Effect of Selenium Against Lead-Induced Damage on the Gene Expression of Heat Shock Proteins and Inflammatory Cytokines in Peripheral Blood Lymphocytes of Chickens

Molecular mechanism of selenium against lead-induced apoptosis in chicken brainstem relating to heat shock protein, selenoproteins, and inflammatory cytokines

Extensive application of lead (Pb) brought about environmental pollution and toxic reactions of organisms. Selenium (Se) has the effect of antagonizing Pb poisoning in humans and animals. However, it is still unclear how Pb causes brainstem toxicity. In the present study, we wanted to investigate whether Se can alleviate Pb toxicity in chicken brainstems by reducing apoptosis. One hundred and eighty chickens were randomly divided into four groups, namely the control group, the Se group, the Pb group, and the Se/Pb group. Morphological examination, ultrastructural observation, relative mRNA expressions of genes on heat shock proteins (HSPs); selenoproteins; inflammatory cytokines; and apoptosis-related factors were investigated. The results showed that Pb exposure led to tissue damage and apoptosis in chicken brainstems. Furthermore, an atypical expression of HSPs (HSP27, HSP40, HSP60, HSP70, and HSP90); selenoprotein family glutathione peroxidase (GPx) 1, GPx2, GPx3, and GPx4), thioredoxin reductases (Txnrd) (Txnrd1, Txnrd2, and Txnrd3), dio selenoprotein famliy (diodothyronine deiodinases (Dio)1, Dio2, and Dio3), as well as other selenoproteins (selenoprotein (Sel)T, SelK, SelS, SelH, SelM, SelU, SelI, SelO, Selpb, selenoprotein n1 (Sepn1), Sepp1, Sepx1, Sepw1, 15-kDa selenoprotein (Sep15), and selenophosphate synthetases 2 (SPS2)); inflammatory cytokines (Interleukin 2 (IL-2), IL-4, IL-6, IL-12β, IL-17, and Interferon-γ (IFN-γ)); and apoptosis-related genes (B-cell lymphoma-2 (Bcl-2), tumor protein 53 (p53), Bcl-2 Associated X (Bax), Cytochrome c (Cyt c), and Caspase-3) were identified. An inflammatory reaction and apoptosis were induced in chicken brainstems after exposure to Pb. Se alleviated the abnormal expression of HSPs, selenoproteins, inflammatory cytokines, and apoptosis in brainstem tissues of chickens treated with Pb. The results indicated that HSPs, selenoproteins, inflammatory, and apoptosis were involved in Se-resisted Pb poisoning. Overall, Se had resistance effect against Pb poisoning, and can be act as an antidote for Pb poisoning in animals.

Multi-omics unravel the compromised mucosal barrier function linked to aberrant mucin O-glycans in a pig model

Early weaning stress (EWS) in piglets is associated with intestinal dysfunction. Here, utilizing a pig EWS model to mimic early-life stress (ELS) in humans, we investigated the mechanism of ELS-induced intestinal diseases through integrated multi-omics analyses of proteome, glycome, and microbiome. Our results demonstrated that EWS resulted in disrupted the ileal barrier integrity by reducing tight junction-related gene expression and interfering with cell-cell adhesion paralleled the increased proportion of pathogens such as Escherichia_Shigella and Helicobacter. Furthermore, Proteome data revealed that the accumulation of unfolded proteins and insufficient unfolded protein response (UPR) process caused by EWS led to ER stress. Data from proteome and glycome found that EWS induced aberrant mucin O-glycans, including truncated glycans, reduction in acidic glycans, and increased in fucosylated glycans. In addition, correlation test by taking fucose and inflammatory response into account suggested that enhancement of fucose expression might be a compensatory host response. Taken together, these results extend the comprehensive knowledge of the detrimental impacts and pathogenesis of EWS and help to provide intervention targets for ELS-induced intestinal diseases in the future.

NLRP3 inflammasome is involved in the mechanism of mitigative effect of selenium on lead-induced inflammatory damage in chicken kidneys

Lead (Pb) is a kind of widespread toxic environmental pollutant which can cause harm to organisms. Selenium (Se) has the property of mitigating Pb toxicity through decreasing oxidative stress and inflammation caused by Pb. Nucleotide-binding domain, leucine-rich-containing family, and pyrin-domain containing-3 (NLRP3) inflammasome involve in inflammation process. However, the effect of NLRP3 inflammasome in heavy metal-caused animal damage remains unknown. This research aimed to explore the mechanism of mitigative role of Se on Pb-caused renal inflammatory injury in chickens. One-week-old male chickens were provided a standard diet and drinking water, a standard diet added with 1 mg kg^-1 of Se and drinking water, a standard diet and drinking water added with 350 mg L^-1 Pb, and a standard diet added with 1 mg kg^-1 Se and drinking water added with 350 mg L^-1 Pb. On the 4th, 8th, and 12th weeks, serum was used to measure creatinine (CREA) and uric acid (UA) contents, and kidneys were used to measure Se and Pb concentrations, histological structure, oxidative stress indicators, relative expressions of cytokines, and inflammatory factors. The results showed that Pb accumulated, Se concentration decreased, CREA and UA contents increased, and renal injury occurred in Pb-treated chicken kidneys. Excess Pb increased MDA content and the expressions of IL-1β, IL-6, IL-17, NLRP3, caspase-1, NF-κB, COX-2, TNF-α, and PTGEs and decreased GSH content, GPx and SOD activities, and IFN-γ expression in the chicken kidneys. Se administration alleviated the aforementioned changes. In addition, toxic effect of Pb on the chicken kidneys was time-dependent. NLRP3 inflammasome, caspase-1, and IL-1β may be sensitive indicators in Pb-induced chicken kidney inflammatory damage. In conclusion, NLRP3 inflammasome took part in antagonistic role of Se against Pb-caused inflammation via changing oxidative stress indicators, cytokines, and inflammation-related genes in the chicken kidneys.

The Antagonistic Effects of Selenium Yeast (SeY) on Cadmium-Induced Inflammatory Factors and the Heat Shock Protein Expression Levels in Chicken Livers

Cadmium (Cd) is a ubiquitous toxic heavy metal in the natural environment that can cause multiple organ damage to the bodies of animals and humans. Selenium yeast (SeY) is a kind of organic selenium (Se) that has a very strong function against Cd-induced injury to tissues or organs. The aim of the current study was to investigate the roles of inflammatory factors and heat shock proteins (HSPs) in inflammatory injury triggered by Cd and to analyze the protective effects of SeY on Cd-induced damnification in the livers of chickens. Two hundred 120-day-old layers were randomly divided into four groups and raised on a conventional diet, or with Se (0.5 mg/kg SeY), Cd (150 mg/kg CdCl₂), or Se + Cd (0.5 mg/kg SeY and 150 mg/kg CdCl₂) in their basic diets for 120 days. Then, the liver histopathology, production of nitric oxide (NO), activity of inducible NO synthase (iNOS), and mRNA and protein expression levels of inflammatory factors (iNOS, NF-κB, TNF-α, and PTGE) and heat shock proteins (HSPs 27, 40, 60, 70, and 90) were examined. The results showed that exposure to Cd obviously increased Cd accumulation, NO production, iNOS activity, inflammatory factor, and HSP mRNA and protein expression levels and further caused an inflammatory response. Supplementation with SeY had an antagonistic effect on Cd-induced inflammatory injury in chicken livers. Thus, the present study suggests that SeY can be taken as a potential therapeutic for Cd-induced liver inflammatory injury in chickens.

Impact of Maternal Selenium Supplementation from Late Gestation and Lactation on Piglet Immune Function

The present work aimed at assessing passive, innate, and acquired immunity in piglets from sows supplemented with either organic or inorganic selenium (Se). A total of 12 multiparous pregnant sows were randomly allocated to three groups: selenium-deficient, corn and soy-based diet base diet (BD), 0.3 mg Se/kg as hydroxy-selenomethionine (OH-SeMet), and 0.3 mg Se/kg as sodium selenite (SS). The feeding trial was carried out from gd 84 to weaning on postpartum day 21 (ppd 21). On gd 98 and 105, sows were vaccinated with hen egg white lysozyme (HEWL) to assess passive immunity. On ppd 23, weaned piglets were intramuscularly challenged with lipopolysaccharide (LPS) to trigger an acute-phase response. On ppd 14, 28, and 35, piglets were vaccinated with ovalbumin (OVA) to assess OVA-specific immunoglobulin G (IgG) and dermal hypersensitivity responses. Se levels in piglet plasma, muscle, and liver on ppd 21 were higher in OH-SeMet group. On ppd 2, piglet HEWL-specific IgG levels in OH-SeMet group were significantly increased. IL-10 and haptoglobin (HP) levels in OH-SeMet group were significantly increased 2 h and 48 h post-LPS simulation, respectively. The OVA-specific IgG levels in BD group were significantly higher than the other two groups, and the IL-4 concentration following whole blood ex vivo challenge with either OVA or mitogen was significantly increased in OH-SeMet group. OVA-specific skin swelling was lower in OH-SeMet and SS groups at 3 h and 6 h. This suggests that sow supplementation with OH-SeMet enhances mainly passive immunity through IgG maternal transfer and can influence piglet innate and acquired immunity.

Immunotoxic effects of lead on birds

The ingestion of lead (Pb) shot pellets is a well-known cause of avian mortality, but exposure of birds to Pb may have other sublethal effects that can affect population sustainability. One of these effects is the alteration of the immunological status. Pb can affect most components of the avian immune system and imbalance the relationship among them. Pb exposure typically alters the ratio between T_h1- and T_h2-type responses mounted by different classes of T-lymphocytes, causing the depression of the T_h1 responses that are associated with cell-mediated immunity. Immunodepressing effects of Pb on birds are observed at blood levels above 50 μg dL^-1, but developing birds show immunodepressing effects at much lower concentrations (> 10 μg dL^-1). Impacts of Pb on the avian immune system also relate to reduced resistance to infection. We review immunotoxic effects of Pb on birds affected by shot ingestion as well as by other sources of exposure to this element.

Toxicological effects in children exposed to lead: A cross-sectional study at the Colombian Caribbean coast

Lead (Pb) is an environmental pollutant with a toxicity that is a serious public health problem. The aim of this research was to evaluate the associations between Pb exposure and morphometric, hematological and biochemical parameters, mRNA expression of the P53, SOD1, ALAD, TNF and INF-γ genes, ALAD polymorphisms (db SNP ID: rs1800435) and Intelligence Quotient (IQ) in children from the Colombian Caribbean. Blood lead levels (BLL) were determined in 554 participants between the ages of 5-16 years old, from different places of the Colombian Caribbean. A health survey was given to assess risk factors. Whole blood was used for hematology and plasma employed to analyze markers of hepatic toxicity. Gene expression was quantified from blood mRNA by RT-PCR. The ALAD polymorphism was characterized by PCR-RFLP, and the Kaufman's brief intelligence test was employed to estimate the IQ. The mean BLL was 3.5 ± 0.2 μg/dL. The site of greatest exposure to Pb was Tasajera, a poor fishing community, with an average of 8.9 ± 0.8 μg/dL. Breastfeeding was associated with high BLL. Morphometric characteristics and IQ were negatively correlated with BLL. The blood platelet count and the mean corpuscular hemoglobin concentration showed positive and negative correlations with BLL, respectively. Negative relationships with BLL were observed with the ratios Neutrophils/Eosinophils and Neutrophils/Basophils, whereas for BLL and Neutrophils/Monocytes the association was positive. The associations between morphometric and some hematological parameters with BLL were age- and gender-related. The expression of ALAD, SOD1, INF-γ and P53 mRNA was down-regulated according to the BLL, whereas TNF showed an opposite trend. In short, fishing communities are at a high risk of Pb exposure. This xenobiotic can affect physical development and IQ, as well as hematological parameters, even at low concentrations. In addition, it can regulate the transcription of genes associated with inflammation, apoptosis, cell cycle, heme synthesis, and oxidative stress.

Selenium-Yeast Alleviated Inflammatory Damage Caused by Lead via Inhibiting Ras/ERK Pathway and Inflammatory Factors in Chicken Skeletal Muscles

The aim of this study was to investigate the ameliorative effects of selenium-enriched yeast (Se-yeast) on the inflammatory damage induced by lead (Pb) in chicken skeletal muscles. A total of 108 1-day-old broiler chickens were randomly allocated into four groups (n = 27/group): the control group (C group), the Se-yeast-supplemented group (Se group), the lead-treated group (Pb group), and finally the Se- and Pb-combined group (Pb/Se group). The C group was fed with a basic diet comprising 0.049 mg/kg Se and 0.1 mg/kg Pb while the Se group was fed a Se-yeast diet containing 0.30 mg/kg Se and 0.1 mg/kg Pb. Similarly, the Pb group was fed a Pb acetate diet containing 0.049 mg/kg Se and 350 mg/kg Pb while the Pb/Se group was fed with a Se-yeast diet containing 0.30 mg/kg Se and 350 mg/kg Pb. On days 7, 21, and 35 after commencing the experiment, nine chicks belonging to each group were euthanized and the samples were analyzed by employing the techniques of inductively coupled plasma mass spectrometry and real-time quantitative PCR, along with Western blotting. The results indicated that excess Pb increased the nitric oxide concentration, enhanced the activity of inducible nitric oxide synthase (iNOS), and the mRNA levels of interleukin 1β (IL-1β), interleukin 4 (IL-4), interleukin 10 (IL-10), and interferon gamma (IFN-γ) in a time-dependent manner. Further, it was found that Se reduced damage caused by Pb by decreasing the expression of inflammatory factors in chicken skeletal muscles. Taken together, the results from this study provide the theoretical basis for an alleviate effect of Se on Pb-induced inflammatory damage in chicken skeletal muscles, mediated by inhibiting the Ras/extracellular signal-regulated kinase (ERK) pathway and the inflammatory factors.

Effect of selenium antagonist lead-induced damage on Th1/Th2 imbalance in the peripheral blood lymphocytes of chickens

Lead (Pb) is a type of toxic metal that can hurt the immune system. Selenium (Se) can reduce the damage caused by heavy metals. To investigate the effects of Se against Pb on bird immune cells, as well as the immunotoxin mechanism of Pb, Se supplementation and/or Pb poisoning chicken models were established. One hundred eighty 1-year-old broiler chickens were randomly divided into four groups (n = 6). The four groups were the control group, the selenium-rich group (Se group), the Pb supplementation group (Pb group) and the Se and Pb compound group (Se + Pb group). The peripheral blood lymphocytes of chickens were collected to test the selenoproteins and cytokine mRNA levels at 30 and 60 d. Determination of the content of Se and Pb in the serum, principal component analysis and ingenuity pathway analysis were performed at the two time points. As a result, Pb exposure increased the content of Pb, activating the Th1/Th2 pathway in peripheral blood lymphocytes. Additionally, this experiment showed that Se supplementation and Pb exposure could influence the mRNA levels of selenoproteins and cytokines in the peripheral blood lymphocytes of chickens. However, all of the parameters that we detected in the experiment indicated that Se supplementation could alleviate the increase of selenoproteins and cytokine mRNA levels and the Th1/Th2 imbalance induced by Pb in peripheral blood lymphocytes. In summary, Se can alleviate the toxic effects caused by Pb in the peripheral blood lymphocytes of chickens, suggesting the antagonism between Se and Pb.

Avian Stress-Related Transcriptome and Selenotranscriptome: Role during Exposure to Heavy Metals and Heat Stress

Selenium, through incorporation into selenoproteins, is one of the key elements of the antioxidant system. Over the past few years there has been increased interest in exploring those molecular mechanisms in chicken, responsible for the development of this protection system. In more detail, Cd/Pb poisoning and heat stress increase oxidation, mRNA levels of inflammatory proteins, and apoptotic proteins. Selenium seems to enhance the antioxidant status and alleviates these effects via upregulation of antioxidant proteins and other molecular effects. In this review, we analyze avian transcriptome key elements with particular emphasis on interactions with heavy metals and on relation to heat stress.

Ammonia exposure induced abnormal expression of cytokines and heat shock proteins via glucose metabolism disorders in chicken neutrophils

Ammonia (NH₃) is a highly irritant, alkaline gas. Atmospheric emission of NH₃ was recognized as an environmental challenge. As a global issue, the NH₃ emission survey with spatially detailed information demonstrated that the sources of atmospheric NH₃ include agriculture (livestock wastes, fertilizers) and some industrial activities. As an environmental pollution, excessive NH₃ exposure can induce many bird dysfunction. Neutrophils respond to multiple invading pathogens through different mechanisms. In order to investigate the effect of NH₃ exposure on broilers' neutrophil, 1-day-old broilers were treated with/without NH₃ for 28 days. We extracted neutrophils from peripheral blood of chicken with/without NH₃ exposure and subsequently stimulated with PMA. Changes of cytokines and inflammatory bodies, heat shock proteins (HSPs), and glucose metabolism of neutrophil were examined in both cases. We not only explored that the index associated with inflammation changed due to NH₃ exposure but also observed the status of neutrophils which was treated with PMA stimulation. After NH₃ exposure, IL-1β and IL-6 were significantly increased on broilers neutrophil. Inflammatory-related factors (NLRP3, ASC, and caspase-1) were significantly elevated. The mRNA expression of HSP70 and HSP90 was increased significantly. All glucose metabolism indicators were reduced. In summary, we concluded that NH₃ enhanced inflammation and disrupted glucose metabolism, and increased the expression of HSPs and inflammatory factors. In addition, the sensitivity of neutrophils to exogenous stimuli was diminished. This information can not only be used to evaluate the damage of NH₃-spiked neutrophils to chickens, but also provide clues for human health pathophysiology caused by excess NH₃, providing valuable information for NH₃ risk management.

Dietary selenium supplementation alleviates immune toxicity in the hearts of chickens with lead-added drinking water

Lead (Pb) is an environmental pollutant and can damage organisms. Selenium (Se) can alleviate Pb poisoning. The present study aimed to investigate the alleviative effect of Se on Pb-induced immune toxicity in chicken hearts. One-hundred-and-eighty Hy-line male chickens were randomly divided into four groups at 7 days of age. The control group was offered a standard commercial diet (SD) and drinking water (DW); the Se group was offered SD supplemented with sodium selenite (SeSD) and DW; the Pb + Se group was offered SeSD and DW supplemented with lead acetate (PbDW); and the Pb group was offered SD and PbDW. Relative mRNA expression of inducible nitric oxide synthase (iNOS), interleukins (IL-2, IL-4, IL-6, IL-12β, IL-17 and IFN-γ), and heat shock proteins (HSP27, HSP40, HSP60, HSP70, and HSP90) were determined by means of quantitative real-time PCR. Relative protein expression of iNOS, HSP60, HSP70, and HSP90 was assessed, as well as nitric oxide (NO) content and iNOS activity in heart tissue. The results indicated a down-regulation of interleukin (IL)-2 and IFN-γ and an up-regulation of NO, iNOS, interleukins (IL-4, IL-6, IL-12β, IL-17), and heat shock proteins (HSP27, HSP40, HSP60, HSP70, and HSP90) in Pb-damaged hearts. Se alleviated all of the above Pb-induced changes. There were time-dependent effects on NO content, iNOS activity, and mRNA levels of iNOS, IL-2, IL-4, IL-6, IL-17, HSP27, HSP40, HSP60, HSP70, and HSP90 after Pb treatment in the chicken hearts. Se alleviated Pb-induced immune toxicity in the chicken hearts.

Selenium and zinc protections against metal-(loids)-induced toxicity and disease manifestations: A review

Metals are ubiquitous in the environment due to huge industrial applications in the form of different chemicals and from extensive mining activities. The frequent exposures to metals and metalloids are crucial for the human health. Trace metals are beneficial for health whereas non-essential metals are dangerous for the health and some are proven etiological factors for diseases including cancers and neurological disorders. The interactions of essential trace metals such as selenium (Se) and zinc (Zn) with non-essential metals viz. lead (Pb), cadmium (Cd), arsenic (As), and mercury (Hg) in biological system are very critical and complex. A huge number of studies report the protective role of Se and Zn against metal toxicity, both in animal and cellular levels, and also explain the numerous mechanisms involved. However, it has been considered that a tiny dyshomeostasis in the metals/trace metals status in biological system could induce severe deleterious effects that can manifest to numerous diseases. Thus, in this particular review, we have demonstrated the critical protection mechanism/s of Se and Zn against Cd, Pb, As and Hg toxicity in a one by one manner to clarify the up-to-date findings and perspectives. Furthermore, biomolecular consequences are comprehensively presented in light of particular cellular/biomolecular events which are somehow linked to a subsequent disease. The analyzed reports support significant protection potential of Se and Zn, either alone or in combination with other agents, against each of the abovementioned non-essential metals. However, Se and Zn are still not being used as detoxifying agents due to some unexplained reasons. We hypothesized that Se could be a potential candidate for detoxifying As and Hg regardless of their chemical speciations, but requires intensive clinical trials. However, particularly Zn-Hg interaction warrants more investigations both in animal and cellular level.

The effects of atmospheric hydrogen sulfide on peripheral blood lymphocytes of chickens: Perspectives on inflammation, oxidative stress and energy metabolism

Excessive hydrogen sulfide (H₂S) affects poultry health. Exposure to air pollution induces inflammation, oxidative stress, energy metabolism dysfunction and adverse health effects. However, few detailed studies have been conducted on the molecular mechanisms of H₂S-induced injury in poultry. To understand how H₂S drives its adverse effects on chickens, twenty-four 14-day-old chickens were randomly divided into two groups. The chickens in the control group were raised in a separate chamber without H₂S, and the chickens in the treatment group were exposed to 30 ppm H₂S. After 14 days of exposure, peripheral blood samples were taken and the lymphocytes were extracted to detect inflammation, oxidative stress and energy metabolism in broilers. Overall, an increase in the inflammatory response was detected in the peripheral blood lymphocytes following H₂S exposure compared to the control group, and the expression levels of the heat shock proteins (HSPs) and the transcription factors nuclear factor κB (NF-κB), cyclooxygenase 2 (COX-2) and inducible nitric oxide synthase (iNOS) were up-regulated in the H₂S group, which further suggested that H₂S induced an inflammatory response via the NF-κB pathway. Because of the activation of NF-κB, which is a major regulator of oxidative stress, we also observed that reactive oxygen species (ROS) production was elevated under H₂S exposure. In addition, we presumed that energy metabolism might be damaged due to the increased ROS production, and we found that H₂S down-regulated the expression levels of energy metabolism-related genes, which indicated the occurrence of energy metabolism dysfunction. Altogether, this study suggests that exposure to excessive atmospheric H₂S induces an inflammatory response, oxidative stress and energy metabolism dysfunction, providing a reference for comparative medicine.

The Antagonistic Effect of Selenium on Lead-Induced Immune Dysfunction via Recovery of Cytokine and Heat Shock Protein Expression in Chicken Neutrophils

Lead (Pb) is a ubiquitous and toxic heavy metal and it can damage the immune system in humans and animals. Many researchers have reported that Selenium (Se) could possess various pharmacological effects in mammals. However, few studies have been carried out to investigate the protective role of Se in birds, especially in chickens. In this study, we investigated the protective effects of Se against Pb-induced inflammatory responses and the expression of heat shock proteins (HSPs) in peripheral blood neutrophils. One hundred eighty Hy-Line brown chickens were randomly divided into the control group (Con group), Se supplementation group (+Se group), Pb supplementation group (+Pb group), and the Se and Pb compound group (Se+Pb group). On the 90th day of the experiment, the peripheral blood was collected to extract neutrophils, and then, the levels of HSPs and cytokines were examined. The results showed that, after Pb treatment, the levels of IL-(1β, 1R, 4, 8, 10, and 12β), TGF-β4, and HSP (27, 40, 60, 70, and 90) mRNA were significantly increased and levels of IL-2 and IFN-γ mRNA were decreased compared with those in the control group. Compared with the control group, the protein levels of HSP60 and HSP70 were also increased in the Pb treatment group. Co-administration of Se (1 mg/kg/day) and Pb resulted in a reversal of the Pb-induced cytokine changes in neutrophils accompanied by a significant decrease in HSPs. Our study demonstrated that Pb could decrease the immune function via changing the expression of cytokines and HSPs in chicken neutrophils, but Se could relieve the toxic effect induced by Pb.

Antagonistic effects of selenium on lead-induced autophagy by influencing mitochondrial dynamics in the spleen of chickens

Lead (Pb) may damage the immune function in human and animal. Selenium (Se) has antagonistic effects on Pb. In our study, brown layer chickens were randomly allocated to control group, Se group (1 mg/kg Se), Se+Pb group (1 mg/kg Se and 350 mg/kg Pb), and Pb group (350 mg/kg Pb). The chickens were sacrificed on the 90^th day; spleen tissues were subjected to observation of ultrastructure and detection of spleen-related indexes. The results revealed that in the Pb group, expression levels of the cytokines IL-1 and TNF-α significantly increased, and expression levels of IL-2 and INF-γ significantly decreased; activities of antioxidant enzyme GPX, SOD and CAT significantly decreased, and expression level of malondialdehyde (MDA) significantly increased; expression levels of mitochondrial fission-related genes (Mff and Drp1) significantly increased, and expression levels of mitochondrial fusion-related genes (Opa1, Mfn1 and Mfn2) significantly decreased; expression of autophagy-related genes (Beclin 1, Dynein, Atg 5, LC3-I and LC-II) was upregulated, while expression of mammalian target of rapamycin (mTOR) was downregulated. The results of transmission electron microscopy indicated that Pb induced mitochondrial fragmentation, and triggered autophagy in the spleen of chickens. The Se and Pb co-treatment remarkably alleviated these injuries induced by Pb in the spleen of chickens. In conclusion, Pb can induce the oxidative stress to influence the mitochondrial dynamics balance and lead to autophagy, which triggers the immune dysfunction in the spleen of chickens; the Se exhibits the antagonistic effects on lead-induced autophagy by influencing mitochondrial dynamics in the spleen of chickens.

The Antagonistic Effect of Selenium on Cadmium-Induced Damage and mRNA Levels of Selenoprotein Genes and Inflammatory Factors in Chicken Kidney Tissue

Selenium (Se) is a necessary trace mineral in the diet of humans and animals. Cadmium (Cd) is a toxic heavy metal that can damage animal organs, especially the kidneys. Antagonistic interactions between Se and Cd have been reported in previous studies. However, little is known about the effects of Se against Cd toxicity and on the mRNA levels of 25 selenoprotein genes and inflammatory factors in chicken kidneys. In the current study, we fed chickens with a Se-treated, Cd-treated, or Se/Cd treated diet for 90 days. We then analyzed the mRNA expression of inflammatory factors (including prostaglandin E synthase (PTGES), nuclear factor-kappa B (NF-κB), tumor necrosis factor-α (TNF-α), and cyclooxygenase-2 (COX-2)) and 25 selenoprotein genes (Gpx1, Gpx2, Gpx3, Gpx4, Txnrd1, Txnrd2, Txnrd3, Dio1, Dio2, Dio3, SPS2, Sepp1, SelPb, Sep15, Selh, Seli, Selm, Selo, Sels, Sepx1, Selu, Selk, Selw, Seln, Selt). The results demonstrated that Cd exposure increased the Cd content in the chicken kidneys, renal tubular epithelial cells underwent denaturation and necrosis, and the tubules became narrow or disappeared. However, Se supplementation reduced the Cd content in chicken kidneys and induced normal development of renal tubular epithelial cells. In addition, we also observed that Se alleviated the Cd-induced increase in the mRNA levels of inflammatory factors and ameliorated the Cd-induced downtrend in the mRNA levels of 25 selenoprotein genes in chicken kidneys.

Environmental Lead and Wild Birds: A Review

Lead is a persistent inorganic environmental pollutant that affects humans and animals worldwide. Avian species are especially susceptible to lead exposure through consumption of lead ammunition, lead fishing tackle, and other contaminated food sources such as aquatic species ingesting lead contaminated sediments in mining areas. Even with government regulations on the use of lead ammunition in many countries, including the United States, terrestrial, aquatic, predatory, and scavenger avian species are still at risk of exposure to potentially lethal concentrations of lead. The toxicities seen in these avian species include increased oxidative stress and decreased anti-oxidant enzymes in hepatic and renal tissue. The avian immune system is also a target of lead and displays a number of altered functions suggestive of immune suppression; however, studies in wildlife and laboratory species remain too limited for definitive statements with regard to population risk. In contrast, lead clearly inhibits reproductive capabilities in adult birds, and alters growth and development of hatchlings. Environmental remediation for lead removal, which would lower toxic exposure in wildlife, presently is a monumental and prohibitively expensive effort. Wildlife exposure will therefore continue in contaminated areas, necessitating development of new remediation practices. These plans should aim toward limiting more widespread or heavier contamination of wildlife habitats. This chapter reviews presently available information of lead toxicity in wild bird species, and suggests continued monitoring and reduction strategies to reduce lead exposure for at-risk avian populations.

Arsenic affects inflammatory cytokine expression in Gallus gallus brain tissues

Background

The heavy metal arsenic is widely distributed in nature and posses a serious threat to organism’s health. However, little is known about the arsenic-induced inflammatory response in the brain tissues of birds and the relationship and mechanism of the inflammatory response. The purpose of this study was to explore the effects of dietary arsenic on the expression of inflammatory cytokines in the brains of Gallus gallus.

Results

Seventy-two 1-day-old male Hy-line chickens were divided into a control group, a low arsenic trioxide (As₂O₃)-treated (7.5 mg/kg) group, a middle As₂O₃-treated (15 mg/kg) group, and a high As₂O₃-treated (30 mg/kg) group. Arsenic exposure caused obvious ultrastructural changes. The mRNA levels of the transcription factor nuclear factor-κB (NF-κB) and of pro-inflammatory cytokines, including inducible NO synthase (iNOS), cyclooxygenase-2 (COX-2), and prostaglandin E synthase (PTGEs), in chicken brain tissues (cerebrum, cerebellum, thalamus, brainstem and myelencephalon) on days 30, 60 and 90, respectively, were measured by real-time PCR. The protein expression of iNOS was detected by western blot. The results showed that after being treated with As₂O_3, the levels of inflammatory-related factor NF-κB and pro-inflammatory cytokines in chicken brain tissues increased (P < 0.05).

Conclusions

Arsenic exposure in the chickens triggered host defence and induced an inflammatory response by regulating the expression of inflammatory-related genes in the cerebrum, cerebellum, thalamus, brainstem and myelencephalon. These data form a foundation for further research on arsenic-induced neurotoxicity in Gallus gallus.

Electronic supplementary material

The online version of this article (doi:10.1186/s12917-017-1066-8) contains supplementary material, which is available to authorized users.

Alleviative effect of selenium on inflammatory damage caused by lead via inhibiting inflammatory factors and heat shock proteins in chicken testes

The aim of this study was to investigate ameliorative effect of selenium (Se) on lead (Pb)-induced inflammatory damage in chicken testes. One hundred eighty 7-day-old male chickens were randomly assigned into the control group, the Se group, the Pb group, and the Pb/Se group. Lead acetate was added in drinking water (350 mg/L Pb). Sodium selenite was added in the standard commercial diet (1 mg/kg Se). On the 30th, 60th, and 90th days of the experiment, 15 chickens of each group were euthanized. Inductively coupled plasma mass spectrometry, hematoxylin and eosin staining, real-time quantitative PCR, and Western blot were used. The results indicated that excess Pb increased nitric oxide content; inducible nitric oxide synthase (iNOS) activity; nuclear factor-kappa B (NF-κB), tumor necrosis factor-α, cyclooxygenase-2, prostaglandin E synthases, and iNOS mRNA levels in a time-dependent manner; NF-κB, iNOS, heat shock protein (HSP) 60, HSP70, and HSP90 protein levels; and Pb concentration. Excess Pb decreased Se concentration and induced histological changes. Se-alleviated Pb caused all of the above changes. Se improved Pb-caused inflammatory damage by decreasing the expression of inflammatory factors and heat shock proteins in the chicken testes. Our results provided theoretical basis of an alleviative effect of Se on Pb-induced bird testis damage.

Antagonistic effects of selenium on cadmium-induced apoptosis by restoring the mitochondrial dynamic equilibrium and energy metabolism in chicken spleens

The aim of this study was to investigate the mechanism of cadmium-induced apoptosis in chicken spleens and the antagonistic effects of selenium. We duplicated the selenium-cadmium interaction model and examined the expression of apoptosis-, immune-, mitochondrial dynamics- and energy metabolism-related genes. The results demonstrated that after treatment with cadmium, the frequency of apoptosis was significantly increased, and the morphological characteristics of apoptosis were observed. The expression of pro-apoptotic genes was increased, and that of anti-apoptotic genes was decreased. The mRNA levels of tumor necrosis factor-α and interlenkin-1β were observably increased, but the interlenkin-2 and interferon-γ levels were markedly decreased. Furthermore, the mRNA and protein levels of dynamin-related protein 1 and mitochondrial fission factor were significantly enhanced, whereas mitofusin 1, mitofusin 2, and optic atrophy 1 were markedly decreased. The expression of hexokinase 1, hexokinase 2, aconitase 2, lactate dehydrogenase A, lactate dehydrogenase B, succinatedehydrogenase B, pyruvate kinase and phosphofructokinase were also reduced. Selenium supplements remarkably attenuated cadmium-induced effects (p < 0.05). Based on the above results, conclude that the cadmium treatment promoted a mitochondrial dynamic imbalance and reduced energy metabolism, leading to apoptosis and immune dysfunction in chicken spleens, and selenium had an antagonistic effect on Cd-induced apoptosis.

The influence of occupational chronic lead exposure on the levels of selected pro-inflammatory cytokines and angiogenic factors

The aim of the study was to determine the effect of occupational exposure to lead on the blood levels of pro-inflammatory cytokines and selected factors that influence angiogenesis. The study population was divided into two groups. The first group consisted of 56 male workers chronically exposed to lead. The second group (control) was comprised of 24 male administrative workers. The serum levels of interleukin 1β (IL-1β), interleukin 6 (IL-6), and tumor necrosis factor α (TNF-α) were significantly higher in the group of workers chronically exposed to lead compared to control values by 38%, 68%, and 57%, respectively. Similarly, the values of soluble vascular endothelial growth factor receptor-1 (sVEGFR-1) and fibroblast growth factor-basic (FGF-basic) were higher by 19% and 63%, respectively. In the group of workers chronically exposed to lead, there were positive correlations between the levels of pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α) and angiogenic factors (VEGF, FGF-basic, sVEGFR-1, and soluble angiopoietin receptor). In the control group, there were no correlations between the levels of the abovementioned parameters. Results of the present study indicate that chronic occupational lead exposure promotes inflammatory processes via induction of pro-inflammatory cytokines, modulates angiogenesis, and elicits interdependencies between the immune response and angiogenic factors.

Antagonistic effect of selenium on lead-induced inflammatory injury through inhibiting the nuclear factor-κB signaling pathway and stimulating selenoproteins in chicken hearts

In the chicken model of Pb and Se, Se alleviated Pb-induced the changes of inflammatory factors, selenoproteins, and histology. Se alleviated Pb-induced inflammatory injury through inhibiting NF-κB signaling pathway and stimulating selenoproteins in the chicken hearts.