Protective effects of selenium (Se) and zinc (Zn) on cadmium (Cd) toxicity in the liver of the rat: effects on the oxidative stress

Pancreatic Antioxidative Defense and Heat Shock Proteins Prevent Islet of Langerhans Cell Death After Chronic Oral Exposure to Cadmium LOAEL Dose

Cadmium, a hazardous environmental contaminant, is associated with metabolic disease development. The dose with the lowest observable adverse effect level (LOAEL) has not been studied, focusing on its effect on the pancreas. We aimed to evaluate the pancreatic redox balance and heat shock protein (HSP) expression in islets of Langerhans of male Wistar rats chronically exposed to Cd LOAEL doses, linked to their survival. Male Wistar rats were separated into control and cadmium groups (drinking water with 32.5 ppm CdCl2). At 2, 3, and 4 months, glucose, insulin, and cadmium were measured in serum; cadmium and insulin were quantified in isolated islets of Langerhans; and redox balance was analyzed in the pancreas. Immunoreactivity analysis of p-HSF1, HSP70, HSP90, caspase 3 and 9, and cell survival was performed. The results showed that cadmium exposure causes a serum increase and accumulation of the metal in the pancreas and islets of Langerhans, hyperglycemia, and hyperinsulinemia, associated with high insulin production. Cd-exposed groups presented high levels of reactive oxygen species and lipid peroxidation. An augment in MT and GSH concentrations with the increased enzymatic activity of the glutathione system, catalase, and superoxide dismutase maintained a favorable redox environment. Additionally, islets of Langerhans showed a high immunoreactivity of HSPs and minimal immunoreactivity to caspase associated with a high survival rate of Langerhans islet cells. In conclusion, antioxidative and HSP pancreatic defense avoids cell death associated with Cd accumulation in chronic conditions; however, this could provoke oversynthesis and insulin release, which is a sign of insulin resistance.

Impaired intestinal immunity and microbial diversity in common carp exposed to cadmium

Waterborne cadmium (Cd) accumulates in the fish intestine and causes irreversible toxicity by disrupting intestinal immunity and microbial diversity. To explore the toxicity of environmentally available high Cd concentration on intestinal immunity and microbial diversity of fish, we selected the widely used bioindicator model species, Common carp (Cyprinus carpio). Literature review and Cd pollution data supported sequential doses of 0.2, 0.4, 0.8, 1.6, 3.2, and 6.4 mg/L Cd for 30 days. Based on intestinal tissue Cd accumulation, previous studies, and environmentally available Cd data, 0.4 and 1.6 mg/L Cd were selected for further studies. Intestinal Cd bioaccumulation increased significantly to ~100 times in fish exposed to 1.6 mg/L Cd. We observed villous atrophy, increased goblet cells with mucus production, muscularis erosion, and thickened lamina propria due to intense inflammatory cell infiltration in the intestine at this Cd concentration. Cd-induced immunosuppression occurred with increased lysozyme, alkaline phosphate (AKP), and acid phosphate (ACP). High levels of catalase (CAT), total antioxidant capacity (T-AOC), malondialdehyde (MDA), and hydrogen peroxide (H2O2) suggested induced oxidative stress and poor metabolism by α-amylase and lipase suppression for Cd toxicity. Proteobacteria (41.2 %), Firmicutes (21.8 %), and Bacteroidetes (17.5 %) were the dominant bacterial phyla in the common carp intestine. Additionally, potential pathogenic Cyanobacteria increased in Cd-treated fish. The decrease of beneficiary bacteria like Aeromonas, and Cetobacterium indicated Cd toxicity. Overall, these findings indicate harmful consequences of high Cd concentration in the intestinal homeostasis and health status of fish.

Toxic Effects of Cadmium on Fish

Large amounts of enriched cadmium (Cd) in the environment seriously threatens the healthy and sustainable development of the aquaculture industry and greatly restricts the development of the food processing industry. Studying the distribution and toxic effects of Cd in fish, as well as the possible toxic effects of Cd on the human body, is very significant. A large number of studies have shown that the accumulation and distribution of Cd in fish are biologically specific, cause tissue differences, and seriously damage the integrity of tissue structure and function, the antioxidant defense system, the reproductive regulation system, and the immune system. The physiological, biochemical, enzyme, molecular, and gene expression levels change with different concentrations and times of Cd exposure, and these changes are closely related to the target sites of Cd action and tissues in fish. Therefore, the toxic effects of Cd on fish occur with multiple tissues, systems, and levels.

Protective effect of quercetin on cadmium-induced renal apoptosis through cyt-c/caspase-9/caspase-3 signaling pathway

Cadmium (Cd), a heavy metal, has harmful effects on animal and human health, and it can also obviously induce cell apoptosis. Quercetin (Que) is a flavonoid compound with antioxidant and other biological activities. To investigate the protective effect of Que on Cd-induced renal apoptosis in rats. 24 male SD rats were randomly divided into four groups. They were treated as follows: control group was administered orally with normal saline (10 ml/kg); Cd group was injected with 2 mg/kg CdCl₂ intraperitoneally; Cd + Que group was injected with 2 mg/kg CdCl₂ and intragastric administration of Que (100 mg/kg); Que group was administered orally with Que (100 mg/kg). The experimental results showed that the body weight of Cd-exposed rats significantly decreased and the kidney coefficient increased. In addition, Cd significantly increased the contents of Blood Urea Nitrogen, Creatinine and Uric acid. Cd also increased the glutathione and malondialdehyde contents in renal tissues. The pathological section showed that Cd can cause pathological damages such as narrow lumen and renal interstitial congestion. Cd-induced apoptosis of kidney, which could activate the mRNA and protein expression levels of Cyt-c, Caspase-9 and Caspase-3 were significantly increased. Conversely, Que significantly reduces kidney damage caused by Cd. Kidney pathological damage was alleviated by Que. Que inhibited Cd-induced apoptosis and decreased Cyt-c, Caspase-9 and Caspase-3 proteins and mRNA expression levels. To sum up, Cd can induce kidney injury and apoptosis of renal cells, while Que can reduce Cd-induced kidney damage by reducing oxidative stress and inhibiting apoptosis. These results provide a theoretical basis for the clinical application of Que in the prevention and treatment of cadmium poisoning.

Linarin Protects against Cadmium-Induced Osteoporosis Via Reducing Oxidative Stress and Inflammation and Altering RANK/RANKL/OPG Pathway

Cadmium (Cd) contamination in the environment is a major public health concern since it has been linked to osteoporosis and other bone deformities. Linarin is a flavonoid glycoside, and it can promote osteoblastogenesis. This research aimed to investigate the potential role of linarin against Cd-exposed bone deformations in mice model. In our research, male mice were randomly allocated into four groups: control, Cd-exposed, and Cd + linarin (20 and 40mg/kg/bw, respectively). Linarin prevented body weight loss, increased serum calcium (Ca) and phosphorus (P), and bone alkaline phosphatase (BAP) levels in Cd-exposed groups. Furthermore, linarin treatment at 20 and 40mg/kg/bw significantly decreased RANK and OPG, resulting in an increase in RANKL mRNA levels and protein distribution in the bone of Cd-exposed mice. In addition, the bone of Cd-exposed mice administered with linarin showed higher TRAP, NFATc1, MMP9, and RUNX2 mRNA levels and protein distribution. Linarin significantly decreased oxidative stress in Cd-exposed mice bone by decreasing MDA, a lipid peroxidation product. Moreover, linarin protects Cd-exposed mice antioxidant enzymes by increasing bone SOD, CAT, and GPx levels. Besides, linarin suppresses alterations in the inflammatory system, i.e., NF-κB p65/IKKβ, by reducing NF-κB p65, IKKβ, IL-6, and TNF-α in the bone of Cd-exposed animals. This study concluded that linarin has potential to cure osteoporosis in Cd-exposed mice by reducing oxidative stress and inflammation and modulating the RANK/RANKL/OPG pathway.

Effects of exposure to cadmium (Cd) and selenium-enriched Lactobacillus plantarum in Luciobarbus capito: Bioaccumulation, antioxidant responses and intestinal microflora

Cadmium (Cd) is a dangerous pollutant with multiple toxic effects on aquatic animals, and it exists widely in the environment. Selenium (Se) is a biologically essential trace element. Interactions between heavy metals and selenium can significantly affect their biological toxicity, although little is known about the mechanism of this antagonism. Lactobacillus is one of the dominant probiotics, given that a certain dose promotes host health. In this study, we evaluated the protective effect of a dietary probiotic supplementation, Se-enriched Lactobacillus plantarum (L. plantarum), on the bioaccumulation, oxidative stress and gut microflora of Luciobarbus capito exposed to waterborne Cd. Fish were exposed for 28 days to waterborne Cd at 0.05 mg/L and/or dietary Se-enriched L. plantarum. Exposure to Cd in water leads to Cd accumulation in tissues, oxidative stress and significant changes in gut microflora composition. Adding Se-enriched L. plantarum to the diet can reduce the accumulation of Cd in tissues, enhance the activity of antioxidant enzymes, and reverse changes in intestinal microbial composition after Cd exposure. The results obtained indicate that Se-enriched L. plantarum provides significant protection against the toxicity of Cd by inhibiting bioaccumulation. Selenium reduced oxidative stress by increasing the activity of glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX) and malondialdehyde (MDA). Se-enriched L. plantarum can reduce the increase in the number of pathogenic Aeromonas caviae bacteria in the intestine caused by Cd stress and increase the number of Gemmobacter to regulate the microbial population. The results of this study show that Se-enriched L. plantarum dietary supplements can effectively protect Luciobarbus capito against Cd toxicity at subchronic levels.

Long-term exposure of the binary mixture of cadmium and mercury damages the developed ovary of adult zebrafish

The toxicity of the binary mixture of cadmium (Cd) and mercury (Hg) on the ovary of adult zebrafish was evaluated in the present study. Adult female zebrafish were exposed to cadmium chloride (1 mg/L), mercury chloride (30 µg/L), and a binary mixture of both metals for 21 days. The toxic effects of both metals on the ovary were investigated by evaluating the oxidative stress markers and related gene expression in ovarian tissue along with the histopathological examination. The significantly decreased level of GSH and increased level of MDA in ovarian tissue of adult female zebrafish exposed to Cd + Hg indicated that the exposure of binary mixture of Cd and Hg caused more lipid peroxidation in the ovary. The significant changes in expression of mRNA of catalase (CAT) and nuclear factor erythroid 2 (NF-E2)-related factor 2 (Nrf2) were not observed in the ovary of zebrafish exposed to the binary mixture. Upon histological evaluation, a decreased number of full-growth (mature) oocytes along with degenerative changes due to Cd exposure were noticed, while ovary of zebrafish of the Hg-exposed group had shown a decreased number of pre-and early vitellogenic oocytes along with atretic previtellogenic oocytes compared to the control group. The ovary of zebrafish of the Cd + Hg-exposed group had shown a decreased number of previtellogenic oocytes with marked pathological changes in mature oocytes. Present findings elucidate that simultaneous long-term exposure of Cd and Hg compared to individual exposure significantly damaged the various stages of oocytes of an ovary of adult zebrafish.

Antagonistic Interaction of Selenium and Cadmium in Human Hepatic Cells Through Selenoproteins

Cadmium (Cd) is a highly toxic heavy metal for humans and animals, which is associated with acute hepatotoxicity. Selenium (Se) confers protection against Cd-induced toxicity in cells, diminishing the levels of ROS and increasing the activity of antioxidant selenoproteins such as glutathione peroxidase (GPx). The aim of this study was to evaluate the antagonistic effect of selenomethionine (SeMet) against Cd toxicity in HepG2 cells, through the modulation of selenoproteins. To this end, the cells were cultured in the presence of 100 µM SeMet and 5 μM, 15 µM, and 25 µM CdCl₂ and a combination of both species for 24 h. At the end of the experiment, cell viability was determined by MTT assay. The total metal content of Cd and Se was analyzed by triple-quadrupole inductively coupled plasma–mass spectrometry (ICP-QqQ-MS). To quantify the concentration of three selenoproteins [GPx, selenoprotein P (SELENOP), and selenoalbumin (SeAlb)] and selenometabolites, an analytical methodology based on column switching and a species-unspecific isotopic dilution approach using two-dimensional size exclusion and affinity chromatography coupled to ICP-QqQ-MS was applied. The co-exposure of SeMet and Cd in HepG2 cells enhanced the cell viability and diminished the Cd accumulation in cells. Se supplementation increased the levels of selenometabolites, GPx, SELENOP, and SeAlb; however, the presence of Cd resulted in a significant diminution of selenometabolites and SELENOP. These results suggested that SeMet may affect the accumulation of Cd in cells, as well as the suppression of selenoprotein synthesis induced by Cd.

Protective Role of the Essential Trace Elements in the Obviation of Cadmium Toxicity: Glimpses of Mechanisms

Cadmium (Cd) is toxic non-essential heavy metal that precipitates adverse health effects in humans and animals. Chelation therapy, the typical treatment for cadmium toxicity, has certain safety and efficacy issues to treat long term cadmium toxicity, in particular. Recent studies have shown that essential trace elements can play important roles in obviating experimental Cd toxicity. This study organizes and reviews the prototypical evidences of the protective effects of essential trace elements against Cd toxicity in animals and attempts to point out the underlying mechanisms. Zinc, selenium, iron, and combinations thereof are reported to be active. The major mechanisms elucidated inter alia are-induction of metallothionein (MT) synthesis and Cd-MT binding (for zinc), modulation of oxidative stress and apoptosis, interference in cadmium absorption and accumulation from body-thereby maintenance of essential metal homeostasis and cytoprotection. Based on the findings, essential trace elements can be recommended for the susceptible population. The application of these trace elements appears beneficial for both the prevention and remediation of long-term Cd toxicity operative via multiple mechanisms with no or minimal adverse effects as compared to the conventional chelation therapy.

Understanding the translocation and bioaccumulation of cadmium in the Enshi seleniferous area, China: Possible impact by the interaction of Se and Cd

Selenium (Se) plays an indispensable role in minimizing cadmium (Cd) hazards for organisms. However, their potential interactions and co-exposure risk in the naturally Se-Cd enriched paddy field ecosystem are poorly understood. In this study, rice plants with rhizosphere soils sampled from the Enshi seleniferous region, China, were investigated to resolve this confusion. Here, translocation and bioaccumulation of Cd showed some abnormal patterns in the system of soil-rice plants. Roots had the highest bioaccumulation factors of Cd (range: 0.30-57.69; mean: 11.86 ± 14.32), and the biomass of Cd in grains (range: 1.44-127.70 μg, mean: 36.55 ± 36.20 μg) only accounted for ∼10% of the total Cd in whole plants (range: 14.67-1363.20 μg, mean: 381.25 ± 387.57 μg). The elevated soil Cd did not result in the increase of Cd concentrations in rice grains (r² = 0.03, p > 0.05). Most interestingly, the opposite distribution between Se and Cd in rice grains was found (r² = 0.24, p < 0.01), which is contrary to the positive correlation for Se and Cd in soil (r² = 0.46, p < 0.01). It is speculated that higher Se (0.85-11.46 μg/g), higher Se/Cd molar ratios (mean: 5.42 ≫1; range: 1.50-12.87), and higher proportions of reductive Se species (IV, 0) of the Enshi acidic soil may have the stronger capacity of favoring the occurrence of Se binding to Cd ions by forming Cd-Se complexes (Se^2- + Cd²⁺ =CdSe) under reduction conditions during flooding, and hence change the Cd translocation from soil to roots. Furthermore, the negative correlation (r² = 0.25, p < 0.05) between the Cd translocation factor (TF_{whole grains/root}) and the roots Se indicates that Cd translocation from the roots to rice grains was suppressed, possibly by the interaction of Se and Cd. This study inevitably poses a challenge for the traditional risk assessment of Cd and Se in the soils-crops-consumers continuum, especially in the seleniferous area.

Hexagonal boron nitride nanoparticles trigger oxidative stress by modulating thiol/disulfide homeostasis

BACKGROUND

Hexagonal boron nitride nanoparticles (hBN NPs) are encouraging nanomaterials with unique chemical properties in medicine and biomedical fields. Until now, the optimal hBN NP's dosage and biochemical mechanism that can be used for in vivo systems has not been fully revealed. The main aim of this article is to reveal characteristics, serum and tissue interactions and any acute cytotoxic effect of different dose of hBN NPs for the first time.

METHODS

hBN NPs at concentrations varying between 50-3200 µg/kg was administered by intravenous injection to Wistar albino rats (n = 80) divided into seven dosage and control groups. Blood and tissue samples were taken after 24 hours.

RESULTS

Our findings suggested that higher doses hBN NPs caused oxidative stress on the serum of rats dose-dependently. However, hBN NPs did not affect thiol/disulfide homeostasis on kidney, liver, spleen, pancreas and heart tissue of rats. Furthermore, hBN NPs increased serum disulfide formation by disrupting the thiol/disulfide balance in rats. Also, LOOH and MPO levels increased at high doses, while CAT levels decreased statistically.

CONCLUSION

The results revealed that hBN NPs induce oxidative stress in a dose-dependent manner by modulating thiol/disulfide homeostasis in rats at higher concentrations.

Effect of zinc chloride and sodium selenite supplementation on in vitro maturation, oxidative biomarkers, and gene expression in buffalo (Bubalus bubalis) oocytes

This study examined the effects of zinc chloride (ZnCl2) and sodium selenite (Na2SeO3) supplementation in maturation medium on in vitro maturation (IVM) rate, oxidative biomarkers and gene expression in buffalo oocytes. Ovaries from a slaughterhouse were aspirated and good quality cumulus-oocyte complexes (COCs) with at least four layers of compact cumulus cells and evenly granulated dark ooplasm were selected. COCs were randomly allocated during IVM (22 h) to one of four treatment groups: (1) control maturation medium (basic medium), or basic medium supplemented with (2) ZnCl2 (1.5 µg/ml), (3) Na2SeO3 (5 µg/l), or (4) ZnCl2 + Na2SeO3 (1.5 µg/ml + 5 µg/l, respectively). Oocytes were denuded after 22 h of IVM in the first four replicates. Specimens were fixed and stained to evaluate the stage of nuclear maturation. The spent medium was collected for biochemical assays of total antioxidant capacity (TAC), malondialdehyde (MDA) and hydrogen peroxide concentrations. A second four replicates were used for COCs for RNA extraction. The expression levels of antioxidant (SOD1, GPX4, CAT and PRDX1), antiapoptotic (BCL2 and BCL-XL) and proapoptotic (BAX and BID) genes were measured. Supplementation with ZnCl2 and Na2SeO3 during IVM increased the ratio of oocytes reaching metaphase II at 22 h, increased TAC and decreased MDA and H2O2 concentrations in the maturation medium (P < 0.05). Moreover, beneficial effects were associated with complementary changes in expression patterns of antioxidative, antiapoptotic and proapoptotic genes, suggesting lower oxidative stress and apoptosis. Supplementation medium with zinc chloride and sodium selenite improves the maturation rate, reduces oxidative stress and increases expression levels of antioxidative and antiapoptotic genes.

Cytosolic and Metallothionein-Bound Hepatic Metals and Detoxification in a Sentinel Teleost, Dules auriga, from Southern Rio de Janeiro, Brazil

Dules auriga, a native Brazilian teleost, was applied as a sentinel species regarding metal contamination at Ilha Grande Bay, previously considered a reference site in Southeastern Brazil. Cytosolic (S50) and metallothionein-bound (HTS50) hepatic iron (Fe), zinc (Zn), copper (Cu), manganese (Mn), cadmium (Cd), and silver (Ag) were determined by inductively coupled plasma optical emission spectrometry (ICP-OES), while metallothionein (MT) concentrations were determined by polarography. Ag concentrations in both cytosolic fractions were below the limit of detection. All other HTS50 metal contents were significantly lower than S50 contents. No significant associations were found for MT. Fe and Mn S50 were positively and moderately correlated to total length, as well as HTS50 Mn, while total weight was correlated to both Mn fractions, suggesting that environmental Mn and Fe concentrations may influence fish growth. A moderate correlation between the condition factor and the S50 Cu fraction was observed, also indicating that Cu may affect fish growth. Inter-element correlations were observed, including between Cd, a toxic element, and Mn and Zn, both essential elements. Calculated molar ratios indicate that both Mn and Zn are in molar excesses compared with Cd, corroborating literature assessments regarding protective Mn and Zn effects against Cd. Lack of MT correlations suggests that metal concentrations may not be high enough to reach an MT induction threshold and that MT variability is probably linked to environmental metal concentrations. Therefore, the increased environmental contaminant levels observed in the study area indicate the need for biomonitoring efforts aiming at the application of efficient mitigation measures.

Effects of myricetin against cadmium-induced neurotoxicity in PC12 cells

Cadmium (Cd) is one of the most prevalent toxic metals widely found in the environment. Cd induces toxicity and apoptosis in various organs and cells. The nervous system is one of the primary organs targeted by Cd. Cd toxicity is correlated with induction of severe oxidative stress. Myricetin, a natural product, has been found to exert protective effects against various disease conditions. The present study aimed to evaluate the potential protective effects of myricetin on Cd-induced neurotoxicity in PC12 cells. The cells were pretreated with myricetin in the absence and presence of Cd. The viability of cells was assessed using the MTT assay. Markers of oxidative stress were investigated by the lipid peroxidation (LPO), glutathione (GSH) content, and total antioxidant capacity (TAC). Moreover, activation of caspase 3 was examined by Western blot analysis. Myricetin could significantly enhance the viability of PC12 cells. Pretreatment of the cells with myricetin, prior to Cd exposure, showed a significant decrease in the levels of LPO whereas GSH and TAC levels were increased. In addition, the activity of caspase-3 was notably prevented by myricetin. These findings revealed that myricetin has protective effects on Cd-induced neurotoxicity in PC12 cells, which can be linked to its antioxidant potential, inhibition of LPO, and prevention of caspase-3 activation.

1Selenium supply alters the subcellular distribution and chemical forms of cadmium and the expression of transporter genes involved in cadmium uptake and translocation in winter wheat (Triticum aestivum)

BACKGROUND

Cadmium (Cd) accumulation in crops affects the yield and quality of crops and harms human health. The application of selenium (Se) can reduce the absorption and transport of Cd in winter wheat.

RESULTS

The results showed that increasing Se supply significantly decreased Cd concentration and accumulation in the shoot and root of winter wheat and the root-to-shoot translocation of Cd. Se application increased the root length, surface area and root volume but decreased the average root diameter. Increasing Se supply significantly decreased Cd concentration in the cell wall, soluble fraction and cell organelles in root and shoot. An increase in Se supply inhibited Cd distribution in the organelles of shoot and root but enhanced Cd distribution in the soluble fraction of shoot and the cell wall of root. The Se supply also decreased the proportion of active Cd (ethanol-extractable (FE) Cd and deionized water-extractable (FW) Cd) in root. In addition, the expression of TaNramp5-a, TaNramp5-b, TaHMA3-a, TaHMA3-b and TaHMA2 significantly increased with increasing Cd concentration in root, and the expression of TaNramp5-a, TaNramp5-b and TaHMA2 in root was downregulated by increasing Se supply, regardless of Se supply or Cd stress. The expression of TaHMA3-b in root was significantly downregulated by 10 μM Se at both the 5 μM and 25 μM Cd level but upregulated by 5 μM Se at the 25 μM Cd level. The expression of TaNramp5-a, TaNramp5-b, TaHMA3-a, TaHMA3-b and TaHMA2 in shoot was downregulated by increasing Se supply at 5 μM Cd level, and 5 μM Se upregulated the expression of those genes in shoot at 25 μM Cd level.

CONCLUSIONS

The results confirm that Se application limits Cd accumulation in wheat by regulating the subcellular distribution and chemical forms of Cd in winter wheat tissues, as well as the expression of TaNramp5-a, TaNramp5-b and TaHMA2 in root.

Rosa persica hydroalcoholic extract improves cadmium-hepatotoxicity by modulating oxidative damage and tumor necrosis factor-alpha status

Rosa persica is a member of the Rosaceae family that has a wide range of pharmacological properties. In this study, the antioxidant and therapeutic potential of this plant was investigated on cadmium (Cd)-induced hepatotoxicity. Rosa persica extract (RPE) was prepared by a maceration method in hydroalcoholic solvent, and its antioxidant properties were determined. Then, 36 mice were divided to six groups and treated for 2 weeks as follows: control, Cd (3 mg/kg), RPE (50 mg/kg), and groups 4-6 received Cd (3 mg/kg) and 12.5, 25, and 50 mg/kg of RPE respectively. The total polyphenol, flavonoids contents, and total antioxidant capacity in RPE were measured 263.4 ± 7.2 mg rutin equivalent/g extract, 72.3 ± 2.3 mg quercetin equivalent/g extract, and 8.46 ± 0.27 μmol ferrous sulfate/g extract, respectively. The in vivo results showed that Cd elicited remarkable hepatic injury that was manifested by the significant increase in serum hepatic enzymes. In addition, Cd significantly increased the levels of lipid peroxidation (LPO) and tumor necrosis factor-alpha (TNF-α) and decreased total thiol molecules (TTM) and total antioxidant capacity (TAC) in hepatic tissue. However, RPE decreased serum hepatic enzyme levels and improved oxidative hepatic damage by lowering the LPO and TNF-α levels and raising TAC and TTM in in Cd-treated groups. Although the RPE increased the metallothionein (MT) protein content, there was no change in MT gene expression. The present study showed that the RPE due to having antioxidant properties might partially prevent hepatic oxidative damage by the improvement of oxidant/antioxidant balance in animals exposed to Cd.

Mitigative effects of zinc on cadmium-induced reproductive toxicity in the male freshwater crab Sinopotamon henanense

Cadmium (Cd) is a highly harmful environmental contaminant, which can cause reproductive toxicity. Zinc (Zn) is an essential trance element that may protect the organism from the harmful effects of Cd. However, the mechanism of Zn against Cd-induced reproductive toxicity remained to be elucidated. The aim of this study was to assess the effects of subchronic exposure to Cd on the relative testis weight (RTW), the histopathology, the activity of stress marker antioxidant enzymes, the level of lipid peroxidation of testis, as well as the mitigative effects of Zn on Cd-induced reproductive toxicity in male freshwater crab Sinopotamon henanense. For this purpose, male crabs were divided into 10 groups including a control group (without metals) and metal exposure groups with Cd alone in three concentrations and Cd combined with Zn in six concentrations for 14 days. The results showed that Cd evoked concentration-dependent reproductive toxicity of male Sinopotamon henanense as showed by decreased RTW, appearance of morphological lesions, increased SOD, CAT, GPx activity, and MDA levels. Nevertheless, Zn combined with Cd exposure significantly alleviated Cd-induced reproductive toxicity as proved by increased RTW, reappearance of normal histological morphology, increased SOD activity, recovered CAT and GPx activity, and decreased MDA levels in testis. Our study demonstrated that the application of Zn can mitigate Cd-induced reproductive toxicity by ameliorating the testicular oxidative stress and improving the antioxidant status.

Testicular protective and antioxidant effects of selenium nanoparticles on Monosodium glutamate-induced testicular structure alterations in male mice

Background

Selenium has a protective antioxidant effect on several tissues. Monosodium glutamate (MSG), MSG has been known as flavor enhancer that influences reversely on male reproductive systems and having a number of side effects, including reproductive toxicity.

Objectives

The current study aims to evaluate the possible ameliorative functions of selenium nanoparticles (SeNPs) on MSG-induced reproductive toxicity.

Materials and methods

In total, 42 male mice included in this study were divided into six groups: control, MSG (LD), MSG (HD), SeNPs, MSG (LD) plus SeNPs and finally MSG (HD) plus SeNPs. Testosterone hormone, tumor necrosis factor-alpha (TNF-α), as well as the antioxidant biomarkers: superoxide dismutase [SOD], glutathione peroxidase [GPx], catalase [CAT] and marker of lipid peroxidation [MDA], were examined. Histological and comet assay variations in the testicular tissues as markers of testicular damage after the MSG administration in two doses (MSG-LD and MSG-HD) either alone or combined with SeNPs.MSG in two doses (LD and HD) genotoxic effects were also evaluated and the ameliorative role of SeNPs on the testicular tissues were recorded.

Results

Results proved that the administration of SeNPs diminished the effect of MSG (LD and HD)-that induced decrease in testosterone hormone levels and elevated oxidative stress markers markedly. SeNPs had a potent antioxidant effect and elevated the antioxidant enzymes significantly and decreased lipid peroxidation markers as compared with MSG either (LD and HD) groups.

Conclusion

It is clear from the data that SeNPs inhibit testicular injury and improve the antioxidant state in male mice.

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.

Testicular protective effects of ellagic acid on monosodium glutamate-induced testicular structural alterations in male rats

Ellagic acid (EA) has significant protective and antioxidant effects on several tissues. Monosodium glutamate (MG) is known as a flavor promoter that reversibly influences the male reproductive system. This study aims to assess the ameliorative effect of EA on oxidative stress and testicular damage induced by MG. In total, 48 male rats were included in this study and separated into six groups: control, EA (20 mg/kg), MG (low dose) (17.5 mg/kg), MG (high dose) (60 mg/kg), MG (low dose) combined with EA, and MG (high dose) combined with EA. Testicular antioxidant biomarkers [superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GRx), catalase (CAT), myeloperoxidase (MPO), and xanthine oxidase (XO)] were examined. Testes were examined and scored for histological variation as an indicator of testicular damage following administration of MG alone or in combination with EA. Serum testosterone, inhibin B, 8-hydroxydeoxyguanosine (as a marker of DNA damage), and transmission electron microscope sections of the testis were evaluated, and a comet assay was performed. Results showed that administration of EA combined with MG significantly elevated the levels of enzymatic antioxidants and decreased lipid peroxidation compared with MG treatment alone. EA elevated testosterone hormone levels and thus enhanced male reproductive capacity. It is clear from the data that EA inhibits histological and ultrastructure testicular damage and improves the redox state in male rats.

The Protective Role of Selenium Against AFB1-Induced Liver Apoptosis by Death Receptor Pathway in Broilers

Aflatoxin B1 (AFB₁) is the most toxic among the mycotoxins and causes detrimental health effects on the liver of human and animals. Selenium (Se) plays an important role in protection of various animal species against numerous notorious toxic agents. The present study is designed to explore the protective effects of Se against AFB₁-induced liver pathogenesis by the methods of histopathology, flow cytometry, quantitative real-time polymerase chain reaction (qRT-PCR), and biochemical analysis. A total of 312, 1-day-old healthy Cobb-500 broilers were randomly divided into four groups and fed with basal diet (control group), 0.6 mg/kg AFB₁ (AFB₁ group), 0.4 mg/kg Se (+ Se group), and 0.6 mg/kg AFB₁ + 0.4 mg/kg Se (AFB₁ + Se group) for 21 days, respectively. Our results showed that 0.4 mg/kg Se supplement in broiler's diets could alleviate the AFB₁-induced histological lesions in the liver. The apoptosis analysis by flow cytometry showed that 0.4 mg/kg Se ameliorated the AFB₁-induced apoptosis in the liver. Moreover, the mRNA expression levels of Fas, TNF-α, FAS-associated death domain, TNF receptor-associated death domain, TNF receptor-associated factor 2, caspase 10, caspase 8, B cell lymphoma 2, IκB kinase, X-linked inhibitor of apoptosis protein, caspase 9, and caspase 3 analyzed by qRT-PCR demonstrated that 0.4 mg/kg Se could relieve the impact caused by AFB₁ to these parameters. The biochemical analyses of activities of CAT, GSH-Px and SOD, hydroxyl ion scavenging and contents of MDA and GSH in liver cells also indicated that 0.4 mg/kg Se has positive effect on AFB₁-induced oxidative stress in the liver. In conclusion, Se could relieve AFB₁-induced apoptosis by the molecular regulation of death receptors pathway in the liver of broilers. The outcomes from the present study may lead to a better understanding of the nature of selenium's essentiality and its protective roles against AFB₁.

Augmentation of cadmium-induced oxidative cytotoxicity by pioglitazone in renal tubular epithelial cells

The aim of this study was to examine whether a peroxisome proliferator-activated receptor (PPAR)-γ agonist could affect cadmium (Cd)-induced cytotoxicity via the increased expression of megalin, one of the uptake pathways, using renal epithelial LLC-PK1 cells. The treatment with 1 µM Cd for 24 h was not cytotoxic; however, when the cells were pretreated with 0.1 µM pioglitazone for 12 h and then exposed to 1 µM Cd for 24 h, significant accumulation of Cd and cytotoxicity were detected, with an increase in megalin mRNA expression. In addition, pretreatment with pioglitazone significantly increased the Cd-induced generation of hydrogen peroxide and cell apoptosis. The augmented Cd-induced cytotoxicity and apoptosis on preincubation with pioglitazone were inhibited by prior treatment with GW 9662 (PPAR-γ antagonist). These findings suggest that a PPAR-γ agonist could augment Cd-induced oxidative injury and cell apoptosis, possibly dependent on the expression level of the uptake pathway.

Zn Supplement-Antagonized Cadmium-Induced Cytotoxicity in Macrophages In Vitro: Involvement of Cadmium Bioaccumulation and Metallothioneins Regulation

Cadmium (Cd) is a toxic metal leading to multiple forms of organ damage. Zinc (Zn) was reported as a potential antagonist against Cd toxicity. The present study investigates the antagonistic effect of Zn (20 μM) on Cd (20 or 50 μM) cytotoxicity in macrophages in vitro. The results shows that Cd exposure caused dose-dependent morphologic and ultrastructural alterations in RAW 264.7 macrophages. Zn supplement significantly inhibited Cd cytotoxicity in RAW 264.7 or HD-11 macrophages by mitigating cell apoptosis, excessive ROS output, and mitochondrial membrane depolarization. Notably, Zn supplement for 12 h remarkably prevented intracellular Cd2+ accumulation in 20 μM (95.99 ± 9.93 vs 29.64 ± 5.08 ng/106 cells; P = 0.0008) or 50 μM Cd (179.78 ± 28.66 vs 141.62 ± 22.15 ng/106 cells; P = 0.003) exposed RAW 264.7 cells. Further investigation found that Cd promoted metallothioneins (MTs) and metal regulatory transcription factor 1 (MTF-1) expression in RAW 264.7 macrophages. Twenty μM Zn supplement dramatically enhanced MTs and MTF-1 levels in Cd-exposed RAW 264.7 macrophages. Intracellular Zn2+ chelation or MTF-1 gene silencing inhibited MTs synthesis in Cd-exposed RAW 264.7 macrophages, which was accompanied by the declined expression of MTF-1, indicating that regulation of Zn on MTs was partially achieved by MTF-1 mobilization. In conclusion, this study demonstrates the antagonism of Zn against Cd cytotoxicity in macrophages and reveals its antagonistic mechanism by preventing Cd2+ bioaccumulation and promoting MTs expression.

Regular crabmeat consumers do not show increased urinary cadmium or beta-2-microglobulin levels compared to non-crabmeat consumers

Cadmium (Cd) is a toxic metal that can be relatively high in brown meat from crab and there is concern that it may accumulate in long-term crabmeat consumers posing a health risk. Sixteen healthy habitual crabmeat consumers and twenty five healthy non-crabmeat consumers were recruited through completion of a seafood frequency questionnaire. Whole blood and urine samples were analysed for Cd levels and urinary beta-2-microglobulin, an established marker of Cd-induced kidney toxicity, to determine levels in crabmeat consumers. Whole blood Cd levels were significantly elevated in the crabmeat-consuming group, whereas urinary levels of Cd and beta-2-microglobulin were not. Whole blood Cd levels can be both a short and long-term marker for Cd intake and levels might be expected to be elevated in the crabmeat consumers as crabmeat can contain Cd. However, crabmeat consumers did not show increases in a more established long-term marker of Cd (urinary Cd) and consistent with this, no change in a Cd-induced kidney toxicity marker. Consequently, in conclusion, compared to consumers who reported very little crabmeat consumption, healthy middle-aged consumers who regularly consume brown crabmeat products (an average of 447 g/week) for an average of 16 years showed no change in long-term Cd exposure or kidney toxicity.

Effects of maduramicin on adult zebrafish (Danio rerio): Acute toxicity, tissue damage and oxidative stress

Maduramicin, a potent polyether ionophore antibiotic, has been widely used to control coccidiosis in the poultry production. Nevertheless, incomplete metabolism of maduramicin in chicken may result in its accumulation in the aquatic environment, while maduramicin's threat to fish remains largely unknown. In the present study, we focused on acute toxicity, histopathological lesion and oxidative stress damage of maduramicin in adult zebrafish. Primarily, we obtained that the 96-h median lethal concentration (96 h LC₅₀) of adult zebrafish exposure to maduramicin was 13.568 mg/L. On basis of that, adult zebrafish were separately exposed to 0.1 mg/L (1/125 LC₅₀), 0.5 mg/L (1/25 LC₅₀) and 2.5 mg/L (1/5 LC₅₀) maduramicin for 14 days. On day 3, 0.1 mg/L maduramicin significantly increased the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX) and glutathione s-transferase (GST) in the liver of zebrafish, while the activities of these antioxidant enzymes in the liver were significantly inhibited by 2.5 mg/L maduramicin. Moreover, the contents of malondialdehyde (MDA) in the liver of different dose groups were all significantly promoted after 14 days of exposure. For the gill of zebrafish, the increase in MDA contents was found after only 3 days of exposure to maduramicin. Furthermore, maduramicin treatment significantly up-regulated the mRNA levels of genes (sod1, gpx1a, gstr, nrf2 and keap1) in the liver of zebrafish after 3 days of exposure. On days 6, 9 and 14, maduramicin treatment significantly down-regulated the mRNA levels of these genes in the liver of zebrafish. Meanwhile, maduramicin significantly down-regulated the mRNA levels of genes (sod1, cat, gpx1a, gstr, nrf2 and keap1) in the gill of zebrafish during the 14-day of exposure. In addition, a dose-dependent induction in histopathological lesion was observed in multiple organs after 14 days of exposure, including lamellar fusion, epithelial lifting in the gill and vacuole formation in the liver as well as the fracture of intestinal villus in the intestine. Taken together, our findings demonstrated that waterborne maduramicin (2.5 mg/L) exposure can induce severe oxidative stress and tissue damage in adult zebrafish while this damage was not enough to kill them after 14 days of waterborne exposure.

Selenium reduces cadmium uptake into rice suspension cells by regulating the expression of lignin synthesis and cadmium-related genes

Although previous studies have indicated that selenium (Se) can reduce cadmium (Cd) uptake into rice, the mechanism at the cellular level has not been reported. Here, rice suspension cells exposed to Cd treatment in the presence or absence of Se were characterized. Compared with treatment with alone, pretreatment with Se increased the proportion of live cells by 83.1%. The levels of reactive oxygen species and mitochondrial membrane potential in the Se-pretreated rice cells were decreased by 86.6% and 76.0%, respectively. In addition, non-invasive micro-test technology suggested that the mean values of Cd²⁺ influx decreased significantly in the Se-pretreated rice cells in a concentration-dependent manner. The results of inductively coupled plasma-mass spectrometry (ICP-MS) showed that 67.4%-78.8% Cd accumulated onto the cell walls of the pretreated-Se rice cells. The addition of Se increased the lignin content and thickness of the cell walls, leading to an improved mechanical force of the cell walls, as determined by atomic force microscopy (AFM). Furthermore, Se pretreatment decreased the expression of genes involved in Cd uptake (OsNramp5) and transport (OsLCT1) but activated the expression of genes involved in Cd transport into vacuoles (OsHMA3) and lignin synthesis (OsPAL, OsCoMT and Os4CL3). These results indicated that supplying Se alleviates Cd toxicity by regulating the express of lignin synthesis and Cd-related genes. The present findings provide new insights on a plausible explanation of the Se-reduced Cd uptake into rice.

Royal Jelly Abrogates Cadmium-Induced Oxidative Challenge in Mouse Testes: Involvement of the Nrf2 Pathway

The current study examined the efficacy of royal jelly (RJ) against cadmium chloride (CdCl₂)-induced testicular dysfunction. A total of 28 Swiss male mice were allocated into four groups (n = 7), and are listed as follows: (1) the control group, who was intraperitoneally injected with physiological saline (0.9% NaCl) for 7 days; (2) the RJ group, who was orally supplemented with RJ (85 mg/kg daily equivalent to 250 mg crude RJ) for 7 days; (3) the CdCl₂ group, who was intraperitoneally injected with 6.5 mg/kg for 7 days; and (4) the fourth group, who was supplemented with RJ 1 h before CdCl₂ injection for 7 days. Cd-intoxicated mice exhibited a decrease in serum testosterone, luteinizing hormone (LH), and follicle stimulating hormone (FSH) levels. A disturbance in the redox status in the testicular tissue was recorded, as presented by the increase in lipid peroxidation and nitrate/nitrite levels and glutathione (GSH) depletion. Moreover, the activities of glutathione peroxidase (GPx), glutathione reductase (GR), superoxide dismutase (SOD), catalase (CAT), and nuclear factor (erythroid-derived 2)-like-2 factor (Nrf2) and their gene expression were inhibited. In addition, interleukin-1ß (IL-1β) and tumor necrosis factor-α (TNF-α) levels were elevated. Furthermore, Cd triggered an apoptotic cascade via upregulation of caspase-3 and Bax and downregulation of Bcl-2. Histopathological examination showed degenerative changes in spermatogenic cells, detachment of the spermatogenic epithelium from the basement membrane, and vacuolated seminiferous tubules. Decreased cell proliferation was reflected by a decrease in proliferating cell nuclear antigen (PCNA) expression. Interestingly, RJ supplementation markedly minimized the biochemical and molecular histopathological changes in testes tissue in response to Cd exposure. The beneficial effects of RJ could be attributed to its antioxidative properties.

Review of polyphenol-rich products as potential protective and therapeutic factors against cadmium hepatotoxicity

Recently, the growing attention of the scientific community has been focused on the threat to health created by environmental pollutants, including toxic metals such as cadmium (Cd), and on the need of finding effective ways to prevent and treat the unfavorable health effects of exposure to them. Particularly promising for Cd, and thus arousing the greatest interest, is the possibility of using various ingredients present in plants, including mainly polyphenolic compounds. As the liver is one of the target organs for this toxic metal and disturbances in the proper functioning of this organ have serious consequences for health, the aim of the present review was to discuss the possibility of using polyphenol-rich food products (e.g., chokeberry, black and green tea, blueberry, olive oil, rosemary and ginger) as the strategy in protection from this xenobiotic hepatotoxicity and treatment of this heavy metal-induced liver damage. Owing to the ability of polyphenols to bind ions of Cd and the strong antioxidative potential of these compounds, as well as their abundance in dietary products, it seems to be of high importance to consider the possibility of using polyphenols as potential preventive and therapeutic agents against Cd hepatotoxicity, determined by its strong pro-oxidative properties. Although most of the data on the effectiveness of polyphenols comes from studies in animals, the fact that some of them are derived from experimental models that reflect human exposure to this metal allows us to assume that some polyphenol-rich food products may be promising protective agents against Cd hepatotoxicity in humans.

Ameliorative Effects of Selenium on Cadmium-Induced Injury in the Chicken Ovary: Mechanisms of Oxidative Stress and Endoplasmic Reticulum Stress in Cadmium-Induced Apoptosis

Despite the well-established toxicity of cadmium (Cd) to animals and the ameliorative effects of selenium (Se), some specific mechanisms in the chicken ovary are not yet clarified. To explore the mechanism by which the toxicity effect of Cd is induced and explore the effect of supranutritional Se on Cd toxicity in female bird reproduction, forty-eight 50-day-old Isa Brown female chickens were divided randomly into four groups. Group I (control group) was fed the basic diet containing 0.2 mg/kg Se. Group II (Se-treated group) was fed the basic diet supplemented with sodium selenite (Na₂SeO₃), and the total Se content was 2 mg/kg. Group III (Se + Cd-treated group) was fed the basic diet supplemented with Na₂SeO₃; the total Se content was 2 mg/kg, and it was supplemented with 150 mg/kg cadmium chloride (CdCl₂). Group IV (Cd-treated group) was with the basic diet supplemented with 150 mg/kg CdCl₂. The Cd, estradiol (E2), and progestogen (P4) contents changed after subchronic Cd exposure in chicken ovarian tissue; subsequently, oxidative stress occurred and activated the endoplasmic reticulum (ER) pathway to induce apoptosis. Further, Se decreased the accumulation of Cd in ovarian tissue, increased the E2 and P4 contents, alleviated oxidative stress, and reduced apoptosis via the ER stress pathway. The present results demonstrated that Cd could induce apoptosis via the ER stress pathway in chicken ovarian tissue and that Se had a significant antagonistic effect. These results are potentially valuable for finding a strategy to prevent Cd poisoning.

Age-dependent changes in essential elements and oxidative stress biomarkers in blood of red deer and vulnerability to nutritional deficiencies

Changes in the concentration of circulating essential elements in animals over life may be indicative of periods of vulnerability to deficiencies and associated diseases. Here we studied age-related variations in essential elements (Se, Cu, Zn and Mn) and some selected oxidative stress biomarkers (GPx, SOD, vitamin A and vitamin E) in blood of an Iberian red deer (Cervus elaphus hispanicus) population living in semicaptive conditions. Animals during their first year of life showed to be especially vulnerable to suffer Se- and Cu-related diseases and disorders. Older female deer had lower blood levels of Zn and Mn, which was accompanied by a lower blood SOD activity. On the contrary, GPx blood activity was elevated in older deer, which may help to compensate the reduction of other antioxidants with during aging. Age-related changes in GPx and SOD and their positive relationships with the essential elements suggest that the observed nutritional deficiencies at certain age stages may have a detrimental effect on the antioxidant system, increasing the risk of oxidative stress. Thus, the biomarkers used in the present study may be important tools for the subclinical diagnosis of nutritional disorders and diseases related to the generation of oxidative stress in both domestic and wild ungulates.

Effect of 1-methyl-3-hexylimidazolium bromide on zebrafish (Danio rerio)

Room-temperature ionic liquids, generally referred to ionic liquids (ILs), are "green solvents". Antioxidant responses and DNA damage in zebrafish livers exposed to 1-methyl-3-hexylimidazolium bromide ([C₆mim]Br) were evaluated at various doses (5-40 mg/L) for a 28-day IL-exposure. A significant decrease of superoxide dismutase (SOD) activity was exhibited, and catalase (CAT) was inhibited at the highest dose (40 mg/L). Reactive oxygen species (ROS) levels were significantly promoted at most exposure interval times except for the dose of 5 mg/L on day 21 in male and days 21 and 28 in female. Malonaldehyde (MDA) contents remarkable increased exposed to [C₆mim]Br. Besides, a notable increase was exhibited, which indicated an inducement of DNA damage with respect to control groups. Thus, we believed that [C₆mim]Br causes oxidative stress and DNA damage in zebrafish. Gender differences were insignificant in almost all the tested biomarkers, thus, male and female zebrafish could be mixed at a ratio of 1:1 in the future evaluation. The present study may also provide basic toxicology information for IL evaluation to aquatic organisms.

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.

Maternal exposure to selenium and cadmium, fetal growth, and placental expression of steroidogenic and apoptotic genes

BACKGROUND

Cadmium (Cd) and selenium (Se) antagonistically influence redox balance and apoptotic signaling, with Cd potentially promoting and Se inhibiting oxidative stress and apoptosis. Alterations to placental redox and apoptotic functions by maternal exposure to Cd and Se during pregnancy may explain some of the Cd and Se associations with fetal development.

OBJECTIVES

Investigate associations between Cd and Se concentrations in maternal toenails with placental expression patterns of tumor necrosis factor (TNF) and steroidogenic genes involved in redox reactions and test associations with fetal growth.

METHODS

In a sub-sample from the Rhode Island Child Health Study (n = 173), we investigated the relationships between: (1) maternal toenail Cd and Se concentrations and fetal growth using logistic regression, (2) Cd and Se interactions with factor scores from placental TNF and steroidogenic expression patterns (RNAseq) using linear models, and (3) TNF and steroidogenic expression factors with fetal growth via analysis of covariance.

RESULTS

Se was associated with decreased odds of intrauterine growth restriction (IUGR) (OR = 0.27, p-value = 0.045). Cd was associated with increased odds of IUGR (OR = 1.95, p-value = 0.13) and small for gestational age (SGA) births (OR = 1.46, p-value = 0.11), though not statistically significant. Cd and Se concentrations were antagonistically associated with placental TNF and steroidogenic expression patterns, which also differed by birth size.

CONCLUSIONS

Se may act as an antagonist to Cd and as a modifiable protective factor in fetal growth restriction, and these data suggest these effects may be due to associated variations in the regulation of genes involved in placental redox balance and/or apoptotic signaling.

Astragalus Polysaccharide Protect against Cadmium-Induced Cytotoxicity through the MDA5/NF-κB Pathway in Chicken Peripheral Blood Lymphocytes

Cadmium (Cd) is a known environmental pollutant that is associated with inflammation, oxidative stress, and cell apoptosis. Astragalus polysaccharide (APS) is a major component of Astragalus membranaceus, a vital qi-reinforcing herb medicine with favorable immuneregulation properties. To study the effect of APS on the inhibition of the cadmium-induced injury of peripheral blood lymphocytes (PBLs) in chickens through the MDA5/NF-κB signaling pathway, PLBs acquired from 15-day-old chickens were divided into control group, Cd group, APS + Cd group, anti-MDA5 mAb + Cd group, BAY 11-7082 (a nuclear factor kappa-light chain-enhancer of activated B cells [NF-κB] inhibitor) +Cd group, APS group, anti-MDA5 mAb group, and BAY 11-7082 group. The transcription levels of melanoma differentiation-associated gene 5 (MDA5), interferon promoter-stimulating factor 1 (IPS-1), NF-κB, and inflammatory factors tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6 were measured by quantitative real-time PCR. MDA5 protein expression was measured by western blotting. Levels of malondialdehyde (MDA), glutathione peroxidase (GSH-Px), and superoxide dismutase (SOD) were measured by corresponding antioxidant kit. The morphological change of PBLs was measured by transmission electron microscopy. The results showed that Cd significantly increased the expression of MDA5, IPS-1, NF-κB, and their downstream cytokines, IL-1β and TNF-α, IL-6 in PLBs. In addition, a high level of MDA was observed in the Cd treatment group; the activities of GSH-Px and SOD were significantly lower in the Cd treatment group than those in controls (p < 0.05). Ultrastructural changes of PBLs showed that Cd promoted autophagy, apoptosis, and necrosis in PBLs. However, APS can efficiently improve Cd-induced cell damage by decreasing the activation of the MDA5 signaling pathway. The effect is consistent with that of anti-MDA5 mAb or/and BAY. The results indicated that APS inhibited Cd-induced cytotoxicity through the regulation of MDA5/NF-κB signaling.

The Effect of Selenium on the Cd-Induced Apoptosis via NO-Mediated Mitochondrial Apoptosis Pathway in Chicken Liver

Cd-induced apoptosis and the protective effects of Se against Cd-induced injury have been reported in previous studies. However, little is known regarding the effects of Cd-induced apoptosis in hepatic cells and the antagonistic effects of Se on Cd in poultry. In the present study, 128 healthy 31-week-old laying hens were randomly divided into four groups, which were fed basic diets, with the addition of Se (Na₂SeO₃, 2 mg/kg), Cd (CdCl₂, 150 mg/kg), or Se + Cd (150 mg/kg of CdCl₂ and 2 mg/kg of Na₂SeO₃) for 90 days. Ultrastructural changes, nitric oxide (NO) concentrations, inducible nitric oxide synthase (iNOS) activities, results of the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay of apoptosis, and the expression of iNOS and apoptosis-related genes in livers were determined. It was observed that Cd treatment significantly increased the concentrations of NO and iNOS activity in chicken livers. The production of excessive NO initiated the mitochondrial apoptotic pathway. Exposure to Cd increased the mRNA and the protein expression levels of iNOS, caspase-3, Bax, p53, and Cyt-c. Furthermore, the ratio of Bax/Bcl-2 increased, while the expression of Bcl-2 decreased. Treatment with Se significantly alleviated Cd-induced apoptosis in chicken livers, as evidenced by a reduction in the production of NO, iNOS activity, the number of apoptotic cells, and mRNA and protein expression levels of iNOS, caspase-3, Bax, and Cyt-c. It indicated that Cd induced NO-mediated apoptosis through the mitochondrial apoptotic pathway and Se exerted antagonizing effects. The present study provides new insights as to how Se affects Cd-induced toxicity in the chicken liver.

Complex effect of zinc oxide nanoparticles on cadmium chloride-induced hepatotoxicity in mice: protective role of metallothionein

The wide range of applications of ZnO nanoparticles (nano ZnO) in commercial products and the ubiquitous cadmium (Cd) contamination in the natural environment increase the chance of co-existence of nano ZnO with Cd in the surroundings. To investigate the effects of nano ZnO on CdCl₂-induced hepatotoxicity in mice, the histopathologic changes, metallothionein expression, oxidative stress responses and serum biochemical parameters were determined after oral administration of bulk or nano ZnO and/or CdCl₂ for seven consecutive days. Bulk or nano ZnO had low toxicity in mice. In contrast, CdCl₂ led to significant hepatic oxidative damage, as indicated by hepatic histopathological abnormalities and dysfunction. Bulk and nano ZnO had nearly identical influences on the hepatotoxicity of CdCl₂ in mice. Although co-administration of bulk or nano ZnO with CdCl₂ had a positive cooperative effect on the hepatic uptake of Cd and Zn, both bulk and nano ZnO significantly attenuated CdCl₂-caused hepatic damage via the reduction of oxidative stress. The increase in metallothionein synthesis and the reduction of Cd-induced perturbation of Zn²⁺ homeostasis after co-administration of bulk or nano ZnO with CdCl₂ play two important roles in the protective effect of bulk or nano ZnO on CdCl₂-caused hepatic oxidative 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.

Brown propolis attenuates cerebral ischemia-induced oxidative damage via affecting antioxidant enzyme system in mice

Oxidative stress plays a critical role in ischemic brain injury. Superoxide dismutase (SOD) and glutathione peroxidase (GPx) are the enzymes underlying the endogenous antioxidant mechanisms affected by stroke and are considered as oxidative stress biomarkers. Brown propolis (BP) is a bioactive natural product with a set of biological activities that in turn may differ depending on the area from which the substance is originated. The aim of this study was to investigate the effect of water-extracted brown propolis (WEBPs), from two regions of Iran, against cerebral ischemia-induced oxidative injury in a mouse model of stroke. Experimentally, the chemical characterization and total polyphenol content were determined using GC/MS and Folin-Ciocalteu assay respectively. Seventy-two adult male mice were randomly divided into the surgical sham group, control group (treated with vehicle), and four groups of WEBPs-treated animals. The WEBPs were administered at the doses of 100 and 200mg/kg IP, during four different time points. Oxidative stress biomarkers (SOD and GPx activity, SOD/GPx ratio), lipid peroxidation (LPO) index (malondialdehyde content) and infarct volume were measured 48h post stroke. Behavioral tests were evaluated 24 and 48h after stroke. WEBPs treatment resulted in significant restoration of antioxidant enzymes activity and a subsequent decrease in LPO as well as the infarct volume compared to the control group. Sensory-motor impairment and neurological deficits were improved significantly as well. These results indicate that Iranian BP confers neuroprotection on the stroke-induced neuronal damage via an antioxidant mechanism which seems to be mediated by the endogenous antioxidant system.

Growth inhibition and oxidative stress induced by 1-octyl-3-methylimidazolium bromide on the marine diatom Skeletonema costatum

Marine diatom Skeletonema costatum is an important prey in the marine food web and is often used as a standard test organism in ecotoxicological studies. In this study, in vivo experiments were performed to analyze the effects of 1-octyl-3-methylimidazolium bromide ([C8mim]Br) on the growth, photosynthetic activity, and oxidative stress in S. costatum using 96h growth tests with a batch-culture system. The growth of S. costatum was significantly inhibited by [C8mim]Br with 48 and 96h-EC50 of 17.9 and 39.9mgL(-1), respectively. The maximum quantum yield (Fv/Fm) and the light use efficiency (α) were inhibited by [C8mim]Br, which affected the growth of S. costatum. Subsequent biochemical assays in S. costatum revealed that [C8mim]Br induced changes of Chl a content, soluble protein content, and SOD activity, which had significant increases in low [C8mim]Br treatments (≤20mgL(-1)), but decreased in high [C8mim]Br exposures (≥40mgL(-1)). The increase of SOD activity at low concentrations (≤20mgL(-1)) may be considered as an active defense of S. costatum against [C8mim]Br stress by reactive oxygen species (ROS) quenching. In addition, [C8mim]Br increased ROS level and malondialdehyde (MDA) content in S. costatum, suggesting that the physiological effects of [C8mim]Br are resulted from ROS generation.

Zinc, lead, and cadmium levels in serum and milk of lactating women in Ibadan, Nigeria

Zinc (Zn) is known to interact with lead (Pb) and cadmium (Cd) reversing their toxicity and reducing their concentrations. However, lactating women are at high risk of developing Zn deficiency, which may result in Pb and Cd intoxication or increased exposure of breast-fed infants to Pb and Cd from breast milk. The aim of this study was to determine Zn, Pb, and Cd concentrations and examine their relationship in serum and breast milk of lactating women in Ibadan, Nigeria. Ninety-two lactating women were recruited into this study. Anthropometric measurements were assessed by standard methods while serum and breast milk concentrations of Zn, Pb, and Cd were assessed by atomic absorption spectrophotometry. Data analyzed statistically by Student’s t test, Pearson’s correlation coefficient, and a multiple regression model were significant at p < 0.05. Zn deficiency was observed in 12 (17.1%) of lactating women. Breast milk levels of Zn, Pb, and Cd were significantly higher than their levels in serum, whereas the ratios Zn:Pb and Zn:Cd in milk were significantly less than serum ratios. Significant negative correlation was observed between milk Pb and serum Zn:Pb while milk Cd correlated positively with milk Zn. Significant positive correlations were observed between serum Zn and serum Zn:Pb, serum Zn and serum Zn:Cd, as well as serum Zn:Cd and serum Zn:Pb. Serum Cd and serum Zn were significantly negatively related. Significant negative correlations between serum Pb and serum Zn:Pb as well as milk Zn:Pb. Serum Cd and serum Zn:Pb as well as serum Zn:Cd correlated negatively. Milk Cd and Zn/Cd positively related with milk Pb while milk Zn was a negatively related with milk Pb in a multiple regression model ( R2 = 0.333; p = 0.023). Breast milk may be contaminated by toxic metals. However, Zn supplementation in deficient mothers may protect maternal and infant health.

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

Complex antagonistic interactions between Selenium (Se) and heavy metals have been reported in previous studies. However, little is known regarding the effects of Se on lead (Pb)-induced toxicity and the ion profile in the muscles of chickens. In this present study, we fed chickens either Se or Pb or both Se and Pb supplement and later analyzed the concentrations of 26 ions in chicken muscle tissues. We determined that a Se- and Pb-containing diets significantly affected microelements in chicken muscle. Treatment with Se increased the content of Se but resulted in a reduced concentration of Cu, As, Cd, Sn, Hg, and Ba. Treatment with Pb increased concentrations of Ni while reducing those of B, V, Cr, Fe, Co, Cu, Zn, and Mo. Moreover, Se also reduced the concentration of Pb, Zn, Co, Fe, V, and Cr, which in contrast were induced by Pb. Additionally, we also found that synergistic and antagonistic interactions existed between Se and Pb supplementation. Our findings suggested that Se can exert a negative effect on Pb in chicken muscle tissues and may be related to changes in ion profiles.

Mercuric chloride induced hepatotoxic and hematologic changes in rats

This study focuses on investigating the possible protective effect of sodium selenite (Na2SeO3) and/or vitamin E against mercuric chloride (HgCl2)-induced hepatotoxicity in rat. Male rats were given HgCl2 (1 mg/kg body weight (bw)) and HgCl2 plus Na2SeO3 (0.25 mg/kg bw) and/or vitamin E (100 mg/kg bw) daily via gavage for 4 weeks. HgCl2-treated groups had significantly higher white blood cell and thrombocyte counts than the control group. Serum activities of alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, γ-glutamyl-transferase, and lactate dehydrogenase significantly increased and serum levels of total protein, albumin, triglyceride, total cholesterol, and low-density lipoprotein cholesterol significantly decreased in the HgCl2-treated groups compared with control group. Malondialdehyde level significantly increased and superoxide dismutase, catalase, and glutathione peroxidase activities decreased in liver tissue of HgCl2-treated rats. Also, HgCl2 exposure resulted in histopathological changes. Supplementation of Na2SeO3 and/or vitamin E provided partial protection in hematological and biochemical parameters that were altered by HgCl2. As a result, Na2SeO3 and/or vitamin E significantly reduced HgCl2-induced hepatotoxicity, but not protected completely.