Atrazine Triggers Mitochondrial Dysfunction and Oxidative Stress in Quail ( Coturnix C. coturnix) Cerebrum via Activating Xenobiotic-Sensing Nuclear Receptors and Modulating Cytochrome P450 Systems

Soybean isoflavones protect dopaminergic neurons from atrazine damage by inhibiting VPS13A to increase autophagy

Atrazine (ATR) is a broad-spectrum herbicide with dopaminergic (DAergic) neurotoxicity that can cause Parkinson's disease (PD)-like syndrome. However, research on preventing ATR neurotoxicity is unclear. Soybean isoflavones (SI) are natural plant compounds with neuroprotective effects. In this study, we found that pre-administration of SI prevented ATR-induced motor dysfunction and substantia nigra pathological damage. RNA-seq datasets revealed that the neuroprotective effect of SI was related to autophagy. Further experiments showed that ATR inhibited autophagy, and SI pre-administration before ATR exposure increased autophagy. In addition, single-cell data analysis combined with experimental verification showed that the gene VPS13A was a key target by which SI protected DAergic neurons from ATR damage, and inhibiting VPS13A-induced autophagy was a key mechanism enabling SI prevention of neuron damage. Together, these findings provide new insights for the development of preventive measures and intervention targets protecting against functional neuronal damage caused by ATR and other herbicides.

Effects of environmental relevant concentrations of acetochlor on growth, hematology, serum biochemistry and histopathology of Japanese quail

Acetochlor is frequently applied to various food crops in agriculture sector, and long-term exposure can cause significant endocrine-disrupting effects in exposed animals including impacts on human health. This study aimed to evaluate the effects of acetochlor on the growth, hematology, serum biochemistry, and histopathological alterations in Japanese quail. Eighty male quail were obtained and divided into four groups (A-D) and given acetochlor orally for the period of 45 days. Group A was served as the control, while groups B, C, and D received 20mg/kg, 30mg/kg, and 40mg/kg acetochlor, respectively. The study found that Japanese quail administered higher doses of acetochlor exhibited reduced frequency of crowing and foam production. The results showed that increased concentrations of acetochlor led to adverse effects on the growth parameters of Japanese quail. Hematology analysis indicated that birds exposed to higher concentrations of acetochlor experienced a significant decrease in red blood cell count, hemoglobin concentration, hematocrit (HCT), mean corpuscular volume (MCV) and mean corpuscular hemoglobin concentration (MCHC), along with a significant increase in white blood cell count compared to the control group. Additionally, higher concentrations of acetochlor led to a significant increase in various serological indices including urea, creatinine, alanine aminotransferase (ALT), and aspartate aminotransferase (AST), while the values of total proteins, albumin, and plasma proteins declined. The histopathology results of treated Japanese quail exposed to higher concentrations of acetochlor showed a range of pathological lesions in the testes, heart, and brain. The study concluded that even low concentrations of acetochlor can cause slight to significant changes in Japanese quail, affecting their physical, hematological, histopathological and serum biochemical parameters.

Fumonisin B1 induces endoplasmic reticulum damage and inflammation by activating the NXR response and disrupting the normal CYP450 system, leading to liver damage in juvenile quail

Fumonisin B1 (FB1) is a mycotoxin affecting animal health through the food chain and has been closely associated with several diseases such as pulmonary edema in pigs and diarrhea in poultry. FB1 is mainly metabolized in the liver. Although a few studies have shown that FB1 causes liver damage, the molecular mechanism of liver damage is unclear. This study aimed to evaluate the role of liver damage, nuclear xenobiotic receptor (NXR) response and cytochrome P450 (CYP450)-mediated defense response during FB1 exposure. A total of 120 young quails were equally divided into two groups (control and FB1 groups). The quails in the control group were fed on a normal diet, while those in the FB1 group were fed on a quail diet containing 30 mg/kg for 42 days. Histopathological and ultrastructural changes in the liver, biochemical parameters, inflammatory factors, endoplasmic reticulum (ER) factors, NXR response and CYP450 cluster system and other related genes were examined at 14 days, 28 days and 42 days. The results showed that FB1 exposure impaired the metabolic function and caused liver injury. FB1 caused ER stress and decreased adenosine triphosphatease activity, induced the expression of inflammation-related genes such as interleukin 6 and nuclear factor kappa-B, and promoted inflammation. In addition, FB1 disrupted the expression of multiple CYP450 isoforms by activating nuclear xenobiotic receptors (NXRs). The present study confirms that FB1 exposure disturbs the homeostasis of cytochrome P450 systems (CYP450s) in quail liver by activating NXR responses and thereby causing liver damage. This study's findings provide insight into the molecular mechanisms of FB1-induced hepatotoxicity.

Single and mixture exposure to atrazine and ciprofloxacin on Clarias gariepinus antioxidant defense status, hepatic condition and immune response

Atrazine (ATRA) and ciprofloxacin (CPRO) are widely detected, persistent and co-existing aquatic pollutants. This study investigated effects of 14-day single and joint ATRA and CPRO exposure on juvenile Clarias gariepinus. Standard bioassay methods were used to determine responses of oxidative stress, hepatic condition, and immunological biomarkers on days 7 and 14. Seven groups were used: Control, CPROEC, CPROSubl, ATRAEC, ATRASubl, CPROEC+ATRAEC, and CPROSubl+ATRASubl. The test substances caused decreased activity of superoxide dismutase, catalase, and glutathione peroxidase. Lipid peroxidation was elevated, especially in CPRO-ATRA mixtures. Serum aminotransferases (ALT, and AST), and alkaline phosphatase activity increased significantly. Total protein, albumin, total immunoglobulin, and respiratory burst decreased significantly. Therefore, single and joint exposure to CPRO and ATRA poses adverse consequences on aquatic life.

Acute atrazine intoxication in heifers: Case report and toxicological studies

Atrazine is a triazine organochloride herbicide, frequently used in different agricultural activities. Rare acute intoxication with atrazine is reported in production animals, and its metabolism in mammals is unknown. We report a spontaneous case of atrazine acute intoxication in 16.1% animals of a 168-beef heifer herd exposed to the herbicide at a farm located in Buenos Aires province, Argentina. Affected heifers showed different neurological signs and died suddenly, similar to the previous natural atrazine intoxication report. During autopsy, no gross lesions were observed. Different body fluids and tissues samples were collected during postmortem examination. No relevant histopathological findings were observed. High levels of atrazine and its metabolites were detected in different fluids and tissues by ultra-liquid chromatography high performance coupled to triple quadrupole mass spectrometry. These findings suggest ruminal or hepatic metabolization of atrazine in the exposed cattle. This is the first report of quantification and distribution of atrazine and its metabolites in intoxicated mammals providing relevant information for diagnostic purposes.

Exposure to toxicologically relevant atrazine concentrations impair the glycolytic function of mouse Sertoli cells through the downregulation of lactate dehydrogenase

Atrazine (ATZ), a widely used herbicide with potent endocrine-disrupting properties, has been implicated in hormonal disturbances and fertility issues. Sertoli cells (SCs) play a crucial role in providing mechanical and nutritional support of spermatogenesis. Herein, we aimed to study the effects of environmentally relevant ATZ concentrations on the nutritional support of spermatogenesis provided by SCs. For that, mouse SCs (TM4) were exposed to increasing ATZ concentrations (in μg/L: 0.3, 3, 30, 300, or 3000). After 24 h, cellular proliferation and metabolic activity were assessed. Mitochondrial activity and endogenous reactive oxygen species (ROS) production were evaluated using JC-1 and CM-H2DCFDA probes, respectively. We also analyzed protein levels of lactate dehydrogenase (LDH) using Western Blot and live cells glycolytic function through Seahorse XF Glycolysis Stress Test Kit. ATZ exposure decreased the activity of oxidoreductases in SCs, suggesting a decreased metabolic activity. Although ATZ is reported to induce oxidative stress, we did not observe alterations in mitochondrial membrane potential and ROS production across all tested concentrations. When we evaluated the glycolytic function of SCs, we observed that ATZ significantly impaired glycolysis and the glycolytic capacity at all tested concentrations. These results were supported by the decreased expression of LDH in SCs. Overall, our findings suggest that ATZ impairs the glycolytic function of SCs through LDH downregulation. Since lactate is the preferential energetic substrate for germ cells, exposure to ATZ may detrimentally impact the nutritional support crucial for spermatogenesis, hinting for a relationship between ATZ exposure and male infertility.

The ROS/SIRT1/STAR axis as a target for melatonin ameliorating atrazine-induced mitochondrial dysfunction and steroid disorders in granulosa cells

The granulosa cells (GCs) of birds are essential for the reproduction and maintenance of populations in nature. Atrazine (ATR) is a potent endocrine disruptor that can interfere with reproductive function in females and Diaminochlorotriazine (DACT) is the primary metabolite of ATR in the organism. Melatonin (MT) is an endogenous hormone with antioxidant properties that plays a crucial role in development of animal germ cells. However, how ATR causes mitochondrial dysfunction, abnormal secretion of steroid hormones, and whether MT prevents ATR-induced female reproductive toxicity remains unclear. Thus, the purpose of this study is to investigate the protective effect of MT against ATR-induced female reproduction. In the present study, the GCs of quail were divided into 6 groups, as follows: C (Serum-free medium), MT (10 µM MT), A250 (250 µM ATR), MA250 (10 µM MT+250 µM ATR), D200 (200 µM DACT) and MD200 (10 µM MT+200 µM DACT), and were cultured for 24 h. The results revealed that ATR prevented GCs proliferation and decreased cell differentiation. ATR caused oxidative damage and mitochondrial dysfunction, leading to disruption of steroid synthesis, which posed a severe risk to GC's function. However, MT supplements reversed these changes. Mechanistically, our study exhibited that the ROS/SIRT1/STAR axis as a target for MT to ameliorate ATR-induced mitochondrial dysfunction and steroid disorders in GCs, which provides new insights into the role of MT in ATR-induced reproductive capacity and species conservation in birds.

Holistic Assessment Based On Hepatocyte Mitochondria: Lycopene Repairs Oxidized mtDNA to Alleviate Mitochondrial Stress Induced by Atrazine

Atrazine (ATZ) is a highly persistent herbicide that harms organism health. Lycopene (LYC) is an antioxidant found in plants and fruits. The aim of this study is to investigate the mechanisms of atrazine-induced mitochondrial damage and lycopene antagonism in the liver. The mice were divided into seven groups by randomization: blank control (Con group), vehicle control (Vcon group), 5 mg/kg lycopene (LYC group), 50 mg/kg atrazine (ATZ1 group), ATZ1+LYC group, 200 mg/kg atrazine (ATZ2 group), and ATZ2+LYC group. The present study performed a holistic assessment based on mitochondria to show that ATZ causes the excessive fission of mitochondria and disrupts mitochondrial biogenesis. However, the LYC supplementation reverses these changes. ATZ causes increased mitophagy and exacerbates the production of oxidized mitochondrial DNA (Ox-mtDNA) and mitochondrial stress. This study reveals that LYC could act as an antioxidant to repair Ox-mtDNA and restore the disordered mitochondrial function caused by ATZ.

Zinc Oxide Nanoparticles and Vitamin C Ameliorate Atrazine-Induced Hepatic Apoptosis in Rat via CYP450s/ROS Pathway and Immunomodulation

Atrazine, as an herbicide, is used widely worldwide. Because of its prolonged persistence in the environment and accumulation in the body, atrazine exposure is a potential threat to human health. The present study evaluated the possible protective effects of zinc oxide nanoparticles and vitamin C against atrazine-induced hepatotoxicity in rats. Atrazine administered to rats orally at a dose of 300 mg/kg for 21 days caused liver oxidative stress as it increased malondialdehyde (MDA) formation and decreased reduced glutathione (GSH) contents. Atrazine induced inflammation accompanied by apoptosis via upregulation of hepatic gene expression levels of NF-κB, TNF-α, BAX, and caspase-3 and downregulation of Bcl-2 gene expression levels. Additionally, it disturbed the metabolic activities of cytochrome P450 as it downregulated hepatic gene expression levels of CYP1A1, CYP1B1, CYP2E1. The liver function biomarkers were greatly affected upon atrazine administration, and the serum levels of AST and ALT were significantly increased, while BWG%, albumin, globulins, and total proteins levels were markedly decreased. As a result of the above-mentioned influences of atrazine, histopathological changes in liver tissue were recorded in our findings. The administration of zinc oxide nanoparticles or vitamin C orally at a dose of 10 mg/kg and 200 mg/kg, respectively, for 30 days prior and along with atrazine, could significantly ameliorate the oxidative stress, inflammation, and apoptosis induced by atrazine and regulated the hepatic cytochrome P450 activities. Furthermore, they improved liver function biomarkers and histopathology. In conclusion, our results revealed that zinc oxide nanoparticles and vitamin C supplementations could effectively protect against atrazine-induced hepatotoxicity.

Involvement of the heat shock response (HSR) regulatory pathway in cadmium-elicited cerebral damage

The heat shock response (HSR) is a cellular protective mechanism that is characterized by the induction of heat shock transcription factors (HSFs) and heat shock proteins (HSPs) in response to diverse cellular and environmental stressors, including cadmium (Cd). However, little is known about the relationship between the damaging effects of Cd and the HSR pathway in the chicken cerebrum following Cd exposure. To explore whether Cd exposure elicits cerebral damage and triggers the HSR pathway, chicks were exposed to Cd in the daily diet at different concentrations (35, 70, or 140 mg/kg feed) for 90 days, while a control group was fed the standard diet without Cd. Histopathological examination of cerebral tissue from Cd-exposed chickens showed neuronal damage, as evidenced by swelling and degeneration of neurons, loss of neurons, and capillary damage. Cd exposure significantly increased mRNA expression of HSF1, HSF2, and HSF3, and mRNA and protein expression of three major stress-inducible HSPs (HSP60, HSP70, and HSP90). Moreover, Cd exposure differentially modulated mRNA expression of small HSP (sHSPs), most notably reducing expression of HSP27 (HSPB1). Furthermore, Cd exposure increased TUNEL-positive neuronal apoptotic cells and up-regulated protein expression of caspase-1, caspase-8, caspase-3, and p53, leading to apoptosis. Taken together, these data demonstrate that activation of the HSR and apoptotic pathways by Cd exposure is involved in Cd-elicited cerebral damage in the chicken. Synopsis for the graphical abstract Cadmium (Cd)-induced neuronal damage triggers the heat shock response (HSR) by activating heat shock transcription factors (HSFs) and subsequent induction of major heat shock proteins (notably, HSP60, HSP70, and HSP90). Moreover, Cd exposure activates caspase-1, caspase-8, caspase-3, and p53 protein, thereby resulting in neuronal apoptosis in the chicken brain.

Resveratrol protects against cadmium-induced cerebrum toxicity through modifications of the cytochrome P450 enzyme system in microsomes

BACKGROUND

Cadmium (Cd), known as a vital contaminant in the environment, penetrates the blood-brain barrier and accumulates in the cerebrum. Acute toxicosis of Cd, which leads to lethal cerebral edema, intracellular accumulation and cellular dysfunction, remains to be illuminated with regard to the exact molecular mechanism of cerebral toxicity. Resveratrol (RES), present in the edible portions of numerous plants, is a simply acquirable and correspondingly less toxic natural compound with neuroprotective potential, which provides some theoretical bases for antagonizing Cd-induced cerebral toxicity.

RESULTS

This work was executed to research the protective effects of RES against Cd-induced toxicity in chicken cerebrum. Markedly, these lesions were increased in the Cd group, which also exhibited a thinner cortex, reduced granule cells, vacuolar degeneration, and an enlarged medullary space in the cerebrum. Furthermore, Cd induced CYP450 enzyme metabolism disorders by disrupting the nuclear xenobiotic receptor response (NXRs), enabling the cerebrum to reduce the ability to metabolize exogenous substances, eventually leading to Cd accumulation. Meanwhile, accumulated Cd promoted oxidative damage and synergistically promoted the damage to neurons and glial cells.

CONCLUSION

RES initiated NXRs (especially for aromatic receptor and pregnancy alkane X receptor), decreasing the expression of CYP450 genes, changing the content of CYP450, maintaining CYP450 enzyme normal activities, and exerting antagonistic action against the Cd-induced abnormal response of nuclear receptors. These results suggest that the cerebrum toxicity caused by Cd was reduced by pretreatment with RES. © 2023 Society of Chemical Industry.

DBP induced autophagy and necrotic apoptosis in HepG2 cells via the mitochondrial damage pathway

Phthalate esters (PAEs) are widely present in human tissues and pose significant health risks. In this study, HepG2 cells were treated with 0.0625, 0.125, 0.25, 0.5 and 1 mM Dibutyl phthalate (DBP) for 48 h to investigate mitochondrial toxicity. The results showed that DBP caused mitochondrial damage, autophagy, apoptosis and necroptosis; Transcriptomics analysis identified that MAPK and PI3K were significant factors in the cytotoxic changes induced by DBP; N-Acetyl-L-cysteine (NAC), SIRT1 activator, ERK inhibitor, p38 inhibitor and ERK siRNA treatments counteracted the changes of SIRT1/PGC-1α and Nrf2 pathway-related proteins, autophagy and necroptotic apoptosis proteins induced by DBP. While PI3K and Nrf2 inhibitors exacerbated the changes in SIRT1/PGC-1α, Nrf2-associated proteins and autophagy and necroptosis proteins induced by DBP. In addition, the autophagy inhibitor 3-MA alleviated the increase in DBP-induced necroptosis proteins. These results suggested that DBP-induced oxidative stress activated the MAPK pathway, inhibited the PI3K pathway, which in turn inhibited the SIRT1/PGC-1α pathway and Nrf2 pathway, thereby causing cell autophagy and necroptosis.

Dietary myricetin assuages atrazine-mediated hypothalamic-pituitary-testicular axis dysfunction in rats

Atrazine (ATZ) exposure is associated with reproductive dysfunction in both animals and humans. Myricetin, a flavonoid compound, is well documented for its numerous pharmacological activities. However, the impact of myricetin on the atrazine-mediated dysfunctional hypothalamic-pituitary-testicular axis is not known. This study investigated the role of myricetin on the atrazine-induced alterations in the male reproductive axis in rats orally gavaged with ATZ alone (50 mg/kg) or co-treated with ATZ + myricetin (MYR) at 5, 10, and 20 mg/kg for 30 consecutive days. Myricetin assuaged ATZ-induced reductions in intra-testicular testosterone, serum follicle-stimulating hormone, luteinizing hormone, and testosterone, coupled with decreases in alkaline phosphatase, acid phosphatase, lactate dehydrogenase, and glucose-6-phosphate dehydrogenase activities. Also, MYR treatment improved epididymal sperm count and motility and decreased sperm defects in ATZ-treated rats. Testicular sperm number, daily sperm production, and sperm viability remained unchanged in all treatment groups. Administration of MYR abated ATZ-mediated depletion in antioxidant status, an increase in myeloperoxidase activity, nitric oxide, hydrogen peroxide, malondialdehyde levels, and reactive oxygen and nitrogen species, as well as the histological lesions in the hypothalamus, epididymis, and testes of treated animals. All in all, MYR mitigated atrazine-mediated functional changes in the reproductive axis via anti-inflammatory and antioxidant mechanisms in atrazine-exposed rats. Dietary intake of MYR could be a worthy chemoprotective approach against reproductive dysfunction related to ATZ exposure.

Kynurenine/Aryl Hydrocarbon Receptor Modulates Mitochondria-Mediated Oxidative Stress and Neuronal Apoptosis in Experimental Intracerebral Hemorrhage

Aims: Oxidative stress and neuronal apoptosis play crucial roles in the pathological processes of secondary injury after intracerebral hemorrhage (ICH). Aryl hydrocarbon receptor (AHR), together with its endogenous ligand kynurenine, is known to mediate free radical accumulation and neuronal excitotoxicity in central nervous systems. Herein, we investigate the pathological roles of kynurenine/AHR after ICH. Results: Endogenous AHR knockout alleviated reactive oxygen species accumulation and neuronal apoptosis in ipsilateral hemisphere at 48 h after ICH in mice. The ICH insult resulted in an increase of total and nucleus AHR protein levels and AHR transcriptional activity. Inhibition of AHR provided both short- and long- term neurological benefits by attenuating mitochondria-mediated oxidative stress and neuronal apoptosis after ICH in mice. RhoA-Bax signaling activated mitochondrial death pathway and participated in deleterious actions of AHR. Finally, we reported that exogenous kynurenine aggravated AHR activation and mediated the brain mentioned earlier. Male animals were used in the experiments. Innovation: We show for the first time that kynurenine/AHR mediates mitochondria death and free radical accumulation, at least partially via the RhoA/Bax signaling pathway. Pharmacological antagonists of AHR and kynurenine may ameliorate neurobehavioral function and improve the prognosis of patients with ICH. Conclusion: Kynurenine/AHR may serve as a potential therapeutic target to attenuate mitochondria-mediated oxidative stress and neuronal cells impairment in patients with ICH. Antioxid. Redox Signal. 37, 1111-1129.

Tannic acid through ROS/TNF-α/TNFR 1 antagonizes atrazine induced apoptosis, programmed necrosis and immune dysfunction of grass carp hepatocytes

Atrazine (ATR) is a commonly used triazine herbicide, which will remain in the water source, soil and biological muscle tissue for a long time, threatening the survival of related organisms and future generations. Tannic acid (TAN), a glucosyl compound found in gallnuts, has previously been shown to antagonize heavy metal toxicity, antioxidant activity, and inflammation. However, it is unclear whether TAN can antagonize ATR-induced Grass carp hepatocytes (L8824 cells) cytotoxicity. Therefore, we treated L8824 cells with 3 μg mL^-1 ATR for 24 h to establish a toxic group model. The experimental data of flow cytometry and AO/EB staining together showed that the ratio of apoptosis and necrosis in L8824 cells after ATR exposure was significantly higher than that in the control group. Furthermore, RT-qPCR showed that inflammatory factors (TNF-α, IL-1β, IL-6, INF-γ) were up-regulated and antimicrobial peptides (hepcidin, β-defensin and LEAP2) were induced down-regulated in L8824 cells, leading to immune dysfunction. The measurement results of oxidative stress-related indicators showed that the levels of ROS and MDA increased after ATR exposure, the overall anti-oxidative system was down-regulated. Western blotting confirmed that TNF-α/TNFR 1-related genes were also up-regulated. This indicates that ATR stimulates oxidative stress in L8824 cells, which in turn promotes the binding of TNF-α to TNFR 1. In addition, TRADD, FADD, Caspase-3, P53, RIP1, RIP3 and MLKL were found to be significantly up-regulated by Western blotting and RT-qPCR. Conditioned after ATR exposure compared to controls. It indicates that ATR activates apoptosis and necrosis of TNF-α/TNFR 1 pathway by inducing oxidative stress in L8824 cells. Furthermore, the use of TAN (5 μM) significantly alleviated the toxic effects of ATR on L8824 cells mentioned above. In conclusion, TAN restrains ATR-induced apoptosis, programmed necrosis and immune dysfunction through the ROS/TNF-α/TNFR 1 pathway.

DEHP triggers a damage severity grade increase in the jejunum in quail (Coturnix japonica) by disturbing nuclear xenobiotic receptors and the Nrf2-mediated defense response

As a plasticizer, di-2-ethylhexyl phthalate (DEHP) has been listed as a potential endocrine disruptor by The World Health Organization. The toxicity of DEHP has been widely studied, but its toxicity on the digestive tract of birds has not been clarified. Female quail were treated by gavage with DEHP (250, 500, 750 mg/kg), with the blank and vehicle control groups reserved. The result showed that DEHP raised the damage severity grade, and decreased the ratio of villus length to crypt depth. The content and activity of cytochrome P450 system (CYP450s) were increased by DEHP. DEHP interfered with the transcription of nuclear xenobiotic receptors (NXRs), CYP isoforms, and the nuclear factor-E2-related factor 2 (Nrf2) signaling pathway. This study revealed DEHP could cause the imbalance in CYP450s mediated by NXRs, and then promote Nrf2 mediated antioxidant defense. This study provided new evidence about the mechanisms of DEHP-induced toxic effects on digestive tract.

Tox21-Based Comparative Analyses for the Identification of Potential Toxic Effects of Environmental Pollutants

Chemical pollution has become a prominent environmental problem. In recent years, quantitative high-throughput screening (qHTS) assays have been developed for the fast assessment of chemicals' toxic effects. Toxicology in the 21st Century (Tox21) is a well-known and continuously developing qHTS project. Recent reports utilizing Tox21 data have mainly focused on setting up mathematical models for in vivo toxicity predictions, with less attention to intuitive qHTS data visualization. In this study, we attempted to reveal and summarize the toxic effects of environmental pollutants by analyzing and visualizing Tox21 qHTS data. Via PubMed text mining, toxicity/structure clustering, and manual classification, we detected a total of 158 chemicals of environmental concern (COECs) from the Tox21 library that we classified into 13 COEC groups based on structure and activity similarities. By visualizing these COEC groups' bioactivities, we demonstrated that COECs frequently displayed androgen and progesterone antagonistic effects, xenobiotic receptor agonistic roles, and mitochondrial toxicity. We also revealed many other potential targets of the 13 COEC groups, which were not well illustrated yet, and that current Tox21 assays may not correctly classify known teratogens. In conclusion, we provide a feasible method to intuitively understand qHTS data.

Lycopene ameliorates atrazine-induced pyroptosis in spleen by suppressing the Ox-mtDNA/Nlrp3 inflammasome pathway

Nlrp3 is a vital integration point of diverse extracellular stimuli and cellular stress. However, the inappropriate activation of Nlrp3 results in the progression of autoinflammatory and metabolic disorders. Atrazine, which is used widely in the agricultural sector, is toxic to humans. Herein, this study found that atrazine could induce oxidative stress and the expression of Nfkb and IRF1 in spleen, promoting the ox-mtDNA formation. Also, production and release of ox-mtDNA stimulated the Nlrp3 inflammasome. Lastly, atrazine induced pyroptosis in spleen, mediating the activation of Nlrp3 inflammasome. In addition, lycopene, a kind of carotenoid, is natural bioactive component in fruits and vegetables, which is applied toward reducing oxidative stress. It was found that lycopene could ameliorate the pyroptosis induced by atrazine via the inhibition of ox-mtDNA production. The results also provided evidence that lycopene had a potential role in the prevention of Nlrp3 inflammasome activation by depleting the ox-mtDNA.

DEHP-induced mitophagy and mitochondrial damage in the heart are associated with dysregulated mitochondrial biogenesis

Di(2-ethylhexyl) phthalate (DEHP) is a plasticizer widely used in agricultural and industrial plastic products. Many researchers have demonstrated that DEHP can cause varying degrees of harm to the heart. This research investigated the mechanism by which DEHP causes heart damage in quail. The quail were treated with DEHP (250 mg/kg BW/day, 500 mg/kg BW/day or 750 mg/kg BW/day) for 45 days. The present study suggested that DEHP could cause varying levels of heart damage, including disordered myocardial fiber arrangements, myocardial fiber breakage and myocardial cell swelling. The results showed that DEHP induced mitochondrial damage, such as cavitation lesions and mitochondrial crest breakage. DEHP damaged mitochondria and inhibited nuclear respiratory factor 1 (Nrf1)-mediated mitochondrial biogenesis, which led to mitochondrial damage. DEHP caused oxidative stress in the heart and activated the defense mechanism of the nuclear factor red blood cell 2 related factor 2 (Nrf2) system. DEHP-induced mitophagy was related to a decline in mitochondrial biogenesis and disordered mitochondrial dynamics. The data indicated that DEHP exposure damaged cardiac mitochondria and caused mitophagy and cardiotoxicity. Of note, this study showed that DEHP-induced mitophagy and mitochondrial damage are associated with the dysregulation of mitochondrial biogenesis.

The Role of AhR in the Hallmarks of Brain Aging: Friend and Foe

In recent years, aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor, has been considered to be involved in aging phenotypes across several species. This receptor is a highly conserved biosensor that is activated by numerous exogenous and endogenous molecules, including microbiota metabolites, to mediate several physiological and toxicological functions. Brain aging hallmarks, which include glial cell activation and inflammation, increased oxidative stress, mitochondrial dysfunction, and cellular senescence, increase the vulnerability of humans to various neurodegenerative diseases. Interestingly, many studies have implicated AhR signaling pathways in the aging process and longevity across several species. This review provides an overview of the impact of AhR pathways on various aging hallmarks in the brain and the implications for AhR signaling as a mechanism in regulating aging-related diseases of the brain. We also explore how the nature of AhR ligands determines the outcomes of several signaling pathways in brain aging processes.

Cadmium induced cerebral toxicity via modulating MTF1-MTs regulatory axis

Metal-responsive transcription factor 1 (MTF1) participates in redox homeostasis and heavy metals detoxification via regulating the expression of metal responsive genes. However, the exact role of MTF1 in Cd-induced cerebral toxicity remains unclear. Herein, we explored the mechanism of Cd-elicited cerebral toxicity through modulating MTF1/MTs pathway in chicken cerebrum exposed to different concentrations of Cd (35 mg, 70 mg, and 140 mg/kg CdCl₂) via diet. Notably, cerebral tissues showed varying degrees of microstructural changes under Cd exposure. Cd exposure significantly up-regulated the expression of metal transporters (DMT1, ZIP8, and ZIP10) with concomitant elevated Cd level, as determined by ICP-MS. Cd significantly altered other cerebral biometals concentrations (particularly, Zn, Fe, Se, Cr, Mo, and Pb) and redox balance, resulting in increased cerebral oxidative stress. More importantly, Cd exposure suppressed MTF1 mRNA and nuclear protein levels and its target metal-responsive genes, notably metallothioneins (MT1 and MT2), and Fe and Cu transporter genes (FPN1, ATOX1, and XIAP). Moreover, Cd disrupted the regulation of expression of selenoproteome (particularly, GPxs and SelW), and cerebral Se level. Overall, our data revealed that molecular mechanisms associated with Cd-induced cerebral damage might include over-expression of DMT1, ZIP8 and ZIP10, and suppression of MTF1 and its main target metal-responsive genes as well as several selenoproteins.

Lycopene prevents DEHP-induced hepatic oxidative stress damage by crosstalk between AHR-Nrf2 pathway

Di (2-ethylhexyl) phthalate (DEHP) is a widespread plasticizer that persists in the environment and can significantly contribute to serious health hazards of liver especially oxidative stress injury. Lycopene (LYC) as a carotenoid has recently gained widespread attention because of antioxidant activity. However, the potential mechanism of DEHP-induced hepatotoxicity and antagonism effect of LYC on it are still unclear. To explore the underlying mechanisms of this hypothesis, the mice were given by gavage with LYC (5 mg/kg) and DEHP (500 or 1000 mg/kg). The data suggested that DEHP caused liver enlargement, reduction of antioxidant activity markers, increase of oxidative stress indicators and disorder of cytochrome P450 enzymes system (CYP450s) homeostasis. DEHP-induced reactive oxygen species (ROS) activated the NF-E2-relatedfactor2 (Nrf2) and nuclear xenobiotic receptors (NXRs) system including Aryl hydrocarbon receptor (AHR), Pregnane X receptor (PXR) and Constitutive androstane receptor (CAR). Interestingly, these disorders and injuries were prevented after LYC treatment. Taken together, DEHP administration resulted in hepatotoxicity including oxidative stress injury and disordered CYP450 system, but these alterations might be ameliorated by LYC via crosstalk between AHR-Nrf2 pathway.

The protection of selenium against cadmium-induced mitophagy via modulating nuclear xenobiotic receptors response and oxidative stress in the liver of rabbits

Cadmium (Cd) is a harmful heavy metal that can cause many health problems, while selenium (Se) is an essential nutrient for organisms that can protect them from heavy metal-induced damage. To explore the effects of Se on Cd-induced mitophagy in the liver, forty 3-month-old New Zealand white rabbits (2-2.5 kg), half male and half female, were randomly divided into four groups: the Control group, the Se (0.5 mg/kg body weight (BW)) group, the Cd (1 mg/kg BW) group and the Se+Cd group. After 30 days, the toxicity from Cd in the liver was assessed in terms of the nuclear xenobiotic receptor (NXR) response, oxidative stress and mitophagy. It was found that Cd decreased the activities of CYP450 enzymes and antioxidant enzymes and increased the contents of malondialdehyde (MDA) and hydrogen peroxide (H₂O₂) and also increased the consumption of reduced glutathione (GSH). Moreover, the mRNA levels of NXRs (CAR, PXR, AHR and Nrf2), some mitochondrial function factors (PGC-1α, Sirt1, Sirt3, Nrf1 and TFAM) and mitochondrial fusion factors (Mfn1, Mfn2 and OPA1) were downregulated, but the mRNA levels of other mitochondrial function factors (VDAC1, Cyt C and PRDX3), mitochondrial fission factors (Fis1 and MFF) and those in the PINK1/Parkin-mediated mitophagy pathway (p62, Bnip3 and LC3) were upregulated under Cd exposure. The protein expression levels of Nrf2, SOD2, PGC-1α, PINK1 and Parkin were consistent with the mRNA expression levels in the Cd group. Se alleviated the changes in the abovementioned factors induced by Cd. In conclusion, the results indicate that Cd can cause oxidative stress in rabbit livers by inhibiting NXRs and the antioxidation response leading to mitophagy, and these harmful changes caused by Cd can be alleviated by Se.

Atrazine intoxication in cattle, confirmed by gas chromatography-mass spectrometry

Ten of 40 cows died within 48 h of gaining access to a barn in which various chemicals were stored. Some of the surviving cows exhibited drooling, muscle tremors, and agitation. Postmortem examinations of 2 cows were performed in the field, and revealed nonspecific, moderate-to-severe pulmonary congestion. Liver and rumen contents, each from a different cow, were analyzed using a qualitative, multi-residue GC-MS method validated for the detection of pesticides and other chemical analytes. Using this method, extracts from the liver and rumen content samples were compared to atrazine (neat standard) and matrix-matched, control samples fortified with atrazine. GC-MS analysis detected atrazine at 215 m/z (NIST match >97%) with a retention time of ~13 min in liver and rumen content samples from our case. Detection of atrazine in the samples from the cows in this herd, combined with the clinical history, indicate that atrazine toxicity was the likely cause of clinical signs and death observed in this herd.

Cadmium and molybdenum co-exposure triggers autophagy via CYP450s/ROS pathway in duck renal tubular epithelial cells

Cadmium (Cd) and excessive molybdenum (Mo) are detrimental to animals, but the combined nephrotoxic impacts of Cd and Mo on duck are still unclear. To evaluate the combined impacts of Cd and Mo on autophagy via Cytochrome P450s (CYP450s)/reactive oxygen species (ROS) pathway, duck renal tubular epithelial cells were treated with 3CdSO₄·8H₂O (4.0 μM Cd), (NH₄)₆Mo₇O₂₄·4H₂O (500.0 μM Mo), butylated hydroxy anisole (BHA) (100.0 μM) and combination of Cd and Mo or Cd, Mo and BHA for 12 h, and combined cytotoxicity was investigated. The results indicated that Mo or/and Cd induced CYP1A1, CYP1B1, CYP2C9, CYP3A8 and CYP4B1 mRNA levels, decreased superoxide dismutase (SOD), catalase (CAT) activities and glutathione peroxidase (GSH-Px) content, and increased malondialdehyde (MDA) and hydrogen peroxide (H₂O₂) contents. Besides, Mo or/and Cd elevated the number of autophagosome and microtubule-associated protein light chain 3 (LC3) puncta, upregulated mRNA levels of Beclin-1, LC3A, LC3B, Atg5 and adenosine 5'-monophosphate (AMP)-activated protein kinase α1 (AMPKα-1), inhibited Dynein, p62 and mammalian target of rapamycin (mTOR) mRNA levels, increased Beclin-1 and LC3II/LC3I protein levels. Moreover, the changes of these factors in Mo and Cd co-treated groups were more apparent. Additionally, BHA could efficiently alleviate the changes of above these indicators co-induced by Mo and Cd. Overall, these results manifest Cd and Mo co-exposure may synergistically trigger autophagy via CYP450s/ROS pathway in duck renal tubular epithelial cells.

Neural stem cell-based in vitro bioassay for the assessment of neurotoxic potential of water samples

Intensive agriculture activities, industrialization and growing numbers of wastewater treatment plants along river banks collectively contribute to the elevated levels of neurotoxic pollutants in natural water reservoirs across Europe. We established an in vitro bioassay based upon neural stem cells isolated from the subventricular zone of the postnatal mouse to evaluate the neurotoxic potential of raw wastewater, treated sewage effluent, groundwater and drinking water. The toxic potential of water samples was evaluated employing viability, proliferation, differentiation and migration assays. We found that raw wastewater could reduce the viability and proliferation of neural stem cells, and decreased the neuronal and astrocyte differentiation, neuronal neurite growth, astrocyte growth and cell migration. Treated sewage water also showed inhibitory effects on cell proliferation and migration. Our results indicated that relatively high concentrations of nitrogenous substances, pesticides, mercuric compounds, bisphenol-A, and phthalates, along with some other pollutants in raw wastewater and treated sewage water, might be the reason for the neuroinhibitory effects of these water samples. Our model successfully predicted the neurotoxicity of water samples collected from different sources and also revealed that the incomplete removal of contaminants from wastewater can be problematic for the developing nervous system. The presented data also provides strong evidence that more effective treatments should be used to minimize the contamination of water before release into major water bodies which may be considered as water reservoirs for human usage in the future.

Selenium sources differ in their potential to alleviate the cadmium-induced testicular dysfunction

Cadmium (Cd), a major environmental contaminant, is closely associated with male reproductive health. Selenium (Se) has been recognized as an effective chemo-protectant against Cd toxicity, but the underlying mechanisms remain unclear. The objective of present study was to illustrate the toxic effect of Cd on testis, and then compare the antagonistic effect among different Se sources on growth performance, testicular damage, ion homeostasis, antioxidative potential, and the expression of selenotranscriptome and biosynthetic related factors in Cd-treated chicken. Male chickens were fed with (Ⅰ) Control group: basal diet; (Ⅱ) Cd group: basal diet with 140 mg/kg CdCl₂; (Ⅲ) YSe + Cd group: basal diet with 140 mg/kg CdCl₂ and 3 mg/kg Yeast-Se; (Ⅳ) NSe + Cd group: basal diet with 140 mg/kg CdCl₂ and 1 mg/kg Nano-Se; (Ⅴ) SSe + Cd group: basal diet with 140 mg/kg CdCl₂ and 3 mg/kg Na₂SeO₃. It was observed that different Se treatments dramatically alleviated Cd-induced testicular developmental disorder, ion homeostasis disorder, hormone secretion disorder and oxidative stress. Simultaneously, Se mitigated Cd-induced testicular toxicity by regulating selenoprotein biosynthetic related factors to promote selenoprotein transcription. Finally, this study indicated that dietary supplementation of Yeast-Se produced an acceptable Se form to protect testis from Cd exposure.

Ameliorative effects of resveratrol against cadmium-induced nephrotoxicity via modulating nuclear xenobiotic receptor response and PINK1/Parkin-mediated Mitophagy

Cadmium (Cd) is a toxic pollutant with high nephrotoxicity in the agricultural environment. Resveratrol has been found to have a renoprotective effect but the underlying mechanisms of this have not yet been fully elucidated. The aim of this study is to illustrate the antagonism of resveratrol against Cd-induced nephrotoxicity. A total of 80 birds were divided randomly into 4 groups and treated via diet for 90 days as follows: control group (Con); 400 mg kg-1 resveratrol group (Resv); 140 mg kg-1 Cd group (Cd 140); and 140 mg kg-1 Cd + 400 mg kg-1 resveratrol group (Cd + Resv). It was observed that resveratrol treatment dramatically alleviated Cd-induced histopathological lesions of the kidney. Simultaneously, resveratrol mitigated Cd-induced oxidative stress by reducing MDA and H2O2 production, alleviating GSH depletion and restoring the activity of antioxidant enzymes (T-SOD, Cu-Zn SOD, CAT, GST and GSH-Px). Resveratrol activated NXRs (CAR/PXR/AHR/Nrf2) signaling pathways and exerted antidotal roles by enhancing the phase I and II detoxification systems to relieve oxidative damage. Moreover, resveratrol ameliorated Cd-induced ultrastructural abnormality and mitochondria dysfunction by recovering mitochondrial function-related factors VDAC1, Cyt C and Sirt3 upregulation and Sirt1, PGC-1α, Nrf1 and TFAM transcription restrictions. Resveratrol attenuated Cd-induced excessive mitochondrial fission and promoted mitochondrial fusion, which reversed PINK1/Parkin-mediated mitophagy initiation. Collectively, our findings explicate the potential protection against Cd-induced nephrotoxicity and mitochondria damage.

Di-(2-ethylhexyl) phthalate induced developmental abnormalities of the ovary in quail (Coturnix japonica) via disruption of the hypothalamic-pituitary-ovarian axis

An increasing number of epidemiologic studies show that women have a special exposure profile to phthalates, and the exposures have attracted attention regarding their potential health hazards. Here, we developed a model for studying the ovarian action of di-(2-ethylhexyl) phthalate (DEHP) and its major metabolite monoethylhexyl phthalate (MEHP). In vivo, treatment with DEHP (250, 500, and 1000 mg kg^-1) induced decreased thickness of ovarian granulosa cell layer and mitochondrial damage in quail, caused oxidative stress, interfered with the transcription of hypothalamic-pituitary-ovarian axis (HPOA) steroid hormone-related factors (increased transcription of StAR, 3β-HSD, P450scc, and LH and decreased transcription of 17β-HSD, P450arom, FSH, and ERβ), and blocked the secretion of steroid hormones (decreased FSH, E₂, and T levels and increased LH, P, and PRL levels). In vitro, granulosa cells were cultured with MEHP (50, 100, and 200 μM), activator of PPARγ (rosiglitazone, 50 μM), or antagonist of PPARγ (GW9662, 10 μM) for 24 h and gene and protein expression were analyzed by real time RT-PCR and western blot. Rosiglitazone, like MEHP, significantly decreased mRNA and protein levels of P450arom. Antagonist GW9662 partially blocked the suppression of P450arom by MEHP, suggesting that MEHP acts through PPARγ, but not exclusively. Our model shows that MEHP acts on granulosa cells in quail by stimulating PPARs, which leads to decreased gene and protein expression of P450arom. Therefore, the environmental endocrine disruptor DEHP and its major metabolite MEHP act through a receptor-mediated signaling pathway to inhibit the production of estradiol, interfere with the modulation of HPOA, suppress the synthesis of sex hormones, and cause sex hormone secretion disorders, resulting in severe toxicity in the female reproductive system. A framework for an adverse outcome pathway of DEHP/MEHP-induced ovarian toxicity was constructed, which can facilitate an improved understanding of the mechanism of female reproductive toxicity.

Selenium mitigates cadmium-induced crosstalk between autophagy and endoplasmic reticulum stress via regulating calcium homeostasis in avian leghorn male hepatoma (LMH) cells

Cadmium (Cd) is a toxic heavy metal and widespread in environment and food, which is adverse to human and animal health. Food intervention is a hot topic because it has no side effects. Selenium (Se) is an essential trace element, found in various fruits and vegetables. Many previous papers have described that Se showed ameliorative effects against Cd. However, the underlying mechanism of antagonistic effect of Se against Cd-induced cytotoxicity in avian leghorn male hepatoma (LMH) cells is unknown, the molecular mechanism of Se antagonistic effect on Cd-induced and calcium (Ca²⁺) homeostasis disorder and crosstalk of ER stress and autophagy remain to be explored. In order to confirm the antagonistic effect of Se on Cd-induced LMH cell toxicity, LMH cells were treated with CdCl₂ (2.5 μM) and Na₂SeO₃ (1.25 and 2.5 μM) for 24 h. In this study, Cd exposure induced cell death, disrupted intracellular Ca²⁺ homeostasis and Ca²⁺ homeostasis related regulatory factors, interfered with the cycle of cadherin (CNX)/calreticulin (CRT), and triggered ER stress and autophagy. Se intervention inhibited Cd-induced LDH release and crosstalk of ER stress and autophagy via regulating intracellular Ca²⁺ homeostasis. Moreover, Se mitigated Cd-induced Intracellular Ca²⁺ overload by Ca²⁺/calmodulin (CaM)/calmodulin kinase IV (CaMK-IV) signaling pathway. Herein, CNX/CRT cycle played a critical role for the protective effect of Se on Cd-induced hepatotoxicity. Based on these findings, we demonstrated that the application of Se is beneficial for prevention and alleviation of Cd toxicity.

Assessment of ionic homeostasis imbalance and cytochrome P450 system disturbance in mice during fumonisin B1 (FB1) exposure

Fumonisin B1 (FB1) is a mycotoxin frequently found in agricultural commodities, and poses a considerable risk for human and animal health. The aim of this study was to investigate the toxic effect of FB1 in mice intestine. Male Kunming mice (n = 40) were treated with FB1 diet for 42 days. Histopathological and biochemical analyses, including ion concentrations, transcription of ATPase subunits and mRNA expression of cytochrome P450s (CYP450s) analyses were performed on duodenum, cecum and colon of mice. The results revealed that FB1 caused histological alterations, including partial shedding of villous epithelial cells and inflammatory cell infiltration. Furthermore, a significant change in Na⁺, K⁺ and Ca²⁺ in serum, and the mRNA expression of ATPase subunits and CYP450s in intestinal tracts were observed in FB1-exposed mice. Our results suggested that FB1 exposure induce histopathological injury via disrupting CYP isoforms transcription and triggering ion homeostasis imbalance in mice intestinal tracts.

`Cadmium induced cardiac inflammation in chicken (Gallus gallus) via modulating cytochrome P450 systems and Nrf2 mediated antioxidant defense

Cadmium (Cd) has been implicated in the pathogenesis of inflammation, myocardial infarction, angiocardiopathy, even cancers. However, it is unknown that Cd-induced cardiac toxicity through Nrf2-mediate antioxidant defense and Cytochrome P450 (CYP450) system. To ascertain the chemoprevention of Cd-induced cardiac toxicity, total 60 newborn chicks were fed with different doses of Cd (0 mg/kg, 35 mg/kg and 70 mg/kg) for a period of 90 days feed administration. Results indicated Cd exposure caused cardiac histopathology changed and functions abnormal, induced NOS activities raised and cardiac inflammation, triggering inflammation factors (IL-6, IL-8, TNF-α, and NF-κb) upregulation and inhabitation of IL-10. Cd caused increase of total CYP450 and Cytochrome b5 (Cyt b5) contents, while erythromycin N-demethylase (ERND), aminopyrin N-demethylase (APND), aniline-4-hydeoxylase (AH) and NADPH-cytochrome c reductase (NCR) indicated opposite situations with different degrees of reduction in microsomes. The mRNA level of most CYP450s isoforms (CYP1A1, CYP1A2, CYP1A5, CYP1B1, CYP2C18, CYP2C45, CYP3A4, CYP3A7 and CYP3A9) were significantly increase but CYP2D6 expression level changed not obvious. Furthermore, Cd treatment caused increased the peroxidation product (MDA) and H₂O₂ over accumulation, the decreased of T-AOC accompanied by decreased activity of antioxidant enzymes (T-SOD, GST and GPX). Over accumulation of Cd lead to oxidative stress and activated Nrf2 signal pathway through upregulating pivotal target genes (HO-1, NQO1, GCLC, GCLM and SOD). These findings suggested Cd exposure caused cardiotoxicity through CYP450s enzymes homeostasis disturbance and Nrf2-mediated oxidative stress signal pathways defense. These results may provide new evidence on molecular mechanism of Cd-induced cardiac toxicity.

Chronic Copper Exposure Induces Hypospermatogenesis in Mice by Increasing Apoptosis Without Affecting Testosterone Secretion

Chronic copper exposure impaired spermatogenesis in adult male mice. The aim of this study was to determine whether chronic copper exposure can induce apoptosis of testicular cell and hypospermatogenesis via disturbing testosterone synthesis in adult male mice. In the present study, sixty CD-1 male mice were randomly divided into four groups, and were continuously administered for 8 weeks by oral gavage with copper sulfate at a dose of 0, 25, 100, and 150 mg/kg/day, respectively. We determined the content of serum and testicular copper, testicular coefficient, testicular histopathology, sperm count and motility, the mRNA and protein levels of Caspase-3, Bax, and Bcl-2, Leydig cell count, testosterone content, testosterone synthetase, and testosterone synthesis-related genes. The results showed that the copper levels in serum increased in a dose-dependent manner, and the copper levels in testes were significantly related to serum copper levels. Male mice given copper sulfate 100 and 150 dosage groups showed significant decreased in sperm motility and sperm number as well as increased in testes damage, and there was no significant change in testicular coefficient in the four groups. The mRNA levels of Bcl-2 decreased and Caspase-3 increased in 150 dosage group, and Bax increased in two higher dosage groups. Meanwhile, Caspase-3 and Bax proteins increased in 150 dosage group, and Bcl-2 protein decreased in three copper treatment groups. Nevertheless, there were no differences on the levels of testosterone content and testosterone synthetase of 3β-HSD, 17β-HSD, 17α-Hyd, and 20α-Hyd, mRNA levels of Cyp11a1, Cyp17a1, and Star, and quantity of Leydig cells in four groups. Overall, these data showed that chronic copper exposure led to copper residues in the testes, and the doses of 100 and 150 mg/kg/day copper sulfate may induce hypospermatogenesis by increasing apoptosis without affecting testosterone secretion.

Di-(2-ethylhexyl) phthalate induced nephrotoxicity in quail (Coturnix japonica) by triggering nuclear xenobiotic receptors and modulating the cytochrome P450 system

Di-(2-ethylhexyl) phthalate (DEHP), a plasticizer that is mainly used in the production of polyvinyl alcohol-containing chloride products, has attracted attention due to potential threats to human health and the environment. Nevertheless, knowledge of DEHP-induced nephrotoxicity is still limited. To explore the mechanism of DEHP-induced nephrotoxicity, quail were treated with 0, 250, 500 and 1000 mg/kg DEHP by oral gavage for 45 days. Based on the results of histopathological analysis, DEHP exposure induced a disorganized renal structure, a partially dilated glomerulus and an atrophied Bowman's space. Renal tubular epithelial cells were unclear, and swelling of columnar epithelial cells was observed, suggesting that DEHP exposure caused renal disease and renal injury. Notably, DEHP interfered with the homeostasis of cytochrome P450 systems (CYP450s) by increasing the activities or contents of CYP450s (total CYP450, Cyt b5, ERND, APND, AH and NCR). The expression levels of certain CYP450 isoforms (CYP1A, CYP1B, CYP2C, CYP2D, CYP2J and CYP3A) were significantly downregulated in the kidney in DEHP-treated quail. Furthermore, DEHP induced the expression of nuclear receptors (AHR, CAR and PXR) in a dose-dependent manner. The results of this study suggested that DEHP-induced nephrotoxicity in quail was associated with the induction of nuclear xenobiotic receptor (NXR) responses and interference with CYP450 homeostasis. In conclusion, all data indicated that DEHP induced nephrotoxicity by triggering NXRs and modulating the cytochrome P450 system. The results of this study provide a new basis for understanding the nephrotoxicity of DEHP.

Selenium prevent cadmium-induced hepatotoxicity through modulation of endoplasmic reticulum-resident selenoproteins and attenuation of endoplasmic reticulum stress

Cadmium (Cd), a heavy metal contaminant, exists in humans and animals throughout life and closely associate with severe hepatotoxicity. Selenium (Se) has been recognized as an effective chemo-protectant of Cd, but the underlying mechanisms remain unclear. The objective of the present study is to illustrate the antagonistic effect of Se against Cd-induced hepatotoxicity. Primary hepatocytes were cultured in the presence of 5 μM Cd, 1 μM Se and the mixture of 1 μM Se and 5 μM Cd for 24 h. Cell viability and morphology, antioxidant status, endoplasmic reticulum (ER) stress response and selenotranscriptome were assessed. It was observed that Se treatment dramatically alleviated Cd-induced hepatocytes death and morphological change. Simultaneously, Se mitigated Cd-induced oxidative stress by reducing ROS production, increasing reduced glutathione (GSH) level and increasing selenoenzyme (glutathione peroxidase, GPX) activity. Cd induced hepatotoxicity via disordering ER-resident selenoproteins transcription and triggering ER stress and unfolded protein response. Supplementary Se evidently relieved hepatocytes injury via modulating ER-resident selenoproteins transcription to inhibit ER stress. Collectively, our findings showed a potential protection of Se against Cd-induced hepatotoxicity via suppressing ER stress response.

The constitutive androstane receptor and pregnane X receptor in the brain

Since their discovery, the orphan nuclear receptors constitutive androstane receptor (CAR;NR1I3) and pregnane X receptor (PXR;NR1I2) have been regarded as master regulators of drug disposition and detoxification mechanisms. They regulate the metabolism and transport of endogenous mediators and xenobiotics in organs including the liver, intestine and brain. However, with proposals of new physiological functions for NR1I3 and NR1I2, there is increasing interest in the role of these receptors in influencing brain function. This review will summarise key findings regarding the expression and function of NR1I3 and NR1I2 in the brain, hereby highlighting the need for further research in this field.

Selenium-Rich-Yeast Protects Against Aluminum-Induced Activating Nuclear Xenobiotic Receptors and Triggering Inflammation and Cytochromes P450 Systems in Mice Heart

Aluminum (Al) poisoning is linked to the development of cardiovascular diseases, and dietary supplementation with selenium-rich-yeast (SeY) has been shown to prevent inflammatory conditions. We evaluated the preventive effect of SeY on Al-induced cardiotoxicity, and the possible underlying mechanisms. Mice were treated with SeY (0.1 mg/kg) and/or Al (10 mg/kg) by oral gavage for 4 weeks. Histopathological damage was observed in the heart of Al-treated mice, in addition to the transcriptional up/downregulation of nuclear xenobiotic receptors (NXRs), inflammatory cytokines and 15 CYP450s genes. SeY significantly inhibited these Al-induced histopathological and molecular changes, and restored these indicators to the control levels. These results suggest that SeY exerts a cardio-protective effect against Al-induced toxicity through the NXR system, inflammatory cytokines, and CYP450s genes.

Fluoride-induced rectal barrier damage and microflora disorder in mice

Intestinal microflora plays a key role in maintaining the homeostasis between immune and host health. Here, we reported the fluoride-induced changes of rectal structure and microflora in mice. The morphology of rectal tissue was observed by hematoxylin and eosin staining. The rectal development parameters (the thickness of mucosa, intestinal gland and muscle layer) were evaluated. The proliferation of rectal epithelial cells was evaluated via BrdU labeling. The distribution of goblet, glycoprotein and mast cell were evaluated by specific staining. Rectal microflora was detected using 16S rRNA high-throughput sequencing. The results showed that the rectal structure was seriously damaged and the proliferation of rectal epithelial cells was significantly inhibited by fluoride. The distribution of goblet cells, glycoprotein and mast cells decreased significantly after fluoride exposure. The relative richness of microfloras was changed after fluoride treatment, such as increased Bacteroidetes and decreased Firmicutes. In summary, this study indicated that excessive fluoride damages the intestinal structure, disturbs the intestinal micro-ecology and causes intestinal microflora disorder in mice. Findings mentioned in the present study enrich a new scope for elucidating fluoride toxicity from intestinal homeostasis.

Lycopene Prevents DEHP-Induced Leydig Cell Damage with the Nrf2 Antioxidant Signaling Pathway in Mice

As a plasticizer, di(2-ethylhexyl) phthalate (DEHP) is the most usually used phthalate. Leydig cell is a male-specific cell, which plays a principal role in spermatogenesis and masculinization by the androgens of synthesis and secretion. Numerous researchers have indicated that DEHP can result in testicular toxicity by inducing oxidative stress. Lycopene (LYC) is a possible treatment option for male infertility due to its natural antioxidant properties. Our study was aimed to investigate whether LYC could rescue DEHP-induced Leydig cell damage. The mice were treated with DEHP (500 mg/kg BW/day or 1000 mg/kg BW/day) and/or LYC (5 mg/kg BW/day) for 28 days. We found that LYC attenuated DEHP-induced Leydig cell damage. Moreover, the protective role of LYC was verified by the histopathological and ultrastructural analysis of the Leydig cell. LYC suppressed oxidative stress that was induced by DEHP. In the Leydig cell, the expressions of the nuclear factor erythroid 2-related factor 2 (Nrf2) and its downstream target genes were improved through LYC-mediated protection in DEHP-induced Leydig cell damage. Our findings indicated that LYC could increase the antioxidant capacity via mediating Nrf2 signaling pathway, thereby attenuating DEHP-induced Leydig cell damage.

Arsenic trioxide or/and copper sulfate co-exposure induce glandular stomach of chicken injury via destruction of the mitochondrial dynamics and activation of apoptosis as well as autophagy

Arsenic and copper are naturally occurring element. Contamination from natural processes and anthropogenic activities can be discovered all over the world and their unique interactions with the environment lead to widespread toxicity. When the content was excessive, the organism would be hurt seriously. The glandular stomach is an important organ of the poultry gastrointestinal tract. This study was aimed to investigate the toxicity of arsenic trioxide or/and copper sulfate (As or/and Cu) on chicken glandular stomach. Seventy-two 1-day-old Hy-Line chickens were randomly divided into control (C) group, arsenic trioxide (As) group, copper sulfate (Cu) group and arsenic trioxide and copper sulfate (AsCu) group, and exposed to 30 mg/kg arsenic trioxide or/and 300 mg/kg copper sulphates for 12 weeks. The indicators of mitochondrial dynamics, apoptosis and autophagy were tested in the glandular stomach. The results showed that exposure to As or/and Cu caused mitochondrial dynamic imbalance. Additionally, the levels of pro-apoptosis and autophagy indicators were increased and the levels of anti-apoptosis indicators were decreased in the treatment groups. Beyond that, in the treatment groups, we could clearly see karyopyknosis and chromatin condensation were associated with increased apoptosis rate, as well as the disappearance of the nuclear membrane, the swelling of mitochondria and the accumulation of autophagosomes were involved in the death of cells. It was worth noting that the glandular stomach lesions were time-dependent, and the combination of As and Cu were worse than the As and Cu alone. Collectively, our results suggest that As or/and Cu aggravate mitochondrial dysfunction, apoptosis and autophagy in a time-dependent manner, and the combined toxicity of As and Cu was higher.

Atrazine exposure in gestation and breastfeeding affects Calomys laucha sperm cells

The present study evaluated the effects of low doses of atrazine administered during gestation and breastfeeding on sperm characteristics of the wild rodent Calomys laucha. Adult females were divided into groups of 10 and administered different doses of atrazine through gavage, during gestational or breastfeeding period. At 3 months of age, the F1 adult male progeny of these females was evaluated. We observed a drastic reduction in the total and progressive motility of male sperm cells at all doses and during both the exposure periods. Moreover, the plasma membrane integrity of adult male sperm cells decreased at all doses of atrazine administered during the breastfeeding, whereas the membrane fluidity of these cells increased at all tested doses. Atrazine led to a decrease in the sperm mitochondrial functionality at all doses and during both exposure periods. The damage to the sperm DNA was higher in males exposed to the highest dose (1.0 mg/kg) during the gestation period, and in animals exposed to the lowest dose of atrazine (0.1 mg/kg) during breastfeeding period. Furthermore, the highest dose (1.0 mg/kg) of atrazine reduced the sperm concentration. Furthermore, the reduced levels of reactive oxygen species (ROS) were observed at all evaluated doses in males exposed during the gestation period. These results suggest that the administration of low doses of atrazine at critical periods of development may permanently reduce the sperm quality in C. laucha.

Taxifolin alleviates apoptotic injury induced by DEHP exposure through cytochrome P450 homeostasis in chicken cardiomyocytes

Di-2-ethylhexyl phthalate (DEHP), widely used as a plasticizer, is a ubiquitous artificial pollutant. DEHP can induce biological toxicity in various organs, with an especially high potential for toxicity to the cardiovascular system. Taxifolin (TAX) is used in the treatment of cardiovascular diseases due to its antioxidative capacities. However, it is not clear whether TAX can alleviate apoptosis induced by DEHP exposure through the cytochrome P450 (CYP) pathway in cardiomyocytes. To understand the role of TAX in attenuating cardiomyocyte toxicity induced by DEHP, primary cardiomyocytes were divided into 4 groups (control group, DEHP group, TAX group and DEHP + TAX group). The results showed that in the cardiomyocytes, DEHP initiated apoptosis by increasing the expression of caspase-3, caspase-9, cyt c, and Bax at both the mRNA and protein levels and by decreasing the Bcl-2 levels compared with that of the control group. In addition, the activities of catalase (CAT), superoxide dismutase (SOD), and total antioxidative capacity (T-AOC) were clearly decreased (P < 0.05), while in the DEHP group, the malondialdehyde (MDA) and hydrogen peroxide (H₂O₂) levels were observably increased (P < 0.05), compared with those in control group. Furthermore, compared with the control group, the DEHP group demonstrated a clear partial decrease in the expression of the mRNA levels of CYP1B1 and CYP2C18 (P < 0.05), and DEHP/TAX cotreatment partially prevented apoptosis and oxidative stress damage (P < 0.05). These results showed that exposure to DEHP induced apoptosis in chicken cardiomyocytes, while TAX could antagonize the toxicity of DEHP on cardiomyocytes by attenuating oxidative stress responses and modulating CYPs.

Cadmium exposure triggers mitochondrial dysfunction and oxidative stress in chicken (Gallus gallus) kidney via mitochondrial UPR inhibition and Nrf2-mediated antioxidant defense activation

Cadmium (Cd) is a widespread environmental pollutant that accumulates in living systems and represents a significant global health hazard. Cd poses a toxicity threat to both human and animal health, including that of birds. Further knowledge of Cd toxicology pathways will allow for a better understanding of Cd-induced nephrotoxicity. To evaluate Cd-induced nephrotoxicity through potential oxidative damage, male chickens were treated with 0 mg/kg, 35 mg/kg or 70 mg/kg CdCl₂ in diet for 90 days. Markedly, histopathology indicated renal tubular epithelial cell swelling, renal function CREA content abnormalities, biochemical and morphologic indices indicative of Cd-induced kidney injury. Cd toxicity induced the up-regulation of Nrf2 and downstream target genes that relieve oxidative stress. Meanwhile, Cd disrupted the homeostasis of trace elements and promoted oxidative damage. Cd interfered with mitochondrial unfolded protein response (UPR^mt)-related factors (SIRT1, SIRT3, PGC-1α, TFAM, Nrf1, and HTRA2) and disrupted the homeostasis of mitochondrial dynamics (OPA1, MFN1, MFN2, Fis1 and MFF), thereby exacerbating mitochondrial structural damage and mitochondrial dysfunction. In conclusion, our study demonstrated that the nephrotoxicity of Cd exposure results in oxidative stress and mitochondrial dysfunction by activating the Nrf2 signaling pathway and inhibiting UPR^mt in the kidneys.

Nuclear receptor AHR-mediated xenobiotic detoxification pathway involves in atrazine-induced nephrotoxicity in quail (Coturnix C. coturnix)

Atrazine (ATR), one of the most widely used pesticides in agricultural production, are gradually concerned due to potential ecosystem and health risks. Further, the induction of ATR nephrotoxicity and detoxification response is still unknown. To evaluate ATR-induced nephrotoxicity, quails were treated with 0, 50, 250 or 500 mg/kg ATR by gavage administration for 45 days. Histopathology indicated that ATR exposure caused renal tubular epithelial cell swelling and endoplasmic reticulum degeneration, suggesting that ATR exposure causes renal impairment even renal diseases. Notably, ATR interfered cytochrome P450 system (CYP450s) homeostasis by enhancing contents or activities of CYP450s (total CYP450, Cyt b5, AH, APND, NCR and ERND) and the expression of CYP450 isoforms (CYP1A, CYP1B, CYP2C and CYP3A). ATR triggered phase II detoxifying reaction, reflected by the elevated GSH level, GST activity and the up-regulation of GST isoforms (GSTa, GSTa3 and GSTt1) and GSH synthetase (GCLC). Moreover, ABC transporters were activated to expel ATR from the body by increasing expression of MRP1 and P-GP gene. Accompanying these alterations, the nuclear receptors (AHR, CAR and PXR) were activated by ATR in a dose-dependent manner. Analysis results of present study demonstrated that the induction of phase II detoxifying enzyme system and ABC transporters could be modulated by nuclear receptors response and CYP450s disturbance in low-dose ATR-treated quail. In conclusion, all data suggested that nuclear receptors AHR-mediated detoxification pathway was involved in ATR-induced nephrotoxicity. These results provided new evidence about the nephrotoxic effects of ATR on the response of biotransformation and detoxification system.

Copper-induced apoptosis and autophagy through oxidative stress-mediated mitochondrial dysfunction in male germ cells

Excess copper reduces sperm number and motility but the causes are unclear. We investigated the toxic effects of copper exposure on the immortalized male germ cell line GC-1. Copper addition to cells altered viability and morphology in a dose-dependent manner. Copper addition resulted in increased levels of reactive oxygen species (ROS), malonaldehyde (MDA) and lactate dehydrogenase (LDH) while catalase (CAT) activity and glutathione (GSH) declined. The mitochondrial transmembrane potential and ATP levels decreased in response to copper as did mitochondria fission that led to mitochondrial dysfunction. The apoptosis rate was also proportional to the level of copper in the growth medium. Copper also down-regulated Bcl2 and up-regulated Bax, Casp8 and Casp3 linking the effects of copper to increased apoptosis. The levels of mRNA for the autophagy-related genes (Atg3, Atg5, p62, Lc3b/Lc3a) and proteins (Lc3b/Lc3a, BECN1, Atg5, p62) all increased in copper-treated cells as were levels Lc3 determined by fluorescence microscopy. These results indicated that copper induces apoptosis and autophagy through oxidative stress-mediated mitochondrial dysfunction.

Xenobiotic mediated diabetogenesis: Developmental exposure to dichlorvos or atrazine leads to type 1 or type 2 diabetes in Drosophila

The increased incidence of diabetes to the magnitude of a global epidemic is attributed to non-traditional risk factors, including exposure to environmental chemicals. However, the contribution of xenobiotic exposure during the development of an organism to the etiology of diabetes is not fully addressed. Developing stages are more susceptible to chemical insult, but knowledge on the consequence of the same to the onset of diabetes is residual. In this context, by using Drosophila melanogaster having conserved Insulin/Insulin growth factor-like signaling (IIS) as well as glucose homeostasis as a model, we evaluated the potential of developmental exposure to dichlorvos (DDVP, an organophosphorus pesticide) or atrazine (herbicide) to cause diabetes in exposed organisms. Flies exposed to DDVP during their development display insulin deficiency or type 1 diabetes (T1D) while those exposed to atrazine show insulin resistance or type 2 diabetes (T2D), suggesting that exposure to these xenobiotics during organismal development can result in diabetes and that different mechanisms underlie pesticide mediated diabetes. We show that oxidative stress-mediated c-Jun N-terminal kinase (JNK) signaling activation underlies insulin resistance in flies exposed to atrazine during their development while DDVP-mediated T1D involves activation of caspase-mediated cell death pathway. Mitigation of oxidative stress through over-expression of SOD2 in atrazine (20μg/ml) exposed flies, revealed significantly decreased oxidative stress levels and reduced phosphorylation of JNK. Moreover, glucose and Akt phosphorylation levels in SOD2 over-expression flies exposed to atrazine were comparable to those in controls, suggesting restoration in insulin sensitivity. Therefore, exposure to xenobiotics during development is a common risk factor for the development of type 1 or type 2 diabetes. Accordingly, the present study cautions against the use of such diabetogenic pesticides. Also, mitigation of oxidative stress or anti-oxidant supplementation could be a potential therapy for xenobiotic mediated type 2 diabetes.

Di (2-ethyl hexyl) phthalate (DEHP)-induced spleen toxicity in quail (Coturnix japonica) via disturbing Nrf2-mediated defense response

Di(2-ethylhexyl) phthalate (DEHP), as a widely used plasticizer, is reported to have widespread environmental and global health hazards. Trace amounts of phthalates in the environment are sufficient to disrupt ecological balance and affect human health. However, DEHP-induced splenic toxicity remains in an unknown state. Therefore, to explore the mechanism of DEHP-induced splenic toxicity, male quail were employed with 0, 250, 500 and 750 mg/kg body weight DEHP by daily gastric perfusion for 45 days. Notably, splenic corpuscular border and cell gap enlargement were observed in the spleen tissue of DEHP-exposed quail under the histopathological analysis. Furthermore, DEHP induced dysregulation of oxidative stress markers by increasing malondialdehyde (MDA) content and decreasing superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) activities. Low concentration of DEHP (≤250 mg/kg) exposure suppressed nuclear factor-E2-related factor 2 (Nrf2) signaling pathway, while high concentration of DEHP (≥500 mg/kg) exposure activated Nrf2-mediated defense response. DEHP induced splenic oxidative stress via interfering Nrf2 signal pathway and altering the transcription of its downstream genes. In conclusion, this study suggested that DEHP induced splenic toxicity.