Arsenic induces hepatotoxicity in chickens via PANoptosis pathway.

Environmental pollution caused by arsenic or its compounds is called arsenic pollution. Arsenic pollution mainly comes from people's mining and smelting of arsenic compounds. In addition, the widespread use of arsenic compounds, such as the use and production of arsenic-containing pesticides, is also a source of arsenic contamination. Arsenic contamination leads to an increased risk of arsenic exposure, and the multi-organ toxicity induced by arsenic exposure is a global health problem. As a non-mammalian vertebrate with high nutrient levels, chickens readily absorb and accumulate arsenic from their food. Relevant studies have shown that arsenic exposure induces hepatotoxicity in chickens, and there has been a steady stream of research into the specific mechanisms involved. PANoptosis, a newly discovered and unique mode of programmed cell death (PCD) characterized by both apoptosis, cellular pyroptosis, and necroptosis. There are no studies to indicate whether chicken liver toxicity due to arsenic is associated with PANoptosis. Therefore, we established chicken animal models and chicken primary hepatocyte models exposed to different arsenic concentrations to dissect the role and mechanism of PANoptosis in arsenic exposure-induced hepatotoxicity in chickens. Our histopathological results showed that arsenic treatment caused dose-dependent damage to chicken liver structure. Meanwhile, different doses of arsenic treatment groups caused significant up-regulation of the protein level of ZBP1, a key factor of PANoptosis. And then consequently triggered the abnormal gene and protein expression levels of apoptosis-associated factors (Caspase-8, Caspase-7, Caspase-3), cellular pyroptosis-associated factors (NLRP3, ASC, GSDMD) and necroptosis-associated factors (RIPK1, RIPK3, MLKL). In conclusion, our study revealed that PANoptosis is involved in arsenic-induced chicken hepatotoxicity. Our findings provide a new perspective on the pathogenesis of arsenic exposure-induced hepatotoxicity in chickens.

Arsenic trioxide induces innate immune response and inflammatory response in chicken liver via cGAS-STING/NF-κB pathway.

Arsenic is a toxic metal-like element widely used in the pesticide, preservative and semiconductor industries. However, accumulation of arsenic through the food chain can cause serious damage to animal and human health. However, the toxic mechanism of arsenic-induced hepatotoxicity in chickens is not clear, and the present study aimed to investigate the potential role of cGAS-STING and NF-κB pathways on inflammatory injury in chicken liver. In this study, 75 white-feathered broilers were divided into a control group, a low-dose arsenic group (4 mg/kg) and a high-dose arsenic group (8 mg/kg) to investigate the toxic effects of arsenic on chicken liver. In this study, we found that pathological changes such as inflammatory cell infiltration and vesicular degeneration occurred in the liver when exposed to ATO. Crucially, exposure to ATO triggered the cGAS-STING pathway and markedly raised the levels of mRNA and protein expression of cGAS, STING, TBK1, and IRF7. The type I interferon response was also triggered. Simultaneously, STING induced the activation of the conventional NF-κB signaling pathway and stimulated the expression of genes associated with inflammation, such as IL-6, TNF-α and IL-1ß. In summary, the induction of inflammatory responses via cGAS-STING and NF-κB signaling pathways under high ATO exposure provides new ideas for further studies on the toxicological mechanisms of arsenic.

Mitochondrial miR-12294-5p-Regulated Copper Exposure-Caused Mitochondrial-Dependent Ferroptosis by Targeted Inhibition of CISD1 in Chicken Hepatocytes.

Copper (Cu) is a common trace element additive in animal and human foods, and excessive intake of Cu has been shown to cause hepatotoxicity, but the underlying mechanism remains unclear. Our previous research found that Cu exposure dramatically upregulated mitochondrial miR-12294-5p expression and confirmed its targeted inhibition of CISD1 expression in chicken hepatocytes. Thus, we aimed to explore the potential role of mitomiR-12294-5p/CISD1 axis in Cu exposure-resulted hepatotoxicity. Here, we observed that Cu exposure resulted in Cu accumulation and pathological injury in chicken livers. Moreover, we found that Cu exposure caused mitochondrial-dependent ferroptosis in chicken hepatocytes, which were prominent on the increased mitochondrial Fe2+ and mitochondrial lipid peroxidation, inhibited levels of CISD1, GPX4, DHODH, and IDH2, and also enhanced level of PTGS2. Notably, we identified that inhibition of mitomiR-2954 level effectively mitigated Cu-exposure-resulted mitochondrial Fe2+ accumulation and mitochondrial lipid peroxidation and prevented the development of mitochondrial-dependent ferroptosis. However, increasing the mitomiR-12294-5p expression considerably aggravated the influence of Cu on these indicators. Meanwhile, the overexpression of CISD1 effectively alleviated Cu-caused mitochondrial-dependent ferroptosis, while silent CISD1 eliminated the therapeutic role of mitomiR-12294-5p inhibitor. Overall, our findings indicated that mitomiR-12294-5p/CISD1 axis played a critical function in Cu-caused hepatotoxicity in chickens by regulating mitochondrial-dependent ferroptosis.

Copper exposure promotes ferroptosis of chicken (Gallus gallus) kidney cells and causes kidney injury.

PURPOSE: While copper (Cu) is essential for biological organisms, excessive Cu can be harmful. Ferroptosis is a programmed cell death pathway, but the role of ferroptosis in renal injury induced by Cu is limited. The aim of this study was to investigate the role of ferroptosis in kidney injury in chickens and the molecular mechanism by which Cu promotes renal ferroptosis. MATERIALS AND METHODS: Chicken were subjected to Cu treatment by artificially adding excess Cu to the basal diet (the Cu concentration in the diet was supplemented to 110-330 mg/kg), and the impact on kidney fibrosis, tissue structure, and ferroptosis-related molecular markers was studied. Then, the expression levels of genes and proteins related to ferroptosis, iron metabolism and ferroautophagy were detected to explore the promoting effect of Cu on ferroptosis in chicken kidney. MAIN FINDINGS: Cu treatment resulted in significant fibrosis and tissue structure damage in chicken kidneys. Molecular analysis revealed a significant upregulation of LC3Ⅱ, P62, ATG5, and NCOA4, along with a decrease in FTH1 and FTL protein levels. Additionally, crucial markers of ferroptosis, including the loss of GPX4, SLC7A11, and FSP1, and an increase in PTGS2 and ACSL4 protein levels, were observed in chicken kidneys after Cu exposure. CONCLUSION: Our study showed that dietary Cu excess caused kidney injury in brochickens and exhibited ferroptosis-related features, including lipid peroxidation, reduction of ferritin, and downregulation of FSP1 and GPX4. These results indicate that excess Cu can induce renal ferroptosis and lead to kidney injury in chickens. This study highlights the complex interplay between Cu ions and ferroptosis in the context of renal injury and provides a new perspective for understanding the mechanism of Cu-induced renal injury.

Co-exposure of arsenic and polystyrene-nanoplastics induced kidney injury by disrupting mitochondrial homeostasis and mtROS-mediated ferritinophagy and ferroptosis.

Arsenic (As) and polystyrene nanoplastics (PSNPs) co-exposure induced biotoxicity and ecological risks have attracted wide attention. However, the combined effects of As and PSNPs on the kidney and their underlying mechanisms of toxicities remain to be explored. Here, we investigated the effects of As and PSNPs co-exposure on structure and function in mice kidney, and further explored the possible mechanisms. In this study, we identified that co-exposure to As and PSNPs exhibited conspicuous renal structural damage and pathological changes, accompanied by renal tissue fibrosis (increased protein expression of Collagen I and α-SMA and deposition of collagen fibers), whereas alone exposure to As or PSNPs does not exhibit nephrotoxicity. Subsequently, our results further showed that combined action of As and PSNPs induced mitochondrial oxidative damage and impaired mitochondrial dynamic balance. Furthermore, co-treatment with As and PSNPs activated NCOA4-mediated ferritinophagy and ferroptosis in mice kidney and TCMK-1 cells, which was confirmed by the changes in the expression of ferritinophagy and ferroptosis related indicators (NCOA4, LC3, ATG5, ATG7, FTH1, FTL, GPX4, SLC7A11, FSP1, ACSL4 and PTGS2). Meaningfully, pretreatment with the mtROS-targeted scavenger Mito-TEMPO significantly attenuated As and PSNPs co-exposure induced mitochondrial damage, ferritinophagy and ferroptosis. In conclusion, these findings demonstrated that mtROS-dependent ferritinophagy and ferroptosis are important factors in As and PSNPs co-exposure induced kidney injury and fibrosis. This study provides a new insight into the study of combined toxicity of nanoplastics and heavy metal pollutants.

Curcumin attenuates aflatoxin B1-induced ileum injury in ducks by inhibiting NLRP3 inflammasome and regulating TLR4/NF-κB signaling pathway.

Aflatoxin B1 (AFB1) is a widespread toxic contamination in feed for animals. The primary active component of turmeric, curcumin (Cur), is an antioxidant and an anti-inflammatory. However, it is yet unknown how AFB1 affects the intestinal epithelial barrier and whether Cur acts as a protective mechanism when exposed to AFB1. Here, we explored the mechanism of AFB1-induced intestinal injury from intestinal epithelial barrier, inflammation, pyroptosis, and intestinal flora, and evaluated the protective role of Cur. We found that AFB1 caused weight loss and intestinal morphological damage that is mainly characterized by shortened intestinal villi, deepened crypts, and damaged intestinal epithelium. Exposure to AFB1 decreased the expression of Claudin-1, MUC2, ZO-1, and Occludin and increased the expression of pyroptosis-related factors (NLRP3, GSDMD, Caspase-1, IL-1ß, and IL-18) and inflammation-related factors (TLR4, NF-κB, IκB, IFN-γ, and TNF-α). Furthermore, ileal gut microbiota was altered, and simultaneously, the Lactobacillus abundance was decreased. The gut microbiota interacts with a wide range of physiologic functions and disease development in the host through its metabolites, and disturbances in gut microbial metabolism can cause functional impairment of the ileum. Meanwhile, Cur can ameliorate histological ileum injuries and intestinal flora disturbance caused by AFB1. We found that Cur reversed the effects of AFB1 through modulating both NLRP3 inflammasome and the TLR4/NF-κB signaling pathway. In conclusion, AFB1 can induce inflammatory damage and pyroptosis in duck ileum, while Cur has obviously protective effects on all the above damages.

Copper Exposure Induced Chicken Hepatotoxicity: Involvement of Ferroptosis Mediated by Lipid Peroxidation, Ferritinophagy, and Inhibition of FSP1-CoQ10 and Nrf2/SLC7A11/GPX4 Axis.

Copper (Cu) is one of the most significant trace elements in the body, but it is also a widespread environmental toxicant health. Ferroptosis is a newly identified programmed cell death, which involves various heavy metal-induced organ toxicity. Nevertheless, the role of ferroptosis in Cu-induced hepatotoxicity remains poorly understood. In this study, we found that 330 mg/kg Cu could disrupt the liver structure and cause characteristic morphological changes in mitochondria associated with ferroptosis. Additionally, Cu treatment increased MDA (malondialdehyde) and LPO (lipid peroxide) production while reducing GSH (reduced glutathione) content and GCL (glutamate cysteine ligase) activity. However, it is noticeable that there were no appreciable differences in liver iron content and key indicators of iron metabolism. Meanwhile, our further investigation found that 330 mg/kg Cu-exposure changed multiple ferroptosis-related indicators in chicken livers, including inhibition of the expression of SLC7A11, GPX4, FSP1, and COQ10B, whereas enhances the levels of ACLS4, LPCAT3, and LOXHD1. Furthermore, the changes in the expression of NCOA4, TXNIP, and Nrf2/Keap1 signaling pathway-related genes and proteins also further confirmed 330 mg/kg Cu exposure-induced ferroptosis. In conclusion, our results indicated that ferroptosis may play essential roles in Cu overload-induced liver damage, which offered new insights into the pathogenesis of Cu-induced hepatotoxicity.

Arsenic and polystyrene-nano plastics co-exposure induced testicular toxicity: Triggers oxidative stress and promotes apoptosis and inflammation in mice.

Co-existing of polystyrene-nano plastics (PSNPs) and arsenic (As) in the environment caused a horrendous risk to human health. However, the potential mechanism of PSNPs and As combination induced testicular toxicity in mammals has not been elucidated. Therefore, we first explore the testicular toxicity and the potential mechanism in male Kunming mice exposed to As or/and PSNPs. Results revealed that compared to the As or PSNPs group, the combined group showed more significant testicular toxicity. Specifically, As and PSNPs combination induced irregular spermatozoa array and blood-testis barrier disruption. Simultaneously, As and PSNPs co-exposure also exacerbated oxidative stress, including increasing the MDA content, and down-regulating expression of Nrf-2, HO-1, SOD-1, and Trx. PSNPs and As combination also triggered testicular apoptosis, containing changes in apoptotic factors (P53, Bax, Bcl-2, Cytc, Caspase-8, Caspase-9, and Caspase-3). Furthermore, co-exposed to As and PSNPs aggravated inflammatory damage characterized by targeted phosphorylation of NF-κB and degradation of I-κB. In summary, our results strongly confirmed As + PSNPs co-exposure induced the synergistic toxicity of testis through excessive oxidative stress, apoptosis, and inflammation, which could offer a new sight into the mechanism of environmental pollutants co-exposure induced male reproductive toxicity.

Long-term Cu exposure alters CYP450s activity and induces jejunum injury and apoptosis in broilers.

Copper (Cu) is an essential trace element that plays a crucial role in numerous physiopathological processes related to human and animal health. In the poultry industry, Cu is used to promote growth as a feed supplement, but excessive use can lead to toxicity on animals. Cytochrome P450 enzymes (CYP450s) are a superfamily of proteins that require heme as a cofactor and are essential for the metabolism of xenobiotic compounds. The purpose of this study was to explore the influence of exposure to Cu on CYP450s activity and apoptosis in the jejunum of broilers. Hence, we first simulated the Cu exposure model by feeding chickens diets containing different amounts of Cu. In the present study, histopathological observations have revealed morphological damage to the jejunum. The expression levels of genes and proteins of intestinal barrier markers were prominently downregulated. While the mRNA expression level of the gene associated with CYP450s was significantly increased. Additionally, apoptosis-related genes and proteins (Bak1, Bax, Caspase-9, Caspase-3, and CytC) were also significantly augmented by excessive Cu, while simultaneously decreasing the expression of Bcl-2. It can be concluded that long-term Cu exposure affects CYP450s activity, disrupts intestinal barrier function, and causes apoptosis in broilers that ultimately leads to jejunum damage.

Multi-omics reveals the protective effects of curcumin against AFB1-induced oxidative stress and inflammatory damage in duckling intestines.

Aflatoxin B1 (AFB1) is the most prevalent and toxic class of aflatoxins, which is considered a significant risk factor for food safety. Curcumin, a phytoconstituent with anti-inflammatory and antioxidant properties, has potential therapeutic value for intestinal inflammatory diseases. In this study, the duckling model susceptible to AFB1 was selected for toxicity testing, aiming to explore the effect of curcumin on AFB1 enterotoxicity and its possible mechanism of action. The results showed that curcumin promoted the growth and development of ducklings and mitigated the changes in morphology and permeability serological index (DAO and D-LA) after AFB1 exposure. Curcumin also mitigated AFB1-induced oxidative stress by activating the Nrf2 pathway, and ameliorated intestinal inflammation by inhibiting the NF-κB/IκB signaling pathway and boosting intestinal autophagy. In terms of gut flora and their metabolites, we found that curcumin supplementation significantly increased the intestinal flora's abundance index and diversity index compared to the AFB1 group, mitigating the decline in the abundance of Actinobacteria and the rise in that of harmful bacteria Clostridia. Furthermore, untargeted metabolomic analysis revealed that the protective effect of curcumin on the intestine was mainly through the regulation of AFB1-induced disorders of lipid metabolism, involving linoleic acid metabolism, α-linolenic acid metabolism, and glycerolipid metabolism. Overall, the enteroprotective effects of curcumin may be of significant value in the future for treating chronic AFB1 poisoning and also provide new therapeutic ideas for other mycotoxicosis.

Arsenic induced neurotoxicity in the brain of ducks: The potential involvement of the gut-brain axis.

BACKGROUND: Arsenic is a widely distributed ecotoxic pollutant that has been found to cause neurotoxicity in a variety of species. Gut-brain axis is a two-way information network between the gut microbiome and the brain, which is closely related to organismal health. However, the role of the gut-brain axis in arsenic-induced neurotoxicity remains largely unknown. METHODS: In order to explore whether there is a relationship between brain and gut microbiota of meat ducks, we performed molecular biological detection including RT-qPCR and Western blot, as well as morphological detection including, HE staining and immunohistochemistry. Meanwhile, intestinal contents were analyzed using 16 S ribosomal RNA gene sequencing and analysis RESULTS: In this study, we investigated whether arsenic trioxide (ATO) can activate the gut microbiome-brain axis to induce intestinal and brain injury. The results showed that ATO-exposure disrupted the diversity balance of intestinal microbiota and integrity and injured the intestinal structure. ATO-exposure also reduced the number of glycogen and goblet cells in the duodenum. In addition, exposure to ATO caused intestinal inflammatory injury by activating NF-κB signaling pathway and promoting the expression of its target genes. Meanwhile, the tight junction-related proteins (ZO-1, occludin) of gut and brain were reduced by ATO exposure. Furthermore, results also revealed that ATO-exposure induced brain injury, including neuronal cell vacuolization and reduced numbers of neuronal cells in the cortex and hippocampus. Remarkably, ATO-exposure also disrupted neurotransmitter levels. Additionally, our further molecular mechanism study revealed that ATO-exposure increased the expression of autophagy and apoptosis related mRNA and proteins levels in the brain tissues. CONCLUSION: Altogether, these findings provide a new insight into that ATO-exposure induced intestinal injury and aggravated neurotoxicity via the gut-brain axis.

Effect of arsenic and copper in kidney of mice: Crosstalk between Nrf2/ Keap1 pathway in apoptosis and pyroptosis.

Arsenic (As) and copper (Cu) are two common contaminants in the environment. When organisms are exposed to As or/ and Cu in large quantities or for sustained periods, oxidative stress is induced, adversely affecting kidney function. However, the molecular mechanisms involved in As or/ and Cu-induced nephrotoxicity remain elusive. In this experiment, wild-type C57BL/6 and Nrf2-knockout mice (n = 24 each) were exposed to arsenic trioxide and copper chloride alone or in combination. Our research findings indicate that exposure to As or/ and Cu can activate the Nrf2 antioxidant pathway by upregulating the levels of Nrf2, HO-1, CAT, and downregulating the level of Keap1, thereby reducing As or/ and Cu-induced oxidative stress. Meanwhile, exposure induced kidney cell pyroptosis and apoptosis by promoting the expression of NLRP3 inflammasomes and Caspase-3, which peaked in mice co-treated with As and Cu. Subsequently, we investigated its role in As or/ and Cu-induced kidney injury by knocking out Nrf2. Our results show that after knocking out Nrf2, the expression of antioxidant factors CAT and HO-1 significantly decreased. Based on the low antioxidant capacity after Nrf2 knockout, the levels of NLRP3 inflammasome, GSDMD, and Caspase1 were significantly upregulated after exposure to As and Cu, indicating more severe cellular pyroptosis. In addition, the level of Caspase3-mediated apoptosis was also more severe. Taken together, there is crosstalk between Nrf2-mediated antioxidant capacity and apoptosis/ pyroptosis induced by exposure to As or/ and Cu. Depletion of Nrf2 alters its antioxidant capacity, ultimately leading to more severe apoptosis, pyroptosis, and nephrotoxicity.

Long-term oral tribasic copper chloride exposure impedes cognitive function and disrupts mitochondrial metabolism by inhibiting mitophagy in rats.

Copper (Cu) is an essential micronutrient element that commonly acted as a feed additive and antimicrobial in agricultural production. Tribasic copper chloride (TBCC) is a relatively new dietary Cu source, and its exposure directly or indirectly affects the safety of animals and ecological environment, thus posing a potential risk to human health. Cu overexposure would produce toxic reactive oxygen species (ROS) that may have toxic effects on the host, but the mechanism of neurotoxicity remains unclear. Herein, to explore the effects of long-term TBCC-induced neurotoxicity, 150 male Sprague-Dawley rats were randomly allocated and treated with different doses of TBCC, and the cortical and hippocampus tissues were harvested at 0, 6, and 12 weeks after treatment. Morris Water Maze (MWM) test showed that excessive intake of TBCC could induce cognitive dysfunction in rats. Moreover, after treatment with 160 mg/kg Cu (276 mg/kg TBCC) for 12 weeks, pathological changes were observed in the cortex and hippocampus, and the number of Nissl bodies decreased significantly in the hippocampus. Additionally, mitochondrial structure was significantly altered and neuronal mitochondrial fusion/fission equilibrium was disrupted in 80 mg/kg and 160 mg/kg Cu groups at 12 weeks. With an increase in TBCC dose and treatment time, the number of mitophagosomes and the expression of mitophagy-related genes were significantly decreased after initially increasing. Furthermore, metformin (Met) and 3-methyladenine (3-MA) were used to regulate the level of mitophagy to further explore the mechanism of Cu-induced nerve cell injury in vitro., and it found that mitophagy activator (Met) would increase mitochondrial fission, while mitophagy inhibitors (3-MA) would aggravate mitochondrial metabolic disorders by promoting mitochondrial fusion and inhibiting mitochondrial division. These results indicate that long-term oral TBCC could impede cognitive function and disrupts mitochondrial metabolism by inhibiting mitophagy, providing an insightful perspective on the neurotoxicity of dietary TBCC.

Mitochondrial miR-12294-5p regulated copper-induced mitochondrial oxidative stress and mitochondrial quality control imbalance by targeted inhibition of CISD1 in chicken livers.

Copper (Cu) is hazardous metal contaminant, which induced hepatotoxicity is closely related to mitochondrial disorder, but exact regulatory mechanism has not yet been revealed. Mitochondrial microRNAs (mitomiRs) are a novel and critical regulator of mitochondrial function and mitochondrial homeostasis. Hence, this study revealed the impact of Cu-exposure on mitomiR expression profiles in chicken livers, and further identified mitomiR-12294-5p and its target gene CISD1 as core regulators involved in Cu-induced hepatotoxicity. Additionally, our results showed that Cu-exposure induced mitochondrial oxidative damage, and mitochondrial quality control imbalance mediated by mitochondrial dynamics disturbances, mitochondrial biogenesis inhibition and abnormal mitophagy flux in chicken livers and primary chicken embryo hepatocytes (CEHs). Meaningfully, we discovered that inhibition of the expression of mitomiR-12294-5p effectively alleviated Cu-induced mitochondrial oxidative stress and mitochondrial quality control imbalance, while the up-regulation of mitomiR-12294-5p expression exacerbated Cu-induced mitochondrial damage. Simultaneously, the above Cu-induced mitochondrial damage can be effectively rescued by the overexpression of CISD1, while knockdown of CISD1 dramatically reverses the mitigating effect that inhibition of mitomiR-12294-5p expression on Cu-induced mitochondrial oxidative stress and mitochondrial quality control imbalance. Overall, these results suggested that mitomiR-12294-5p/CISD1 axis mediated mitochondrial damage is a novel molecular mechanism involved in regulating Cu-induced hepatotoxicity in chickens.

Diagnosis and surgical management of testicular seminoma in captive giant panda (Ailuropoda melanoleuca).

A captive adult male giant panda (Guangzhou Chimelong Safari Park, CHINA) presented with azoospermia and enlarged left testicle. A tentative diagnosis of testicular neoplasia was made, and confirmed as testicular seminoma cases by testicular ultrasound, computed tomography (CT), testicular biopsy, and tumor marker examination findings. Based on the diagnostic results, the treatment of choice was surgical resection of the testicular tumor under general anesthesia. And the histopathological findings of the excised neoplasm were consistent with those of testicular seminoma. In addition, no tumor recurrence was observed after surgery, which indicates that our surgical and post-operative treatments were effective. The surgical treatment adopted in this case report is safe for patients and provides the best solution for the diagnosis and treatment of giant panda testicular seminoma. To our knowledge this is the first detailed report of surgical resection of testicular seminoma in the giant panda.

Effect of Copper Exposure on the Cholesterol Metabolism in Broiler Liver.

Copper (Cu) is a kind of widely used dietary supplement in poultry production, and a common environmental pollutant at the same time. Excess Cu exposure has been reported to accumulate in the liver and induce cytotoxicity, but the effect of Cu toxicity on hepatic cholesterol metabolism is still uncertain. Herein, we aimed to reveal the effect of excess Cu on the liver and primary hepatocytes of broilers at various concentrations. We found that 110 mg/kg Cu supplement remarkably increased blood cholesterol levels by detecting serum TC, LDL-C, and HDL-C in the broilers, while there was no significant difference in 220 and 330 mg/kg Cu supplements. In addition, high Cu exposure resulted in severe hepatic steatosis and hepatic cord derangement in the broilers. Oil red O staining of primary hepatocytes showed that Cu treatment caused intracellular neutral lipid accumulation. However, the hepatic TC content indicated a downward trend in both liver tissues and hepatocytes after Cu exposure. Furthermore, the expression of cholesterol metabolism-related indicators (SREBP2, HMGCR, LDLR, and CYP7A1) was notably decreased in the Cu-treated groups. While the expression of the key enzyme of cholesterol esterification (ACAT2) did not change significantly. Taken together, our findings preliminarily revealed excess Cu-induced hepatic cholesterol metabolism dysfunction, providing a deeper understanding of the molecular mechanisms of Cu-induced hepatotoxicity.

Cuproptosis is involved in copper-induced hepatotoxicity in chickens.

Copper (Cu) is an essential trace element, but it is also a ubiquitous environmental pollutant that threatens public health. Cuproptosis is a recently discovered cell death mode that unlike other programmed cell death, characterized by proteotoxic stress due to lipoylated protein aggregation and iron-sulfur cluster protein loss. Chickens as a high-trophic-level non-mammalian vertebrate that easily absorb and accumulate copper from the environment and food, but it is unclear whether the underlying molecular mechanisms that cause their hepatotoxicity under natural copper stress are related to cuproptosis. Therefore, we established animal models of chickens with different concentrations of copper exposure to dissect the role and mechanism of cuproptosis in chicken hepatotoxicity under natural copper stress. Our histopathological and biochemical results demonstrated that the liver structure with copper-treated exhibited dose-dependent damage. Meanwhile, copper treatment also dramatically increased serum and liver copper content and activated the expression of the membrane-associated copper transporter ATP7B. Furthermore, we found that Cu-exposure significantly increased the MDA content, and reduced the levels of T-AOC and SOD in serum and liver. Additionally, we found that the mRNA and protein levels of FDX1 were significantly upregulated in the 220 and 330 mg/kg Cu-treated groups. In our further studies, we found that copper did not alter protein levels of DLAT and DLST in chicken liver, but significantly increased Lipoylated-DLAT levels and oligomerization of Lipoylated-DLAT in the 330 mg/kg Cu-treatment group. Overall, we identified that FDX1-mediated protein lipoylation and proteotoxic stress indeed participate in copper-induced hepatotoxicity in chickens. Our results present novel insight into the pathogenesis of copper-induced hepatotoxicity in chickens and provide data to support filling in the role of cuproptosis in birds.

Arsenic Trioxide Triggers Mitochondrial Dysfunction, Oxidative Stress, and Apoptosis via Nrf 2/Caspase 3 Signaling Pathway in Heart of Ducks.

Arsenic is a common environmental pollutant and poses a serious threat to human and animal health. In this study, we used the ducks to mimic arsenic trioxide (ATO) exposure and investigated the mechanism of cardiac toxicity. The results indicated that ATO inhibited the body and organ growth of ducks, led to an increase in LDH content, and caused obvious deformity, ischemia infarction. It is found that ATO exacerbated the swell of mitochondrial and the contraction of cell nuclei in the heart of ducks through transmission electron microscopy (TEM). ATO also induced an increase in MDA content; inhibited the activation of the Nrf 2 pathway; downregulated the expression of mRNA and protein of Nrf 2, HO-1, and SOD-1; and upregulated the expression of mRNA and protein of Keap 1. At the same time, ATO induced apoptosis which not only upregulated the expression levels of mRNA and proteins (Caspase 3, Cyt-C, P53, Bax) but also decreased the mRNA and protein expression level of Bcl-2. These results indicated that ATO can lead to oxidative stress and apoptosis in the heart of ducks. In general, our research shows that ATO triggers mitochondrial dysfunction, oxidative stress, and apoptosis via Nrf 2/Caspase 3 signaling pathway in the heart of ducks.

Curcumin antagonizes inflammation and autophagy induced by arsenic trioxide through immune protection in duck spleen.

Arsenic is a toxic heavy metal widely found in the natural environment and has adverse effects on the health of waterfowl and human. Curcumin (CUR), a natural pigment of the golden spice turmeric, exhibits excellent anti-tumor, anti-inflammatory and anti-oxidant activities. But the effects of CUR on duck spleen exposed to arsenic remain largely unknown. In this study, 75 ducks were divided randomly into Control, L-ATO, M-ATO, H-ATO and CUR + H-ATO groups to systematically analyze the underlying role of CUR. The results showed that arsenic trioxide (ATO) led to growth retardation of ducks, hyaline degeneration and sparse cell arrangement on their spleen. And in the ATO-exposed ducks, the levels of immunoglobulins (Ig; IgA, IgG, IgM) in the serum and the expression of autophagy-related genes (Atg5, P62, LC3I, LC3II, LC3II/I, Beclin-1) were significantly upregulated compared with the control ducks. Moreover, ATO also activated NF-κB signal pathway and upregulated the expression of pro-inflammatory cytokines (TNF-α, IFN-γ, IL-1ß, IL-2, IL-18). Meanwhile, application of CUR alleviated the ATO toxicity with the release of growth inhibition, and the reduced hyaline degeneration and distortion of the spleen capsule. CUR also suppressed ATO-induced NF-κB activation, pro-inflammatory cytokine addition and expression of autophagy-related genes. Overall, these results suggested that CUR might exert a protective effect against ATO-induced immunosuppression in ducks via anti-inflammation and autophagy restoring.