Zinc Accumulation In Tissues Research Articles

Joint effects of gamma radiation and zinc on duckweed Lemna minor L.

When assessing the consequences of combined chemical and radiation pollution on bodies of water, it is important to take into account the interaction of different factors, especially the possible synergistic increase in the toxic effect on growth, biochemical and physiological processes of living organisms. In this work, we studied the combined effect of γ-radiation and zinc on freshwater duckweed Lemna minor L. Irradiated plants (doses were 18, 42, and 63 Gy) were placed on a medium with an excess of zinc (3.15, 6.3, 12.6 μmol/L) for 7 days. Our results showed that the accumulation of zinc in tissues increased in irradiated plants when compared to non-irradiated plants. The interaction of factors in assessing their effect on the growth rate of plants was most often additive, but there was also a synergistic increase in the toxic effect at a zinc concentration of 12.6 μmol/L and irradiation at doses of 42 and 63 Gy. When comparing the combined and separate effects of gamma radiation and zinc, it was found that a reduction in the area of fronds (leaf-like plates) was caused exclusively due to the effects of radiation. Zinc and γ-radiation contributed to the enhancement of membrane lipid peroxidation. Irradiation stimulated the production of chlorophylls a and b, as well as carotenoids.

Resolving the immune landscape of human prostate at a single-cell level in health and cancer.

SummaryThe prostate gland produces prostatic fluid, high in zinc and citrate and essential for the maintenance of spermatozoa. Prostate cancer is a common condition with limited treatment efficacy in castration-resistant metastatic disease, including with immune checkpoint inhibitors. Using single-cell RNA-sequencing to perform an unbiased assessment of the cellular landscape of human prostate, we identify a subset of tumor-enriched androgen receptor-negative luminal epithelial cells with increased expression of cancer-associated genes. We also find a variety of innate and adaptive immune cells in normal prostate that were transcriptionally perturbed in prostate cancer. An exception is a prostate-specific, zinc transporter-expressing macrophage population (MAC-MT) that contributes to tissue zinc accumulation in homeostasis but shows enhanced inflammatory gene expression in tumors, including T cell-recruiting chemokines. Remarkably, enrichment of the MAC-MT signature in cancer biopsies is associated with improved disease-free survival, suggesting beneficial antitumor functions.

The effects of EDTA on zinc accumulation in tissues of Cyprinus carpio (Linnaeus 1758)

The present study aimed to determine the zinc accumulation levels in the gill, liver, and muscle tissues of Cyprinus carpio (Linnaeus, 1758) under the effect of zinc (2.0 and 4.0 ppm) and zinc + EDTA (2.0 + 4.0 and 4.0 + 8.0 ppm) for 7, 15, and 30 days and the effects of EDTA on zinc accumulation in tissues. Tissue zinc levels were determined by inductively coupled plasma-mass spectrometry (ICP˗MS). No mortality occurred in fish under the exposure times and concentrations with solutions containing zinc only and zinc combined with EDTA. At the beginning of the metal exposure, various behavioral changes were observed in the fish, and those behaviors returned to normal with longer exposure time. The exposure to both zinc alone and zinc combined with EDTA significantly increased metal accumulation in the tissues and organs (P liver > muscle accumulation relationship was found among the tissues. The results obtained showed that EDTA reduced zinc accumulation in the gill, liver, and muscle tissues when compared to the effect of zinc only.

Effect of the Source of Zinc on the Tissue Accumulation of Zinc and Jejunal Mucosal Zinc Transporter Expression in Holstein Dairy Calves.

Simple SummaryDiarrhea is the main cause of death in newborn calves and is associated with antibiotic use and economic loss for dairy farms. In this study, we evaluated the effects of different sources of the mineral zinc (zinc oxide (ZnO) and zinc methionine (Zn-Met)) on the growth, incidence of diarrhea, tissue zinc accumulation, gene expression of jejunal zinc transporters and serum concentrations of zinc-dependent proteins in newborn Holstein dairy calves. We found that Zn-Met supplementation promoted growth and reduced diarrhea from the second week after birth. It also increased the levels of zinc in the serum and liver, the level of the transporter protein ZIP4 in the jejunal mucosa, as well as the serum alkaline phosphatase and metallothionein concentrations compared to the control group. ZnO supplementation had similar but less marked effects to Zn-Met supplementation. These results suggest that Zn-Met supplementation may be an alternative to antibiotics for the treatment of newborn calf diarrhea.Zinc is considered to be an anti-diarrheal agent, and it may therefore reduce the incidence of diarrhea in young calves. In the present study, we aimed to compare the effect of zinc source on growth performance, the incidence of diarrhea, tissue zinc accumulation, the expression of zinc transporters, and the serum concentrations of zinc-dependent proteins in neonatal Holstein dairy calves. Eighteen male newborn Holstein dairy calves were fed milk and starter diet supplemented with or without 80 mg zinc/d in the form of Zn-Met or ZnO for 14 days, and were then euthanized. Zn-Met supplementation improved average daily gain and feed efficiency, and reduced the incidence of diarrhea, compared with control calves (p < 0.05). It also increased the serum and hepatic zinc concentrations and the mRNA expression of the ZIP4 transporter in the jejunal mucosa of the calves (p < 0.05). In addition, the serum alkaline phosphatase activity and metallothionein concentration were higher in Zn-Met-treated calves than in control calves (p < 0.05). ZnO supplementation had similar effects, but these did not reach significance. Thus, Zn-Met supplementation is an effective means of increasing tissue zinc accumulation and jejunal zinc absorption, and can be used as an anti-diarrheal strategy in neonatal calves.

Assessment of ZnO-NPs toxicity in maize: An integrative microRNAomic approach

Rapid expansion of nanotechnology and indiscriminate discharge of metal oxide nanoparticles (NPs) into the environment pose a serious hazard to the ecological receptors including plants. To better understand the role of miRNAs in ZnO-NPs stress adaptation, two small RNA libraries were prepared from control and ZnO-NPs (800 ppm, <50 nm particle size) stressed maize leaves. Meager performance of ZnO-NPs treated seedlings was associated with elevated tissue zinc accumulation, enhanced ROS generation, loss of root cell viability, increased foliar MDA content, decrease in chlorophyll and carotenoids contents. Deep sequencing identified 3 (2 known and 1 novel) up- and 77 (73 known and 4 novel) down-regulated miRNAs from ZnO-NPs challenged leaves. GO analysis reveals that potential targets of ZnO-NPs responsive miRNAs regulate diverse biological processes viz. plant growth and development (miR159f-3p, zma_18), ROS homeostasis (miR156b, miR166l), heavy metal transport and detoxification (miR444a, miR167c-3p), photosynthesis (miR171b) etc. Up-regulation of SCARECROW 6 in ZnO-NPs treated leaves might be responsible for suppression of chlorophyll biosynthesis leading to yellowing of leaves. miR156b.1 mediated up-regulation of CALLOSE SYNTHASE also does not give much protection against ZnO-NPs treatment. Taken together, the findings shed light on the miRNA-guided stress regulatory networks involved in plant adaptive responses to ZnO-NPs stress.

Effect of dietary zinc pectin oligosaccharides chelate on growth performance, enzyme activities, Zn accumulation, metallothionein concentration, and gene expression of Zn transporters in broiler chickens1.

This study was to investigate the effect of zinc pectin oligosaccharides chelate (Zn-POS) on growth performance, serum enzyme activities, tissue zinc accumulation, metallothionein (MT) concentrations, and gene expression of zinc transporters (ZnT) in broilers. Five hundred forty 1-d-old Arbor Acres broiler chicks were randomly assigned to 5 dietary groups with 6 replicates of 18 birds per replicate. The diets were formulated with the same supplemental Zn level (80 mg/kg diet) but different amount of the Zn-POS: 0, 200, 400, 600, and 800 mg Zn-POS/kg diet. ZnSO4 was used to adjust to the desired amount of the Zn (80 mg/kg) in the Zn-POS diets. Broilers were fed with the experimental diets for 42 d including the starter (days 1 to 21) and grower (days 22 to 42) phases. Our results showed that dietary supplementation of Zn-POS linearly and quadratically increased (P < 0.05) the average daily gain and gain-to-feed ratio during 22 to 42 d and 1 to 42 d as well as body weight on day 42, whereas reduced (P < 0.05) the sum of mortality and lag abnormalities in broilers on day 42. Besides, serum alkaline phosphatase and copper-zinc superoxide dismutase activities increased (P < 0.05) linearly and quadratically in response to dietary Zn-POS supplemental level on day 42. Dietary Zn-POS supplementation increased Zn accumulation in serum (linear, P < 0.05), liver (linear, P < 0.05), and pancreas (linear and quadratic, P < 0.05). In addition, Zn-POS supplementation linearly and quadratically increased (P < 0.01, P < 0.05, respectively) MT concentrations in liver and pancreas of broilers. Pancreatic mRNA levels of MT, ZnT-1, and ZnT-2 increased (P < 0.05) linearly and quadratically, and the mRNA expression of metal response element-binding transcription factor-1 increased linearly (P < 0.05), in response to dietary Zn-POS supplementation. In conclusion, supplementation of Zn-POS in the diet increases Zn enrichment in the metabolic organs such as liver and pancreas and promotes productive performance in broilers.

Effects of Dietary Zinc on Carcass Traits, Meat Quality, Antioxidant Status, and Tissue Zinc Accumulation of Pekin Ducks.

This study investigated the effects of dietary zinc on carcass traits, meat quality, antioxidant capacity, and tissue zinc accumulation of Pekin ducks. A total of 768 1-day-old Pekin ducks were randomly allocated to six dietary treatments and penned in groups of 16 with 8 pens per treatment. Ducks were fed a basal corn-soybean meal diet supplemented with graded levels of zinc sulfate (0, 15, 30, 60, 120, 240mg zinc/kg) for 35days. The slaughter weight, carcass weight, eviscerated weight, and breast and leg muscle weight of Pekin ducks were increased with increasing dietary zinc levels (P < 0.05). Zinc supplementation increased the pH value at 24-h postmortem and the intramuscular fat (IMF) (P < 0.05), but decreased the lightness value, drip loss, and shear force in breast meat of ducks (P < 0.05). Increasing dietary zinc increased the activity of superoxide dismutase (SOD), glutathione peroxidase (GPX), glutathione reductase (GR), catalase (CAT), and the content of glutathione (GSH), as well as decreased the malondialdehyde (MDA) level in breast muscle (P < 0.05). RT-qPCR analysis demonstrated that supplemental zinc notably enhanced the transcription of SOD, GPX, GR, CAT, and nuclear factor erythroid 2-related factor 2 (Nrf2) (P < 0.05). Meanwhile, zinc accumulation in plasma, breast muscle, liver, and tibia were linearly increased with increasing zinc supplementation (P < 0.05). These results indicated that zinc supplementation could improve carcass traits and meat quality and increase the activities and mRNA levels of antioxidant enzymes in breast muscle of Pekin duck. Base on broken-line regression analysis that 91.32mg/kg of dietary zinc was suggested for optimal carcass traits, meat quality, antioxidant capacity, and zinc deposition of Pekin duck.

Protective effect of garlic (Allium sativum) against zinc poisoning in the testicular tissue of goldfish (Carassius auratus)

Zinc is essential to the body; however, in high concentrations, it can be toxic. In this study, the protective effect of garlic (Allium sativum) against the toxic effect of zinc on the testicular tissues of goldfish (Carassius auratus) was assessed. Seventy-five healthy fish were allocated into 5 equal groups: control group, untreated; group 1, exposed to zinc sulfate (Merck, Germany) at dose of 3 mg/L; groups 2, 3, and 4 were also exposed to zinc sulfate in the same concentration as group 1 but their diet was supplemented with garlic (A. sativum) at 0.5, 1, and 2.5% of daily diet, respectively. After 45 days, 8 fish from each group were randomly selected, testicular tissue taken, and assessed histologically. Severe histopathologic lesions were seen in groups 1 and 2 and to lesser extents in groups 3 and 4 as garlic concentration increased. This showed that goldfish testicular tissue is sensitive to zinc toxicity and that garlic can reduce zinc accumulation in tissues, indicating that antioxidant compounds from garlic might act as chelators for zinc, allowing its excretion from the body.

Chronic dietary toxicity of zinc oxide nanoparticles in common carp (Cyprinus carpio L.): Tissue accumulation and physiological responses

Concerns regarding the potential toxic effects of zinc oxide nanoparticles (ZnO NPs) on aquatic organisms are growing due to the fact that NPs may be released into aquatic ecosystems. This study aimed to investigate the effects of dietary exposure to ZnO NPs on juvenile common carp (Cyprinus carpio). Fish were fed a spiked diets at doses 50 and 500mg of ZnO NPs per kg of feed for 6 weeks followed by a 2-week recovery period. Fish were sampled every 2 weeks for haematology trends, blood biochemistry measures, histology analyses, and determination of the accumulation of zinc in tissues. At the end of the exposure and post-exposure periods, fish were sampled for an assessment of lipid peroxidation levels. Dietborne ZnO NPs had no effects on haematology, blood biochemistry, and lipid peroxidation levels during the exposure period. After the recovery period, aspartate aminotransferase activity significantly (p < 0.05) increased and alanine transferase activity significantly (p < 0.05) decreased in the higher exposure group. The level of lipid peroxidation significantly (p < 0.05) decreased in liver of treated fish after 2 weeks post-exposure period. A histological examination revealed mild histopathological changes in kidneys during exposure. Our results did not show a significant increase of zinc content at the end of experiment in any of tested organs. However, chronic dietary exposure to ZnO NPs might affect kidney and liver function.

Effects of dietary substitution of zinc-methionine for inorganic zinc sources on growth performance, tissue zinc accumulation and some blood parameters in broiler chicks.

This study was designed to evaluate the effects of dietary inclusion of zinc-methionine (ZnMet) as a replacement for conventional inorganic zinc sources on performance, tissue zinc accumulation and some plasma indices in broiler chicks. A total of 450-day-old Ross male broiler chicks were randomly assigned to five pen replicates of nine experimental diets. Dietary treatments consisted of two basal diets supplemented with 40 mg/kg added Zn as feed-grade Zn sulphate or Zn oxide in which, Zn was replaced with that supplied from ZnMet complex by 25, 50, 75 or 100%. At 42 days of age, three randomly selected birds from each pen were bled to measure plasma metabolites; then, the chicks were slaughtered to evaluate carcass characteristics. Results showed that dietary treatments affected (p < 0.05) feed intake during the starter period, and chicks on Zn oxide diets consumed more feed than sulphate counterparts. Furthermore, dietary substitution of inorganic Zn sources by ZnMet caused improvements (p < 0.01) in body weight gain during all experimental periods. Dietary supplementation of ZnMet improved feed conversion efficiency during 1-21 and 1-42, but not in 21-42 days of age. Complete replacement of inorganic Zn by that supplied from ZnMet caused an increase (p < 0.05) in relative liver weight. Similarly, dietary inclusion of ZnMet increased breast meat and carcass yields and reduced abdominal fat percentage (p < 0.05). Incremental levels of ZnMet increased (p < 0.05) zinc concentrations in liver and thymus, and the highest zinc accumulations were seen in 100% ZnMet-supplemented birds. Interestingly, introduction of ZnMet into the diets partially in place of inorganic sources resulted in decreases (p < 0.01) in plasma uric acid and triglycerides concentrations. The present findings indicated that dietary ZnMet inclusion in replacement of inorganic sources in addition to improving growth performance, reduced plasma uric acid and triglycerides concentrations, consequently decreased abdominal fat pad and increased carcass meat yield.

Effects of different sources and levels of zinc on growth performance and tissue zinc accumulation of the young Elco rabbit.

Effects of different sources and levels of zinc on growth performance and tissue zinc accumulation of the young Elco rabbit.

A High Amount of Dietary Zinc Changes the Expression of Zinc Transporters and Metallothionein in Jejunal Epithelial Cells in Vitro and in Vivo but Does Not Prevent Zinc Accumulation in Jejunal Tissue of Piglets1–3

High dietary zinc concentrations are used to prevent or treat diarrhea in piglets and humans, but long-term adaptation to high zinc supply has yet not been assessed. Intestinal zinc uptake is facilitated through members of zinc transporter families SLC30 (ZnT) and SLC39 (ZIP). Whereas in rodents, regulation of zinc homeostasis at low or adequate zinc supply has been described, such mechanisms are unclear in piglets. A total of 54 piglets were fed diets containing 57 [low dietary zinc (LZn)], 164 [normal dietary zinc (NZn)], or 2425 [high dietary zinc (HZn)] mg/kg dry matter zinc. After 4 wk, 10 piglets/group were killed and jejunal tissues taken for analysis of zinc transporters SLC30A1 (ZnT1), SLC30A2 (ZnT2), SLC30A5 (ZnT5), SLC39A4 (ZIP4), divalent metal transporter 1 (DMT1), and metallothionein-1 (MT). Weight gain was higher (P < 0.05) in pigs fed HZn than in the LZn and NZn groups during the first 2 wk. Food intake did not differ between groups. The digesta and jejunal tissue zinc concentrations were higher (P < 0.05) in the HZn pigs than in NZn and LZn pigs. Expression of ZnT1 was higher (P < 0.05) and ZIP4 lower (P < 0.05) in HZn pigs than in the 2 other groups, whereas expression of ZnT5 and DMT1 did not differ between treatments. Expression of ZnT2 was lower (P < 0.05) in the LZn group than in the HZn and NZn groups. The mRNA expression and protein abundance of MT was higher (P < 0.05) in the HZn group than in the NZn and LZn groups. Studies with intestinal porcine cell line intestinal epithelial cell-J2 confirmed the dose-dependent downregulation of ZIP4 and upregulation of ZnT1 and MT (P < 0.05) with increasing zinc concentration within 24 h. In conclusion, high dietary zinc concentrations increase intracellular zinc, promote increased zinc export from intestinal tissues into extracellular compartments, and decrease zinc uptake from the gut lumen. The adaptive process appears to be established within 24 h; however, it does not prevent tissue zinc accumulation.

Performance, organ zinc concentration, jejunal brush border membrane enzyme activities and mRNA expression in piglets fed with different levels of dietary zinc

This study aimed at investigating the effect of dietary zinc on performance, jejunal brush border membrane enzyme activities and mRNA levels of enzymes and two zinc transporters in piglets. A total of 126 piglets were weaned at 26 ±1 days of age and randomly allocated into three groups fed with diets 50, 150 and 2500 mg zinc/kg. Performance was recorded and at weekly intervals, eight piglets per group were killed. The activities of isolated brush border membrane enzymes including lactase, maltase, sucrase, aminopeptidase-N and intestinal alkaline phosphatase (IAP), and the relative transcript abundance of aminopeptidase-N (APN), sucrase–isomaltase (SUC), IAP and the two zinc transporters SLC39A4 (ZIP4) and SLC30A1 (ZnT1) were investigated in the jejunum. Feeding pharmacological zinc levels increased weight gain (p < 0.001) during the first week, but performance was lower (p < 0.05) in the third week. Organ zinc concentrations were increased by high dietary zinc level. The activity of IAP was higher (p < 0.05) with the highest dietary zinc level, no effects were determined for other enzymes. Dietary zinc level had no effect on transcript abundance of digestive enzymes. The mRNA levels decreased (p < 0.001) for ZIP4, and increased for ZnT1 (p < 0.05) with pharmacological zinc levels. In conclusion, pharmacological zinc levels improved performance in the short-term. Intestinal mRNA level of zinc transporters changed with high zinc supply, but this did not prevent zinc accumulation in tissues, suggesting hampered homoeostatic regulation. This might cause impaired performance during longer supply.

Zinc toxicity with pancreatic acinar necrosis in piglets receiving total parenteral nutrition.

Two Hampshire-Duroc cross piglets maintained on 100% total parenteral nutrition (TPN) for 3 weeks developed pancreatic epithelial cell necrosis, diffuse acinar atrophy, and marked interstitial fibrosis. In addition, the piglets had severe villus atrophy in the small intestine as a result of TPN. Atomic absorption spectrophotometric analysis of liver samples revealed toxic hepatic zinc levels (513.5 and 491.2 ppm) in the TPN piglets (40-90 ppm in control piglets). Administering TPN bypasses homeostatic control mechanisms regulating zinc absorption at the gastrointestinal level and may reduce pancreatic secretion contributing to the accumulation of zinc in tissues. Intestinal villus atrophy, a sequela to TPN, may have also affected zinc excretion by impairing intestinal flux and desquamation. These factors should be considered in formulating TPN solutions and zinc levels administered must be reduced accordingly to avoid toxicity. Furthermore, sources and tissue levels of zinc should be investigated when necrosis, acinar atrophy, and fibrosis of the pancreas are encountered in young pigs.

Forced Resting by High Dietary Zinc: Tissue Zinc Accumulation and Reproductive Organ Weight Changes

An experiment was conducted to investigate the effects of high dietary zinc, as a means of inducing a forced-rest, on selected organ accumulation of zinc and reproductive function in terms of ovary and oviduct weight in the laying hen. Single Comb White Leghorn hens laying approximately at 60% production were fed either 10,000 ppm zinc as zinc oxide (10 Zn) or 20,000 ppm zinc (20 Zn) for a period of 4 days. At the initiation of the experiment (Day 0), five hens were killed and organs obtained for analysis. On 4, 10, 16, and 22 days afterward, similar samples were obtained from 5 hens per treatment. Ovary and oviduct weights were determined and zinc analysis performed on the latter as well as liver, kidney, and pancreas. The brief 4-day feeding of either high zinc diet caused a marked 80% reduction in ovary weight by Day 10. The oviduct, although less affected, was still reduced approximately 60% in weight after feeding either 10 Zn or 20 Zn for 4 days. The oviduct exhibited a statistically significant elevation in zinc concentration on Day 4 but was normal by Day 10 (6 days following the refeeding of a normal diet) and not different between treatments. There was extensive accumulation of zinc in kidney, liver, and especially pancreas after 4 days of feeding either 10 Zn or 20 Zn. The level of dietary zinc had no effect on the extent of accumulation in any tissue. The depletion of tissue zinc roughly corresponded to the magnitude of increase in the concentration of zinc observed at Day 4. Possible ramifications of the dramatic increase observed in pancreatic zinc were discussed. We concluded that feeding either 10 Zn or 20 Zn as a means of inducing a forced rest effects a marked and rapid reduction in ovary and oviduct weight as well as an extensive increase in renal, hepatic, and especially pancreatic zinc.

Influence of parathyroid hormone and calcitonin on tissue zinc homeostasis in the rat

Tissue zinc accumulation kinetics and compartmental analysis models were evaluated in thyroparathyroidectomized (TPTX) rats treated with parathyroid extract or calcitonin. The animals were injected with 65Zn and studied at multiple time intervals. SAAM-25 was utilized to generate models from the plasma specific activity decay curves. Calcitonin had a marked effect to decrease the fractional influx and efflux transfer coefficients in the model and inhibit tissue zinc accumulation in several, but not all, tissues. Parathyroid extract increased accumulation in all tissuesstudied, but had minimal effects on the model. It is concluded that parathyroid hormone acts nonspecifically and that calcitonin appears to have specific influences on zinc homeostasis.

Influence of cholecalciferol on tissue zinc homeostasis in the rat.

A role for calciferol in zinc homeostasis was investigated by radioisotope uptake and compartmental analysis techniques. cholecalciferol was injected into rats 4-5 days prior to radioisotopic study of rapidly exchangeable pools (< 4 h). Kidney, liver, and duodenum had significant increases in zinc uptake rates. Bone and skeletal muscle had significant decreases. No other tissues had significant differences. Compartmental analysis models generated by the SAAM-25 digital computer program suggested a decrease in the fractional tissue to plasma coefficient to be the mechanism for the observed changes in the serum zinc concentration and tissue zinc accumulation rates. It is not clear whether this is a specific effect of calciferol on zinc homeostasis or is a nonspecific response which may reflect some role for zinc in calciferol metabolism.