Pyrethroid exposure and neurotoxicity: a mechanistic approach

Thymoquinone ameliorate oxidative stress, GABAergic neuronal depletion and memory impairment through Nrf2/ARE signaling pathway in the dentate gyrus following cypermethrin administration

BACKGROUND

Exposure to chemical toxins, including insecticides, harms bodily organs like the brain. This study examined the neuroprotective of thymoquinone on the cypermethrin's harmful effects on the histoarchitecture of the dentate gyrus and motor deficit in the dentate gyrus.

METHODS

Forty adult male rats (180-200 g) were randomly divided into 5 groups (n = 8 per group). Groups I, II, III, IV, and V received oral administration of 0.5 ml of phosphate-buffered saline, cypermethrin (20 mg/kg), thymoquinone (10 mg/kg), cypermethrin (20 mg/kg) + thymoquinone (5 mg/kg), and cypermethrin (20 mg/kg) + thymoquinone (10 mg/kg) for 14 days respectively. The novel object recognition test that assesses intermediate-term memory was done on days 14 and 21 of the experiment. At the end of these treatments, the animals were euthanized and taken for cytoarchitectural (hematoxylin and eosin; Cresyl violet) and immunohistochemical studies (Nuclear factor erythroid 2-related factor 2 (Nrf2), Parvalbumin, and B-cell lymphoma 2 (Bcl2).

RESULT

The study shows that thymoquinone at 5 and 10 mg/kg improved Novelty preference and discrimination index. Thymoquinone enhanced Nissl body integrity, increased GABBAergic interneuron expression, nuclear factor erythroid 2-derived factor 2, and enhanced Bcl-2 expression in the dentate gyrus. It also improved the concentration of nuclear factor erythroid 2-derived factor 2, increased the activities of superoxide dismutase and glutathione, and decreased the concentration of malondialdehyde level against cypermethrin-induced neurotoxicity.

CONCLUSION

thymoquinone could be a therapeutic agent against cypermethrin poisoning.

Pesticides and the Gut Microbiota: Implications for Parkinson's Disease

Parkinson's disease (PD) affects more people worldwide than just aging alone can explain. This is likely due to environmental influences, genetic makeup, and changes in daily habits. The disease develops in a complex way, with movement problems caused by Lewy bodies and the loss of dopamine-producing neurons. Some research suggests Lewy bodies might start in the gut, hinting at a connection between these structures and gut health in PD patients. These patients often have different gut bacteria and metabolites. Pesticides are known to increase the risk of PD, with evidence showing they harm more than just dopamine neurons. Long-term exposure to pesticides in food might affect the gut barrier, gut bacteria, and the blood-brain barrier, but the exact link is still unknown. This review looks at how pesticides and gut bacteria separately influence PD development and progression, highlighting the harmful effects of pesticides and changes in gut bacteria. We have examined the interaction between pesticides and gut bacteria in PD patients, summarizing how pesticides cause imbalances in gut bacteria, the resulting changes, and their overall effects on the PD prognosis.

Understanding role of pesticides in development of Parkinson's disease: Insights from Drosophila and rodent models

Parkinson's disease is a neurodegenerative illness linked to ageing, marked by the gradual decline of dopaminergic neurons in the midbrain. The exact aetiology of Parkinson's disease (PD) remains uncertain, with genetic predisposition and environmental variables playing significant roles in the disease's frequency. Epidemiological data indicates a possible connection between pesticide exposure and brain degeneration. Specific pesticides have been associated with important characteristics of Parkinson's disease, such as mitochondrial dysfunction, oxidative stress, and α-synuclein aggregation, which are crucial for the advancement of the disease. Recently, many animal models have been developed for Parkinson's disease study. Although these models do not perfectly replicate the disease's pathology, they provide valuable insights that improve our understanding of the condition and the limitations of current treatment methods. Drosophila, in particular, has been useful in studying Parkinson's disease induced by toxins or genetic factors. The review thoroughly analyses many animal models utilised in Parkinson's research, with an emphasis on issues including pesticides, genetic and epigenetic changes, proteasome failure, oxidative damage, α-synuclein inoculation, and mitochondrial dysfunction. The text highlights the important impact of pesticides on the onset of Parkinson's disease (PD) and stresses the need for more research on genetic and mechanistic alterations linked to the condition.

Exposure to the pesticide tefluthrin causes developmental neurotoxicity in zebrafish

BACKGROUND

The insecticide tefluthrin is widely used in agriculture, resulting in widespread pollution. Tefluthrin is a type I pyrethroid characterized by its high persistence in the environment. Understanding the mechanisms of toxicity of tefluthrin will improve its risk assessment.

OBJECTIVES

We aimed to decipher the molecular modes of action of tefluthrin.

METHODS

Phenotypic developmental toxicity was assessed by exposing zebrafish embryos and larvae to increasing concentrations of tefluthrin. Tg(mnx:mGFP) line was used to assess neurotoxicity. Multi-omics approaches including transcriptomics and lipidomics were applied to analyze RNA and lipid contents, respectively. Finally, an in-silico ligand-protein docking computational method was used to study a possible interaction between tefluthrin and a protein target.

RESULTS

Tefluthrin exposure caused severe morphological malformations in zebrafish larvae, including motor neuron abnormalities. The differentially expressed genes were associated with neurotoxicity and metabolic disruption. Lipidomics analysis revealed a disruption in fatty acid, phospholipid, and lysophospholipid recycling. Protein docking modeling suggested that the LPCAT3 enzyme, which recycles lysophospholipids in the Land's cycle, directly interacts with tefluthrin.

CONCLUSIONS

Tefluthrin exposure causes morphological and neuronal malformations in zebrafish larvae at nanomolar concentrations. Multi-omics results revealed a potential molecular initiating event i.e., inhibition of LPCAT3, and key events i.e., an altered lysophospholipid to phospholipid ratio, leading to the adverse outcomes of neurotoxicity and metabolic disruption.

Neurotoxicity of Pyrethroids in neurodegenerative diseases: From animals' models to humans' studies

Neurodegenerative diseases are associated with diverse symptoms, both motor and mental. Genetic and environmental factors can trigger neurodegenerative diseases. Chemicals as pesticides are constantly used in agriculture and also domestically. In this regard, pyrethroids (PY), are a class of insecticides in which its main mechanism of action is through disruption of voltage-dependent sodium channels function in insects. However, in mammals, they can also induce oxidative stress and enzyme dysfunction. This review investigates the association between PY and neurodegenerative diseases as Alzheimer's, Huntington's, Parkinson's, Amyotrophic Lateral Sclerosis, and Autism in animal models and humans. Published works using specific and non-specific models for these diseases were selected. We showed a tendency toward the development and/or aggravating of these neurodegenerative diseases following exposure to PYs. In animal models, the biochemical mechanisms of the diseases and their interaction with the insecticides are more deeply investigated. Nonetheless, only a few studies considered the specific model for each type of disease to analyze the impacts of the exposure. The choice of a specific model during the research is an important step and our review highlights the knowledge gaps of PYs effects using these models reinforcing the importance of them during the design of the experiments.

Biomarkers of oral subacute toxicity of deltamethrin in exposed male Albino rats

Deltamethrin is one of the most effective pyrethroid compounds, widely employed in veterinary medicine, public health, and farming. Deltamethrin-triggered oxidative stress largely causes serious harm to an organism. Acute toxicity of this compound was extensively investigated, while less information is available on its oral sub-acute effects. This study assessed, in the male Albino rats, the effects of oral gavage of either 0.874 mg/kg (0.01 LD50) or 8.740 mg/kg (0.10 LD50) of deltamethrin for successive 14 days to investigate its effects on biomarkers and to detect the tissue injury in rats following subacute deltamethrin treatment. It was found that levels of glutathione peroxidase, superoxide dismutase, and catalase in the brain, kidney, and liver, alkaline phosphatase (ALP), and uric acid in serum, hematocrit, mean corpuscular volume (MCV), white blood cells (WBC)s, eosinophils, and basophils were significantly reduced compared with untreated rats. However, when rats were treated with deltamethrin for successive 14 days, alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) activities in serum and the levels of thiobarbituric acid reactive substances (TBARs) in brain, kidney, and liver, red blood cell distribution width (RDW-CV), total protein, monocytes, and basophils and the ratios of neutrophils to lymphocytes, an aggregated marker of systemic inflammation and systemic immune inflammation indexes, significantly increased compared with the control group. Histologic lesions were observed in the liver, kidney, brain, testis, and epidemies in rats exposed to subacute deltamethrin for 14 days, and most tissues of rats treated with 0.10 LD50 of deltamethrin were more affected than those treated with 0.01 LD50. These findings strongly suggest that subacute exposure to deltamethrin caused significant systemic toxicity through oxidative stress resulting in biochemical and histological changes in the studied tissues. These findings highlight the potential harmful effects of deltamethrin and emphasize the importance of understanding the subacute effects of this compound, particularly in the context of veterinary medicine, public health, and farming.

Childhood exposure to pyrethroids and neurodevelopment in Canadian preschoolers

BACKGROUND

Pyrethroid insecticides are used both residentially and agriculturally and their toxicity targets the nervous system of insects. They might also interfere with development and function of the human brain. A few epidemiological studies suggest that exposure to pyrethroids may be associated with neurobehavioral problems in children but there is little data on potential associations with cognitive outcomes. Furthermore, many studies showed that the neurotoxic effects of several pesticides are modified by sex, hence, considerations of potential sex-differences are important to investigate.

OBJECTIVE

To study the cross-sectional association between urinary levels of pyrethroid metabolites and neurodevelopment, including neurobehavioral and cognitive outcomes, in preschool-age children, and to examine whether sex might modify these associations.

METHODS

We used data from a follow-up examination of the Maternal-Infant Research on Environmental Chemicals (MIREC), the MIREC Child Development study (MIREC-CD Plus) on children at age 3-4 years living in 6 Canadian cities. For each participant, we collected a urine sample for measurements of pyrethroids metabolites (cis-DBCA, cis-DCCA, trans-DCCA, 3-PBA, 4-F-3-PBA). We assessed neurodevelopment with the Wechsler Primary and Preschool Scale of Intelligence-III (WPPSI-III) and two scales of the Behavior Rating Inventory of Executive Function-Preschool (BRIEF-P). Parents reported children's behavior using the Behavior Assessment System for Children-2 (BASC-2) and the Social Responsiveness Scale-2 (SRS-2). We examined associations between children's urinary pyrethroid metabolite concentrations and neurodevelopmental scores with multiple linear regression models, adjusting for confounders, in boys and girls separately.

RESULTS

The study included 179 children (mean age: 3.2 y, range 2.8-4.0). The detection frequencies were high for most pyrethroid metabolites (83-100%), but lower for 4-F-3-PBA (36%). Higher concentrations of cis-DBCA were significantly associated with lower verbal, performance and full-scale IQ scores in boys (e.g., for a 2-fold increase in cis-DBCA, β = -2.0; 95% CI: -3.4, -0.6 for full-scale IQ). In girls, the only metabolite associated with cognitive scores was 3-PBA, which was associated with lower verbal IQ scores (β = -1.3, 95% CI: -2.6, -0.1). For neurobehavioral outcomes in boys, there were associations between poorer BASC-2 Adaptive Skills scores with higher concentrations of cis-DCCA (β = -1.6, 95% CI: -2.3, -0.9), trans-DCCA (β = -1.5, 95% CI: -2.2, -0.8), 3-PBA (β = -1.7, 95% CI: -2.5, -0.9), and sum of pyrethroid metabolites (β = -1.8, 95% CI: -2.6, -0.9). In girls, we observed a significant association between higher concentration of cis-DCCA and better BASC-2 Adaptive Skills score (β = 1.0; 95% CI, 0.2, 1.8), but not with other urinary pyrethroids metabolites. Scores on the SRS-2 and BRIEF-P were not associated with pyrethroid metabolites.

CONCLUSION

There were associations between some pyrethroid pesticide metabolites and indicators of neurodevelopmental disorder, especially among boys. These associations are in agreement with previous studies and could suggest that exposure to pyrethroid pesticides represents a risk of potential toxicity for the cognitive development of children, and a risk for behavioral development. However, the cross-sectional nature of this study limits causal inferences.

Fenpropathrin causes alterations in locomotion and social behaviors in zebrafish (Danio rerio)

Fenpropathrin is one of the widely used pyrethroid pesticides in agriculture and is frequently detected in the environment, groundwater, and food. While fenpropathrin was found to have neurotoxic effects in mammals, it remains unclear whether it has similar effects on fish. Here, we used adult zebrafish to investigate the impacts of fenpropathrin on fish social behaviors and neural activity. Exposure of adult zebrafish to 500 ppb of fenpropathrin for 72 h increased anxiety levels but decreased physical fitness, as measured by a novel tank diving test and swimming tunnel test. Fish exposed to fenpropathrin appeared to spend more time in the conspecific zone of the tank, possibly seeking greater comfort from their companions. Although learning, memory, and aggressive behavior did not change, fish exposed to fenpropathrin appeared to have shorter fighting durations. The immunocytochemical results showed the tyrosine hydroxylase antibody-labeled dopaminergic neurons in the teleost posterior tuberculum decreased in the zebrafish brain. According to a quantitative polymerase chain reaction (qPCR) analysis of the brain, exposure to fenpropathrin resulted in a decrease in the messenger (m)RNA expression of monoamine oxidase (mao), an enzyme that facilitates the deamination of dopamine. In contrast, the mRNA expression of the sncga gene, which may trigger Parkinson's disease, was found to have increased. There were no changes observed in expressions of genes related to antioxidants and apoptosis between the control and fenpropathrin-exposed groups. We provide evidence to demonstrate the defect of the neurotoxicity of fenpropathrin toward dopaminergic neurons in adult zebrafish.

An adverse outcome pathway-based approach to assess the neurotoxicity by combined exposure to current-use pesticides

Exposure to multiple pesticides in daily life has become an important public health concern. However, the combined effects of pesticide mixtures have not been fully elucidated by the conventional toxicological testing used for individual chemicals. Grouping of chemicals by mode of action using common key events (KEs) in the adverse outcome pathway (AOP) as endpoints could be applied for efficient risk assessment of combined exposure to multiple chemicals. The purpose of this study was to investigate whether exposure to multiple pesticides has synergistic neurotoxic effects on mammalian nervous systems. According to the AOP-based approach, we evaluated the effects of 10 current-use pesticides (4 neonicotinoids, 4 pyrethroids and 2 phenylpyrazoles) on the common KEs in AOPs for neurotoxicity, such as KEs involving mitochondrial and proteolytic functions, in a mammalian neuronal cell model. Our data showed that several pyrethroids and phenylpyrazoles partly shared the effects on several common KEs, including decreases in mitochondrial membrane potential and proteasome activity and increases in autophagy activity. Furthermore, we also found that combined exposure to a type-I pyrethroid permethrin or a type-II pyrethroid deltamethrin and the phenylpyrazole fipronil decreased the cell viability and the benchmark doses much more than either single exposure, indicating that the pair exhibited synergistic effects, since the combination indexes were less than 1. These findings revealed that novel pairs of different classes of pesticides with similar effects on common KEs exhibited synergistic neurotoxicity and provide new insights into the risk assessment of combined exposure to multiple chemicals.

Early-Life Exposure to Commercial Formulation Containing Deltamethrin and Cypermethrin Insecticides Impacts Redox System and Induces Unexpected Regional Effects in Rat Offspring Brain

Several studies have shown that the oxidative impact of pesticides is most prevalent in rural environments where they are intensively used. At different levels, pyrethroids are reported to promote neurodegeneration; they share the ability to promote oxidative stress, and to induce mitochondrial impairments, α-synuclein overexpression and neuronal cell loss. The present study evaluates the impact of early-life exposure to a commercial formulation containing deltamethrin (DM) and cypermethrin (CYP) at a dose of 1/100 LD50 (1.28 and 2.5 mg/kg, respectively). Rats aged 30 days old, treated from the 6th to the 21st day of life, were tested for brain antioxidant activity and α-synuclein levels. Four regions of the brain were analyzed: the striatum, cerebellum, cortex and hippocampus. Our data demonstrated a significant increase in catalase (CAT), superoxide dismutase (SOD) and glutathione (GSH) antioxidant levels in the brain regions compared to the controls. Pups exhibited no significant changes in protein carbonyl levels and lipid peroxidation. Striatal α-synuclein expression was significantly reduced in the rats exposed to DM + CYP, while the treatment resulted in a non-significant increase in the other brain areas. These findings indicate unexpected effects of postnatal treatment with the commercial formulation containing DM and CYP on brain redox state and α-synuclein expression, suggesting an adaptive response.

Bio-efficacy of aluminum phosphide and cypermethrin against some physiological and biochemical aspects of Chrysomya megacephala maggots

Carrion flies play a significant role in forensic entomotoxicology, where they are employed as alternative samples when traditional samples are unavailable. In situations of poisoned death, these toxins disrupt insect development and affect forensic entomology analyses. So, forensic entomotoxicologists must be aware of this impact. The present study aimed to determine the effects of aluminum phosphide (AlP) and cypermethrin (CP) on the biochemical parameters and antioxidant enzymes of the third instar of Chrysomya megacephala maggots. C. megacephala was reared on normal and poisoned rabbit carcasses with aluminum phosphide and cypermethrin. The third larval instar of C. megacephala was studied using by spectrophotometer for detection of total protein, (TP), aspartate aminotransferase (AST), alanine aminotransferase (ALT), total antioxidant capacity (TAC), superoxide dismutase (SOD), glutathione s-transferase (GST), catalase (CAT) and malondialdehyde (MDA). The results indicated to significantly decrease of TP, TAC, SOD, GST and CAT and increase of AST, ALT and MDA in the maggots reared on the poisoned carcasses with AlP or CP compared with control group. In conclusion, the tested insecticides brought about a decrease antioxidant enzyme activity and increase of MDA could be involved in free radicals in C. megacephala larvae leading to oxidative stress by these insecticidal components.

Exploratory analysis of the association between pyrethroid exposure and rheumatoid arthritis among US adults: 2007-2014 data analysis from the National Health and Nutrition Examination Survey (NHANES)

Previous studies indicate that pesticide use may play an important role in the occurrence and development of rheumatoid arthritis (RA); however, little is known about the effect of specific pesticides on RA. The objective of this study was to evaluate whether pyrethroid exposure was linked to RA in adults. Data were originated from the 2007-2014 National Health and Nutrition Examination Survey (NHANES). The levels of pyrethroid exposure were assessed by 3-phenoxybenzoic acid (3-PBA) concentrations in urine samples. We built multivariate logistic regression models to assess associations between pyrethroid exposure and RA among US adults. A restricted cubic spline plot (three knots) was applied to test whether there was a nonlinear relationship between exposure to pyrethroid pesticides and the prevalence of RA. Finally, 4384 subjects were included in our analysis with 278 RA patients. In crude model, higher level of 3-PBA (creatinine-adjusted) was positively associated with RA (OR: 1.51, 95% CI: 1.07, 2.15). After adjustment for sex, race/ethnicity, education, body mass index, family poverty income, level of education, marital status, smoking status, alcohol usage, physical activity, hypertension, and urinary creatinine, the highest (vs lowest) quartile of 3-PBA was associated with an increased prevalence of RA (OR: 1.23, 95% CI: 0.86, 1.79). Significantly positive associations between 3-PBA concentration and RA were observed in the population aged between 40 and 59 years and with lower level of education. The restricted cubic spline plot presented an increase in trend and indicated that pyrethroid exposure was linearly associated with occurrence of RA (p for nonlinearity = 0.728). In conclusion, our study indicated that pyrethroid pesticide exposure was associated with an increased risk of RA. Higher levels of pyrethroid exposure were linearly associated with increased prevalence of RA in adults. Certainly, our findings are in great need of further corroboration by prospective studies with strict design.

Mitochondrial Toxicant-Induced Neuronal Apoptosis in Parkinson's Disease: What We Know so Far

Parkinson's disease (PD) is one of the most common progressive neurodegenerative diseases caused by the loss of dopamine-producing neuronal cells in the region of substantia nigra pars compacta of the brain. During biological aging, neuronal cells slowly undergo degeneration, but the rate of cell death increases tremendously under some pathological conditions, leading to irreversible neurodegenerative diseases. By the time symptoms of PD usually appear, more than 50 to 60% of neuronal cells have already been destroyed. PD symptoms often start with tremors, followed by slow movement, stiffness, and postural imbalance. The etiology of PD is still unknown; however, besides genetics, several factors contribute to neurodegenerative disease, including exposure to pesticides, environmental chemicals, solvents, and heavy metals. Postmortem brain tissues of patients with PD show mitochondrial abnormalities, including dysfunction of the electron transport chain. Most chemicals present in our environment have been shown to target the mitochondria; remarkably, patients with PD show a mild deficiency in NADH dehydrogenase activity, signifying a possible link between PD and mitochondrial dysfunction. Inhibition of electron transport complexes generates free radicals that further attack the macromolecules leading to neuropathological conditions. Apart from that, oxidative stress also causes neuroinflammation-mediated neurodegeneration due to the activation of microglial cells. However, the mechanism that causes mitochondrial dysfunction, especially the electron transport chain, in the pathogenesis of PD remains unclear. This review discusses the recent updates and explains the possible mechanisms of mitochondrial toxicant-induced neuroinflammation and neurodegeneration in PD.

Pesticides and the Microbiome-Gut-Brain Axis: Convergent Pathways in the Pathogenesis of Parkinson's Disease

The increasing global burden of Parkinson's disease (PD), termed the PD pandemic, is exceeding expectations related purely to population aging and is likely driven in part by lifestyle changes and environmental factors. Pesticides are well recognized risk factors for PD, supported by both epidemiological and experimental evidence, with multiple detrimental effects beyond dopaminergic neuron damage alone. The microbiome-gut-brain axis has gained much attention in recent years and is considered to be a significant contributor and driver of PD pathogenesis. In this narrative review, we first focus on how both pesticides and the microbiome may influence PD initiation and progression independently, describing pesticide-related central and peripheral neurotoxicity and microbiome-related local and systemic effects due to dysbiosis and microbial metabolites. We then depict the bidirectional interplay between pesticides and the microbiome in the context of PD, synthesizing current knowledge about pesticide-induced dysbiosis, microbiome-mediated alterations in pesticide availability, metabolism and toxicity, and complex systemic pesticide-microbiome-host interactions related to inflammatory and metabolic pathways, insulin resistance and other mechanisms. An overview of the unknowns follows, and the role of pesticide-microbiome interactions in the proposed body-/brain-first phenotypes of PD, the complexity of environmental exposures and gene-environment interactions is discussed. The final part deals with possible further steps for translation, consisting of recommendations on future pesticide use and research as well as an outline of promising preventive/therapeutic approaches targeted on strengthening or restoring a healthy gut microbiome, closing with a summary of current gaps and future perspectives in the field.

Evaluation of Toxic Effects Induced by Sub-Acute Exposure to Low Doses of α-Cypermethrin in Adult Male Rats

To contribute new information to the pyrethroid pesticide α-cypermethrin toxicity profile, we evaluated its effects after oral administration to Wistar rats at daily doses of 2.186, 0.015, 0.157, and 0.786 mg/kg bw for 28 days. Evaluations were performed using markers of oxidative stress, cholinesterase (ChE) activities, and levels of primary DNA damage in plasma/whole blood and liver, kidney, and brain tissue. Consecutive exposure to α-cypermethrin affected the kidney, liver, and brain weight of rats. A significant increase in concentration of the thiobarbituric acid reactive species was observed in the brain, accompanied by a significant increase in glutathione peroxidase (GPx) activity. An increase in GPx activity was also observed in the liver of all α-cypermethrin-treated groups, while GPx activity in the blood was significantly lower than in controls. A decrease in ChE activities was observed in the kidney and liver. Treatment with α-cypermethrin induced DNA damage in the studied cell types at almost all of the applied doses, indicating the highest susceptibility in the brain. The present study showed that, even at very low doses, exposure to α-cypermethrin exerts genotoxic effects and sets in motion the antioxidative mechanisms of cell defense, indicating the potential hazards posed by this insecticide.

Neurotoxicity of pesticides - A link to neurodegeneration

Parkinson's disease (PD) is a neurodegenerative disorder which mainly targets motor symptoms such as tremor, rigidity, bradykinesia and postural instability. The physiological changes occur due to dopamine depletion in basal ganglia region of the brain. PD aetiology is not yet elucidated clearly but genetic and environmental factors play a prominent role in disease occurrence. Despite of various environmental factors, pesticides exposure has been convicted as major candidate in PD pathogenesis. Among various pesticides 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) has been widely investigated in PD following with paraquat (PQ), maneb (MB), organochlorines (OC) and rotenone. Effect of these pesticides has been suggested to be involved in oxidative stress, alterations in dopamine transporters, mitochondrial dysfunction, α-synuclein (αSyn) fibrillation, and neuroinflammation in PD. The present review discusses the influence of pesticides in neurodegeneration and its related epidemiological studies conducted in PD. Furthermore, we have deliberated the common pesticides involved in PD and its associated genetic alterations and the probable mechanism of them behind PD pathogenesis. Hence, we conclude that pesticides play a prominent role in PD pathogenesis and advance research is needed to investigate the alterations in genetic and mechanistic aspects of PD.

The pyrethroids metabolite 3-phenoxybenzoic acid induces dopaminergic degeneration

Exposure to pyrethroids, a significant class of the most widely used agricultural chemicals, has been associated with an increased risk of Parkinson's disease (PD). However, although many different pyrethroids induce roughly the same symptoms of Parkinsonism, the underlying mechanisms remain unknown. To find the shared key features among these mechanisms, we focused on 3-phenoxybenzoic acid (3-PBA), a common and prominent metabolite of most pyrethroids produced via hydrolysis by CEs in mammals. To determine the contribution of 3-PBA to the initiation and progression of PD, we performed in vivo and in vitro experiments, respectively, and found that 3-PBA not only accumulates in murine brain tissues over time but also further induces PD-like pathologies (increased α-syn and phospho-S129, decreased TH) to the same or even greater extent than the precursor pyrethroid. A before-after study of PET-DAT in the same mice revealed that low concentrations of 3-PBA (0.5 mg/kg) could paradoxically cause DAT to increase (22.46% higher than pre-drug test). The intervention of DAT inhibitors and activators respectively alleviated and enhanced the dopaminergic toxicity of 3-PBA, indicating that 3-PBA interacts with DAT. In particular, low concentrations of 3-PBA increase the DAT, which in turn induces 3-PBA to enter the dopaminergic neurons to exert toxic effects. Finally, we described a mechanism underlying this potential role of 3-PBA in the pathological aggregation of α-syn. Specifically, 3-PBA was found to dysregulate C/EBP β levels and further anomalously activate AEP in vivo and in vitro, accompanied by increased accumulation of pathologically cleaved α-syn (N103 fragments) and accelerated α-syn aggregation. All these results suggest that 3-PBA exposure could mimic the pathological and pathogenetic features of PD, showing that this metabolite is a key pathogenic compound in pyrethroid-related pathological effects and a possible dopamine neurotoxin. Additionally, our findings provide a crucial reference for the primary prevention of PD.

Effect of subacute poisoning with lambdacyhalothrin on vascular endothelial growth factor 2 receptor in mice kidneys

BACKGROUND

Pyrethroids are used for insect control. They act on voltage-gated sodium channels in neurons. Lambdacyhalothrin (LCH) is a type II pyrethroid producing choreoatetosis and salivation in rodents. Vascular endothelial growth factor (VEGF) expression in the kidney is high in the glomerular podocytes and kidney tubules. VEGF receptor 2 (VEFGR2) is the main mediator in angiogenesis and it regulates blood vessel permeability. Lack of VEGF in podocytes impairs filtration. The nuclear factor κB (NFκB) is widely known as an important mediator of inflammation. The aim of the study was to check if subacute oral intoxication with 0.1LD50 of LCH affects kidney size, function and VEGFR2 and NFκB in mice kidneys.

METHODS

A total of 32 Albino Swiss mice was used: females controls, males controls, females receiving 2 mg/kg LCH, males receiving 2 mg/kg LCH orally for 7 days. On day 8 animals were sacrificed, blood and kidneys were obtained. Kidney mass was determined, creatinine concentration was measured in blood sera, VEGFR2 and NFκB in kidney homogenate supernatant with ELISA kit.

RESULTS

There was no statistically significant differences in kidney mass, creatinine concentration in blood sera nor NFκB but mean VEGFR2 concentration in the kidneys of females exposed to LCH was 128.01 ng/ml and showed statistically significant difference in comparison with control females. There was no statistically significant difference between VEGFR2 concentration in the kidneys of males exposed to LCH and control males.

CONCLUSION

The VEGFR2 increases in the course of LCH intoxication in females probably due to the protective effect of oestrogens.

Influence of perinatal deltamethrin exposure at distinct developmental stages on motor activity, learning and memory

BACKGROUND

Perinatal exposure to deltamethrin (DM) causes attention-deficit/ hyperactivity disorder-like behaviors. However, the vulnerable time window to DM exposure and the possible mechanism are obscure. We aimed to identify the critical window(s) at perinatal stages for DM exposure and the possible mechanism.

METHOD

Pregnant mice were exposed to DM (0.5 mg/kg) at three different prenatal stages [gestational day (GD) 0-5, 6-15 and 16-birth (16-B)] and early postnatal stage (PD 0-10). Locomotor activity, learning and memory were evaluated using open field and Y-maze test, respectively. Nissl staining and western blots were used to examine the neuronal loss and the protein expression, respectively.

RESULTS

Perinatal exposures to DM had no effect on reproductive and growth index of offspring. However, mice receiving DM exposure during GD 16-B displayed significantly higher mortality suggesting GD 16-B is the most vulnerable time window to DM exposure. Prenatal but not early postnatal DM exposure impaired locomotor activity, learning and memory, and caused neuron loss in the dentate gyrus of male offspring. However, neither prenatal nor postnatal DM exposure affected mouse behavior of female offspring. Prenatal DM exposures decreased the protein levels of NR2A and NR2B in both hippocampi and cerebral cortices of male offspring. However, female mice receiving DM exposure at GD 16-B but not other stages displayed increased expression levels of NR2A and NR2B in hippocampi.

CONCLUSION

Prenatal but not early postnatal DM exposure impairs the neuron development in male but not female mice. Altered NMDA receptor expression may correlate to DM-induced behavioral deficits.

Cardiac and respiratory arrest in a 12-year-old girl with acute permethrin oral toxicity: A case report

Permethrin (PER) is widely employed as the most frequently used type I synthetic pyrethroid insecticide. Despite its worldwide application, reports of pediatric toxicity following permethrin administration are scarce. The present report describes the case of a 12-year-old girl with cardiac and respiratory arrest resulting from self-induced oral toxicity by permethrin.

Protective Effect of Nigella sativa and Onion Extract against 5-Fluorouracil-Induced Hepatic Toxicity

Aim: The present study intended to compare the antioxidant, anti-lipid peroxidation, and anti-inflammatory potentials of Nigella Sativa (NS) and onion extract on 5-FU-induced liver damage in rats. Material and methods: 48 rats were divided into control, control group of the onion extract, control group of the NS extract, 5-FU-treated, concomitant NS-treated, and concomitant onion extract-treated. Liver sections were processed for histological analysis (light and electron microscopic examination). Liver enzymes (ALT, AST, and ALP), inflammatory markers (TNF-α and IL-1), antioxidant markers (SOD, GSH, and GSH/GSSG ratio), 4-HNE, NF-κB, and Nrf2 were evaluated. Results: The 5-FU-treated group exhibited inflammation, congested hepatic sinusoid, and steatosis. Improvement with few pathological residues was seen in the concomitant extract-treated groups. The 5-FU-treated group showed higher liver enzymes. The enzymes decreased in the concomitantly treated groups. 5-FU induced liver damage through oxidative stress, inflammation, and lipid peroxidation. Concomitantly using NS and onion extracts resulted in a reduction in oxidative stress, lipid peroxidation, and inflammation. Conclusion: NS and onion extracts attenuated 5-FU-induced liver damage via antioxidative, anti-lipid peroxidative, and anti-inflammatory mechanisms. NS's role was exceptional when compared with onion extract.

Cypermethrin induces Sertoli cell apoptosis through mitochondrial pathway associated with calcium

Cypermethrin, one kind of pyrethroid pesticides, has been shown to act as endocrine-disrupting chemicals (EDCs). The purpose of this study was to explore the roles of Sertoli cell apoptosis through mitochondrial pathway associated with calcium (Ca²⁺) in cypermethrin-induced male reproductive toxicology. The mouse Sertoli cells TM4 were cultured with 0 μM, 10 μM, 20 μM, 40 μM and 80 μM of cypermethrin. We used flow cytometry, Fluo-4 AM, western blot and JC-1 Assay Kit to examine apoptosis, intracellular Ca²⁺, expressions of mitochondrial apoptotic pathway-related proteins and mitochondrial membrane potential. We found cypermethrin increased apoptosis rate of TM4 cells significantly and with a significant increase in intracellular Ca²⁺ concentration. Cypermethrin significantly decreased the protein expressions of cytosolic B-cell lymphoma-2 (Bcl-2) and mitochondrial cytochrome c (Cyt-c). The protein expressions of cytosolic Bcl-2-associated x (Bax), Cyt-c, cleaved caspase-3, calmodulin (CaM), Ca²⁺/CaM-dependent protein kinases II (CaMKII) and phosphorylated CaMKII were increased significantly in cypermethrin-exposed TM4 cells. Cypermethrin decreased mitochondrial membrane potential significantly. Then, Bcl-2 family and Ca²⁺/CaM/CaMKII pathway participate in cypermethrin-induced homeostasis. Ca²⁺ overload activates mitochondrial pathway by increasing permeability of mitochondrial membrane and decreasing mitochondrial membrane potential. We suggest cypermethrin induces Sertoli cell apoptosis involving mitochondrial pathway associated with Ca²⁺ regulated by Bcl-2 family and Ca²⁺/CaM/CaMKII pathway. The study provides a new insight into mechanisms involved in cypermethrin-induced male reproductive toxicology.

Mechanistic insight into toxicity of phthalates, the involved receptors, and the role of Nrf2, NF-κB, and PI3K/AKT signaling pathways

The wide use of phthalates, as phthalates are used in the manufacturing of not only plastics but also many others goods, has become a main concern in the current century because of their potency to induce deleterious effects on organism health. The toxic effects of phthalates such as reproductive toxicity, cardiotoxicity, hepatotoxicity, nephrotoxicity, teratogenicity, and tumor development have been widely indicated by previous experimental studies. Some of the important mechanisms of toxicity by phthalates are the induction and promotion of inflammation, oxidative stress, and apoptosis. Awareness of the involved molecular pathways of these mechanisms will permit the detection of exact molecular targets of phthalates to protect or treat their toxicity. Up to now, various transcription factors and signaling pathways have been associated with phthalate-induced toxicity which by influencing on nuclear surface and the expression of different genes can alter cell hemostasis. In different studies, the role of nuclear factor erythroid 2-related factor 2 (Nrf2), nuclear factor-κB (NF-κB), and phosphatidylinositol-3-kinase (PI3K)/AKT signaling pathways in processes of oxidative stress, inflammation, apoptosis, and cancer has been shown following exposure to phthalates. In the present review, we aim to survey experimental studies (in vitro and in vivo) in order to show firstly the most involved receptors and also the importance and the role of the mentioned signaling pathways in phthalate-induced toxicity, and with considering this point, the future studies can focus on these molecular targets as a strategic method to reduce environmental chemicals-induced toxicity especially phthalates toxic effects.

Involvement of Peroxiredoxin-3, Thioredoxin-2, and Protein Deglycase-1 in Cypermethrin-Induced Parkinsonism

Owing to its lipophilic nature, cypermethrin makes entry into the brain through the blood-brain barrier and causes severe damage to the nigrostriatal dopaminergic neurons after prolonged exposure. Following substantial accrual in the brain, cypermethrin induces the abnormal expression and accumulation of α-synuclein. Besides, cytochrome P450 2E1 (CYP2E1) causes free radical generation leading to lipid peroxidation in toxicant-induced parkinsonism. Conversely, 4-hydroxynonenal (4-HNE), a byproduct of lipid peroxidation, is known to contribute to neuronal damage. The current investigation aimed to explicate the participation of endogenous redox-sensitive proteins in cypermethrin-induced cellular and animal models of parkinsonism. The qualitative and quantitative expressions of selected redox-sensitive proteins were evaluated employing the standard procedures. Cypermethrin reduced the expression of peroxiredoxin 3 (Prx3), thioredoxin 2 (Trx2), and protein deglycase-1 (DJ-1). Knocking down of Prx3, Trx2, or DJ-1 further reduced the level of expression in the cypermethrin-treated group. Reduction in the expression of Prx3, Trx2, or DJ-1 was found to be associated with overexpression of α-synuclein and 4-HNE modification of proteins. Besides, cypermethrin increased the expression of CYP2E1, which was not altered after Prx3 or Trx2 knockdown. However, knocking down the DJ-1 augmented the level of CYP2E1 both in the cypermethrin-treated group and its respective control. The outcomes of the study demonstrate that cypermethrin reduces the level of Prx3, Trx2, and DJ-1 proteins. While the reduction in the expression of selected redox-sensitive proteins leads to α-synuclein overexpression and 4-HNE modification of proteins, DJ-1 attenuation is also linked with increased CYP2E1 expression, which in turn could lead to oxidative stress-mediated neuronal damage.

Determination of 113 pesticides in hot pepper powder in Korea

In five regions of Korea, a total of 963 hot pepper powder samples were analyzed for 113 pesticides and one synergist using gas chromatography-mass spectrometry. For three years, sampling was performed every producing day in production plants according to ISO 24153 : 2009 methods. The limit of detection and limit of quantification ranges were 0.17-1.46 and 0.52-4.44 µg kg^-1, respectively. The recovery ranges were 62.8-128.6% when spiked with 10 and 100 µg kg^-1 of pesticides. Certified reference materials, such as chlorfenapyr and indoxacarb, were used for the validation of the analytical method. In total, 21 pesticides and one synergist were detected. Six pesticides, chlorfenapyr, indoxacarb, chlorantraniliprole, cypermethrin, difenoconazole, and pendimethalin, were detected at more than 50%, and nine pesticides, cyhalothrin, fenvalerate, picoxystrobin, deltamethrin, pyridalyl, propiconazole, iprodione, prochloraz, and bifenthrin, were detected at more than 10%. All monitoring results were under the Korean maximum residue limit.

Effect of diosmin on lipid peoxidation and organ damage against subacute deltamethrin exposure in rats

The aim of this study was to investigate the protective efficacy of diosmin against subacute deltamethrin exposure. For this purpose, 40 male Wistar albino rats were used. The animals were assigned to the following 4 groups: control group (received corn oil vehicle alone), diosmin-treated group (50 mg/kg bw/day orally), deltamethrin-exposed group (5 mg/kg bw/day, orally) and coadministered group (5 mg/kg bw/day deltamethrin and 50 mg/kg bw/day diosmin, orally) for 28 days. Some lipid peroxidation/antioxidant status/biochemical markers were evaluated in blood/tissue (liver, kidney, brain, heart and testis) samples and the histopathological architecture was assessed. Compared with the control group, no alteration was detected in the parameters and histological findings of the diosmin-treated group. Deltamethrin toxicity was associated with significantly increased plasma, cardiac, hepatic, renal, cerebral and testicular levels of MDA and NO, and significantly decreased GSH levels (p < 0.05). Antioxidant enzyme status (SOD, CAT and GSH-Px activities) displayed either decrease or increase (p < 0.05). Significant increase was detected in AST and ALT activities and urea and creatinine levels (p < 0.05). The values of the group coadministered with deltamethrin and diosmin were similar to the values of the control group. Diosmin ameliorated deltamethrin-induced lymphocytic and histiocytic infiltration and subendocardial oedema in the heart. Combined administration also minimized hepatic, renal, testicular and cerebral histopathological findings. The alterations detected in various toxicological parameters correlated well with the histopathological changes observed in various organs. In conclusion, it is suggested that diosmin could provide protection against deltamethrin-induced toxicity and organ damage in rats.

Changes of embryonic development, locomotor activity, and metabolomics in zebrafish co-exposed to chlorpyrifos and deltamethrin

Organophosphates (OPs) and pyrethroids (PYRs) are extensively used pesticides and often occur in the form of mixture, whereas little was known about their joint toxicities. We aim to investigate the individual and joint effects of OPs and PYRs exposure on zebrafish embryo by employing chlorpyrifos (CPF) and deltamethrin (DM) as representatives. Zebrafish embryos at 2 hours post fertilization (hpf) were exposed to CPF (4.80, 39.06, and 78.13 μg/L), DM exposure (0.06, 1.60, and 3.19 μg/L), and CPF + DM (4.80 + 0.06, 39.06 + 1.60, and 78.13 + 3.19 μg/L) until 144 hpf. Embryonic development, locomotor activity, and metabolomic changes were recorded and examined. Results displayed that individual exposure to CPF and DM significantly increased the mortality and malformation rate of zebrafish embryos, but decreased hatching rate was only found in CPF + DM co-exposure groups (p < .05). Meanwhile, individual CPF exposure had no detrimental effect on locomotor activity, high dose of individual CPF exposure decreased the swimming speed but had adaptability to the conversion from dark to light, whereas high dose of CPF + DM co-exposure exhibited not only significant decline in swimming speed but also no adaptability to the repeated stimulations, suggesting deficit in learning and memory function. In metabolomic analysis, individual CPF exposure mainly influenced the metabolism of glycerophospholipids and amino acids, individual DM exposure mainly influenced glycerophospholipids, and CPF + DM co-exposure mainly influenced glycerophospholipids and amino acids. Taken together, our findings suggested the embryonic toxicities and neurobehavioral changes caused by CPF and/or DM exposure. The disorder metabolomics of glycerophospholipids and amino acids might be involved in the underlying mechanism of those toxicities.

Metabolomic Profiles in the Brains of Juvenile Steelhead (Oncorhynchus mykiss) Following Bifenthrin Treatment

The pyrethroid insecticide, bifenthrin, is frequently measured at concentrations exceeding those that induce acute and chronic toxicity to several invertebrate and fish species residing in the Sacramento-San Joaquin Delta of California. Since the brain is considered to be a significant target for bifenthrin toxicity, juvenile steelhead trout (Oncorhynchus mykiss) were treated with concentrations of bifenthrin found prior to (60 ng/L) and following (120 ng/L) major stormwater runoff events with nontargeted metabolomics used to target transcriptomic alterations in steelhead brains following exposure. Predicted responses were involved in cellular apoptosis and necrosis in steelhead treated with 60 ng/L bifenthrin using the software Ingenuity Pathway Analysis. These responses were predominately driven by decreased levels of acetyl-l-carnitine (ALC), docosahexaenoic acid (DHA), and adenine. Steelhead treated with 120 ng/L bifenthrin had reductions of lysophosphatidylcholines (LPC), lysophosphatidylethanolamines (LPE), and increased levels of betaine, which were predicted to induce an inflammatory response. Several genes predicted to be involved in apoptotic (caspase3 and nrf2) and inflammatory (miox) pathways had altered expression following exposure to bifenthrin. There was a significantly increased expression of caspase3 and miox in fish treated with 120 ng/L bifenthrin with a significant reduction of nrf2 in fish treated with 60 ng/L bifenthrin. These data indicate that bifenthrin may have multiple targets within the brain that affect general neuron viability, function, and signaling potentially through alterations in signaling fatty acids.

ASSOCIATION BETWEEN DIABETICS AND INTESTINAL CANCER WITH THE RISK OF MUTATION IN CD38 GENE IN IRANIAN POPULATION

BACKGROUND

Intestinal cancer often occurs in type 2 diabetic patients. The concept of increasing insulin levels and insulin-like growth factor in the blood with type 2 diabetes are stimulated with the growth and depletion of cloned cell walls, and the continuation of this process leads to the cellular deformation. This is the evidence for intestinal cancer in type 2 diabetes in population.

OBJECTIVE

In this study, we aimed to find out the relationship between diabetics and intestinal cancer based on CD38 gene mutation.

METHODS

Samples were collected from 200 population including normal and case ones. PCR products related to rs 6449181 of CD38 gene was amplified with ARMS-PCR technique, and a 420-bp sharp banding was observed as well. According three ARMS-PCR techniques, three primers were designed by oligo7 software. Primers include F1, F2 and R (amplifying for normal, mutant and reverse primer respectively).

RESULTS

This band was observed using a primer F1 that carries the wild type nucleotide using a primer, and when it is used with the F2 primer, it brings the mutant primer to populations of patients with diabetes and diabetes-cancer. In addition, the clinical results including body mass index, blood glucose and insulin level were analyzed. The means ±SD and Tuckey's post hoc test were significant between the clinical characterization parameters between cases and healthy populations. The allelic gene frequencies and Hardy-Weinberg equilibrium between nucleotides were evaluated, and the significant level between the alleles and gene frequencies was observed.

CONCLUSION

In general, the current study found that there is a relationship between diabetes and intestinal cancer among the studied populations.

Association between pyrethroid pesticide exposure and hearing loss in adolescents

BACKGROUND

Hearing loss in adolescents is a serious public health problem with a high prevalence. Pyrethroids are one of the most widely applied insecticides that have been linked to neurotoxicity. However, there is no study about the effect of pyrethroid insecticide exposure on the auditory system in the general population.

OBJECTIVE

To investigate the association between pyrethroid pesticide exposure and hearing loss in adolescents in the United States.

METHODS

A total of 720 adolescents aged 12-19 years who participated in the National Health and Nutrition Examination Survey (NHANES, 2007-2010) were considered. 3-phenoxybenzoic acid (3-PBA), a urinary metabolite, was applied as a biomarker to assess pyrethroid exposure. Hearing loss in adolescents was defined as a pure-tone average (PTA) > 15 dB in either ear. Multivariate linear and logistic regression analyses were conducted to examine the associations of urinary 3-PBA with PTA hearing thresholds and risk of hearing loss, respectively.

RESULTS

The weighted geometric mean of 3-PBA levels in urine was 0.32 μg/g creatinine, and 7.62% of adolescents had hearing loss. After adjusting for age, sex, race/ethnicity, BMI, serum cotinine, annual family income and exposure to loud noise/music, linear regression analyses found that Ln-transformed 3-PBA was positively correlated with increase of hearing thresholds in either left (β = 0.61, 95% CI: 0.20-1.01) or right ear (β = 0.52, 95% CI: 0.16-0.89). Logistic regression analyses showed that adjusted odds ratio (OR) for hearing loss in adolescents with the highest tertile (≥0.52 μg/g creatinine) of 3-PBA were 3.12 (95% CI: 1.42-6.83) compared with the lowest tertile (<0.18 μg/g creatinine), with significant linear trends across tertiles.

CONCLUSION

Pyrethroid pesticide exposure was positively associated with hearing loss in U.S. adolescents. This study provides new evidence for the association between pyrethroid exposure and auditory function.

Redox toxicology of environmental chemicals causing oxidative stress

Living organisms are surrounded with heavy metals such as methylmercury, manganese, cobalt, cadmium, arsenic, as well as pesticides such as deltamethrin and paraquat, or atmospheric pollutants such as quinone. Extensive studies have demonstrated a strong link between environmental pollutants and human health. Redox toxicity is proposed as one of the main mechanisms of chemical-induced pathology in humans. Acting as both a sensor of oxidative stress and a positive regulator of antioxidants, the nuclear factor erythroid 2-related factor 2 (NRF2) has attracted recent attention. However, the role NRF2 plays in environmental pollutant-induced toxicity has not been systematically addressed. Here, we characterize NRF2 function in response to various pollutants, such as metals, pesticides and atmospheric quinones. NRF2 related signaling pathways and epigenetic regulations are also reviewed.

Single or combined exposure to chlorpyrifos and cypermethrin provoke oxidative stress and downregulation in monoamine oxidase and acetylcholinesterase gene expression of the rat's brain

The extensive uses of organophosphates and pyrethroids have made it necessary to investigate the neurotoxicity of their combination as they may implicate in the neurodegenerative syndromes. Monoamine oxidase-A (MAO-A) and acetylcholinesterase (AChE) gene expression in the rat brain were evaluated after independent and combined intoxications with chlorpyrifos and cypermethrin. Twenty-four mature male rats were equally distributed into four groups. The first one was kept as a control group, whereas the second, third and fourth were orally gavage with chlorpyrifos (16.324 mg/kg), cypermethrin (25.089 mg/kg) and their combination (9.254 mg/kg), respectively, for 4 weeks. As compared to the control group, intoxications with chlorpyrifos and/or cypermethrin revealed significant (P < 0.05) declines in the levels of brain neurotransmitters (dopamine and serotonin) plus the enzymatic activities of MAO-A, AChE and sodium-potassium adenosine triphosphatase. The mRNA genes expression of MAO-A and AChE have also confirmed the enzymatic actions. Moreover, the oxidative injury recorded as the levels of malondialdehyde and nitric oxide markedly increased (P < 0.01), while the total thiol content reduced and the histopathological outcomes have confirmed these impacts. In conclusion, chlorpyrifos and cypermethrin revealed antagonistic inhibitions on the brain MAO-A and AChE gene regulation through neurotransmission deteriorations and oxidative damage, which could describe their contributions in the neuropathological progressions.

Nano-curcumin versus curcumin in amelioration of deltamethrin-induced hippocampal damage

We aimed to prove that oxidative stress is the main mechanism responsible for hippocampal neurotoxicity induced by deltamethrin (DLM). The protective role of curcumin (CMN) and nano-curcumin (NCMN) over this toxicity was studied. The rats were categorized into four groups: control, DLM, CMN and NCMN. The study continued for 30 days. Hippocampus was processed for histological, biochemical and immunohistochemical studies. Caspase-3, glial fibrillar acidic protein (GFAP), acetylcholinesterase (AChE), malondialdehyde (MDA), glutathione (GSH), catalase (CAT) and superoxide dismutase (SOD) were measured for DLM-induced oxidative stress (increased MDA by 354%/decreased GSH by 61%, SOD by 61%, CAT 57%). Oxidative stress induced apoptosis of hippocampal neurons through increasing Nrf2, gamma-glutamyl cysteine synthetase heavy subunit (GCS-HS) and light subunit (GCS-LS) and decreasing AChE. It increases the activity of astrocytes through increasing GFAP. Finally, oxidative stress has a bad impaction on cognitive function. Improvement of oxidative stress was observed with use of CMN and NCMN (decrease of MDA/increase of GSH, SOD, CAT). The level of Nrf2, GCS-HS and GCS-LS decreased, while AChE, GFAP increased. Improvement of cognitive function was observed in both groups. In conclusion, oxidative stress is the common mechanism responsible for DLM-induced hippocampal neurotoxicity. It exerts apoptosis of hippocampal neurons through increasing Nrf2, HS-GCS, LS-GCS and decreasing AChE. In addition, it activates astrocytes through increasing expression of GFAP. The protective role of CMN and CMMN is related to their potent antioxidant effect. Much improvement has been detected with NCMN as compared to CMN.

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.

METALLOTHIONEIN-2A (RS1610216&RS28366003) GENE POLYMORPHISMS AND THE RISK OF STOMACH ADENOCARCINOMA

ABSTRACT BACKGROUND: Gastric cancer is the fourth most common cause of worldwide cancer. Also in contrast to the huge advances in curing, the chance of living is very low even in surgery cases. Having a genetic predisposition plays an important role in cancer development. The association between Metallothionein-2A gene polymorphisms and the risk of adenocarcinoma has been widely studied, yet there is only one study on stomach diseases. OBJECTIVE: In this study, we aimed to investigate the association between 2 (MT-2A) polymorphisms and adenocarcinoma. METHODS: This cross-sectional case control study was performed between Mach 2014 and January 2015 at the Tuba Hospital of Sari, Iran. Peripheral blood samples were collected in EDTA tube. DNA extraction was performed using the spin column procedure. The MT-2A polymorphisms MT-2A (rs1610216), (rs28366003) were determined by polymerase chain reaction-restriction fragment length polymorphism analysis in 95 a topic adenocarcinoma patients and 90 healthy individuals from Iranian population. RESULTS: The MT-2A rs1610216 polymorphism increased the risk of adeno carcinoma in our Iranian population [OR: 3.8533; 95%CI, 1.3155-11.2869; P=0.0139] and rs28366003 [OR: 4.0978; 95%CI, 1.2521-13.4108; P=0.0197]. CONCLUSION: The MT-2A gene polymorphism was associated with the risk of adenocarcinoma in the Iranian population.

CYTOTOXIC EFFECTS OF DULOXETINE ON MKN45 AND NIH3T3 CELL LINES AND GENOTOXIC EFFECTS ON HUMAN PERIPHERAL BLOOD LYMPHOCYTES

ABSTRACT BACKGROUND: Gastric cancer is the second leading cause of cancer-related death globally. Unfortunately, the survival rate of the gastric cancer patients who underwent chemotherapy following surgery has been less than a half. Besides, chemotherapy has many side effects. Current evidence suggests that some antidepressants like duloxetine have growth-inhibiting effects against a number of cancer cell lines. OBJECTIVE: Thus, the aim of this study was to determine the cytotoxic and genotoxic effects of duloxetine on gastric cancer. METHODS: In this regard, the cytotoxicity and genotoxicity of duloxetine were investigated in MKN45 and NIH3T3 cell lines by MTT assay and on peripheral blood lymphocytes by MN assay. For this purpose, cells were cultured in 96 wells plate. Stock solutions of duloxetine and cisplatin were prepared. After cell incubation with different concentrations of duloxetine (1, 10, 25, 50, 100 and 200 μL), MTT solution was added. For micronucleus assay fresh blood was added to RPMI culture medium 1640 supplemented, and different concentrations of duloxetine (1, 10, 25, 50, 100 and 200 μL) were added. RESULTS: The cytotoxicity of duloxetine on MKN45 cancer cell line and NIH3T3 normal cell line were studied followed by MTT assay. duloxetine exhibited higher IC50 in the MKN45 cells in comparison with the NIH3T3 cells. In addition, genotoxic effect of duloxetine was evaluated by micronucleus assay. The results revealed that duloxetine induced more DNA damage at 100 and 200 μM and no significant difference at 200 μM with respect to cisplatin, but it had less genotoxic effects at 100 and 50 μM concentrations. CONCLUSION: Although, in this study, duloxetine had less genotoxicity than cisplatin in concentrations under 200 μM and showed cytotoxic effects as well, due to its IC50, it cannot be considered as a better choice for gastric cancer therapies with respect to cisplatin as a common anticancer drug.

Effect of a beta-cypermethrin and emamectin benzoate pesticide mixture on reproductive toxicity in male mice in a greenhouse environment

With the widespread use of pesticides, the resistance to pesticides of pests has gradually increased, caused mixed pesticides to become even more widely used for practical applications. To investigate the effects of mixed pesticides on reproductive health in an occupational greenhouse environment, the greenhouse environment and the characteristics of the actual application were constructed, and then the male mice were comprehensively exposed to a mixture of the beta-cypermethrin and emamectin benzoate environmental. Additionally, the effect of the beta-cypermethrin and emamectin benzoate mixture on the reproductive health of male mice was known. The results showed that with the prolongation of exposure duration, the activities of Glutathione Peroxidase (GSH-Px), Total Superoxide Dismutase (T-SOD), Lactate dehydrogenase (LDH) and Acid phosphatase (ACP) in the testes of mice gradually decreased and the activity of Malondialdehyde (MDA) gradually increased. It was also found that the apoptosis rate of murine testicular cells increased and that DNA damage occurred with prolonged exposure duration. Therefore, it can be inferred that exposure to a mixture of the pesticides beta-cypermethrin and emamectin benzoate in the greenhouse environment may have adverse effects on the reproductive health of male mice.