Avermectin inhibits neutrophil extracellular traps release by activating PTEN demethylation to negatively regulate the PI3K-ERK pathway and reducing respiratory burst in carp

Oxidative toxicity mediated oophoritis alters ovarian growth in Channa punctatus under prolonged exposure to herbicide, paraquat dichloride

Herbicide paraquat dichloride, a potent redox agent found its way to natural water bodies and influences their health; however, its impact on the reproductive health of fish is potentially less studied and requires clear investigation. This study was conducted to elucidate its effect on the gonadal health of female fish, Channa punctatus over 60 days. The 96-h LC50 of test herbicide was calculated as 0.24 mL/L for the fish under examination, subsequently, three sub-lethal concentrations were taken in addition to control for the study. The experimental methodology included assessment of oxidative stress markers, hormone levels, expression of interrelated genes, and histological analysis to ascertain the damage to the ovary. At each exposure period, a significant (p < 0.05) rise in endogenous reactive oxygen species in blood cells and activities of oxidative markers in the ovary tissue were observed in treated groups. The gonadosomatic index of the ovary and hormone concentration in plasma decreased at the highest treatment concentration. A significant (p < 0.05) change in the expression of target genes for ovary growth, inflammation, and apoptosis was observed in the treated fish. Histopathological and ultrastructural investigations of the ovary tissue revealed the occurrence of oophoritis and reduced growth of the ovary in herbicide-treated fish. The findings conclude that, herbicide paraquat dichloride causes inflammation in the ovary, in addition to its growth reduction that ultimately, poses a threat to the fish population.

Selenium Ameliorates Aluminum Poisoning-Induced Impaired Production of Neutrophil Extracellular Traps in Chicken

Neutrophil extracellular traps (NETs) are released by neutrophils to modulate the immune response. Aluminum (Al) poisoning is linked to immunotoxicity, and selenium (Se) can maintain immune homeostasis. In this study, we investigated the toxic effects of Al on the release of NETs, the antagonistic effect of Se on Al-induced toxicity, and the potential molecular mechanisms underlying these processes. We assessed the cytotoxicity of aluminum on neutrophils using CCK-8 assay, visualized the structure of selenium/aluminum-induced NETs through immunofluorescence and scanning electron microscope, quantified ROS release during NETs formation using fluorescence microplate analysis, and employed the selenoprotein levels to dissect the mechanisms underlying selenium and aluminum-induced NETs release. Peripheral blood neutrophils were exposed to zymosan for a duration of 3 h to induce the formation of NETs. Microscopic analysis indicated that NETs formation was inhibited in the presence of aluminum. Furthermore, assessments using a multifunctional microplate reader demonstrated that aluminum suppressed both the production of extracellular DNA and the reactive oxygen species burst in neutrophils. Western blot analysis revealed that aluminum altered the levels of cellular selenoproteins. In contrast, Se reduced the Al-induced toxic reaction including restored NETs production, ROS burst, and selenoprotein levels. These results indicate that Al decreases the formation of NETs induced by Zym, while Se inhibits the Al toxicity, promoting the formation of NETs by modulating the expression of selenoprotein.

Silybin prevented avermectin-induced cardiotoxicity in carp by modulating oxidative stress, inflammation, endoplasmic reticulum stress, mitochondrial apoptosis, and autophagy

Avermectin is one of the widely used anthelmintics in aquaculture and exhibits substantial toxicity to aquatic organisms. Silybin is extensively used for its anti-inflammatory, antioxidant and anti-apoptotic biological properties. Heart is essential for the survival of fish and plays a vital role in pumping blood oxygen and nutrients. Residual avermectin in water poses harm to carp. However, there is still insufficient research on whether silybin can mitigate the toxicity of avermectin to carp heart tissues. In this research, we established a model involving carp subjected to acute avermectin exposure and administered diets containing silybin to explore the potential protective effects of silybin against avermectin-induced cardiotoxicity. The results revealed that avermectin induced oxidative stress, inflammation, endoplasmic reticulum (ER) stress, mitochondrial pathway apoptosis and autophagy in the cardiac tissues of carp. Compared with the avermectin group, silybin significantly reduced ROS accumulation in cardiac tissues, restored antioxidant enzyme activity, inhibited mRNA transcript levels of pro-inflammatory-related factors, and attenuated ER stress, mitochondrial pathway apoptosis and autophagy. Protein-protein interaction (PPI) analysis demonstrated that silybin mitigated avermectin-induced cardiac oxidative stress, inflammation, ER stress, mitochondrial pathway apoptosis and autophagy. Silybin exerted anti-inflammatory effects through the Nuclear Factor kappa B (NF-κB) pathway, antioxidant effects through the Nuclear factor erythroid 2-related factor 2 (Nrf2) - Kelch-like ECH-associated protein 1 (Keap1) pathway, alleviated cardiac ER stress through the Glucose-regulated protein 78 (GRP78)/Activating Transcription Factor 6 (ATF6)/C/EBP homologous protein (CHOP) axis, suppressed apoptosis through the mitochondrial pathway, and inhibited excessive autophagy initiation through the PTEN-induced putative kinase 1 (PINK1)/Parkin RBR E3 ubiquitin protein ligase (PARKIN) signaling pathway. This study provided evidence supporting the protective effect of silybin against avermectin-induced cardiotoxicity in carp, highlighting its potential as a dietary additive to protect fish from adverse effects caused by avermectin exposure.

Cadmium aggravates liver injury by activating ferroptosis and neutrophil extracellular traps formation in Nile tilapia (Oreochromis niloticus)

Cadmium (Cd) is a pervasive environmental contaminant and a significant risk factor for liver injury. The present study was undertaken to evaluate the involvement of ferroptosis and neutrophil extracellular traps (NETs) in Cd-induced liver injury in Nile tilapia (Oreochromis niloticus), and to explore its underlying mechanism. Cd-induced liver injury was associated with increased total iron, malondialdehyde (MDA), and Acyl-CoA synthetase long-chain family member 4 (ACSL4), together with reduced levels of glutathione, glutathione peroxidase-4a (Gpx4a), and solute carrier family 7 member 11 (SLC7A11), which are all hallmarks of ferroptosis. Moreover, liver hyperemia, neutrophil infiltration, increased inflammatory factors and myeloperoxidase, as well as elevated serum DNA content in Cd-stimulated Nile tilapia suggested that a considerable number of neutrophils were recruited to the liver. Furtherly, in vitro experiments demonstrated that Cd induced the formation of NETs, and the possible mechanism was related to the generation of reactive oxygen species and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, along with the P38 and extracellular regulated protein kinase (ERK) signaling pathways. We concluded that ferroptosis and NETs are the critical mechanisms contributing to Cd-induced liver injury in Nile tilapia. These findings will contribute to Cd toxicological studies in aquatic animals.

TAN (tannic acid) inhibits BPA-induced pyroptosis of L8824 (grass carp hepatocytes) by regulating PTEN/PI3K/AKT pathway

Bisphenol A (BPA) and its analogues are still one of the most important substances that pollute aquatic systems and pose a threat to aquatic organisms. Tannic acid (TAN) is a kind of glycosyl compound, which has the functions of anti-oxidation, anti-inflammation and anti-apoptosis. However, it is unknown if BPA can regulate PTEN/PI3K/AKT pathway to induce pyroptosis of grass carp hepatocytes (L8824) and the antagonistic effect of tannic acid (TAN) through oxidative stress. Therefore, we established the grass carp hepatocytes (L8824) cell model treated with BPA. The oxidative stress indexes (SOD, CAT, GSH, H2O2 and T-AOC) were detected by oxidative stress kit, mRNA and protein expression of associated genes were examined using qRT-PCR and western blotting. The results showed that BPA treatment increased the content of hydrogen peroxide and decreased the activities of antioxidant enzymes and antioxidants (SOD, CAT, GSH, and T-AOC) in L8824 cells. We also found that PTEN/PI3K/AKT pathway was activated dramatically and the expression of pyroptosis-related genes (GSDMD, NLRP3, Caspase1, ASC and IL-1β) was increased significantly. In addition, TAN could significantly reduce the toxicity of BPA on L8824 cells. After the addition of PTEN specific inhibitor SF1670, the activation of PTEN/PI3K/AKT pathway decreased by BPA was inhibited and the expression of scorch related genes was decreased. On the whole, TAN inhibits BPA-induced pyroptosis of L8824 by modulating the PTEN/PI3K/AKT pathway. The present study provides a novel perspective for toxicological mechanism of BPA, and new insights into the detoxification mechanism of TAN.

Studies on immunotoxicity induced by emamectin benzoate in zebrafish embryos based on metabolomics

Emamectin benzoate (EMB) is an insecticide for the control of agricultural lepidoptera pests, and also an anti-parasiticide for the control of exoparasites in aquaculture industry. Increased studies suggest that EMB could cause toxicity to non-targeted organisms, but its immunotoxicity to human remains unclear. In this study, zebrafish were used to investigate the immunotoxic effects induced by environmentally relevant doses of EMB. We observed that EMB exposure led to embryo mortality and delayed hatching, as well as increased malformations. Meanwhile, zebrafish exposed to EMB exhibited a significant decrease in the number of neutrophils and macrophages. In addition, untargeted metabolomics approach was developed to elucidate the mechanism of EMB-induced immunotoxicity. We found that a total of 10 shared biomarkers were identified in response to EMB exposure. Furthermore, pathway analysis identified glycerophospholipid metabolism was the most relevant pathway. Within this pathway, it was observed abnormal increases in glycerol 3-phosphate content, which could be attributed to the increased expression of GK5 and decreased expression of GPAT3. Our study provided novel and robust perspectives, which showed that EMB exposure to zebrafish embryos could cause metabolic disturbances that adversely affected development and immune system.

Polystyrene microplastics with different sizes induce the apoptosis and necroptosis in liver through the PTEN/PI3K/AKT/autophagy axis

The production of plastics worldwide has been instrumental in the progress of modern society, while the increasing accumulation of plastics castoff in oceans, soils and anywhere else has become a major pressure source on environmental sustainability and animal health. Meanwhile, from a biological perspective, our understanding of the toxicological fingerprints of plastics, especially microplastics (MPs), is still poor. Here, we reported a phenomenon of hepatotoxicity dominated by MPs in the form of polystyrene (PS), was observed in mice model systems and cellular assays. Apoptosis and necroptosis related to the size of particles were seen upon PS-MPs introduction, as revealed by transmission electron microscopy, fluorescence microscopy, flow cytometry, and quantitative analysis of signaling pathways in vivo and vitro. Collectively, the current study demonstrated that the levels of liver cell injury caused by PS-MPs were negatively correlated with the particle diameters. Small-sized particles (1-10 μm) induced cell death primarily as necroptosis whereas the large-sized particles (50-100 μm) mainly induced apoptosis, which was directly accomplished by PTEN/PI3K/AKT signaling axis and its targeted autophagy flux. More interestingly, inhibition of autophagy not only alleviated PS-MPs-triggered cell death, but also changed the form of death injury to a certain extent. This uncovered crosstalk relationship opens up a new avenue for investigating the biological and toxicological effects of MPs, and may provide important insights for preventing and limiting of health hazards from MPs.

Ferulic acid alleviates carp brain damage and growth inhibition caused by avermectin by modulating the Nrf2/Keap1 and NF-κB signaling pathways

The increasing concern over environmental pollution caused by the pesticide avermectin used in aquaculture has attracted significant attention. The use of avermectin, a neurotoxic pesticide, in aquatic environments leads to toxic effects on non-target organisms, particularly causing harm to fish. The phenolic compound ferulic acid possesses excellent anti-inflammatory and antioxidant capabilities. This study was conducted by establishing a chronic exposure experiment to avermectin, proposes the use of ferulic acid as a dietary additive to protect the carp brain from damage caused by exposure to avermectin. Furthermore, it investigates the anti-inflammatory and antioxidant effects of ferulic acid in the carp brain under chronic exposure to avermectin. The experimental results demonstrate that ferulic acid can alleviate brain tissue inflammation and oxidative stress by modulating the Nrf2/Keap1 and NF-κB signaling pathways. It protects the carp brain from chronic avermectin-induced damage, preserves the integrity of the carp blood-brain barrier, enhances the levels of feeding factors, and thereby alleviates carp growth inhibition. These findings provide new therapeutic strategies and a theoretical foundation for the sustainable development of carp aquaculture.

The mechanism of acrolein exposure inhibited the release of neutrophil extracellular traps: By reducing respiratory burst and Raf/MEK/ERK pathway and promote cell apoptosis

Acrolein (AC) is a highly toxic volatile substance in the environment, and studies have found that excessive AC had a toxic effect on the immune system. Neutrophils are the first line of defense against pathogen invasion. The release of neutrophil extracellular traps (NETs) is a protective mechanism for neutrophils, and its release is affected by environmental pollutants. However, the effect of AC on NETs release and its mechanism remains unclear. In this study, chicken peripheral blood neutrophils were pretreated with 20 μM AC and treated with 5 μM Phorbol 12-myristate 13-acetate (PMA) to stimulate the release of NETs. The results showed that AC exposure significantly inhibited the release of NETs induced by PMA, respiratory burst, and the expression levels of phospho-rapidly accelerated fibrosarcoma (p-Raf), phospho-mitogen-activated extracellular signal-regulated kinase (p-MEK) and phospho-extracellular regulated protein kinases (p-ERK). In addition, AC exposure significantly inhibited the expression of B-cell lymphoma-2 (Bcl-2) and promoted the expression of apoptotic factors Bcl2-Associated X (Bax), cytochrome c (Cyt C), cysteinyl aspartate specific proteinase 9 (Casp 9) and cysteinyl aspartate specific proteinase 3 (Casp 3). Further inhibition of neutrophil apoptosis significantly improved the release of NETs. The above results indicated that AC exposure led to a decrease in the formation of NETs, which is caused by excessive AC-induced neutrophil apoptosis. Our study clarified the immune toxicity mechanism of AC on chickens, which is of great significance and reference value for protecting the ecological environment and poultry health.

Preclinical efficacy of TZG in myofascial pain syndrome by impairing PI3K-RAC2 signaling-mediated neutrophil extracellular traps

Tianhe Zhuifeng Gao (TZG) shows a satisfying therapeutic efficacy in treating arthromyodynia, which shares similar etiology to myofascial pain syndrome (MPS). We herein aim to explore whether TZG could be a potential prescription for MPS therapy. An MPS rat model was successfully established presenting with reduced pain thresholds, abnormal local switch responses, etc., which was effectively reversed by TZG treatment externally. A transcriptome sequencing based on the active MTrPs samples of rats, combined with network analysis revealed that TZG might ameliorate the progression of MPS by impairing neutrophil extracellular traps (NETs) release through inhibiting PI3K-RAC2 signaling to reduce NADPH oxidase-originated ROS. Experimentally, the expression levels of inducers, biomarkers of NETs formation and vessel injury, and p-PI3K, p-P47, and RAC2 proteins were all significantly up-regulated in affected tissues, which were markedly reversed by TZG. Our results not only shed light into broadening the clinical indications of TZG, but benefit MPS therapy.

Transcriptome analysis reveals the mechanism of the effect of perfluorocaproic acid exposure on brain injury in Carassius auratus

Perfluorocaproic acid (PFHxA) has received much attention as an emerging pollutant linked to neurological problems in humans and fish. However, the potential mechanism remains unknown. In this study, the pathological damage to tissue sections demonstrated that perfluorocaproic acid caused brain tissue damage, and the increased antioxidant index malondialdehyde (MDA) and decrease in superoxide Dismutase (SOD), acid phosphatase (ACP), alkaline phosphatase (AKP), glutathione peroxidase (GSH-Px), Catalase (CAT), and Lysozyme (LZM) that perfluorocaproic acid activated antioxidant stress and caused brain damage. Transcriptome sequencing discovered 1,532 divergent genes, 931 upregulated, and 601 down-regulated. Furthermore, according to GO enrichment analysis, the differently expressed genes were shown to be involved in biological processes, cellular components, and molecular functions. The MAPK, calcium, and Neuroactive ligand-receptor interaction were considerably enriched in the KEGG enrichment analysis. We then analyzed qRT-PCR and chose ten essential differentially expressed genes for validation. The qRT-PCR results followed the same pattern as the RNA-Seq results. In conclusion, our study shows that perfluorocaproic acid exposure causes oxidative stress in the brain. It establishes a theoretical foundation for future research into genes linked to perfluorocaproic acid toxicity.

Ambient NO2 hinders neutrophil extracellular trap formation in rats: Assessment of the role of neutrophil autophagy

NO₂ has been known to impair immunity and exacerbate susceptibility to infectious diseases. However, scant notice has been taken of the effect of NO₂ on neutrophils. Neutrophil extracellular traps (NETs) formation is necessary for NETosis development by neutrophils as an immune system against pathogens. By analyzing the morphology and signature components of NETs, we focused for the first time on finding that 10 ppm of NO₂ exposure for 15 consecutive days can hinder the formation of NETs. Next, we used NO₂ in vivo derivatives to probe the mechanism for NETs formation in vitro. Our findings showed that NO₂ suppression of respiratory burst levels and mitogen-activated protein kinase (MAPK)/Phosphoinositide 3-kinase (PI3K)-protein kinase B (AKT) signaling was related to NO₂ reduction in NETs formation. Inhibition of phorbol myristate acetate (PMA)-induced NETs formation by NO₂ hindered autophagy, as evidenced by increased mTOR protein expression, decreased LC3 protein expression, and reduced autophagic vesicles. By activating mTOR-mediated autophagy, rapamycin (Rapa) reduced the inhibition of PMA-induced NETs by NO₂. This study will provide valuable insights into the mechanisms of immunotoxicity of NO₂, new insights into the etiology of diseases linked to NETs formation, and a theoretical basis for protection against such illnesses.

Tannin alleviates glyphosate exposure-induced apoptosis, necrosis and immune dysfunction in hepatic L8824 cell line by inhibiting ROS/PTEN/PI3K/AKT pathway

Glyphosate can cause tissue damage such as liver and kidney in mammals. Tannin has anti-inflammatory, antibacterial and anti-inflammatory properties. However, the effect of glyphosate on the growth of L8824 cell line and the effect of tannin on antagonism of glyphosate through the ROS/PTEN/PI3K/AKT axis are unclear. In this study, L8824 cells were treated with glyphosate (50 μg/mL) and/or tannin (4.5 μM) for 24 h to establish a model. The results showed that glyphosate exposure increased ROS and MDA levels, decreased CAT and SOD activities. PTEN was activated and the PI3K/AKT signaling pathway was inhibited. The P53/Bcl-2/Bax/CytC/Caspase3 and RIPK1/RIPK3/MLKL pathways were also activated. In addition, the cytokines and antimicrobial peptides LEAP-2, TNF-α and IL-1β were increased while β-defensin, Hepcidin, IL-2 and IFN-γ were decreased. The use of tannin reduced the adverse effects of glyphosate exposure on L8824 cells significantly. In conclusion, tannin can trigger oxidative stress via PTEN/PI3K/AKT pathway to cause apoptosis, necroptosis and immune dysfunction of L8824 cells.

Combined negative effects of microplastics and plasticizer DEHP: The increased release of Nets delays wound healing in mice

Environmental harmful pollutants microplastics (MPs) and di (2-ethyl) hexyl phthalate (DEHP) are widely residual in the environment, which may cause lesion to multiple apparatus by inducing oxidative stress, threatening the health of human and animals. Neutrophil extracellular traps (Nets) are involved in skin wound healing. Most studies focused on the individual effects of different poisons on animals and ecosystems, but there are few studies on the accumulation and interaction of multiple poisons. The purpose of this study is to explore the effect of DEHP and MPs co-exposure on skin wound healing and the formation of Nets. For this purpose, we detected this hypothesis by replicating the DEHP and MPs-exposed skin wound model in mice, as well as the co-culture system of neutrophil and fibroblast. The results displayed that MPs and DEHP exposure delayed skin healing, which was more pronounced in the combined exposure group. In vitro and in vivo experiments confirmed that compared with the DEHP or MPs group, the DEHP+MPs group had more significant oxidative stress, increased Nets release and inflammatory factors, and inhibited the Wnt/β-catenin pathway and fibrosis-related factors. N-acetylcysteine (NAC) attenuated these phenomena. Through the co-culture system, we confirmed that the overproduction of Nets induced fibroblasts to exacerbate inflammatory responses and inhibit Wnt pathway and fibrosis. Overall, DEHP and MPs can produce synergistic toxic injury in mice skin wounds, and the excessive activation of ROS/Nets can aggravate inflammatory and inhibit fibrosis, resulting in delayed wound healing.

Acute toxicity, biochemical and transcriptomic analysis of Procambarus clarkii exposed to avermectin

BACKGROUND

Pesticides are extensively applied globally. Pesticide residues induce calamitous effects on the environment and untargeted organisms. Public concerns for the safety of freshwater organisms and the challenges posed by aquatic contaminants remain high. In the present study, the acute toxicity of avermectins (AVMs) to the crayfish, Procambarus clarkii was evaluated. We also evaluated the potential effects of AVM on the biochemical and transcriptomic status of the hepatopancreas and gastrointestinal tract in P. clarkii.

RESULTS

The 24, 48, 72, 96 h median lethal concentrations (LC₅₀ ) of AVM on crayfish were 2.626, 1.162, 0.723, 0.566 mg L^-1 , respectively. The crayfish were then exposed to 0.65 mg L^-1 of AVM for 96 h. AVM significantly altered biochemical parameters including AChE and CAT activities in the hepatopancreas, and AChE, SOD and Na + -K + -ATPase activities in the gastrointestinal tract at several time points. Furthermore, transcriptomic analysis identified 953 and 1851 differentially-expressed genes (DEGs) in the hepatopancreas and gastrointestinal tract, respectively. KEGG enrichment showed that the gene expression profiles of the hepatopancreas and gastrointestinal tract were distinct from each other. The DEGs in the hepatopancreas were mostly enriched with stress-response pathways, while the majority of the DEGs in the gastrointestinal tract belonged to metabolism-related pathways.

CONCLUSION

We demonstrated that the AVM induced acute toxicity, oxidative stress, osmoregulation disturbance, neurotoxicity and transcriptome imbalance in crayfish. These findings unraveled the detrimental effects of AVMs exposure on crayfish. © 2022 Society of Chemical Industry.

Neutrophil Extracellular Traps in Cerebral Ischemia/Reperfusion Injury: Friend and Foe

Cerebral ischemic injury, one of the leading causes of morbidity and mortality worldwide, triggers various central nervous system (CNS) diseases, including acute ischemic stroke (AIS) and chronic ischemia-induced Alzheimer's disease (AD). Currently, targeted therapies are urgently needed to address neurological disorders caused by cerebral ischemia/reperfusion injury (CI/RI), and the emergence of neutrophil extracellular traps (NETs) may be able to relieve the pressure. Neutrophils are precursors to brain injury following ischemic stroke and exert complicated functions. NETs extracellularly release reticular complexes of neutrophils, i.e., double-stranded DNA (dsDNA), histones, and granulins. Paradoxically, NETs play a dual role, friend and foe, under different conditions, for example, physiological circumstances, infection, neurodegeneration, and ischemia/reperfusion. Increasing evidence indicates that NETs exert anti-inflammatory effects by degrading cytokines and chemokines through protease at a relatively stable and moderate level under physiological conditions, while excessive amounts of NETs release (NETosis) irritated by CI/RI exacerbate the inflammatory response and aggravate thrombosis, disrupt the blood-brain barrier (BBB), and initiates sequential neuron injury and tissue damage. This review provides a comprehensive overview of the machinery of NETs formation and the role of an abnormal cascade of NETs in CI/RI, as well as other ischemia-induced neurological diseases. Herein, we highlight the potential of NETs as a therapeutic target against ischemic stroke that may inspire translational research and innovative clinical approaches.

Selenium mitigates the inhibitory effect of TBBPA on NETs release by regulating ROS/MAPK pathways-induced carp neutrophil apoptosis and necroptosis

Tetrabromobisphenol A (TBBPA) is one of the most common and persistent organic pollutants found in the environment. When TBBPA is ingested by organisms through various pathways and stored in the body, it shows obvious harmful effects. Selenium (Se) works as an antioxidant in the body, allowing it to withstand the poisonous effects of dangerous substances. The effects and mechanisms of Se and TBBPA on carp neutrophil immune function, apoptosis, and necroptosis, however, are unknown. As a result, we created TBBPA exposure and Se antagonism models using carp neutrophils as study objects, and we investigated the expression of genes implicated in extracellular traps (NETs), cytokines, apoptosis, and necroptosis. The findings demonstrated that extracellular traps neutrophils in the TBBPA group displayed the inhibition of NETs, apoptosis, and necrosis, as well as an increase in Reactive oxygen species (ROS) levels and activation of the MAPK pathway. The expression of genes related to the mitochondrial apoptosis pathway (Bax, Cyt-c, Bcl-2 and Caspase-3) and necroptosis pathway (MLKL, RIPK1, RIPK3, Caspase-8 and FADD) were activated. The expression of inflammatory factors IL-1 and TNF-α were increased, and the expression of IL-2 and IFN-γ were decreased. But an appropriate concentration of Se can mitigate the effects of TBBPA. Our results suggest that Se can mitigate the inhibitory effect of TBBPA on NETs release by regulating apoptosis and necroptosis of carp neutrophil via ROS/MAPK pathways. These results provide a basis information for exploring the toxicity of TBBPA, and enrich the anti-toxicity mechanism of trace element Se in the body.

Subcellular-Level Mitochondrial Energy Metabolism Response in the Fat Body of the German Cockroach Fed Abamectin

Mitochondria are the leading organelle for energy metabolism. The toxic effects of environmental toxicants on mitochondrial morphology, energy metabolism, and their determination of cell fate have already been broadly studied. However, minimal research exists on effects of environmental toxicants such as pesticides on mitochondrial energy metabolism at in vitro subcellular level, particularly from an omics perspectives (e.g., metabolomics). Here, German cockroach (Blattella germanica) was fed diets with (0.01 and 0.001 mg/mL) and without abamectin, and highly purified fat body mitochondria were isolated. Swelling measurement confirmed abnormal mitochondrial swelling caused by abamectin stress. The activity of two key mitochondrial energy metabolism-related enzymes, namely succinic dehydrogenase and isocitrate dehydrogenase, was significantly affected. The metabolomic responses of the isolated mitochondria to abamectin were analyzed via untargeted liquid chromatography/mass spectrometry metabolomics technology. Fifty-two differential metabolites (DMs) were identified in the mitochondria between the 0.001 mg/mL abamectin-fed and the control groups. Many of these DMs were significantly enriched in pathways involved in ATP production and energy consumption (e.g., oxidative phosphorylation, TCA cycle, and pentose phosphate pathway). Nineteen of the DMs were typically related to energy metabolism. This study is valuable for further understanding mitochondrial toxicology under environmental toxicants, particularly its subcellular level.

Combined exposure to di(2-ethylhexyl) phthalate and polystyrene microplastics induced renal autophagy through the ROS/AMPK/ULK1 pathway

Di(2-ethylhexyl) phthalate (DEHP) and polystyrene microplastics (PS-MPs) are new environmental pollutants that attracted increased attention. At present, the effects and underlying mechanisms of action of combined exposure of DEHP and PS-MPs on the kidney have not been elucidated. To investigate the renal toxicity of DEHP and PS-MPs exposure, we established single and combined DEHP and PS-MPs exposure models in mice and HEK293 cells, respectively. Hematoxylin and eosin staining, transmission electron microscopy, monodansylcadaverine staining, immunofluorescence, real-time quantitative PCR, Western blot analysis and other methods were used to detect relevant indicators. The results showed that the expression levels of ROS/AMPK/ULK1 and Ppargc1α/Mfn2 signaling pathway-related genes were significantly increased in the DEHP and PS-MPs exposure models. The mRNA and protein expression levels of autophagy markers were also upregulated. In addition, we found that the expression levels of mRNAs and proteins in the combined exposure group were more significantly increased than those in the single exposure group. In conclusion, combined exposure to DEHP and PS-MPs caused oxidative stress and activated the AMPK/ULK1 pathway, thereby inducing renal autophagy. Our results enhance the field of nephrotoxicity studies of plasticizers and microplastics and provide new light on combined toxicity studies of DEHP and PS-MPs.

Zinc oxide nanoparticles (ZnO-NPs) exhibit immune toxicity to crucian carp (Carassius carassius) by neutrophil extracellular traps (NETs) release and oxidative stress

Zinc oxide nanoparticles (ZnO-NPs) are widely used in sunscreens, cosmetics, paint, construction materials, and other products. ZnO-NPs released into the environment can harm aquatic creatures and pose a health risk to humans through the food chain. ZnO-NPs are toxic to fish, but there are few reports on its immunotoxicity on crucian carp (Carassius carassius). In this study, ZnO-NPs increased the biochemical indexes of the liver in serum, including aspartate aminotransferase (AST) and alanine aminotransferase (ALT). In histopathological observation, many inflammatory cells were filled in the liver's central vein stimulated by ZnO-NPs. Furthermore, ZnO-NPs could increase malondialdehyde (MDA) level, lessen superoxide dismutase (SOD) level, and elevate the level of neutrophil extracellular traps (NETs). However, deoxyribonuclease I (DNase I) alleviated all biochemical indexes and histopathological changes. Immunofluorescence in vitro confirmed that NETs were composed of citrullinated histone 3, myeloperoxidase, and neutrophil elastase. ZnO-NPs-increased NETs were dependent on reactive oxygen species (ROS) and nicotinamide adenine dinucleotide phosphate (NADPH)-oxidase and were also related to partial processes of glycolysis. Our study confirms that ZnO-NPS has a toxic effect on the liver of crucian carp. DNase I can prevent liver damage caused by ZnO-NPs, which provides a new insight into the immunotoxicity of ZnO-NPs to fish.

Cadmium induces apoptosis by miR-9-5p targeting PTEN and regulates the PI3K/AKT pathway in the piglet adrenal gland

Cadmium (Cd) is an environmental pollutant that can cause endocrine organ damage. To explore the effect of subacute CdCl₂ exposure on piglet adrenal gland tissue and its mechanism based on the establishment of this model, bioinformatics, TUNEL assay, western blot (WB), and qRT-PCR methods were used to detect related indicators. The results showed that after Cd exposure, antioxidant enzymes decreased, heat shock protein increased, and miR-9-5p-gene of phosphatase and tensin homolog (PTEN) upregulates the phosphatidylinositol-3-kinase (PI3K/AKT) pathway. After this pathway was activated, the expression of the apoptosis-related factors cysteinyl aspartate-specific proteinase 3 and 9 (caspase 3 and 9), B-cell lymphoma-2-associated X (BAX) was increased sharply, and the expression of B-cell lymphoma-2 (BCL2) was significantly decreased. The changes in these indicators indicate that Cd exposure induces apoptosis and causes tissue damage in the adrenal gland of piglets. This study aims to reveal the toxic effects of CdCl₂ in animals and will provide new ideas for the toxicology of Cd.

Melatonin attenuates chronic stress-induced hippocampal inflammatory response and apoptosis by inhibiting ADAM17/TNF-α axis

Melatonin, as a dietary supplement, has a potent neuroprotective effect and exerts a certain antidepressant effect. This study explored the molecular mechanisms and targets of melatonin on chronic stress-induced hippocampal damage from the perspective of inhibiting inflammatory cytokines release. Our results indicated that melatonin alleviated chronic restraint stress (CRS)-induced inflammatory response and apoptosis, thus improving hippocampal structural damage and subsequent depression-like behaviors in rats. The radar map displayed that the change of TNF-α content was the most significant. Meanwhile, correlation analysis showed that TNF-α content was highly positively correlated with apoptosis. Molecular autodocking studies suggested that TNF-α converting enzyme ADAM17 as a potential target has a priority in docking with melatonin. Molecular mechanism studies indicated that melatonin inhibited CRS-induced activation of the ADAM17/TNF-α axis and its downstream proteins p38 and p53 phosphorylation in the hippocampus. Analogously, Both ADAM17 inhibitor TMI-1 and TNF-α inhibitor thalidomide relieved the effects of CRS on ADAM17/TNF-α axis and its downstream proteins phosphorylation, hippocampal apoptosis, hippocampal inflammatory response, and depression-like behaviors in rats. Altogether, these findings reveal that melatonin relieves CRS-induced inflammatory response and apoptosis, and subsequent depression-like behaviors by inhibiting ADAM17/TNF-α axis.

Effect of propiconazole on neutrophil extracellular traps formation: Assessing the role of autophagy

Propiconazole (Pcz) is a kind of triazole fungicide which has an important impact on the environment. With the extensive use of Pcz in agricultural production activities, the pesticides are left in soil, water, crops and food, and will enter the organisms in the form of residues. Neutrophils play a key role in the body's innate immunity against pathogens, and the formation of neutrophil extracellular traps (NETs) is an important way for neutrophils to exert their immune function. In the present study, we focused on the effect of Pcz on the NETs of Sprague-Dawley (SD) rats for the first time. Our data demonstrated that Pcz could hinder NETs formation via inhibiting the Phosphoinositide 3-kinase (PI3K)/rapidly accelerated fibrosarcoma (Raf)/extracellular signal-regulated kinase (ERK) signaling. In the meanwhile, we assessed the role of autophagy played in this process and revealed that Pcz may inhibit the respiratory burst in neutrophils. This study provided new insights into the immunotoxic hazards of Pcz and additional laboratory evidence for assessing the impact of Pcz on terrestrial organisms.

Selenium Deficiency Induces Autophagy in Chicken Bursa of Fabricius Through ChTLR4/MyD88/NF-κB Pathway

To explore the role of ChTLR4/MyD88/NF-κB signaling pathway on autophagy induced by selenium (Se) deficiency in the chicken bursa of Fabricius, autophagosome formation in the bursa of Fabricius was observed by transmission electron microscopy. Quantitative real-time PCR (qRT-PCR) and Western blot were used to detect the expression of ChTLR4 and its signaling pathway molecules (MyD88, TRIF, and NF-κB), inflammatory factors (IL-1β, IL-8, and TNF-α), and autophagy-related factors (ATG5, Beclin1, and LC3-II) in the Se-deficient chicken bursa of Fabricius at different ages. The results showed that ChTLR4/MyD88/NF-κB signaling pathway was activated in the chicken bursa of Fabricius and autophagy was induced at the same time by Se deficiency. In order to verify the relationship between the autophagy and ChTLR4/MyD88/NF-κB signaling pathway, HD11 cells were used to establish the normal C group, low Se group, and low Se + TLR4 inhibitor (TAK242) group. The results demonstrated that autophagy could be hindered when the TLR4 signaling pathway was inhibited under Se deficiency. Furthermore, autophagy double-labeled adenovirus was utilized to verify the integrity of autophagy flow induced by Se deficiency in HD11 cells. The results showed that it appeared to form a complete autophagy flow under the condition of Se deficiency and could be blocked by TAK242. In summary, we found that Se deficiency was involved in the chicken bursa of Fabricius autophagy occurring by activating the ChTLR4/MyD88/NF-κB pathway.

Effects of dibutyl phthalate and di (2-ethylhexyl) phthalate on hepatic structure and function of adult male mice

The objective of the present research was to determine if dibutyl phthalate (DBP) and di-(2-ethylhexyl) phthalate (DEHP) alone and combined exposure induced pathological alterations in laboratory reared albino mice. Adult male mice were equally divided (n = 10) into Control, corn oil (CO), DBP, DEHP, and DBP+DEHP treated groups. Dibutyl phthalate (250 mg/kg), DEHP (300 mg/kg), and DBP+DEHP (250+300 mg/kg), respectively, were administered by oral gavage mixed in corn oil (0.2 mL) for 28 days. All animals were sacrificed following 28 days of treatment and blood was collected for serum lipid profiles and liver function tests. Liver samples were also collected for observation of histological changes. Microphotographs of hematoxylin and eosin-stained sections were used for computer-based micrometry. CO, DBP, DEHP, and DBP+DEHP treatment resulted in a significant increase in the mean body and liver weights as compared with the Control group. Histological examination of the livers with DBP and/or DEHP treatment showed marked alterations leading to hepatic hypertrophy. In the treated groups, a significant increase in the mean number of mononucleated, binucleated cells, and oval cells per unit area was noticed with disorganized trabecular arrangement as compared with the Control group. Treatment with DBP and/or DEHP resulted in large regeneration zones in the liver and an increased relative nucleo-cytoplasmic index of mononuclear shepatocytes when compared with the Control group. All treatments caused a significant increases in the liver enzymes and proteins as well as altered serum cholesterol, triglycerides, LDL, and VLDL levels. The histopathological and serological findings confirmed the toxic potentials to hepatic tissue of DBP and DEHP either given alone or in combination.

TRAF2/ASK1/JNK Signaling Pathway Is Involved in the Lung Apoptosis of Swine Induced by Cadmium Exposure

Cadmium (Cd), a toxic heavy metal, exists widely in the environment, which can enter organisms through a variety of ways and cause damage to various organs and tissues. However, the mechanism of lung toxicity in swine after Cd exposure is still unclear. To explore the molecular mechanism of swine lung damage caused by Cd exposure, we established the model of Cd exposure, and Cd chloride (20 mg/kg CdCl₂) was added to the diet of swine for continuous exposure for 40 days. TUNEL staining showed that the apoptosis of swine lung increased significantly after Cd exposure. Meanwhile, the results of qRT-PCR showed that Cd induced oxidative stress and inhibited the expression of antioxidant enzymes including CAT, GCLM, GST, SOD, and GSH-px in lung tissue. Cd exposure activated mitochondrial apoptosis pathway via the TRAF2/ASK1/JNK signaling pathway. In brief, we considered that Cd exposure causes oxidative stress in lung and induces lung cell apoptosis through the TRAF2/ASK1/JNK pathway and increases the expression of HSPs to resist the toxicity of Cd. Our research enriches the theoretical basis of Cd toxicity and provides reference for comparative medicine.

A new discovery of polystyrene microplastics toxicity: The injury difference on bladder epithelium of mice is correlated with the size of exposed particles

Microplastics (MPs), as widespread hazardous substances in the environment, can cause potential adverse effects on biological health. However, reports on the toxic effects of different diameters MPs on urinary system are limited. Here, we investigated the types and mechanisms of damage to mice bladder epithelial cells treated with diameter (1-10 μm and 50-100 μm) polystyrene microplastics (PS-MPs). The results showed that exposure to PS-MPs of both diameters resulted in necroptosis and inflammation to bladder epithelium. However, 1-10 μm PS-MPs posed more severe necroptosis and 50-100 μm PS-MPs led to a higher degree of inflammatory injury at the same exposure concentration. Mechanistically, PS-MPs were found to induce necroptosis as well as p-NFκB-mediated inflammation by triggering oxidative stress and excessive release of reactive oxygen species (ROS). Furthermore, N-Acetyl-l-cysteine (NAC) attenuated the toxic effects of PS-MPs on bladder epithelial cells. In conclusion, our study demonstrated for the first time that PS-MPs caused necroptosis and inflammation in mice bladders tissues, and the difference of injury correlates with the size of PS-MPs particles.

What can we learn from commercial insecticides? Efficacy, toxicity, environmental impacts, and future developments

Worldwide pesticide usage was estimated in up to 3.5 million tons in 2020. The number of approved products varies among different countries, however, in Brazil, there are nearly 5000 of such products available. Among them, insecticides correspond to a group of mounting importance for controlling crop pests and disease-associated vectors in public health. Unfortunately, resistance to commercially approved insecticides is commonly observed, limiting the use of these products. Thus, the search for more effective and environmentally friendly products is both a challenge and a necessity since several insecticides are no longer allowed in many countries. In this review, we discuss the historical strategies used in the development of modern insecticides, including chemical structure alterations, mechanism of action and their impact on insecticidal activity. The environmental impact of each pesticide class is also discussed, with persistence data and activity on non-target organisms, along with the human toxicological effect. By tracing the historical route of discovery and development of blockbuster pesticides like DDT, pyrethroids and organophosphates, we also aim to categorize and relate the successful chemical alterations and novel pesticide development strategies that resulted in safer alternatives. A brief discussion on the Brazilian registration procedure and a perspective of insecticides currently approved in the country was also included.

Melatonin relieves 2,2,4,4-tetrabromodiphenyl ether (BDE-47)-induced apoptosis and mitochondrial dysfunction through the AMPK-Sirt1-PGC-1α axis in fish kidney cells (CIK)

Polybrominated diphenyl ethers (PBDEs) exist in aquatic environments with nephrotoxicity to non-target aquatic species. Melatonin (MT) exhibits an inhibitory effect of oxidative stress and apoptosis in various diseases. 2, 2', 4, 4'-tetrabromodiphenyl ether (BDE-47) is the main homolog of PBDE samples. Therefore, we investigated the toxic mechanism of BDE-47 and the alleviation effect of MT, the ctenopharyngodon idellus kidney (CIK) cells were treated with BDE-47 (100 μM) and/or MT (60 μM) for 24 h. Firstly, BDE-47 exposure could inhibit oxidative stress-related antioxidant enzymes (T-AOC, SOD, CAT and GPx) and increase the content of malondialdehyde (MDA) to cause oxidative stress. Secondly, BDE-47 enhanced mitochondrial division and inhibited fusion to induce mitochondrial membrane potential in CIK cells. BDE-47 enhanced the mRNA and protein levels of mitochondrial-pathway apoptosis related genes (Cas 3, Cyt-c, and BAX). Thirdly, BDE-47 treatment decreased the expression levels of mitochondrial-related regulatory factors AMPK-Sirt1-PGC-1α signal pathway. Intriguingly, BDE-47-induced oxidative stress, mitochondrial pathway apoptosis and mitochondrial dynamics disorder could be alleviated by MT treatment. Overall, we concluded that MT could relieve BDE-47-induced oxidative stress, mitochondrial dysfunction and apoptosis through the AMPK-Sirt1-PGC-1α axis. These results enrich the mechanisms of BDE-47 poisoning and reveal that MT treatment may be a potential strategy for solving BDE-47 poisoning.

Albicanol modulates oxidative stress and the p53 axis to suppress profenofos induced genotoxicity in grass carp hepatocytes

The organophosphorus pesticide profenofos (PFF) is widely used as an environmental contaminant, and it can remain in water bodies causing serious harm to aquatic organisms. Albicanol is a sesquiterpenoid with potent antioxidant and antagonistic activities against heavy metal toxicity. However, the mechanism of PFF induced genotoxicity in fish hepatocytes and the role Albicanol can play in this process are unknown. In this study, the model was established by treating grass carp hepatocytes with PFF (150 μM) and/or Albicanol (5 × 10^-5 μg mL^-1) for 24 h. The results showed that PFF exposure arrested L8824 cells in the G1-S phase. PFF caused the increase of MDA level in L8824 cells, while the decrease of SOD, CAT and T-AOC levels caused oxidative stress. Elevated levels of γH2AX, tail moment, tail length, % DNA and 8-OHdG indicated that PFF caused DNA damage in L8824 cells. PFF inhibited the expression levels of cell cycle related regulatory genes (cyclin A, cyclin D, cyclin E, CDK2 and CDK4) by upregulating p53/p21 genes and activating the p53 signaling pathway. Albicanol was used to significantly reduce the above effects caused by PFF exposure on hepatocytes in grass carp. Albicanol could reduce the increase in the proportion of cells in the G1-S phase caused by PFF. In summary, Albicanol could inhibit the genotoxicity of L8824 cells resulted from PFF exposure by decreasing oxidative stress and the p53 pathway.

ERK/p38/ROS burst responses to environmentally relevant concentrations of diphenyl phosphate-evoked neutrophil extracellular traps formation: Assessing the role of autophagy

Organophosphorus compounds were proposed to impair immune surveillance and increase the total burden of pathogens. However, scarce attention has been paid to the effects of organophosphate flame retardants (OPFRs) on neutrophils. Previous literature outlined that neutrophil extracellular traps (NETs) death (NETosis) is associated with autophagy-related signaling. Here we found that 20 μM diphenyl phosphate (DPHP) could promote NETs formation via assessing markers of NETs and the morphological changes. Concurrently, flow cytometry and western blot analysis revealed that DPHP-triggered NETs formation was associated with reactive oxygen species (ROS) burst and activation of extracellular signal-regulated kinase (ERK) and p38. Additionally, the results revealed that autophagy occurred in DPHP-triggered NETs formation, manifested as enhanced LC3B protein expressions and reduced p62 protein expressions. Mechanism dissection revealed that inhibition of autophagy by 3-methyladenine (3-MA) alleviated the ROS burst and subsequent NETosis caused by DPHP. Conversely, autophagy enhancer Rapamycin (Rapa) augmented the above effects of DPHP, including the generation of ROS and NETosis. Collectively, these data suggested ERK/p38 signaling and ROS burst might be an important cause of DPHP-triggered NETs formation, while suppression of excessive autophagy could rescue these actions. These observations provided a theoretical basis for the treatment and prevention of OPFRs-induced immunotoxicity.

Cadmium and molybdenum co-induce pyroptosis and apoptosis by PTEN/PI3K/AKT axis in the liver of ducks

Cadmium (Cd) and excessive molybdenum (Mo) have adverse impacts on animals. However, the hepatotoxicity co-induced by Cd and Mo in ducks has not been fully elucidated. In order to explore...

Exposure to imidacloprid induce oxidative stress, mitochondrial dysfunction, inflammation, apoptosis and mitophagy via NF-kappaB/JNK pathway in grass carp hepatocytes

Imidacloprid (IMI) is a neonicotinoid compound widely used in agriculture production, causing surface water pollution and threatening non-target organisms. The aim of this study was to analyze the effects of IMI on grass carp (Ctenopharyngodon idellus) liver cell (L8824) injury. The L8824 cells were exposed to different doses of IMI (65 mg/L, 130 mg/L and 260 mg/L) for 24 h. Our results demonstrated that exposure IMI significantly suppressed the activity of anti-oxidant enzymes (SOD, CAT and T-AOC) and accumulated oxidase (MDA) levels, and promoting reactive oxygen species (ROS) generation in L8824 cells. Additionally, mitochondrial membrane potential (ΔΨ m), mitochondria-derived ROS and ATP content and the MitoTracker Green indicated that IMI aggravated mitochondrial dysfunction, thereby inducing inflammation and enhancing pro-inflammatory genes (NF-kappaB, TNFα, IL-1β and IL-6) expressions. However, the addition of 2 mM N-acetyl-l-cysteine (NAC) can reverse these adverse effects of high-dose IMI- induced. Hence, ROS is the main factor of IMI-induced mitochondrial dysfunction and inflammation. We further found that exposure to IMI induced apoptosis, which is characterized by promoting release of cytochrome c (Cyt-C), and increasing the expression of Bcl-2-Associated X (BAX), cysteinyl aspartate specific proteinases (Caspase 9 and 3), decreasing Bcl-2 level. Immunofluorescent staining, qRT-PCR and Western Blot results indicated that IMI exposure also activated mitophagy, which was demonstrated by the expression of mitophagy-related genes (BNIP3, LC3B and P62). Conversely, scavenging JNK by SP600125(10 μM) alleviated the expression of mitochondrial apoptosis and mitophagy-related gene induced by high-dose IMI. Therefore, these results of study demonstrated that IMI-induced oxidative stress to regulate mitochondrial dysfunction, thus causing inflammation, mitochondrial apoptosis and mitophagy in grass carp hepatocytes through NF-kappaB/JNK pathway.

Heat shock proteins took part in oxidative stress-mediated inflammatory injury via NF-κB pathway in excess manganese-treated chicken livers

Manganese (Mn) is an essential metal in humans and animals. However, excess Mn entered environment due to the wide application of Mn in industry and agriculture, and became an environmental pollutant. Exposure to high doses of Mn is toxic to humans and animals (including chickens). Liver is a target organ of Mn poisoning. Nevertheless, there were few studies on whether Mn poisoning damages chicken livers and poisoning mechanism of Mn in chicken livers. Herein, the aim of this study was to explore if oxidative stress, heat shock proteins (HSPs), and inflammatory response were involved in the mechanism of Mn poisoning-caused damage in chicken livers. A chicken Mn poisoning model was established. One hundred and eighty chickens were randomly divided into one control group (containing 127.88 mg Mn kg^-1) and three Mn-treated groups (containing 600, 900, and 1800 mg Mn kg^-1, respectively). Histomorphological structure was observed via microstructure and ultrastructure. Spectrophotometry was used to detect total antioxidant capacity (T-AOC) and inducible nitric oxide synthase (iNOS) activity, as well as nitric oxide (NO) content. And qRT-PCR was performed to measure mRNA expression of inflammatory genes (nuclear factor kappa B (NF-κB), tumor necrosis factor α (TNF-α), cyclooxygenase-2 (COX-2), prostaglandin E2 (PGE2), and iNOS) and heat shock protein (HSP) genes (HSP27, HSP40, HSP60, HSP70, and HSP90). Multivariate correlation analysis, principal component analysis, and cluster analysis were used to demonstrate the reliability of mechanism of Mn poisoning in our experiment. The results indicated that excess Mn led to inflammatory injury at three contents and three time points. Meanwhile, we found that NO content, iNOS activity, and NF-κB, TNF-α, COX-2, PGE2, and iNOS mRNA expression increased after Mn treatment, meaning that exposure to Mn induced inflammatory response via NF-κB pathway in chicken livers. Moreover, excess Mn decreased T-AOC activity, indicating that Mn exposure caused oxidative stress. Furthermore, mRNA expression of above five HSP genes was up-regulated during Mn exposure. Oxidative stress triggered the increase of HSPs and the increase of HSPs mediated inflammatory response induced by Mn. In addition, there were time- and dose-dependent effects on Mn-caused chicken liver inflammatory injury. Taken together, HSPs participated in oxidative stress-mediated inflammatory damage caused by excess Mn in chicken livers via NF-κB pathway. For the first time, we found that oxidative stress can trigger HSP70 and HSPs can trigger poisoning-caused inflammatory damage, which needs to be further explored. This study provided a new insight into environmental pollutants and a reference for further study on molecular mechanisms of poisoning.

Microplastics pollution and risk assessment in water bodies of two nature reserves in Jilin Province: Correlation analysis with the degree of human activity

As a new type of environmental pollutant, microplastics (MPs) are widely present in freshwater systems. The ecological risks of MPs pollution in nature reserves and the correlation between human activities and the abundance of MPs are still unclear. This is the first survey of MPs in freshwater systems in Northeast China. The content and composition of MPs in 19 water samples were investigated in Chagan lake and Xianghai. The abundance of MPs samples in Chagan Lake averages 3.61 ± 2.23 particles/L, and in Xianghai averages 0.29 ± 0.11 particles/L. The main types of MPs in Chagan Lake are PA (23.7%) and PS (53.2%); while in Xianghai are PP (56%) and PS (32.7%). Foam, white and <1 mm are the main shapes, colors and sizes of Chagan Lake MPs, while of Xianghai are film, transparent and <1 mm. This may be related to the well-developed tourism and fishing industry (foam and fishing line) in Chagan Lake and aquaculture in Xianghai (foam and plastic film). The hazard index (HI) indicated a Hazard Level III for MPs pollution in Chagan Lake and Xianghai. Pollution load index (PLI) and potential ecological risk index (RI) indicate that the pollution risk of MPs polymers in the two places is relatively small. The degree of human activity is quantified to analyze the correlation of MPs abundance. The quantified scores are positively correlated with the abundance of MPs at different sampling points (Chagan lake: P < 0.05, 95% Cl; Xianghai: P < 0.05, 95% Cl).

Selenium-Alleviated Testicular Toxicity by Modulating Inflammation, Heat Shock Response, and Autophagy Under Oxidative Stress in Lead-Treated Chickens

Lead (Pb), a toxic pollutant, is toxic to the testis. However, biological events during testicular Pb poisoning were not well understood. Selenium (Se) has the ability to antagonize Pb toxicity. The purpose of this research was to clarify the relief mechanism of Se on testicular toxicity of Pb from the perspective of oxidative stress, inflammation, heat shock response, and autophagy in a chicken model. Sixty male Hyline chickens (7-day-old) were randomly assigned into four groups. The feeding program consisted of a commercial diet, a Se-supplemented diet (1 mg kg^-1 Se), a Pb-supplemented diet (350 mg L^-1 Pb), and a Se- and Pb-supplemented diet, respectively. On the 12th week, serums were collected to measure testosterone level and testes were removed to determine testis weight, histological structure, Pb and Se concentrations, oxidative stress indicators, and mRNA and protein expression of inflammatory cytokines, heat shock proteins, and autophagy-related genes. The results showed that Pb poisoning changed the histological structure of testes; decreased serum testosterone level, testis weight, catalase, glutathione-s-transferase, and total antioxidative capacity activities; increased hydrogen peroxide content; inhibited interleukin (IL)-2 and mammalian target of rapamycin expression; and promoted IL-4, IL-12β, heat shock proteins, Beclin 1, Dynein, autophagy-related proteins 5, light chain 3 (LC3)-I, and LC3-II expression in the testes of chickens. Se intervention mitigated the aforementioned alterations induced by Pb. In conclusion, Pb led to oxidative stress, which triggered inflammation, heat shock response, and autophagy. Se administration mitigated testicular toxicity of Pb mainly by mitigating oxidative stress in male chickens.

Morin alleviates aflatoxin B1-induced liver and kidney injury by inhibiting heterophil extracellular traps release, oxidative stress and inflammatory responses in chicks

Aflatoxin B1 (AFB1) is a secondary metabolite produced by Aspergillus flavus and parasitic aspergillus, mainly existing in cereals, peanuts, corn, and other crops, which seriously endanger poultry, human health, and environment. Morin, a flavonoid compound extracted from moraceae plants, possess antioxidant, antibacterial, and anti-inflammatory effects. However, whether morin has a protective effect on AFB1-induced liver and kidney damage in chicks has not been specifically reported. In this study, we mainly confirmed the protective effect of morin on AFB1-induced liver and kidney damage in chicks and clarified its mechanism. It was found that morin can significantly reduce the liver biochemical indicators of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and kidney indicators of creatinine (CRE) and urea nitrogen (BUN) levels. Meanwhile, histopathological examination showed that morin effectively relieved AFB1-caused liver damage, including hepatocyte disruption, swelling, and inflammatory cell infiltration, and effectively relieved kidney damage, including renal cell necrosis, exfoliation, and vacuolization. Further investigation of its mechanism demonstrated that morin significantly inhibited AFB1-induced heterophil extracellular traps (HETs) release, and decreased the level of malondialdehyde (MDA) but increased the levels of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) in vivo. Moreover, quantitative real-time PCR (qRT-PCR) analysis showed that morin also significantly decreased AFB1-induced mRNA expressions of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-1β (IL-1β), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), caspase-1, caspase-3, and caspase-11. In conclusion, all results confirmed that morin could protect AFB1-caused liver and kidney damage by inhibiting HETs release, regulating oxidative stress, and inhibiting inflammatory response, suggesting that morin can be utilized as a potential drug for prevention and treatment of aflatoxicosis in poultry breeding industry.

Energy metabolism disorder mediated ammonia gas-induced autophagy via AMPK/mTOR/ULK1-Beclin1 pathway in chicken livers

Ammonia gas is a well-known environmental pollution gas, threatening human health. Ammonia gas is also one of the most harmful gases to livestock and poultry for many years. Many studies have demonstrated toxic effect of ammonia gas on animal health, such as eyes, respiratory system, and digestive system. However, the effect of ammonia gas toxicity on chicken livers and underlying molecular mechanism remains unclear. In this study, we selected chicken liver as research object and duplicated successfully ammonia gas poisoning model of chickens. 1-day-old Ross-308 broilers were randomly divided into the control group (the low ammonia gas group), and two treatment groups (the middle ammonia gas group and the high ammonia gas group) (3 replicates per group and 12 chickens per replicate). Ammonia gas concentration in the low ammonia gas group was ≤5 mg/m³ during day 1-42. Ammonia gas concentration in the middle group was set as 10 ± 0.5 mg/m³ during day 1-21, and 15 ± 0.5 mg/m³ during day 22-42). Ammonia gas concentration in the high ammonia gas group was set as 20 ± 0.5 mg/m³ during day 1-21, and 45 ± 0.5 mg/m³ during day 22-42. The ultrastructure of chicken livers was observed. The activities of four ATPases (Na⁺K⁺-ATPase, Mg⁺⁺-ATPase, Ca⁺⁺-ATPase, and Ca⁺⁺Mg⁺⁺-ATPase), the expression of twelve energy metabolism-related genes (HK1, HK2, PK, PFK, PDHX, CS, LDHA, LDHB, SDHA, SDHB, avUCP, and AMPK), as well as the expression of ten autophagy-related genes (PI3K, LC3I, LC3II, Beclin1, SQSTM1, mTOR, ULK1, ATG5, ATG12, and ATG13) were measured to explore the effect of ammonia gas on energy metabolism and autophagy in chicken livers. Our results showed that excess ammonia gas induced mitochondrial and autophagic damage in chicken liver tissue cells. Meanwhile, ATPases activities were inhibited and the expression of energy metabolism-related genes changed during ammonia gas treatment, meaning that excess ammonia gas caused energy metabolism disorder. Furthermore, ammonia gas exposure altered the expression of autophagy-related genes, suggesting that ammonia gas treatment caused autophagy in chicken livers. Moreover, ammonia gas-induced AMPK compensatory up-regulation activated autophagy process through inhibiting mTOR and promoting ULK1. In addition. there were dose-dependent and time-dependent effects on all detected indexes in ammonia gas-caused chicken liver cell damage. Taken together, AMPK/mTOR/ULK1-Beclin1 pathway participated in energy metabolism disorder-mediated autophagic injury caused by ammonia gas exposure in chicken livers.

Albicanol antagonizes Cd-induced apoptosis through a NO/iNOS-regulated mitochondrial pathway in chicken liver cells

Cadmium (Cd) induces hepatocyte injury by oxidative stress. Albicanol is a sesquiterpenoid extracted from the medicinal plant Dryopteris fragrans that has previously been shown to exhibit anti-aging and antioxidant activity. In this study, we explored the mechanism of albicanol inhibition of the Cd-induced apoptosis of chicken hepatoma cells (LMH) by treating these cells with CdCl2 (25 μM) and/or albicanol (2.5 × 10-5 μg mL-1) for 24 h. Under Cd treatment, the research results showed that the apoptosis rate markedly increased in LMH cells. In addition, the iNOS activity and NO content increased significantly, which promoted the expressions of genes associated with the mitochondrial apoptosis pathway (Bax, CytC, Caspase-3 and Caspase-9) and inhibited the expression of Bcl-2 in this pathway. However, Cd + albicanol co-treatment significantly reduced the apoptosis rate and the expressions of iNOS and genes associated with the mitochondrial apoptosis pathway (Bax, CytC, Caspase-3 and Caspase-9), and promoted the expression of Bcl-2 in this pathway. In addition, molecular docking supported a link between the albicanol ligand and the iNOS receptor. These results indicated that albicanol can inhibit Cd-induced apoptosis by regulating the NO/iNOS-mediated mitochondrial pathway.

Microglia extracellular traps in Oreochromis niloticus infected with Weissella cibaria

The mechanism of extracellular traps (ETs) is important in the cellular response against bacteria. Thus, in the present study, we describe for the first time the capacity of the Nile tilapia (Oreochromis niloticus) microglia in the formation of ETs in Weissella cibaria in vitro infection. Thus, we evaluated the ultrastructure of the microglia culture and observed the formation of ETs 6 h after stimulation with lipopolysaccharide (LPS) and during the course of infection. Our results shed light on the mechanism of formation of ETs in the microglia of teleost fish and the ability of W. cibaria to infect these cells.

Akt1/mTORC1 signaling modulates adaptive immune response of Nile tilapia by promoting lymphocyte activation and proliferation

Serving as a significant signaling molecule, RAC-alpha serine/threonine-protein kinase (Akt1) plays indispensable roles in cell cycle, growth, survival, metabolism, as well as immune response. However, how Akt1 regulates adaptive immune response in early vertebrate, especially the teleost, is largely unknown. Here, using a Nile tilapia Oreochromis niloticus model, we investigated the regulatory role of Akt1 in adaptive immunity of teleost. Both sequence and structure of the O. niloticus Akt1 (OnAkt1), were evolutionarily conserved comparing with the counterparts from other vertebrates. mRNA of OnAkt1 was widely expressed in lymphoid organs/tissues of Nile tilapia, with relative higher level in PBL. After Nile tilapia was infected by Aeromonas hydrophila, both transcription and phosphorylation levels of OnAkt1 were obviously elevated in spleen lymphocytes at the adaptive immune stage, suggesting Akt1 participated in primary adaptive immune response of Nile tilapia. Furthermore, OnAkt1 transcript or phosphorylation was dramatically augmented after spleen lymphocytes were activated by T cell specific mitogen PHA or lymphocyte agonist PMA. More critically, inhibition of Akt1 by specific inhibitor crippled the activation of downstream mTORC1 signaling, and impaired the up-regulation of T cell activation markers CD44, IFN-γ and CD122 in spleen lymphocytes upon PHA-induced T cell activation. Meanwhile, blockade of Akt1-activated mTORC1 signaling also decreased the frequency of BrdU⁺ lymphocytes during A. hydrophila infection, indicating the critical role of Akt1 in regulating lymphocyte proliferation of Nile tilapia. Together, our results demonstrated that Akt1 modulated adaptive immune response of Nile tilapia by promoting lymphocyte activation and proliferation via mTORC1 signaling. Our study enriched the regulatory mechanism of lymphocyte-mediated adaptive immunity in teleost, and thus provided novel insights into the evolution of adaptive immune system.

Silencing miRNA-1297 suppresses the invasion and migration of prostate cancer cells via targeting modulation of PTEN and blocking of the AKT/ERK pathway

Phosphatase and tensin homolog (PTEN) loss is a major contributing factor of prostate cancer (PC). miRNA-1297 was reported to serve role in various cancer types; however, the potential roles of miRNA-1297 in PC had not been investigated. In the present study, tumor and adjacent tissues were collected from patients with PC. The gene expression level of miRNA-1297 was measured via polymerase chain reaction. Results indicated that the miRNA-1297 was overexpressed in tumor tissues from PC patients and in PC cell lines. miRNA-1297 also contributed toward the progression of PC. PTEN was confirmed as the direct target of miRNA-1297 and bound with miRNA-1297 via four binding sites. The miRNA-1297 level was negatively associated with the PTEN level. Silencing miRNA-1297 or overexpression of PTEN significantly inhibited the cell migration and invasion. In addition, the AKT/ERK pathway was also inhibited following silencing of miRNA-1297 or overexpression of PTEN. Taken together, the results indicated that silencing miRNA-1297 exerted inhibitory effects on the invasion and migration of PC cells via modulating PTEN and blocking of the AKT/ERK pathway. The results of the present study provided a novel strategy for treatment of prostate cancer cells.

Influence of chronic stress on the mechanism of the cytotoxic system in common carp (Cyprinus carpio)

Aquaculture conditions expose fish to internal and environmental stressors that increase their susceptibility to morbidity and mortality. The brain accumulates stress signals and processes them according to the intensity, frequency duration and type of stress, recruiting several brain functions to activate the autonomic or limbic system. Triggering the autonomic system causes the rapid release of catecholamines, such as adrenaline and noradrenaline, into circulation from chromaffin cells in the head kidney. Catecholamines trigger blood cells to release proinflammatory and regulatory cytokines to cope with acute stress. Activation of the limbic axis stimulates the dorsolateral and dorsomedial pallium to process emotions, memory, behaviour and the activation of preoptic nucleus‐pituitary gland‐interrenal cells in the head kidney, releasing glucocorticoids, such as cortisol to the bloodstream. Glucocorticoids cause downregulation of various immune system functions depending on the duration, intensity and type of chronic stress. As stress persists, most immune functions, with the exception of cytotoxic functions, overcome these effects and return to homeostasis. The deterioration of cytotoxic functions during chronic stress appears to be responsible for increased morbidity and mortality.

Dietary selenomethionine ameliorates lipopolysaccharide-induced renal inflammatory injury in broilers via regulating the PI3K/AKT pathway to inhibit necroptosis

Selenomethionine (SeMet) has antioxidant and anti-inflammatory effects, as a widely used organic Se source in food supplements, and its inhibitory effect on the prevention and treatment of renal inflammatory injury is unclear. Here, in order to explore the protective effect of SeMet on kidney tissue of broilers and determine its potential molecular mechanism, we took broilers as the research object, lipopolysaccharide (LPS) was used as the source of stimulation, and the model was established by adding SeMet to the diet. The histopathological observation indicated that SeMet alleviated the LPS-induced characteristic changes of renal inflammatory injury. Besides, SeMet inhibited LPS-induced PI3K, AKT, caspase 8 and IκB-α downregulation, the necroptosis marker genes (FADD, RIP1, RIP3, MLKL and TNF-α), pro-inflammatory factors (NF-κB, PTGEs, COX-2, iNOS, IL-1β and IL-6) and HSP60, HSP70 and HSP90 overexpression. We concluded that SeMet ameliorates LPS-induced renal inflammatory injury in broilers by inhibiting necroptosis via the regulation of the PI3K/Akt pathway. Thus, we speculated that dietary SeMet may be a potential new strategy for the treatment of renal injury.

Dibutyl phthalate-induced oxidative stress, inflammation and apoptosis in grass carp hepatocytes and the therapeutic use of taxifolin

The widespread use of plastic products has led to the widespread presence of plasticizers in the environment. As a common environmental pollutant, research on plasticizer toxicity is insufficient in fish cells. In particular, research on the toxicity of dibutyl phthalate (DBP) in grass carp hepatocyte lines is insufficient. To further explore these mechanisms, we treated grass carp hepatocytes with 300 μM DBP, a common plasticizer, for 24 h, and hepatocytes were also treated with 1 μM taxifolin (TAX), an antioxidant, for 24 h to study its antagonistic effect on DBP. After DBP exposure, oxidative stress levels and inflammation in hepatocytes increased, and the mRNA and protein expression of apoptosis-related markers increased significantly, leading to hepatocyte apoptosis. Moreover, AO/EB staining, Hoechst staining and flow cytometry also showed that the level of apoptotic cells increased after DBP exposure. Notably, both TAX pretreatment and TAX simultaneous treatment alleviated oxidative stress, increased inflammatory factor levels and apoptosis induced by DBP. In comparison, the effect of simultaneous TAX treatment was better than that of TAX pretreatment. Our results showed that TAX alleviates DBP-induced apoptosis in grass carp hepatocytes through oxidative stress and inflammation, and TAX pretreatment and simultaneous treatment exhibited specific effects. Specifically, simultaneous treatment had a better effect. Our study assessed the toxicity of DBP in grass carp hepatocytes and provided a theoretical and research basis for the in vivo study of animal models in the future. The innovation of this study involves the exploration of the interaction between DBP and TAX for the first time. This study may enrich knowledge regarding the theoretical mechanism of DBP toxicity in fish hepatocytes and propose methods address DBP toxicity.

Cadmium and molybdenum co-induce pyroptosis via ROS/PTEN/PI3K/AKT axis in duck renal tubular epithelial cells

Cadmium (Cd) and excess molybdenum (Mo) are harmful to animals, but the combined nephrotoxic mechanism of Cd and Mo in duck remains poorly elucidated. To assess joint effects of Cd and Mo on pyroptosis via ROS/PTEN/PI3K/AKT axis in duck renal tubular epithelial cells, cells were cultured with 3CdSO₄·8H₂O (4.0 μM), (NH₄)₆Mo₇O₂₄·4H₂O (500.0 μM), MCC950 (10.0 μM), BHA (100.0 μM) and combination of Cd and Mo or Cd, Mo and MCC950 or Cd, Mo and BHA for 12 h, and the joint cytotoxicity was explored. The results manifested that toxicity of non-equitoxic binary mixtures of Mo and Cd exhibited synergic interaction. Mo or/and Cd elevated ROS level, PTEN mRNA and protein levels, and decreased PI3K, AKT and p-AKT expression levels. Simultaneously, Mo or/and Cd upregulated ASC, NLRP3, NEK7, Caspase-1, GSDMA, GSDME, IL-18 and IL-1β mRNA levels and Caspase-1 p20, NLRP3, ASC, GSDMD protein levels, increased the percentage of pyroptotic cells, LDH, NO, IL-18 and IL-1β releases as well as relative conductivity. Moreover, NLRP3 inhibitor MCC950 and ROS scavenger BHA could ameliorate the above changed factors induced by Mo and Cd co-exposure. Collectively, our results reveal that combination of Mo and Cd synergistically cause oxidative stress and trigger pyroptosis via ROS/PTEN/PI3K/AKT axis in duck tubular epithelial cells.

Cadmium induced inflammation and apoptosis of porcine epididymis via activating RAF1/MEK/ERK and NF-κB pathways

Cadmium (Cd) was a serious heavy metal pollutant. Cd exposure will cause damage to reproductive organs. It was largely unknown whether Cd exposure caused inflammation and apoptosis in epididymis. In this study, we established models of Cd exposure in swine, and the apoptotic level of epididymis was detected by in situ TUNEL fluorescence staining assay, the results showed that Cd exposure significantly increased TUNEL-apoptosis index. Furthermore, the results of qRT-PCR and Western blot showed that Cd activated the proto-oncogenic serine/threonine kinase-1 (RAF1)/mitogen-activated protein kinase (MEK)/extracellular signal-regulated kinase (ERK) signal pathway (RAF1/MEK/ERK) and led to the subsequent up-regulation of the nuclear factor-κB (NF-κB), tumor necrosis factor α (TNF-α), cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), interleukin-1β (IL-1β), interleukin-6 (IL-6), interleukin-8 (IL-8), caused inflammation in epididymis. NF-κB inflammation pathway also mediated the tumor protein P53 (P53) and indirectly activated the Cytochrome c (Cytc), B-cell lymphoma-2 (Bcl-2), Bcl-2-Associated X protein (Bax), Caspase 3, Caspase 9. In summary, we believed that the RAF1/MEK/ERK pathway came into play in the apoptosis of epididymal tissues exposed to Cd by activating the NF-κB Inflammation pathway, followed by activation of the mitochondrial apoptotic pathway. This study provides more abundant data for exploring the reproductive toxicity of Cd.

DEHP-induce damage in grass carp hepatocytes and the remedy of Eucalyptol

The wide application of plastic products led to the wide exposure of plasticizer in environment. As a new environmental pollutant, plasticizers' toxicity researches were far from enough in fish. In order to further explore these mechanisms, we used Diethylhexyl phthalate (DEHP), a common plasticizer, treated the grass carp hepatocytes, and selected Eucalyptol (EUC) to study its antagonistic effect on DEHP. The results showed that after DEHP exposure, oxidative stress level and inflammation in grass carp hepatocytes were increased, and then mRNA and protein expression of apoptosis related markers were increased significantly, leading to hepatocytes apoptosis. Moreover, AO/EB staining and Hoethst staining also showed that the number of apoptotic cells increased after DEHP exposure. It should be noted that both EUC pretreatment and EUC simultaneous treatment could alleviate the oxidative stress, levels of inflammatory factors and apoptosis induced by DEHP. In comparison, the effect of EUC simultaneous treatment was better. Our results showed that DEHP induced apoptosis in grass carp hepatocytes through oxidative stress and inflammation, while EUC could alleviate apoptosis by reducing oxidative stress and inflammation caused by DEHP. The innovation of this study was to explore the interaction between DEHP and EUC for the first time. This study found that DEHP could cause apoptosis in grass carp hepatocytes through oxidative stress and inflammation; EUC had a good antagonistic effect on a series of damage in grass carp hepatocytes caused by DEHP, and EUC pretreatment and simultaneous treatment had a certain effect, among which, simultaneous treatment had a better effect. This study enriched the theoretical mechanism of DEHP toxicity in fish hepatocytes, and put forward the methods to solve the toxicity of DEHP.