Neurotoxicity induced by the pyrethroid lambda-cyhalothrin: Alterations in monoaminergic systems and dopaminergic and serotoninergic pathways in the rat brain

Single-quad gas chromatography estimation of a few selected pesticides as residues in spices of the National Capital Region of Delhi

In India, spices play a vital role not only in enhancing the taste and flavor of food but also in offering medicinal properties that help reduce the risk of chronic diseases. However, the extensive and non-judicious use of pesticides in agricultural practices results in the presence of their metabolites in food commodities (fruits, vegetables, spices, cereals) and soil, leading to environmental contamination. Organochlorine (OC) and Synthetic Pyrethroid (SP) pesticides are commonly used for pest control but pose environmental and health risks. These compounds are known for their high toxicity, slow degradation, and bioaccumulation. The present study assessed pesticide residue (OC and SP) levels in 21 spice samples, representing eight condiments-cumin, coriander, chili, fenugreek, black pepper, mustard, ajwain, and dry ginger powder-collected from Delhi-NCR markets, using Gas Chromatography-Mass Spectrometry (GC-MS) and the QuEChERS method. Lambda-cyhalothrin (0.056-0.088 mg/kg), pendimethalin (0.059 mg/kg), γ-HCH (0.089 mg/kg), fenpropathrin (0.062 mg/kg), and hexaconazole (0.050 mg/kg) were detected in some samples. Specifically, cumin was contaminated with lambda-cyhalothrin and hexaconazole, coriander with cyfluthrin, fenugreek with lambda-cyhalothrin, mustard with pendimethalin, and ajwain with γ-HCH, hexaconazole, and lambda-cyhalothrin. Chili, black pepper, and ginger were free from residues. Average recoveries were 75-90% for ten organochlorine pesticides and 72-85% for seven synthetic pyrethroids, and the RSD% was below 5%. All detected residues were below the maximum residue limits set by FSSAI.

λ-cyhalothrin induced sex-specific inflammation, glia activation and GABAergic interneuron disruption in the hippocampus of rats

BACKGROUND

Glia mediated neuroinflammation and degeneration of inhibitory GABAergic interneurons are some of the hall marks of pyrethroid neurotoxicity. Here we investigated the sex specific responses of inflammatory cytokines, microglia, astrocyte and parvalbumin positive inhibitory GABAergic interneurons to λ-cyhalothrin (LCT) exposures in rats.

METHODS

Equal numbers of male and female rats were given oral corn oil, 2 mg/kg.bw and 4 mg/kg.bw of LCT for fourteen days. They were euthanized on day 15, brains were excised and hippocampus (n = 5/group) isolated for interleukin 1 beta (IL-1β) and tumor necrotic factor alpha (TNF-α) analysis. The remaining brains (n = 3/group) were processed for Ionized calcium binding adaptor molecule 1 (Iba1), glial fibrillary acidic protein (GFAP) and parvalbumin (PV) distribution in the hippocampus. All quantitative data was subjected to one way analysis of variance (ANOVA).

RESULTS

LCT caused sex and dose dependent increase in IL-1β and TNF-α concentrations, distribution of microglia (Iba1+) and astrocytes (GFAP+), and reduction of PV + GABAergic interneurons. These effects were greater in males compared to females, and dose-dependent in both sexes.

CONCLUSION

LCT specifically induced inflammation and disrupted GABAergic interneurons' integrities via activation of microglia and reactive astrogliosis and such effects are dose-dependent and sexually dimorphic.

Multigenerational Consequences of Prenatal Exposure to Benzophenone-3 Demonstrate Sex- and Region-Dependent Neurotoxic and Pro-Apoptotic Effects in Mouse Brain

Benzophenone-3 (BP-3), commonly used as a UV filter in personal care products and as a stabilizer, is an alleged endocrine disruptor with potential neurodevelopmental impacts. Despite its abundance in the environment, the studies on its effect on brain development are scarce, especially in terms of multigenerational impact. In this work, for the first time, we examined neurotoxic and pro-apoptotic effects of BP-3 on mouse brain regions (cerebral cortex and hippocampus) in both the first (F1) and second (F2) generations after maternal exposure to environmentally relevant BP-3 levels. We found disregulated markers of cell damage (LDH, H2O2, caspase-3 and -8) and observed increased expression of pro-apoptotic Fas/FAS or Fasl/FASL. BP-3 exposure disrupted the BAX/BCL2 pathway, showing stronger effects in the F1 than in the F2 generation, with a dominance of extrinsic pathway (FAS, FASL, caspase-8) over intrinsic one (BAX, BCL2), suggesting that BP-3-induced apoptosis primarily operates via the extrinsic pathway and could impair brain homeostasis across generations. This study underscores the potential of BP-3 to increase multigenerational risks associated with disrupted neurodevelopment and highlights the importance of understanding its long-term neurotoxic effects.

From growth inhibition to ultrastructural changes: Toxicological assessment of lambda cyhalothrin and fosetyl aluminium against Bacillus subtilis and Pseudomonas aeruginosa

In modern agricultural practices, agrochemicals and pesticides play an important role in protecting the crops from pests and elevating agricultural productivity. This strategic utilization is essential to meet global food demand due to the relentless growth of the world's population. However, the indiscriminate application of these substances may result in environmental hazards and directly affect the soil microorganisms and crop production. Considering this, an in vitro study was carried out to evaluate the pesticides' effects i.e. lambda cyhalothrin (insecticide) and fosetyl aluminum (fungicide) at lower, recommended, and higher doses on growth behavior, enzymatic profile, total soluble protein production, and lipid peroxidation of bacterial specimens (Pseudomonas aeruginosa and Bacillus subtilis). The experimental findings demonstrated a concentration-dependent decrease in growth of both tested bacteria, when exposed to fosetyl aluminium concentrations exceeding the recommended dose. This decline was statistically significant (p < 0.000). However, lambda cyhalothrin at three times of recommended dose induces 10% increase in growth of Pseudomonas aeruginosa (P. aeruginosa) and 76.8% decrease in growth of Bacillus subtilis (B. subtilis) respectively as compared to control. These results showed the stimulatory effect of lambda cyhalothrin on P. aeruginosa and inhibitory effect on B. subtilis. Pesticides induced notable alterations in biomarker enzymatic assays and other parameters related to oxidative stress among bacterial strains, resulting in increased oxidative stress and membrane permeability. Generally, the maximum toxicity of both (P. aeruginosa and B. subtilis) was shown by fosetyl aluminium, at three times of recommended dose. Fosetyl aluminium induced morphological changes like cellular cracking, reduced viability, aberrant margins and more damage in both bacterial strains as compared to lambda cyhalothrin when observed under scanning electron microscope (SEM). Conclusively the, present study provide an insights into a mechanistic approach of pyrethroid insecticide and phosphonite fungicide induced cellular toxicity towards bacteria.

Lambda-cyhalothrin alters locomotion, mood and memory abilities in Swiss mice

Lambda-cyhalothrin (LCT) is a type II pyrethroid widely used in agriculture for plant protection against pests. However, pyrethroids represents a risk for rural female farmworkers, and few studies addressed LCT-behavioural alterations in mice. The present study evaluates the effect of LCT on behaviour of eight weeks aged female mice. Mice were divided into three groups including treated mice that received through gavage (i) 0.5 mg/kg bw and (ii) 2 mg/kg of LCT dissolved in corn oil, and (iii) the vehicle controls. Behavioural tests assess the locomotor activity using open field test, the anxiety by the dark-light box test, the learning memory with novel object recognition test, the memory retention by the elevated plus maze test, and the spatial working memory using the Y-maze test. Subacute treatment with low doses of LCT decreases total distance travelled, induces anxiogenic effect by reducing the time spent in the enlightened compartment, alters memory retention by increasing the latency time, and also affects learning memory by reducing the recognition index parameter. However, LCT does not significantly alter spatial working memory. In conclusion, LCT-treated female mice show an alteration in locomotor activity, mood state and memory abilities probably related to oxidative stress and altered neurotransmission.

Dopaminergic and serotoninergic systems as preferential targets of the pyrethroid tefluthrin exposure in the rat brain

The monoaminergic systems dopamine (DA) and serotonin (5-HT) play important roles in neuromodulation, such as motor control, cognitive, affective, and neuroendocrine functions. In the present research study, we addressed the hypothesis that exposure to Type I pyrethroid tefluthrin may specifically target the dopaminergic and serotoninergic systems. Tefluthrin could modify brain monoamine neurotransmitters, DA and 5-HT levels as well as dopaminergic and serotoninergic signaling pathways. Adult male Wistar rats were treated with tefluthrin [2.2, 4.4 and 5.5 mg/kg bw, equivalent to 1/10, 1/5 and 1/4 of the acute oral rat lethal dose 50 (LD50) value] by oral gavage, six days. After last dose of tefluthrin, DA and 5-HT and metabolites levels were determined in brain regions (striatum, hippocampus, prefrontal cortex and hypothalamus). Tefluthrin induced a decrease of DA, 5-HT and metabolites contents, in a brain regional- and dose-related manner. The major decreases in DA and 5-HT contents were observed in prefrontal cortex tissue. Here, we studied that in vivo exposure to tefluthrin may alter DA and 5-HT neurotransmission in prefrontal cortex. Transcripts related to (i) dopaminergic [dopamine transporter 1 (Dat1), tyrosine hydroxylase (TH), dopamine receptors (Drd1, Drd2)], (ii) serotoninergic [serotonin transporter (SERT), tryptophan hydroxylase 2 (TPH2), serotonin receptors (5-HT1A, 5-HT2A)] and (iii) DA and 5-HT degradation [monoamine oxidases (MAOA, MAOB)] signaling pathways were investigated. Results showed that tefluthrin induced down-regulation of transcripts responsible for the synthesis and action of DA (TH, Drd1, Drd2) and 5-HT (SERT, TPH2). In contrast, tefluthrin treatment induced up-regulation of genes involved in DA transporter (Dat1), 5-HT receptors (5-HT1A, 5-HT2A) and monoamine oxidases (MAOA, MAOB). Given the integral roles of mitochondrial dysfunction and dopaminergic and serotoninergic alterations as hallmarks of neurodegenerative diseases, our data suggest that tefluthrin may be a candidate for pesticides contributing to neurodegenerative disorders pathogenesis by causing damage to the DA and 5-HT systems.

Oxidative stress and mitochondrial damage in lambda-cyhalothrin toxicity: A comprehensive review of antioxidant mechanisms

Lambda-cyhalothrin, also known as cyhalothrin, is an efficient, broad-spectrum, quick-acting pyrethroid insecticide and acaricide and the most powerful pyrethroid insecticide in the world. However, there is increasing evidence that lambda-cyhalothrin is closely related to a variety of toxicity drawbacks (hepatotoxicity, nephrotoxicity, neurotoxicity and reproductive toxicity, among others) in non-target organisms, and oxidative stress seems to be the main mechanism of toxicity. This manuscript reviews the oxidative and mitochondrial damage induced by lambda-cyhalothrin and the signalling pathways involved in this process, indicating that oxidative stress occupies an important position in lambda-cyhalothrin toxicity. The mechanism of antioxidants to alleviate the toxicity of lambda-cyhalothrin is also discussed. In addition, the metabolites of lambda-cyhalothrin and the major metabolic enzymes involved in metabolic reactions are summarized. This review article reveals a key mechanism of lambda-cyhalothrin toxicity-oxidative damage and suggests that the use of antioxidants seems to be an effective method for preventing toxicity.

Risk assessment of honeybee larvae exposure to pyrethroid insecticides in beebread and honey

Honeybee is an essential pollinator to crops, evaluation to the risk assessment of honeybee larvae exposure to pesticides residue in the bee bread and honey is an important strategy to protect the bee colony due to the mixture of these two matrices is main food for 3-day-old honeybee larvae. In this study, a continuous survey to the residue of five pyrethroid insecticides in bee bread and honey between 2018 and 2020 from 17 major cultivation provinces which can be determined as Northeast, Northwest, Eastern, Central, Southwest, and Southern of China, there was at least one type II pyrethroid insecticide was detected in 54.7 % of the bee bread samples and 43.4 % of the honey. Then, we assayed the acute toxicity of type II pyrethroid insecticides based on the detection results, the LD50 value was 0.2201 μg/larva (beta-cyhalothrin), 0.4507 μg/larva (bifenthrin), 2.0840 μg/larva (fenvalerate), 0.0530 μg/larva (deltamethrin), and 0.1640 μg/larva (beta-cypermethrin), respectively. Finally, the hazard quotient was calculated as larval oral ranged from 0.046 × 10-3 to 2.128 × 10-3. Together, these empirical findings provide further insight into the accurate contamination of honey bee colonies caused by chemical pesticides, which can be used as a valuable guidance for the beekeeping industry and pesticide regulation.

Occurrence, spatiotemporal distribution patterns,partitioning and risk assessments of multiple pesticide residues in typical estuarine water environments in eastern China

The low terrain and the prosperous agriculture in the east of China, have caused the accumulation of pesticide residues in the estuaries. Therefore, this study analyzed the spatiotemporal distribution and partition tendency of 106 pesticides based on their abundance, frequencies, and concentrations in the aquatic environment of 16 river estuaries in 7 major basins in the eastern China by using solid-phase extraction (SPE) with high-performance liquid chromatography tandem mass spectrometry (HPLC‒MS/MS) and gas chromatography tandem mass spectrometry (GC‒MS/MS). In addition, potential risk of multiple pesticides was also evaluated. The results showed that herbicides were the dominant pesticide type, while triazines were the predominate substance group of pesticide. In addition, triadimenol, vinclozolin, diethylatrazine, prometryn, thiamethoxam, atrazine, and metalachlor were the major pesticides in the water, while prometryn, metalachlor, and atrazine were the main pesticides in the sediment. The average total concentration of pesticide was 751.15 ng/L in the dry season, 651.17 ng/L in the wet season, and 617.37 ng/L in the normal season, respectively. The estuaries of the Huai River Basin, the Yangtze River Basin, the Hai River Basin, and the Yellow River Basin have been affected by the low pollution treatment efficiency, weak infrastructure, and agricultural/non-agricultural activities in eastern China, resulting in relatively serious pesticide pollution. The estuaries of Huaihe River, Yangtze River, Xiaoqing River, and Luanhe River had large pesticide abundance and comparatively severe pesticide pollution, while the estuaries of Tuhai River and Haihe River had heavy pesticide contamination in the sediment, which might be induced by historical sedimentary factors. The log KOC values showed that except for thioketone, other pesticides were relatively stable due to the adsorption by sediment. The ecological risk assessment results indicated that insecticides had a high risk. Teenagers were the most severely affected by the noncarcinogenic risk of pesticides, while adults were mostly affected by the carcinogenic risk of pesticides. Therefore, pesticide hazards in the water environment of estuaries in eastern China needs to be further close supervision.

Ascorbic acid modulates testicular toxicity of Ampligo® 150 ZC insecticide in male rabbit (Oryctolagus cuniculus)

The present study was designed to evaluate the protective effects of ascorbic acid (AA) against lambda cyhalothrin insecticide formulation Ampligo® (AP)-induced testicular toxicity in rabbit laboratory strain ITELV2006 (Oryctolagus cuniculus). Twenty rabbits were randomly divided into four equal groups and treated by oral gavage for 21 consecutive days: Group 1 served as a control and received 1 ml of distilled water, group 2 was supplemented with1ml of ascorbic acid (AA) dilution (200 mg/kg b.w), Group 3 was treated with a dose of AP at 20 mg/kg bw (1 µl/1 ml of distilled water/animal), whereas group 4 was co-administered AA and AP as the same dose of group 2 and 3, respectively. Hormonal, histomorphometrical, and immunohistochemical methods were performed at the end of the study to detect testes damage. The results showed that AP exposure significantly reduced body weight, absolute and relative testicular weights, and testosterone levels. AP caused changes in testes tissue, namely incomplete spermatogenic series and necrosis of the spermatogonial cells lining in the seminiferous tubules of rabbits. Co-administrating AA clearly modulated body and testes weights, hormonal parameters, and histopathological damage. Furthermore, the findings revealed a significant increase in alpha-fetoprotein (AFP) level expression in the testes of the AP group. However, supplementation of the AP rabbits with AA modulated the observed result. Taken together, these data suggest that AA may protect against Ampligo-induced testicular damage.

New insights into Microalgal astaxanthin's effect on Lambda-cyhalothrin-induced lymphocytes immunotoxicity in Cyprinus carpio: Involving miRNA-194-5p-FoxO1-mediated-mitophagy and pyroptosis

Lambda-cyhalothrin (LC), a pyrethroid insecticide widely used in agriculture, causes immunotoxicity to aquatic organisms in the aquatic environment. Microalgal astaxanthin (MA) is a natural carotenoid that enhances viability of a variety of fish. To investigate the immunotoxicity of LC and the improvement effect of MA in lymphocytes (Cyprinus carpio), lymphocytes were treated with LC (80 M) and/or MA (50 M) for 24 h. Firstly, CCK8 combined with PI staining results showed that MA significantly attenuated the LC-induced lymphocyte death rate. Secondly, LC exposure resulted in excessively damaged mitochondrial and mtROS, diminished mitochondrial membrane potential and ATP content, which could be improved by MA. Thirdly, MA upregulated the levels of mitophagy-related regulatory factors (Beclin1, LC3, ATG5, Tom20 and Lamp2) induced by LC. Importantly, MA decreased the levels of pyroptosis-related genes treated with LC, including NLRP3, Cas-4, GSDMD and active Cas-1. Further study indicated that LC treatment caused excessive miRNA-194-5p and reduced levels of FoxO1, PINK1 and Parkin, which was inhibited by MA treatment. Overall, we concluded that MA could enhance damaged mitochondrial elimination by promoting the miRNA-194-5p-FoxO1-PINK1/Parkin-mitophagy in lymphocytes, which reduced mtROS accumulation and alleviated pyroptosis. It offers insights into the importance of MA application in aquaculture as well as the defense of farmed fish against agrobiological hazards in fish under LC.

Micro-algal astaxanthin improves lambda-cyhalothrin-induced necroptosis and inflammatory responses via the ROS-mediated NF-κB signaling in lymphocytes of carp (Cyprinus carpio L.)

Lambda-cyhalothrin (LCY) is a widely used toxic pesticide that causes harmful effects on the immune organs of fish and aquatic species. Micro-algal astaxanthin (MAA), a heme pigment found in haematococcus pluvialis, has been shown to benefit antioxidants and immunity in aquaculture. To investigate how MAA protects carp lymphocytes from LCY-induced immunotoxicity, a model of fish lymphocytes treated with LCY and/or MAA was established. Lymphocytes from carp (Cyprinus carpio L.) were given LCY (80 μM) and/or MAA (50 μM) as a treatment for a period of 24 h. Firstly, LCY exposure resulted in excessive ROS and malondialdehyde production and reduces antioxidant enzymes (SOD and CAT), indicating a reduced capacity of the antioxidant system. Secondly, the results of flow cytometry and AO/EB labeling proved that lymphocytes treated with LCY have a larger ratio of necroptosis. In addition, LCY upregulated the levels of necroptosis-related regulatory factors (RIP1, RIP3 and MLKL) via the ROS-mediated NF-κB signaling pathway in lymphocytes. Thirdly, LCY treatment caused increased secretion of inflammatory genes (IL-6, INF-γ, IL-4, IL-1β and TNF-α), leading to immune dysfunction in lymphocytes. Surprisingly, LCY-induced immunotoxicity was inhibited by MAA treatment, indicating that it effectively attenuated the LCY-induced changes described above. Overall, we concluded that MAA treatment could ameliorate LCY-induced necroptosis and immune dysfunction by inhibiting the ROS-mediated NF-κB signaling in lymphocytes. It provides insights into the protection of farmed fish from agrobiological threats in fish under LCY and the value of MAA applications in aquaculture.

Lambda cyhalothrin and chlorantraniliprole caused biochemical, histological, and immunohistochemical alterations in male rabbit liver: Ameliorative effect of vitamins A, D, E, C mixture

Pesticides can cause serious environmental and human health consequences such as metabolic disruption and even cancers. Preventive molecules such as vitamins can be an effective solution. The present study aimed to investigate the toxic effect of an insecticide mixture formulation of lambda cyhalothrin and chlorantraniliprole (Ampligo® 150 ZC), on the liver of male rabbits (Oryctolagus cuniculus) and the possible ameliorative effect of vitamins A, D3, E, and C mixture. For that, 18 male rabbits were divided into 3 equal groups: Control (distilled water), AP (20 mg/Kg bw of the insecticide mixture every other day, orally for 28 days), AP+ADEC (20 mg/Kg bw of the insecticide mixture + 0,5 ml of vitamin AD3E+ 200 mg/kg bw of vitamin C every other day). The effects were evaluated on body weight, food intake changes, biochemical parameters, liver histology, and immunohistochemical expression of AFP, Bcl2, E-cadherin, Ki67, and P53. Results indicated that AP reduced weight gain (6.71%) and feed intake, increased ALT, ALP, and TC plasma levels, and caused hepatic tissular damages such as dilatation and congestion of the central vein, sinusoidal dilatation, inflammatory cells infiltration, and collagen deposition. Hepatic immunostaining showed an increase in the tissular expression of AFP, Bcl2, Ki67, and P53 and a significant (p < 0,05) decrease in E-cadherin expression. In contrast, supplementation of vitamins A, D3, E, and C mixture improved the previous observed alterations. Our study revealed that a sub-acute exposure to an insecticide mixture of lambda cyhalothrin and chlorantraniliprole induced numerous functional and structural disorders in the rabbit liver and the addition of vitamins ameliorated these damages.