Toxic effects of pesticides on cellular and humoral immunity: an overview

Pyraclostrobin induces developmental toxicity and cardiotoxicity through oxidative stress and inflammation in zebrafish embryos

Pyraclostrobin, a typical representative of strobilurin fungicides, is extensively used in agriculture to control fungi and is often detected in water bodies and food. However, the comprehensive toxicological molecular mechanism of pyraclostrobin requires further study. To assess the toxic effects and underlying mechanisms of pyraclostrobin on aquatic organisms, zebrafish embryos were exposed to pyraclostrobin (20, 40, and 60 μg/L) until 96 h post fertilization (hpf). These results indicated that exposure to pyraclostrobin induces morphological alterations, including spinal curvature, shortened body length, and smaller eyes. Furthermore, heart developmental malformations, such as pericardial edema and bradycardia, were observed. This indicated severe cardiotoxicity induced by pyraclostrobin in zebrafish embryos, which was confirmed by the dysregulation of genes related to heart development. Besides, our findings also demonstrated that pyraclostrobin enhanced the contents of reactive oxygen species (ROS) and malondialdehyde (MDA), up-regulated catalase (CAT) activity, but inhibited superoxide dismutase (SOD) activity. Subsequently, the NF-κb signaling pathway was further studied, and the results indicated that the up-regulation of tnf-α, tlr-4, and myd88 activated the NF-κb signaling pathway and up-regulated the relative expression level of pro-inflammatory cytokines, such as cc-chemokine, ifn-γ, and cxcl-clc. Collectively, this study revealed that pyraclostrobin exposure induces developmental toxicity and cardiotoxicity, which may result from a combination of oxidative stress and inflammatory responses. These findings provide a basis for continued evaluation of the effects and ecological risks of pyraclostrobin on the early development of aquatic organisms.

Climate Change, Exposome Change, and Allergy: A Review

Climate change is a major threat to human respiratory health and associated allergic disorders given its broad impact on the exposome. Climate change can affect exposure to allergens, such as pollen, dust mites, molds, as well as other factors such as temperature, air pollution, and nutritional factors, which synergistically impact the immune response to these allergens. Exposome change can differentially exacerbate allergic reactions across subgroups of populations, especially those who are more vulnerable to environmental stressors. Understanding links between climate change and health impacts can help inform how to protect individuals and vulnerable populations from adverse health effects.

Mitochondrial impairment related to the immunotoxicity of the herbicides clomazone, glyphosate and sulfentrazone in THP-1 cells

Background

Pesticides are indispensable for the cultivation of crops, especially those of economic importance, such as soybeans. Data on the annual use of herbicides in crops show that they correspond to 50%, making it the most used in agriculture.

Aim

Therefore, the aim of this study was to evaluate the toxicity of the three commercial herbicides (clomazone, glyphosate, and sulfentrazone) in THP-1 cells.

Methods

Cells were incubated with 0-5,000 mg/L of the herbicides for 24 h at 37 °C for cytotoxicity evaluation. Additionally, a few toxicological pathways such as reactive species generation, mitochondrial impairment, and interleukin profile, which have been previously involved in the toxicity of pesticides, were also evaluated.

Results

A potential immunotoxic effect of the herbicides on THP-1 cells was observed, especially glyphosate, as it is a powerful agent of cellular immunotoxicity. It was also possible to verify an increase in oxidative stress and IL-8 levels and mitochondrial dysfunction.

Conclusion

All herbicides showed cytotoxic effects in THP-1 monocytes, which were related to mitochondrial impairment.

Monitoring and method validation of organophosphorus/organochlorine pesticide residues in vegetables and fruits by gas chromatography

In this study, an analytical method was developed and validated for the assessment of pesticide residues in commonly consumed vegetables and fruits. Fresh samples of apple, green peas, tomatoes, and cucumbers were processed and subjected to analysis using a modified QuEChERS (quick, easy, cheap, effective, rugged, safe) extraction technique. Subsequently, quantification of pesticide residues was conducted utilizing gas chromatography (GC)-electron capture detector. Extraction and cleanup parameters were meticulously optimized, resulting in a modification of the original QuEChERS method. This modification aimed to reduce solvent consumption, making the study more environmentally friendly. The developed method was validated in terms of selectivity, specificity, linearity, precision, and accuracy by following the SANTE guidelines. Calibration curves showed good linearity (r > 0.99) within the test range. Precision was evaluated by intra- and inter-day experiments with an acceptable relative standard deviation (<20.0%). Recovery was assessed at the limit of quantification level and was observed to fall within the range of 70%-120%, with relative standard deviations below 5.45%. The validated method presented here can be applied to analyze pesticide residues in various other vegetables, fruits, and cereals. It is essential for ongoing monitoring of pesticide residues to ensure public safety.

Occupational exposure to pesticides dysregulates systemic Th1/Th2/Th17 cytokines and correlates with poor clinical outcomes in breast cancer patients

Pesticides are compounds known to cause immunetoxicity in exposed individuals, which have a potential to substantially modify the prognosis of pathologies dependent on an efficient immune response, such as breast cancer. In this context, we examined the circulating cytokine profile of Th1/Th2/Th17 patterns in women occupationally exposed to pesticides and their correlation with worse prognostic outcomes. Peripheral blood samples were collected from 187 rural working women with breast cancer, occupationally exposed or not to pesticides, to quantify the levels of cytokines IL-1β, IL-12, IL-4, IL-17-A, and TNF -α. Data on the disease profile and clinical outcomes were collected through medical follow-up. IL-12 was reduced in exposed women with tumors larger than 2 cm and in those with lymph node metastases. Significantly reduced levels of IL-17A were observed in exposed patients with Luminal B subtype tumors, with high ki67 proliferation rates, high histological grade, and positive for the progesterone receptor. Reduced IL-4 was also seen in exposed women with lymph node invasion. Our data show that occupational exposure to pesticides induces significant changes in the levels of cytokines necessary for tumor control and correlates with poor prognosis clinical outcomes in breast cancer.

Synergistic effects on oxidative stress, apoptosis and necrosis resulting from combined toxicity of three commonly used pesticides on HepG2 cells

The widespread use of pesticides performs a vital role in safeguarding crop yields and quality, providing the opportunity for multiple pesticides to co-exist, which poses a significant potential risk to human health. To assess the toxic effects caused by exposures to individual pesticides (chlorpyrifos, carbofuran and acetamiprid), binary combinations and ternary combinations, individual and combined exposure models were developed using HepG2 cells and the types of combined effects of pesticide mixtures were assessed using concentration addition (CA), independent action (IA) and combination index (CI) models, respectively, and the expression of biomarkers related to oxidative stress, apoptosis and cell necrosis was further examined. Our results showed that both individual pesticides and mixtures exerted toxic effects on HepG2 cells. The CI model indicated that the toxic effects of pesticide mixtures exhibited synergistic effects. The results of the lactate dehydrogenase (LDH) release and apoptosis assay revealed that the pesticide mixture increased the release of LDH and apoptosis levels. Moreover, our results also showed that individual pesticides and mixtures disrupted redox homeostasis and that pesticide mixtures produced more intense oxidative stress effects. In conclusion, we have illustrated the enhanced combined toxicity of pesticide mixtures by in-vitro experiments, which provides a theoretical basis and scientific basis for further toxicological studies.

Evaluation of the Morphological, Physiological and Biochemical Effects Induced by Coragen 20 SC in Some Non-Target Species

Coragen 20 SC is an insecticide based on chlorantraniliprole that is applied on many crops. Considered an effective product with an incremental cost-benefit ratio, it has been widely used globally. Residual pesticides affect non-target organisms, so it is necessary to explore the possible effects induced by these xenobiotics on different species. This work aimed to assess some morphological, physiological and biochemical effects induced by Coragen 20 SC on two non-target species: Perca fluviatilis (Linné, 1758) and Triticum aestivum L. The concentrations used were the same for all tested species (0.0125, 0.025 and 0.05 mL L^-1), and the experiments were of the acute, subchronic and chronic type. The toxicological effects of Coragen 20 SC on perch recorded behavioral changes, a decrease in respiratory rate and oxygen consumption, an increase in blood glucose levels and a decrease in the number of erythrocytes and leukocytes. The results obtained from the evaluation of Coragen 20 SC toxicity using the Triticum test indicate a weak to moderate phytotoxicity for the considered parameters at the applied doses. Only the assimilatory pigments were significantly modified at the concentration of 0.025 mL L^-1 for the growth of the axial organs and the wet and dry weight, with the changes obtained not being statistically significant.

Immunomodulatory effect of imidacloprid on macrophage RAW 264.7 cells

The neonicotinoid imidacloprid was promoted in the market because of widespread resistance to other insecticides, plus its low mammalian impact and higher specific toxicity towards insects. This study aimed to evaluate the immunomodulatory effect of imidacloprid on macrophages. RAW 264.7 cells were incubated to 0-4000mg/L of imidacloprid for 24 and 96h. Imidacloprid presented a concentration-dependent cytotoxicity after 24h and 96h incubation for MTT reduction (3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide) (EC₅₀ 519.6 and 324.6mg/L, respectively) and Neutral Red (3-amino-7-dimethylamino-2-methylphenazine hydrochloride) assays (EC₅₀ 1139.0 and 324.2mg/L, respectively). Moreover, imidacloprid decreased the cells' inflammatory response and promoted a mitochondrial depolarization. The complex II and succinate dehydrogenase (SDH) activities in RAW 264.7 cells incubated with imidacloprid increased more at 24h. These results suggest that imidacloprid exerts an immunomodulatory effect and mitochondria can act as regulator of innate immune responses in the cytotoxicity mediated by the insecticide in RAW 264.7 cells.

Mancozeb-induced cytotoxicity in human erythrocytes: enhanced generation of reactive species, hemoglobin oxidation, diminished antioxidant power, membrane damage and morphological changes

Mancozeb is an ethylene bis-dithiocarbamate fungicide extensively used in agriculture to safeguard crops from various fungal diseases. The general population is exposed to mancozeb through consumption of contaminated food or water. Here, we have investigated the effect of mancozeb on isolated human erythrocytes under in vitro conditions. Erythrocytes were treated with different concentrations of mancozeb (0, 5, 10, 25, 50, 100 μM) and incubated for 24 h at 37 °C. Analysis of biochemical parameters and cell morphology showed dose-dependent toxicity of mancozeb in human erythrocytes. Mancozeb treatment caused hemoglobin oxidation and heme degradation. Protein and lipid oxidation were enhanced, while a significant decrease was seen in reduced glutathione and total sulfhydryl content. A significant increase in the generation of reactive oxygen and nitrogen species was detected in mancozeb-treated erythrocytes. The antioxidant capacity and the activity of key antioxidant enzymes were greatly diminished, while crucial metabolic pathways were inhibited in erythrocytes. Damage to the erythrocyte membrane on mancozeb treatment was apparent from increased cell lysis and osmotic fragility, along with the impairment of the plasma membrane redox system. Mancozeb also caused morphological alterations and transformed the normal discoid-shaped erythrocytes into echinocytes and stomatocytes. Thus, mancozeb induces oxidative stress in human erythrocytes, impairs the antioxidant defense system, oxidizes cellular components, that will adversely affect erythrocyte structure and function.

Triazine Herbicide and NPK Fertilizer Exposure: Accumulation of Heavy Metals and Rare Earth Elements, Effects on Cuticle Melanization, and Immunocompetence in the Model Species Tenebrio molitor

The increasing use of agrochemicals, including fertilizers and herbicides, has led to worrying metal contamination of soils and waters and raises serious questions about the effects of their transfer to different levels of the trophic web. Accumulation and biomagnification of essential (K, Na, Mg, Zn, Ca), nonessential (Sr, Hg, Rb, Ba, Se, Cd, Cr, Pb, As), and rare earth elements (REEs) were investigated in newly emerged adults of Tenebrio molitor exposed to field-admitted concentrations of a metribuzin-based herbicide and an NPK blend fertilizer. Chemical analyses were performed using inductively coupled plasma tandem mass spectrometry (ICP-MS/MS) supported by unsupervised pattern recognition techniques. Physiological parameters such as cuticle melanization, cellular (circulating hemocytes), and humoral (phenoloxidase enzyme activity) immune responses and mass loss were tested as exposure markers in both sexes. The results showed that NPK fertilizer application is the main cause of REE accumulation in beetles over time, besides toxic elements (Sr, Hg, Cr, Rb, Ba, Ni, Al, V, U) also present in the herbicide-treated beetles. The biomagnification of Cu and Zn suggested a high potential for food web transfer in agroecosystems. Gender differences in element concentrations suggested that males and females differ in element uptake and excretion. Differences in phenotypic traits show that exposure affects metabolic pathways involving sequestration and detoxification during the transition phase from immature-to-mature beetles, triggering a redistribution of resources between sexual maturation and immune responses. Our findings highlight the importance of setting limits for metals and REEs in herbicides and fertilizers to avoid adverse effects on species that provide ecosystem services and contribute to soil health in agroecosystems.

Binding and Detoxification of Insecticides by Potentially Probiotic Lactic Acid Bacteria Isolated from Honeybee (Apis mellifera L.) Environment-An In Vitro Study

Lactic acid bacteria (LAB) naturally inhabiting the digestive tract of honeybees are known for their ability to detoxify xenobiotics. The effect of chlorpyrifos, coumaphos, and imidacloprid on the growth of LAB strains was tested. All strains showed high resistance to these insecticides. Subsequently, the insecticide binding ability of LAB was investigated. Coumaphos and chlorpyrifos were bound to the greatest extent (up to approx. 64%), and imidacloprid to a much weaker extent (up to approx. 36%). The insecticides were detected in extra- and intracellular extracts of the bacterial cell wall. The ability of selected LAB to reduce the cyto- and genotoxicity of insecticides was tested on two normal (ovarian insect Sf-9 and rat intestinal IEC-6) cell lines and one cancer (human intestinal Caco-2) cell line. All strains exhibited various levels of reduction in the cyto- and genotoxicity of tested insecticides. It seems that coumaphos was detoxified most potently. The detoxification abilities depended on the insecticide, LAB strain, and cell line. The detoxification of insecticides in the organisms of honeybees may reduce the likelihood of the penetration of these toxins into honeybee products consumed by humans and may contribute to the improvement of the condition in apiaries and honeybee health.