memantine treatment. Moreover, NMDAR/BDNF signaling may be associated with the effects of prenatal exposure to deltamethrin on cognitive ability in offspring.

Effect of titanium dioxide nanoparticles on the bioavailability and neurotoxicity of cypermethrin in zebrafish larvae

In aquatic environment, the presence of nanoparticles (NPs) has been reported to modify the bioavailability and toxicity of the organic toxicants. Nevertheless, the combined toxicity of NPs and the pesticides that were used world-widely still remains unclear. Cypermethrin (CYP), a synthetic pyrethroid insecticide, is commonly used for controlling agricultural and indoor pests. Therefore, the effects of titanium dioxide NPs (nTiO₂) on CYP bioconcentration and its effects on the neuronal development in zebrafish were investigated in our study. Zebrafish embryos (2- hour-post-fertilization, hpf) were exposed to CYP (0, 0.4, 2 and 10 μg/L) alone or co-exposed with nTiO₂ (1 mg/L) until 120-hpf. nTiO₂ is taken up by zebrafish larvae and also it can adsorb CYP. The zebrafish body burdens of CYP was observed and CYP uptake was increased by nTiO₂, indicating that the nTiO₂ could accelerate the bioaccumulation of CYP in larvae. Co-exposure of nTiO₂ and CYP induced the generation of reactive oxygen species. Exposure to CYP alone significantly decreased the mRNA expression of genes, including glial fibrillary acidic protein (gfap), α1-tubulin, myelin basic protein (mbp) and growth associated protein (gap-43). Besides, reductions of serotonin, dopamine and GABA concentrations were observed in zebrafish and the larval locomotion was significantly decreased in response to the lower level of the neurotransmitters. Moreover, co-exposure of nTiO₂ and CYP caused further significantly decreased in the locomotion activity, and enhanced the down-regulation of the mRNA expression of specific genes and the neurotransmitters levels. The results demonstrated that nTiO₂ increased CYP accumulation and enhanced CYP-induced developmental neurotoxicity in zebrafish.

Endosulfan and Cypermethrin Pesticide Mixture Induces Synergistic or Antagonistic Effects on Developmental Exposed Rats Depending on the Analyzed Behavioral or Neurochemical End Points

Exposure to pesticides has been associated with neurodevelopmental toxicity. Usually people are exposed to mixtures of pesticides. However, most studies analyze the effects of individual pesticides. Developmental exposure to mixtures of pesticides may result in additive effects or in antagonistic or synergistic effects. The aim of this work was to compare the effects of developmental exposure of rats to cypermethrin or endosulfan with the effects of its mixture on cognitive and motor function and on some underlying mechanisms. Exposure to individual pesticides or the mixture was from gestational day 7 to postnatal day 21. We analyzed the effects, in males and females, on spatial learning and memory, associative learning, anxiety, motor coordination, and spontaneous motor activity. We also analyzed neuroinflammation and NMDA receptor subunits in hippocampus and extracellular GABA in cerebellum. Exposure to the mixture, but not to individual pesticides, impaired spatial memory in males, associative learning in females, and increased motor activity in males and females. This indicates a synergistic effect of cypermethrin and endolsufan exposure on these end points. In contrast, motor coordination was impaired by individual exposure to endosulfan or cypermethrin, associated with increased extracellular GABA in cerebellum, but these effects were prevented in rats exposed to the mixture, indicating an antagonistic effect of cypermethrin and endolsufan exposure on these end points. The results show different interaction modes (synergism or antagonism) of the pesticides, depending on the end point analyzed and the sex of the rats.

In utero and lactational exposure to low-doses of the pyrethroid insecticide cypermethrin leads to neurodevelopmental defects in male mice-An ethological and transcriptomic study

Accumulating evidence suggests that developmental exposure to environmental chemicals may modify the course of brain development, ultimately leading to neuropsychiatric / neurodegenerative disorders later in life. In the present study, we assessed the impact of one of the most frequently used pesticides in both residential and agricultural applications − the synthetic pyrethroid cypermethrin (CYP) − on developmental neurotoxicity (DNT). Female mice were perinatally exposed to low doses of CYP (5 and 20 mg/kg body weight) from gestation to postnatal day 15. Behavioral analyses were performed during the offspring’s early life and during adulthood. Postnatal analyses revealed that perinatal exposure to CYP disturbed motor development without modifying sensory and communicative skills. We found that later in life, CYP-exposed offspring expressed maladaptive behaviors in response to highly challenging tasks and abnormal sociability. Transcriptomic analyses performed in the offspring’s brain at the end of the exposure, highlighted mitochondrial dysfunction as a relevant pathomechanism underlying CYP-induced DNT. Interestingly, several genes involved in proteostasis maintenance were also shown to be dysregulated suggesting that alterations in biogenesis, folding, trafficking and degradation of proteins may significantly contribute to CYP-related DNT. From a regulatory perspective, this study highlights that behavioral and transcriptomic analyses are complementary tools providing useful direction for better DNT characterization, and as such, should be used together more systematically.

Endosulfan poisoning: An overview

Endosulfan, an organochlorine (OC) insecticide, is a widely used agricultural pesticide, despite its life threatening toxic effects. In this review, the pharmacokinetics of endosulfan, mechanism of endosulfan toxicity, clinical presentations and management, histopathological findings, and toxicological analysis are described, in addition to its environmental toxicity. The toxic effects of endosulfan can affect many organs and systems presenting in a wide array of signs and symptoms. Although termed a restricted OC-classed pesticide, it continues to be used, especially in the developing world, owing to its beneficial effects on agriculture. Several cases of endosulfan poisoning have been reported from different regions of the world. Whether accidental or intentional, endosulfan ingestion proves to be fatal unless immediate, aggressive treatment is initiated. Management is mainly supportive as no antidote exists for endosulfan poisoning as yet. The use of endosulfan needs to be strictly regulated and eventually banned worldwide altogether to lower the current morbidity and mortality resulting from this pesticide. Additionally, monitoring biological samples, using non-invasive techniques such as breast milk sampling, can provide an effective method of observing the elimination of this environmentally persistent organic pollutant from the general population.

Consequences of acute Nav1.1 exposure to deltamethrin

BACKGROUND

Pyrethroid insecticides are the most popular class of insecticides in the world, despite their near-ubiquity, their effects of delaying the onset of inactivation of voltage-gated sodium (Nav) channels have not been well-evaluated in all the mammalian Nav isoforms.

OBJECTIVE

Here we compare the well-studied Nav1.6 isoforms to the less-understood Nav1.1 in their responses to acute deltamethrin exposure.

METHODS

We used patch-clamp electrophysiology to record sodium currents encoded by either Nav1.1 or Nav1.6 channels stably expressed in HEK293 cells. Protocols evaluating both resting and use-dependent modification were employed.

RESULTS

We found that exposure of both isoforms to 10μM deltamethrin significantly potentiated persistent and tail current densities without affecting peak transient current densities, and only Nav1.1 maintained these significant effects at 1μM deltamethrin. Window currents increased for both as well, and while only Nav1.6 displayed changes in activation slope and V1/2 of steady-state inactivation for peak currents, V1/2 of persistent current activation was hyperpolarized of ∼10mV by deltamethrin in Nav1.1 cells. Evaluating use-dependence, we found that deltamethrin again potentiated persistent and tail current densities in both isoforms, but only Nav1.6 demonstrated use-dependent enhancement, indicating the primary deltamethrin-induced effects on Nav1.1 channels are not use-dependent.

CONCLUSION

Collectively, these data provide evidence that Nav1.1 is indeed vulnerable to deltamethrin modification at lower concentrations than Nav1.6, and this effect is primarily mediated during the resting state.

GENERAL SIGNIFICANCE

These findings identify Nav1.1 as a novel target of pyrethroid exposure, which has major implications for the etiology of neuropsychiatric disorders associated with loss of Nav1.1-expressing inhibitory neurons.

Biomarkers indicate mixture toxicities of fluorene and phenanthrene with endosulfan toward earthworm (Eisenia fetida)

α-Endosulfan and some polycyclic aromatic compounds (PAHs) are persistent in the environment and can reach crop products via contaminated agricultural soils. They may even be present as mixtures in the soil and induce mixture toxicity in soil organisms such as earthworms. In this study, the combined toxicities of PAHs with α-endosulfan were determined in Eisenia fetida adults using an artificial soil system. α-Endosulfan and five PAHs were tested for their acute toxicity toward E. fetida in artificial soils. Only α-endosulfan, fluorene, and phenanthrene showed acute toxicities, with LC₅₀ values of 9.7, 133.2, and 86.2 mg kg^-1, respectively. A mixture toxicity assay was conducted using α-endosulfan at LC₁₀ and fluorene or phenanthrene at LC₅₀ in the artificial soils. Upon exposure to the mixture of fluorene and α-endosulfan, earthworms were killed in increasing numbers owing to their synergistic effects, while no other mixture showed any additional toxicity toward the earthworms. Along with the acute toxicity results, the biochemical and molecular changes in the fluorene- and phenanthrene-treated earthworms with or without α-endosulfan treatment demonstrated that enhancement of glutathione S-transferase activity was dependent on the addition of PAH chemicals, and the HSP70 gene expression increased with the addition of α-endosulfan. Taken together, these findings contribute toward understanding the adverse effects of pollutants when present separately or in combination with other types of chemicals.

Endosulfan induces apoptosis by activating the negative regulation pathway of cell cycle and death receptor pathway in spermatogenic cells

The male reproductive toxicity of endosulfan has been proved. Nevertheless, the underlying molecular mechanisms of the apoptosis caused by endosulfan in spermatogenic cells remains poorly understood. In order to investigate the reproductive toxicity mechanism caused by endosulfan, there were four groups, which had eight Wistar male rats randomly assigned to them, and the rats in different groups received different doses of endosulfan for a period of 21 days. GC-1 spermatogenic cell lines were divided into four groups, and each group was exposed to different doses of endosulfan for 24 hours. The results of this research showed that endosulfan decreased the cell viability, damaged cell membranes and induced apoptosis in spermatogenic cells. Endosulfan had obviously activated the protein expression of PKC-δ, p53, p^21cip1, p^27kip1, Fas, FasL, Caspase-8, Caspase-3, and inhibited the expression of E₂F-1. Endosulfan also induced oxidative stress and DNA damage in spermatogenic cells. The results of this research suggested that endosulfan could lead to E₂F-1-induced apoptosis of spermatogenic cells by activating the negative regulation factors of the cell cycle, and endosulfan might cause apoptosis by death receptor pathway, causing oxidative stress.

Pyrethroid Pesticide Metabolite in Urine and Microelements in Hair of Children Affected by Autism Spectrum Disorders: A Preliminary Investigation

The number of children affected by Autism Spectrum Disorders (ASD) is dramatically increasing as well as the studies aimed at understanding the risk factors associated with the development of ASD. Since the etiology of ASD is partly genetic and partly environmental, factors (i.e., heavy metals, pesticides) as well as lifestyle seem to have a key role in the development of the disease. ASD and Control (CTR) children, aged 5–12 years, were compared. Gas chromatography coupled with trap mass detector was used to measure the level of 3-PBA, the main pyrethroid metabolite in urine in a group of ASD patients, while optical emission spectrometry analysis was employed to estimate the level of metals and microelements in hair in a different group of ASD children. The presence of 3-PBA in urine seems to be independent of age in ASD children, while a positive correlation between 3-PBA and age was observed in the control group of the same age range. Urine concentration of 3-BPA in ASD children had higher values than in the control group, which were marginally significant (p = 0.054). Mg results were significantly decreased in ASD with respect to controls, while V, S, Zn, and Ca/Mg were marginally increased, without reaching statistical significance. Results of Principal Component (PC) analysis of metals and microelements in hair were not associated with either age or health status. In conclusion, 3-PBA in urine and Mg in hair were changed in ASD children relative to control ones.

Prenatal Paraquat exposure induces neurobehavioral and cognitive changes in mice offspring

In the present work, we investigated developmental toxicity of Paraquat (PQ), from the 1st or 6th day of mating and throughout the gestation period. We have examined several parameters, including toxicity indices, reproductive performance, sensorimotor development, as well as anxiety and cognitive performance of the offspring. Our results showed that exposure to 20mg/kg of Paraquat during the first days of pregnancy completely prevents pregnancy in treated mice, but from the 6th day of pregnancy, an alteration in fertility and reproductive parameters was observed. In offspring, the PQ was responsible for an overall delay of innate reflexes and a deficit in motor development. All exposed animals showed a decrease in the level of locomotor activity, increased levels of anxiety-like behavior and pronounced cognitive impairment in adulthood. These results demonstrated that Paraquat led to the onset of many behavioral changes that stem from the impairment of neuronal developmental processes in prenatally exposed mice.

Autism genes are selectively targeted by environmental pollutants including pesticides, heavy metals, bisphenol A, phthalates and many others in food, cosmetics or household products

The increasing incidence of autism suggests a major environmental influence. Epidemiology has implicated many candidates and genetics many susceptibility genes. Gene/environment interactions in autism were analysed using 206 autism susceptibility genes (ASG's) from the Autworks database to interrogate ∼1 million chemical/gene interactions in the comparative toxicogenomics database. Any bias towards ASG's was statistically determined for each chemical. Many suspect compounds identified in epidemiology, including tetrachlorodibenzodioxin, pesticides, particulate matter, benzo(a)pyrene, heavy metals, valproate, acetaminophen, SSRI's, cocaine, bisphenol A, phthalates, polyhalogenated biphenyls, flame retardants, diesel constituents, terbutaline and oxytocin, inter alia showed a significant degree of bias towards ASG's, as did relevant endogenous agents (retinoids, sex steroids, thyroxine, melatonin, folate, dopamine, serotonin). Numerous other suspected endocrine disruptors (over 100) selectively targeted ASG's including paraquat, atrazine and other pesticides not yet studied in autism and many compounds used in food, cosmetics or household products, including tretinoin, soy phytoestrogens, aspartame, titanium dioxide and sodium fluoride. Autism polymorphisms influence the sensitivity to some of these chemicals and these same genes play an important role in barrier function and control of respiratory cilia sweeping particulate matter from the airways. Pesticides, heavy metals and pollutants also disrupt barrier and/or ciliary function, which is regulated by sex steroids and by bitter/sweet taste receptors. Further epidemiological studies and neurodevelopmental and behavioural research is warranted to determine the relevance of large number of suspect candidates whose addition to the environment, household, food and cosmetics might be fuelling the autism epidemic in a gene-dependent manner.

Endosulfan inhibiting the meiosis process via depressing expressions of regulatory factors and causing cell cycle arrest in spermatogenic cells

Endosulfan is a persistent organic pollutant and widely used in agriculture as a pesticide. It is present in air, water, and soil worldwide; therefore, it is a health risk affecting especially the reproductive system. The aim of this study was to evaluate the toxicity of endosulfan in the reproductive system. To investigate the effect of endosulfan on meiosis process, 32 rats were divided into four groups, treated with 0, 1, 5, and 10 mg/kg/day endosulfan, respectively, and sacrificed after the 21 days of treatments. Results show that endosulfan caused the reductions in sperm concentration and motility rate, which resulted into an increased in sperm abnormality rate; further, endosulfan induced downregulation of spermatogenesis- and oogenesis-specific basic helix-loop-helix transcription factor (Sohlh1) which controls the switch on meiosis in mammals, as well cyclin A1, cyclin-dependent kinases 1 (CDK1), and cyclin-dependent kinases 2 (CDK2). In vitro, endosulfan induced G2/M phase arrest in the spermatogenic cell cycle and caused proliferation inhibition. Moreover, endosulfan induced oxidative stress and DNA damage in vivo and vitro. The results suggested that endosulfan could inhibit the start of meiosis by downregulating the expression of Sohlh1 and induce G2/M phase arrest of cell cycle by decreasing the expression of cyclin A1, CDK1, and CDK2 via oxidative damage, which inhibits the meiosis process, and therefore decrease the amount of sperm.

The Synapse as a Central Target for Neurodevelopmental Susceptibility to Pesticides

The developmental period of the nervous system is carefully orchestrated and highly vulnerable to alterations. One crucial factor of a properly-functioning nervous system is the synapse, as synaptic signaling is critical for the formation and maturation of neural circuits. Studies show that genetic and environmental impacts can affect diverse components of synaptic function. Importantly, synaptic dysfunction is known to be associated with neurologic and psychiatric disorders, as well as more subtle cognitive, psychomotor, and sensory defects. Given the importance of the synapse in numerous domains, we wanted to delineate the effects of pesticide exposure on synaptic function. In this review, we summarize current epidemiologic and molecular studies that demonstrate organochlorine, organophosphate, and pyrethroid pesticide exposures target the developing synapse. We postulate that the synapse plays a central role in synaptic vulnerability to pesticide exposure during neurodevelopment, and the synapse is a worthy candidate for investigating more subtle effects of chronic pesticide exposure in future studies.