Effects of Dietary Selenium Against Lead Toxicity Are Related to the Ion Profile in Chicken Muscle

Selenium and zinc supplementation mitigates metals-(loids) mixture- mediated cardiopulmonary toxicity via attenuation of antioxidant, anti-inflammatory and antiapoptotic mechanisms in female Sprague Dawley rats

This study evaluated the cardiopulmonary protective effects of essential elements (Zn and Se) against heavy metals mixture (HMM) exposure. Twenty five female Sprague Dawley albino rats, divided in to five groups: controls were orally treated only with distilled water; next, group 2 was exposed to HMM with the following concentrations: 20 mg/kg of Pb body weight, 0.40 mg/kg of Hg, 0.56 mg/kg of Mn, and 35 mg/kg of Al. Groups 3, 4 and 5 were exposed to HMM and co-treated with zinc chloride (ZnCl2; 0.80 mg/kg), sodium selenite (Na2SeO3;1.50 mg/kg) and both zinc chloride and sodium selenite, respectively. The experiment lasted for 60 days. Afterwards animals were sacrificed, and we conduced biochemical and histopathological examination of the heart and lungs. HMM only exposed animals had an increased levels of malondialdehyde (MDA) and nitric oxide (NO), increased IL-6 and TNF-α, attenuated SOD, GPx, CAT and GSH and caspase 3 in the heart and lungs. HMM affected NF-kB and Nrf2 in the heart muscle with histomorphological alterations. Zn and Se attenuated adverse effects of HMM exposure. Essential element supplementation ameliorated heavy metal cardiopulmonary intoxication in rats.

A combination of selenium and Bacillus subtilis improves the quality and flavor of meat and slaughter performance of broilers

This study aimed to investigate the effects of the combination of selenium and Bacillus subtilis (Se-BS) on the quality and flavor of meat and slaughter performance of broilers. A total of 240 one-day-old Arbor Acres broilers were randomly allotted to four treatments of a basal diet supplemented with no selenium (control), sodium selenite (SS), BS, or Se-BS and raised for 42 days. Compared with the control group, Se-BS significantly increased the carcass weight, the half-eviscerated weight, the completely eviscerated weight, the carcass rate, and redness in broiler muscles; improved the antioxidant state by increasing glutathione peroxidase (GPx) and glutathione S-transferase activities, the total antioxidant capacity, and GPx-1 and thioredoxin reductase 1 messenger RNA (mRNA) levels; promoted biological activity by increasing the contents of glutamate, phenylalanine, lysine, and tyrosine; and increased Se and five types of nitrogenous volatile substances in muscles. On the other hand, Se-BS treatment decreased the shear force, drip loss, and the malondialdehyde, glutathione, and lead contents in muscles. Se-BS exerted a better effect on slaughter performance, the physicochemical quality of meat, the redox status, the amino acid contents, the trace element contents, and volatile substances compared with SS and BS. In conclusion, Se-BS had a positive effect on the quality and flavor of meat and slaughter performance of broilers, suggesting that Se-BS may be a beneficial feed additive.

Molecular Mechanisms of Selenium Mitigating Lead Toxicity in Chickens via Mitochondrial Pathway: Selenoproteins, Oxidative Stress, HSPs, and Apoptosis

Lead (Pb), a hazardous heavy metal, can damage the health of organisms. However, it is not clear whether Pb can damage chicken cerebellums and thalami. Selenium (Se), an essential nutrient for organisms, has a palliative effect on Pb poisoning in chickens. In our experiment, a model of chickens treated with Pb and Se alone and in combination was established to investigate the molecular mechanism of Se alleviating Pb-caused damage in both chicken cerebellums and thalami. Our morphological results indicated that Pb caused apoptotic lesions, such as mitochondrial and nuclear damage. Further, the anti-apoptotic gene Bcl-2 decreased; on the contrary, four pro-apoptotic genes (p53, Bax, Cyt c, and Caspase-3) increased under Pb treatment, meaning that Pb caused apoptosis via the p53-Cyt c-Caspase-3 pathway. Furthermore, we further demonstrated that Pb elevated four HSPs (HSP27, HSP40, HSP70, and HSP90), as well as HSP70 took part in the molecular mechanism of Pb-caused apoptosis. In addition, we found that Pb exposure led to oxidative stress via up-regulating the oxidant H2O2 and down-regulating four antioxidants (CAT, SOD, GST, and GPx). Moreover, Pb decreased three Se-containing factors (Txnrd1, Txnrd2, and Txnrd3), further confirming that Pb caused oxidative stress. Interestingly, Se supplementation reversed the above changes caused by Pb and alleviated Pb-induced oxidative stress and apoptosis. A time dependency was demonstrated for Bcl-2, Bax, and Cyt c in the cerebellums, as well as CAT, GPx, and p53 in the thalami of Pb-exposed chickens. HSP70 in cerebellums and HSP27 in thalami were more sensitive than those in thalami and cerebellums, respectively, under Pb exposure. Pb-induced apoptosis of thalami was more severe than cerebellums. In conclusion, after Pb treatment, Txnrds mediated oxidative stress, oxidative stress up-regulated HSPs, and finally, HSP70 triggered apoptosis. Se supplementation antagonized Pb-induced oxidative stress and apoptosis via the mitochondrial pathway and selenoproteins in chicken cerebellums and thalami. This study provides new information for the mechanism of environmental pollutant poisoning and the detoxification of Se on abiotic stress.

Molybdenum fertilizer improved antioxidant capacity of Chinese Merino sheep under compound contamination

To investigate the response of different levels of molybdenum (Mo) fertilizer to Chinese Merino sheep (Junken Type) grazing on natural heavy metal-contaminated meadows, this study was carried out in the Bayanbulak Grassland lying in the northwest of Xinjiang Uygur Autonomous Region, China. A total of 24-hm2 polluted meadows were fenced and were randomly divided into four groups (3 replication/group and 2 hm2/replication) applied 0-kg Mo, 1-kg Mo, 2-kg Mo, and 3-kg Mo (ammonium molybdate tetrahydrate) per hectare for the CON group, group I, group II, and group III, respectively. Seventy-two healthy 1-year-old Chinese Merino sheep (45.56 ± 2.35 kg) were randomly assigned to the tested pastures for 90 days. Compared with the CON group, the Mo content from fertilized groups and the Se content from group II and group III in serums and livers were significantly increased (P < 0.05), and the Cu content from fertilized groups in serums and livers was significantly decreased (P < 0.05). The levels of blood Hb and RBC, and the activities of serum SOD, CAT, GSH-Px, and Cp in group III, were significantly higher (P < 0.05) than those in the CON group, group I, and group II. Serum MDA content in group III was significantly lower (P < 0.05) than that in the other three groups. In summary, Mo fertilization improved the antioxidant capacity of grazing sheep and also reduced the toxic damage to Chinese Merino sheep grazing on natural grasslands contaminated by heavy metals, but Mo poisoning caused by excessive fertilization should be prevented.

Selenium alleviates cadmium-induced oxidative stress, endoplasmic reticulum stress and programmed necrosis in chicken testes

Cadmium (Cd) is a common heavy metal pollutant, and one of the important target organs of its toxicity is the testis. Selenium (Se) has the ability to antagonize the toxicity of Cd. However, the mechanism of the alleviating effects of Se on Cd in chicken testis injury through oxidative stress, endoplasmic reticulum stress (ERS), and programmed necrosis remained unclear. To explore this, 80 7-day-old chickens were divided into the Control group, the Se group (1.00 mg/kg Se), the Cd group (150.00 mg/kg Cd), and the CdSe group. On the 30th and 60th days, serum and chicken testis tissue samples were collected for testing. The results showed that Cd exposure resulted in swelling and deformation of seminiferous tubules, and thinning of the seminiferous epithelium. The ROS and MDA increased, and the SOD, CAT, GSH, GSH-Px decreased. The expression of GRP78, PERK, IRE1, ATF6, CHOP, and JNK in the Cd group increased. The expression of TNF-α, TNFR1, RIP1, RIP3, MLKL, and PARP1 increased, while the expression of Caspase-8 decreased. Histopathological changes, oxidative stress, ERS, and programmed necrosis were improved after CdSe treatment. In conclusion, Se antagonized the toxicity of Cd, and Se could alleviate Cd-induced oxidative stress, ERS, and programmed necrosis in chicken testis.

Associations of blood metals with liver function: Analysis of NHANES from 2011 to 2018

BACKGROUND

Heavy metals have been reported to affect liver function. However, there is currently little and inconsistent knowledge about the effects of combined and individual blood metals on specific parameters of liver function in the general population. Hence, this study aimed to elucidate their associations.

METHODS

Data from National Health and Nutrition Examination Survey (NHANES) 2011-2018 were used in this cross-sectional study. Multivariate linear, and a quantile-based g-computation (qgcomp) were applied to explore the associations between blood metals [mercury (Hg), manganese (Mn), lead (Pb), cadmium (Cd), selenium (Se)], alone and in combination, and liver function parameters [alanine transaminase (ALT), aspartate transaminase (AST), ALT/AST, alkaline phosphatase (ALP), gamma-glutamyl transferase (GGT) and serum total bilirubin (TBIL)].

RESULTS

A total of 15,328 were included. Multivariate linear models indicated that liver function was significantly associated with blood heavy metals. The most significant relationship was found between Se and AST (β 5.09, 95%CI (3.28,6.91), p＜0.001), Mn and ALT (β 1.24, 95%CI (0.57, 1.91), p＜0.001). Furthermore, the qgcomp analysis showed that the combination of five blood metals was positively associated with AST, ALT, GGT, TBIL and HSI. Cd contributed the most to the correlation of AST (weight = 0.447), Se contributed the most to the association of ALT (weight = 0.438) and HSI (weight = 0.570), Pb contributed the most to the association of GGT (weight = 0.421) and Hg contributed the most to the correlation of TBIL (weight = 0.331).

CONCLUSIONS

Blood heavy metal levels were significantly associated with liver function parameters. Further studies are required to clarify the relationship between heavy metals and liver function.

Association Between the Ratios of Selenium to Several Elements and Mild Cognitive Impairment in the Elderly

To investigate the relationship between the correlation ratios of selenium (Se) and other elements and mild cognitive impairment (MCI) among older adults. A total of 1000 individuals participated in our research analysis. The concentrations of elements in whole blood were determined using inductively coupled plasma mass spectrometry to reflect their exposure levels. Participants' cognitive function was assessed using the Mini-Mental State Examination. Logistic regression analysis was used to evaluate the relationship between elemental ratios and MCI. Se concentration was positively correlated with red blood cell count (r = 0.219, p < 0.001), haemoglobin level (r = 0.355, p < 0.001), haematocrit (r = 0.215, p < 0.001), mean corpuscular haemoglobin (r = 0.294, p < 0.001) and mean corpuscular haemoglobin concentration (r = 0.428, p < 0.001) and negatively correlated with red cell volume distribution width-standard deviation (r = -0.232, p < 0.001) and platelet distribution width (r = -0.382, p < 0.001). Compared with the normal group, the ratios of Se/vanadium (V), Se/lead (Pb) and Se/cadmium (Cd) in the whole blood of the MCI group were significantly lower (all p < 0.001), while the ratios of manganese (Mn)/Se and iron (Fe)/Se were higher (all p < 0.001). The increase in the ratios of Se/V, Se/Pb and Se/Cd is related to a decreased risk of MCI among older adults; contrarily, an increase in the ratios of Mn/Se and Fe/Se may be a risk factor for MCI.

Effects of Selenium Supplementation on the Ion Homeostasis in the Reproductive Organs and Eggs of Laying Hens Fed With the Diet Contaminated With Cadmium, Lead, Mercury, and Chromium

The objective of this study was to explore the toxic effects of different heavy metals in combination with their deposition and ion homeostasis in the reproductive organs and eggs of laying hens, as well as the alleviating action of selenized yeast. A total of 160 Lohmann pink-shell laying hens (63-week-old) were randomly allocated into four treatments with 10 replicates of four hens each. The four dietary treatments were the corn-soybean meal basal dietary (control; CON); the CON dietary supplemented with 0.4 mg/kg selenium from selenized yeast (Se); the CON dietary supplemented with 5 mg/kg Cd + 50 mg/kg Pb +3 mg/kg Hg + 5 mg/kg Cr (HEM), and the HEM dietary supplemented with 0.4 mg/kg selenium from selenized yeast (HEM+Se). The dietary HEM significantly increased Cd, Pb, and Hg deposition in the egg yolk and ovary, and Cd and Hg deposition in the oviduct and in the follicular wall (p < 0.05). The HEM elevated Fe concentration in the egg yolk, ovary, and oviduct (p < 0.05). The HEM decreased Mn concentration in the egg yolk, Fe, Mn, and Zn concentrations in the egg white, Cu concentration in the ovary, Mg concentration in the oviduct, as well as Ca, Cu, Zn, and Mg concentrations in the follicular walls (p < 0.05). Dietary Se addition elevated Se concentration in the egg yolk, oviduct, and follicular walls and Mg concentration (p < 0.05) in the oviduct, whereas it reduced Fe concentration in the oviduct compared with the HEM-treated hens. Some positive or negative correlations among these elements were observed. Canonical Correlation Analysis showed that the concentrations of Pb and Hg in the egg yolk were positively correlated with those in the ovary. The concentration of Cd in the egg white was positively correlated with that in the oviduct. In summary, dietary Cd, Pb, Hg, and Cr in combination caused ion loss and deposition of HEM in reproductive organs of laying hens. Dietary Se addition at 0.4 mg/kg from selenized yeast alleviated the negative effects of HEM on Fe and Mg ion disorder in the oviduct and follicle wall of hens.

Effect of Dietary Enrichment with Flaxseed, Vitamin E and Selenium, and of Market Class on the Broiler Breast Meat-Part 1: Nutritional and Functional Traits

The effect of dietary enrichment with flaxseed, selenium and vitamin E, and market class on the nutritional and functional value of breast meat was evaluated. A completely randomized block design was set up, where the experimental unit (n = 6000 birds) received conventional or enriched diet and was slaughtered at 37 (light class), 47 (medium class), or 57 (heavy class) days of life. Hence, functional and standard Pectoralis major muscles from every market class were analyzed for FA composition, inorganic elements and vitamin E. Lipid metabolism indices and health lipid indicators were assessed along with the nutritional value. A multiple linear model revealed that in breasts, the dietary treatment significantly influenced (p < 0.05) the FA profile, lipid metabolism and health lipid indices, while the slaughtering weight was related (p < 0.05) to most of elements (e.g., Na, Mg, K, Mn, and Se) and vitamin E. The interdependence of the two factors had strong relations (p < 0.05) with total PUFAs, including linolenic acid, desaturase activities, health lipid indices, trace essential elements and vitamin E. Consequently, enriched meat from heavy chickens showed the best functional and nutritional traits. Overall, the study pointed out that both market class and dietary manipulation are two relevant factors to consider for producing breast meat with higher nutritional and functional value.

Dose-dependent effect of chronic exposure to lead acetate on the dynamics of the content of delta-aminolevulinic acid and essential trace elements in the serum of laying hens

  One of the most global and dangerous pollutants is considered to be lead, due to its ability to accumulate in living organisms, to be included in the metabolic cycle, to form highly toxic organometallic compounds, not being biodegradable. To study the chronic effects of lead acetate, an experiment was performed on laying hens of Lohmann Brown cross. For research, one control and three experimental groups were formed, 20 chickens in each. Birds of the experimental groups were administered lead acetate daily with compound feed in doses (in terms of metal): Group I – 50 mg/kg of feed, II – 75 mg/kg of feed, III – 150 mg/kg of feed. Access to water was not restricted. The birds of the control group received a complete diet without lead acetate. On the 30th, 90th, 120th days of the experiment and the 20th day after withdrawal of the toxicant (the 140th day of the experiment), we took blood samples from birds for biochemical and toxicological studies. The concentration of delta-aminolevulinic acid (δ-ALA) in the serum of laying hens was determined by reversed-phase high-performance liquid chromatography. Determination of the content of lead in the serum of laying hens was performed by X-ray fluorescence analysis. The concentration of total calcium, inorganic phosphorus, and magnesium in the serum of the laying hens was determined using production kits. We detected the dose-dependent chronic effect of lead acetate on the dynamics of the content of delta-aminolevulinic acid and essential trace elements in the serum of laying hens. The administration of lead acetate into the body of productive poultry for 120 days in doses of 50, 75, and 150 mg/kg with feed did not cause visible clinical signs of poisoning, but caused a violation of porphyrin metabolism, manifested in a reliable increase in the concentration of delta-aminolevulinic acid in serum on the 30th, 90th and 120th days of the experiment. It has been experimentally proven that the administration into the body of laying hens of lead acetate in doses of 50, 75 and 150 mg/kg of feed for 120 days leads to the maximum accumulation of lead in the serum on the 30th, 90th, and 120th days of the experiment. Prolonged administration of lead acetate to laying hens at high concentrations is characterized by a reliable decrease in the content of total calcium, inorganic phosphorus and magnesium in the serum of laying hens and a reliable increase in the content of ferrum. In the future it is necessary to study the intensity of lipid peroxidation processes in laying hens under chronic exposure to lead acetate.

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.

Trace elements in children with autism spectrum disorder: A meta-analysis based on case-control studies

Autism spectrum disorder (ASD) is a common childhood neurodevelopmental disorder that may be related to trace elements. However, reports on the relationship between them are still inconsistent. In this article, we conducted a meta-analysis on this issue. We searched the PubMed, EMBASE, and Cochrane databases as of November 15, 2019. A random-effects model was used, and subgroups of studies were analyzed using samples of different measurements. Twenty-two original articles were identified (18 trace elements, including a total of 1014 children with ASD and 999 healthy controls). In autistic children, the overall levels of barium (Ba), mercury (Hg), lithium (Li), and lead (Pb) were higher. There were significant differences in the levels of copper (Cu) in the hair and serum between autistic children and the control group. The levels of Hg, Li, Pb and selenium (Se) in the hair of autistic children were higher than those of healthy children, while the levels of zinc (Zn) in the blood were lower. Excessive exposure to toxic heavy metals and inadequate intake of essential metal elements may be associated with ASD. Preventing excessive exposure to toxic metals and correcting poor dietary behaviors may be beneficial for the prevention and treatment of the disease.

Cadmium-induced Oxidative Stress and Immunosuppression Mediated Mitochondrial Apoptosis via JNK-FoxO3a-PUMA pathway in Common Carp (Cyprinus carpio L.) Gills

Cadmium (Cd)-caused water environment pollution has become a matter of concern. Gill is an organ with respiratory and mucosal immune functions, and is also one of the organs directly attacked by pollutants. It was found that excess Cd could cause Cd accumulation and gill injury in carp. However, the mechanism of Cd-caused damage in common carp gills is still unclear. Oxidative stress, immunosuppression, and apoptosis took part in the mechanism of poisoning caused by some harmful substances. The aim of the study was to investigate complex molecular mechanism of apoptotic injury caused by Cd in common carp gills. Hence, in this study, we established a Cd poisoning model to explore whether excess Cd can induce apoptosis through observing histomorphology and apoptotic cells; and determining mineral elements, oxidative stress-related factors, immune-related, and apoptosis-related genes in common carp gills. Fifty-four fish were randomly separated into the control group and the Cd group and were cultured for 45 days. The water of the control group was drinking water and the water of the Cd group was CdCl₂-added drinking water (0.26 mg/L Cd). In our results, we found that excess Cd increased Cd level, decreased the levels of essential mineral elements (Cu, Fe, Zn, and Mn), damaged mitochondria, and increased apoptotic cells in common carp gills, meaning that excess Cd caused Cd accumulation and apoptotic injury via mitochondrion in common carp gills. Furthermore, we found that Cd inhibited anti-apoptosis-related gene Bcl-2 and stimulated pro-apoptosis-related genes (JNK, FoxO3a, PUMA, Bax, Apaf-1, Caspase-9, and Caspase-3) on 15th, 30th, and 45th days. Above data meant that Cd exposure caused apoptosis via mitochondrion and JNK-FoxO3a-PUMA pathway in common carp gills. In addition, in our experiment, Cd treatment increased oxidants (H₂O₂ and MDA) and decreased antioxidants (CAT, GPx, GST, SOD, T-AOC, and GSH), indicating that Cd caused oxidative stress via oxidation/antioxidation imbalance. Meanwhile, compared to the control group, T-help 17 (Th17) cell-related factors (IL-17, TNF-α, and RORγ) were up-regulated, regulatory T (Treg) cell-related factors (IL-10 and Foxp3) were down-regulated, and IL-17/IL-10, TNF-α/IL-10, and RORγ/Foxp3 were increased in Cd-exposed group; meaning that excess Cd induced immunosuppression via the imbalance of Th17/Treg cells. Taken together, our findings indicated that JNK-FoxO3a-PUMA pathway and mitochondrion participated in oxidative stress and immunosuppression-mediated apoptosis caused by Cd in common carp (Cyprinus carpio L.) gills. Our data provided new perspectives on the negative effects of heavy metal pollutants on fish.

Inhibition of ROS/NLRP3/Caspase-1 mediated pyroptosis alleviates excess molybdenum-induced apoptosis in duck renal tubular epithelial cells

OBJECTIVE

Excess molybdenum (Mo) is harmful to the body, and the kidney is the vital target organ for Mo exposure. This study focused on the impacts of excess Mo on pyroptosis and the relationship between pyroptosis and apoptosis in kidney.

METHODS

The duck renal tubular epithelial cells were treated with (NH₄)₆Mo₇O₂₄·4H₂O (0, 480, 720 and 960 μM Mo), N-acetyl-L-cysteine (NAC) (100 μM), Z-YVAD-fluoromethylketone (YVAD) (10 μM) and the combination of Mo and NAC or YVAD for 12 h. The LDH release and IL-1β, IL-18 contents of cell supernatant were detected by LDH and ELISA kits. The MMP and ROS level were measured using MMP and ROS kits by flow cytometry. The apoptotic rate of cell was detected by AO/EB counterstaining. Pyroptosis and apoptosis-related factors mRNA and protein levels were assayed by real-time qPCR and western blot, respectively.

RESULTS

Excessive Mo markedly increased LDH, IL-18, IL-1β releases and induced overproduction of ROS, pyroptosis-related factors mRNA and protein levels. NAC and YVAD dramatically decreased pyroptosis induced by Mo. Simultaneously, YVAD significantly changed apoptosis-related factors mRNA and protein levels, and reduced cell apoptotic rate.

CONCLUSION

Excessive Mo exposure can induce pyroptosis by the ROS/NLRP3/Caspase-1 pathway in duck renal tubular epithelial cells, and restraining pyroptosis of Caspase-1 dependence might weaken excess Mo-induced apoptosis. The study provides theoretical basis for excess Mo exposure nephrotoxic researches on waterfowl and the interplay between pyroptosis and apoptosis highlights a new sight into the mechanism of Mo-induced nephrotoxicity.

Selenium Mitigates Cadmium-Induced Adverse Effects on Trace Elements and Amino Acids Profiles in Chicken Pectoral Muscles

Cadmium (Cd), as one of the most toxic heavy metals, has become a widespread environmental contaminant and threats the food quality and safety. The protective effect of selenium (Se) on Cd-induced tissue lesion and cytotoxicity in chicken has been extensively reported. The objective of this study was to investigate the antagonistic effect of Se on Cd-induced damage of chicken pectoral muscles via analyzing the trace elements and amino acids profiles. Firstly, 19 trace elements contents were analyzed by inductively coupled plasma mass spectrometry (ICP-MS). The results showed that under Cd exposure, the contents of Cd, lead (Pb), mercury (Hg), aluminum (Al), and lithium (Li) were significantly elevated, and the contents of Se, iron (Fe), and chromium (Cr) were significantly reduced. However, supplementing Se significantly reversed the effects induced by Cd. Secondly, the amino acids contents were detected by L-8900 automatic amino acid analyzer. The results showed that supplementing Se increased significantly Cd-induced decrease of valine (Val), leucine (Leu), arginine (Arg), and proline (Pro). Thirdly, the results of principal component analysis (PCA) showed that cobalt (Co), manganese (Mn), silicium (Si), and Pro may play special roles in response to the process of Se antagonizes Cd-induced damage of pectoral muscles in chickens. In summary, these results indicated that different trace elements and amino acids possessed and exhibited distinct responses to suffer from Se and/or Cd in chicken pectoral muscles. Notably, Se alleviated Cd-induced adverse effects by regulating trace elements and amino acids profiles in chicken pectoral muscles.

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.

Selenium alleviates cadmium-induced inflammation and meat quality degradation via antioxidant and anti-inflammation in chicken breast muscles

Cadmium (Cd) as a widespread toxic heavy metal accumulates in animal food including chicken meat through food chain enrichment and finally threatens human health. Selenium (Se) is an essential mineral and possesses antagonistic effects on Cd-induced multiple organs' toxicity in chickens. The objective of the present study was to reveal the antagonistic mechanisms of Se to Cd from the aspects of oxidative stress, inflammation, and meat quality in chicken breast muscles. Firstly, the results showed that Cd significantly elevated the levels of malondialdehyde (MDA), hydrogen peroxide (H₂O₂), and protein carbonyl, and declined the levels of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and catalase (CAT) to trigger oxidative stress in chicken breast muscles. However, Se treatment significantly alleviated Cd-induced oxidative stress by increasing the levels of GSH-Px, SOD, and CAT, and decreasing the levels of MDA, H₂O₂, and protein carbonyl. Secondly, Se obviously inhibited the expressions of Cd-activated inflammation-related genes including tumor necrosis factor (TNF-α), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), inducible nitric oxide synthase (iNOS), prostaglandin-endoperoxide synthase 2 (COX-2), and prostaglandin E synthase (PTGEs) in chicken breast muscles. Thirdly, meat quality-related parameters including pH_45min, ultimate pH (pHu), and drip loss were also detected, and the results showed that Se markedly recovered Cd-induced dropt of pH_45min and increase of drip loss in chicken breast muscles. In brief, these findings demonstrated that Se significantly alleviated Cd-induced oxidative stress and inflammation, and declined meat quality of chicken breast muscles.

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.

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.

microRNA-33-3p involved in selenium deficiency-induced apoptosis via targeting ADAM10 in the chicken kidney

Selenium (Se) deficiency induces typical clinical and pathological changes and causes various pathological responses at the molecular level in several different chicken organs; the kidney is one of the target organs of Se deficiency. To explore the mechanisms that underlie the effects of microRNA-33-3p (miR-33-3p) on Se deficiency-induced kidney apoptosis, 60 chickens were randomly divided into two groups (30 chickens per group). We found that Se deficiency increased the expression of miR-33-3p in the chicken kidney. A disintegrin and metalloprotease domain 10 (ADAM10) was verified to be a target of miR-33-3p in the chicken kidney. The overexpression of miR-33-3p decreased the expression levels of β-catenin, cyclinD1, T-cell factor (TCF), c-myc, survivin, and Bcl-2; it increased the expression levels of E-cadherin, Bak, Bax, and caspase-3; and it increased the number of chicken kidney cells in the G0/G1 phase. In addition, Se deficiency caused the ultrastructure of the kidney to develop apoptotic characteristics. The results of flow cytometry analysis and AO/EB staining showed that the number of apoptotic chicken kidney cells increased in the miR-33-3p mimic group. All these results suggest that Se deficiency-induced cell cycle arrest and apoptosis in vivo and in vitro in the chicken kidney via the regulation of miR-33-3p, which targets ADAM10.

The antagonistic effect of selenium on cadmium-induced apoptosis via PPAR-γ/PI3K/Akt pathway in chicken pancreas

The animal experiment was preformed to investigate the roles of PPAR-γ/PI3K/Akt pathway in apoptosis triggered by cadmium (Cd) and in the antagonistic effects of selenium (Se) on Cd in the pancreas of chicken. The current study showed that Cd treatment obviously increased the accumulation of Cd and directly led to lower activities of amylase, trypsin and lipase in chicken pancreas. The expression of PPAR-γ, PI3K, and Akt was declined, whereas the level of Bax, Cyt C and caspase-3 were increased in Cd group. In the result of TUNEL assay and the histological examination, typical apoptosis characteristics in the pancreas of Cd group were confirmed. Cd group also showed high levels of inducible nitric oxide synthase (iNOS) activity and nitric oxide (NO) content in pancreas. However, those Cd-induced changes were obviously alleviated in Cd + Se group. Our study revealed that Cd could impact the pancreas function and induce the activation of Bax and the overproduction of NO via PPAR-γ/PI3K/Akt pathway to promote apoptosis in chicken pancreas. However, Se could reduce Cd accumulation and antagonize Cd-triggered apoptosis in chicken pancreas.

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.

Selenium Antagonizes the Lead-Induced Apoptosis of Chicken Splenic Lymphocytes In Vitro by Activating the PI3K/Akt Pathway

Lead (Pb) pollution has become one of the most serious global ecological problems. In animals, Pb ingestion induces apoptosis in many tissues. However, the mechanisms by which Pb induces apoptosis in chicken splenic lymphocytes in vitro via the PI3K/Akt pathway and the antagonistic effect of selenium (Se) on Pb remain unclear. Therefore, we established the in vitro Se-Pb interaction model in chicken splenic lymphocytes and examined the frequency of apoptotic cells using acridine orange/ethidium bromide (AO/EB) staining and the TdT-mediated dUTP nick end labeling assay and detected the activities of glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT), as well as the levels of malondialdehyde (MDA) and reactive oxygen species (ROS). The expression of PI3K/Akt pathway-related genes was also examined by qRT-PCR and western blotting. MDA and ROS levels were markedly increased, whereas the activities of GPx, SOD, and CAT were significantly decreased; the levels of the PI3K, Akt, and Bcl-2 messenger RNAs (mRNAs) and proteins were decreased; and the levels of the p53, Bax, cytochrome c (Cyt-c), caspase 3, and caspase 9 mRNAs and proteins were increased in the Pb group. In addition, the frequency of apoptotic cells was also significantly increased by the Pb treatment. However, Se supplementation during Pb exposure observably attenuated Pb-induced apoptosis; increased the levels of the PI3K, Akt, and Bcl-2 mRNAs and proteins; and decrease the levels of the p53, Bax, Cyt-c, caspase 3, and caspase 9 mRNAs and proteins in the chicken spleen. In conclusion, Pb exposure causes oxidative stress, inhibits the PI3K/Akt pathway, and subsequently induces apoptosis in chicken splenic lymphocytes in vitro, and these effects are partially attenuated by Se supplementation. To the best of our knowledge, this study is the first to reveal the antagonistic effect of Se on Pb-induced apoptosis of chicken splenic lymphocytes in vitro via the activation of the PI3K/Akt pathway.

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.

Selenium antagonizes cadmium-induced apoptosis in chicken spleen but not involving Nrf2-regulated antioxidant response

The nuclear transcription factor NF-E2-related factor 2 (Nrf2) binds to antioxidant response elements (AREs) and is involved in the regulation of genes participated in defending cells against oxidative damage, which have been confirmed in animal models. Selenium (Se), known as an important element in the regulation of antioxidant activity, can antagonize Cadmium (Cd) toxicity in birds. However, the role of Nrf2 in selenium-cadmium interaction has not been reported in birds. To further explore the mechanism of selenium attenuating spleen toxicity induced by cadmium in chickens, cadmium chloride (CdCl₂, 150mg/kg) and sodium selenite (Na₂SeO₃, 2mg/kg) were co-administrated or individually administered in the diet of chickens for 90 days. The results showed that Cd exposure increased the level of hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) and decreased the antioxidant enzyme activities, including superoxide dismutase (SOD), glutathione peroxidase (Gpx), total antioxidative capacity (T-AOC), catalase (CAT). Cd exposure increased obviously nuclear accumulation of Nrf2, and the expression of Nrf2 downstream heme oxygenase-1 (HO-1) and NAD(P)H: quinine oxidoreductase 1 (NQO1), reduced the expression of Kelch-like ECH-associated protein (keap1), Gpx-1 and thioredoxin reductase-1 (TrxR1). In addition, Cd induced the increase of bak, caspase9, p53, Cyt c mRNA levels, increased bax/bcl-2 ratio, increased caspase3 mRNA and protein levels. Selenium treatment reduced the accumulation of Cd in the spleen, attenuates Cd-induced Nrf2 nuclear accumulation, enhanced antioxidant enzyme activities, ameliorated Cd-induced oxidative stress and apoptosis in the spleen. In summary, our results demonstrate that Se ameliorated spleen toxicity induced by cadmium by modulating the antioxidant system, independently of Nrf2-regulated antioxidant response pathway.

Selenium for the mitigation of toxicity induced by lead in chicken testes through regulating mRNA expressions of HSPs and selenoproteins

Lead (Pb) is a toxic element and environmental pollutant. Pb toxicity and antagonistic effect of selenium (Se) on Pb have been deeply studied in mammals. The testis is one of the target organs of Pb in birds. The aim of this study was to investigate the mitigating effect of Se on Pb toxicity in chicken testes by determining messenger RNA (mRNA) expressions of 5 heat shock proteins (HSPs) and 25 selenoproteins. Sixty male chickens (7-day-old) were randomly divided into the control group, the Se group, the Pb group, and the Pb + Se group, and were fed for 90 days. The feeding methods of chickens were as follows: The control group was fed drinking water and commercial diet (0.49 mg/kg Se). Lead acetate was added into the drinking water (350 mg/L Pb). Sodium selenite was added into the commercial diet (1 mg/kg Se). Multivariate correlation analysis and principal component analysis (PCA) were used to define the relationships among all the measured factors and the most important parameters that could be used as key factors, respectively. The results indicated that Se decreased the increase of mRNA expressions of all the HSPs and increased the decrease of mRNA expressions of all the selenoproteins induced by Pb in the chicken testes. HSP70 may be a biomarker of Pb poisoning in the chicken testes. Se alleviated Pb-induced toxicity in the chicken testes through regulating mRNA expressions of HSPs and selenoproteins.

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.

Ameliorative Effects of Dietary Selenium Against Cadmium Toxicity Is Related to Changes in Trace Elements in Chicken Kidneys

The ameliorative effects of selenium (Se) against cadmium (Cd)-induced toxicity have been reported extensively. However, few studies have assessed the effects of multiple ions simultaneously on the variations of elements. In this study, the changes in Se, Cd, and 26 other element concentrations were investigated in chicken kidneys. One hundred and twenty-eight 31-week-old laying hens were fed a diet supplemented with either Se, Cd, or both Se and Cd for 90 days. The ion content was analyzed by inductively coupled plasma mass spectrometry (ICP-MS). We found that the Se, Cd, and combined Se and Cd treatments significantly affected the trace elements in the chicken kidneys. The Cd supplement caused ion profile disorders, including reduced concentrations of V, Cr, Mn, Mo, As, Ba, Hg, Ti, and Pb and increased Si, Cu, Li, Cd, and Sb. The Se supplement reduced the contents of Co, Mo, and Pb and increased the contents of Cr, Fe, and Se. Moreover, Se also increased the concentrations of Cr, Mn, Zn, and Se and decreased those of Li and Pb, which in contrast were induced by Cd. Complex interactions between elements were analyzed, and both positive and negative correlations among these elements are presented. The present study indicated that Se can help against the negative effects of Cd and may be related to the homeostasis of the trace elements in chicken kidneys.

Alleviation of lead-induced oxidative stress and immune damage by selenium in chicken bursa of Fabricius

We investigated lead (Pb)-induced oxidative stress and immune damage in the chicken bursa of Fabricius (BF) and the ameliorative effect of selenium (Se). Seven-day-old male chickens were randomly divided into four groups and were provided standard diet and drinking water, Na₂SeO₃ added to the standard diet and drinking water, standard diet and (CH₃COO)₂Pb added to drinking water, and Na₂SeO₃ added to the standard diet and (CH₃COO)₂Pb added to drinking water for 30, 60, and 90 days. The presence of Pb inhibited total antioxidant capacity (T-AOC), glutathione peroxidase (GPx), glutathione S-transferase (GST), superoxide dismutase (SOD), and catalase (CAT) activities; decreased glutathione (GSH) content; increased malondialdehyde (MDA) and hydrogen peroxide (H₂O₂) contents; inhibited interleukin (IL)-2 and interferon-γ (IFN-γ) messenger RNA (mRNA) expression; and increased IL-4, IL-6, IL-10, IL-12β, and IL-17 mRNA expression. The presence of Se relieved all of the above Pb-induced changes. There were close correlations among GSH, CAT, T-AOC, SOD, GPx, MDA, and H₂O₂ and among IL-2, IL-4, IL-6, IL-12β, IL-17, and IFN-γ. Our data showed that Pb caused oxidative stress and immune damage in the chicken BF. Se alleviated Pb-induced oxidative stress and immune damage in the chicken BF.