Metallothionein Levels Research Articles

Consequences of prenatal exposure to contaminants in elasmobranchs: Biochemical outcomes during the embryonic development of Pseudobatos horkelii

Coastal elasmobranchs are vulnerable to chemicals mostly due to their k-strategic life history characteristics and high trophic positions. Embryos might be particularly exposed through the maternal offloading of contaminants, possibly leading to disruptions during critical developmental phases. Yet, knowledge on biochemical outcomes of prenatal exposure in elasmobranchs is notably limited. Therefore, we aimed to investigate the effects of prenatal exposure to contaminants in embryos of the critically endangered Brazilian guitarfish, Pseudobatos horkelii. Polybrominated diphenyl ethers (PBDEs), polycyclic aromatic hydrocarbons (PAHs), pharmaceuticals and personal care products, and metals were determined in embryos. Additionally, glutathione S-transferase activity (GST), glutathione (GSH), and metallothionein levels (MT) were analyzed. Finally, lipid peroxidation levels (LPO) and protein carbonyl groups (PCO) were assessed. Embryonic exposure depended on yolk consumption, which was conspicuous in earlier development. We observed a dilution effect of contaminants levels, potentially related to biotransformation of these compounds throughout the embryonic development. Nevertheless, GST was not correlated to contaminant concentrations. The multivariate relationship between antioxidant components (GSH and GST) and LPO and PCO was negative, suggesting the lack of efficient defense of these biomarkers in early development, leading to oxidative damage. In this context, our results indicate that prenatal exposure to contaminants might impact the redox status in embryos of P. horkelii, leading to oxidative damage. Furthermore, metal concentrations influenced MT levels, suggesting this as a potential detoxification pathway in this species.

Placental Barrier on Cadmium Transfer from Mother to Fetus in Related to Pregnancy Complications.

As two of the most severe and common medical disorders during pregnancy, gestational diabetes mellitus (GDM) and hypertensive disorder complicating pregnancy (HDCP) cause adverse effects on placental barrier function and thus may lead to a high risk of intrauterine exposure to toxic metals from mother to fetus. This study investigates the impact of the placental barrier on the transfer of cadmium (Cd) from mother to fetus and the relationship between pregnancy complications. A total of 107 pairs of samples were collected in Kunming, China; 29 were from healthy pregnant women, and 78 were from patients with pregnancy complications. Cd was measured in each mother's placenta and maternal and umbilical cord blood. The expressions of MT and Cd-MT complex in blood and placental tissue samples were determined by enzyme-linked immunosorbent assay (ELISA). The cesarean section rate in the whole pathological group (60.7%) was higher than that in the normal group (20.7%), and the ratio of the effective barrier (ratio of maternal blood to umbilical cord blood>1) in the pathological group (74%) was lower than that in the normal group (79%). In addition, the proportion of practical placental barriers in women aged 20-25 years was 83.3%, 76.3% in women aged 26-30 years, 74.3% in women aged 31-35 years, 70% in women aged 36-40 years, and 71% in women aged 40-45 years. The Cd content in the placenta of the three pathological groups was significantly higher than that in maternal and umbilical cord blood (P<0.05), and the distribution of Cd was the same as that in the normal group. However, there was no significant difference between maternal and umbilical cord blood Cd concentrations in the pathological group. The Cd concentration in the normal group's maternal blood was significantly higher than that in cord blood (P<0.05). In addition, the expression levels of both metallothionein (MT) and Cd-MT complex in placenta is much higher than in maternal and umbilical blood, and which in normal group are significantly higher than those in pathological group. Both mothers and fetuses are at increased health risk for pregnancy disorders when maternal age, BMI, or body weight increases. Increased maternal age increases the likelihood of Cd transfer from the mother to the fetus. Pregnancy complications may induce lower expression of MT, thus reducing the Cd-MT complex in the placenta, weakening the placental barrier, and increasing the risk of Cd transfer and exposure to the fetus.

Oxidative stress, neurotoxicity, and intestinal microbial regulation after a chronic zinc exposure: an experimental study on adult zebrafish (Danio rerio)

Abstract Zinc is one of the heavy metals present in textile wastewater with high concentrations. However, the chronic toxic effects of zinc on aquatic vertebrates are still ambiguous. Zinc accumulation in zebrafish after chronic zinc exposure and toxic effects on the intestines, muscles, and gills were investigated in this study. The results showed that a significant accumulation of zinc in the intestine, muscle, and gill was observed after 25 d of zinc exposure. The toxic effects of zinc were mainly in the form of zinc-induced oxidative stress in zebrafish, potential neurotoxicity, and changes in intestinal microbes. Significant changes in the levels of superoxide dismutase, catalase, metallothionein, glutathione, and malondialdehyde indicated that zinc damaged the antioxidant system of adult zebrafish. Zinc exposure resulted in a significant decrease in acetylcholinesterase activity and abnormal neural signaling. Furthermore, zinc exposure resulted in increased intestinal microbial richness and decreased the Simpson index in adult zebrafish. At the phylum and genus levels, the predominant microbes in the intestine are altered by zinc. In summary, this study provides an analysis of the toxic effects of chronic zinc exposure on adult zebrafish and the potential mechanisms, which are important for assessing the dual effects of zinc on aquatic organisms.

Development of an in Vitro Digestion System to Study the Bioavailability and Bioreactivity of Zinc Sulfate and Zn-Bioplex in Fish Using the RTgutGC Cell Line

Here, we report the development of a novel in vitro digestion system that mimics the digestive process in fish and uses the RTgutGC cell line, a model of the rainbow trout (Oncorhynchus mykiss) intestine, to study the bioavailability, bioreactivity, and toxicity of Zn added as an inorganic (ZnSO4) and organic zinc compound (Zn-Bioplex). Our results showed that, before digestion, Zn-Bioplex was more bioavailable than ZnSO4. However, after in vitro digestion, ZnSO4 and Zn-Bioplex accumulated and were transported equally across the RTgutGC cell epithelium. However, Zn-Bioplex was shown to be less bioreactive than ZnSO4, suggesting that peptide complexation might reduce the intracellular release of zinc as shown by a reduced induction of metallothionein and ZnT1 mRNA levels. This novel method shows promise as a standardized in vitro fish digestion model to study the interactions occurring at the lumen of the intestine and the bioavailability and toxicity of digested compounds in the fish gut.

Sequential exposures of single walled carbon nanotubes and heavy metal ions to macrophages induce different cytotoxicity

The probability of occupational exposure rises with the increasing production and biomedical application of carbon nanotubes (CNTs). Thus, the risk of co-exposure of nanomaterials with environmental pollutants is also increasing. Although many studies have focused on the combined toxicity of nanomaterials and pollutants, more attention has been paid to the toxicity of nanomaterials after adsorbing pollutants or the toxicity of nanomaterials and pollutants exposed simultaneously. Few studies have been conducted on the toxicity and toxicity mechanisms of nanomaterials and environmental pollutants following sequential exposure. In this study, we employed THP-1 cells to investigate how pristine single walled CNTs (p-SWCNTs) and oxidized single walled CNTs (SWCNT-COOHs) pretreatments at a non-lethal dose of 10 μg/mL affect cell responses to metal ions (i. e., Pb2+, Cu2+, and Cr(VI)). We found that p-SWCNTs caused more significant damage to cell membrane integrity than SWCNT-COOHs, which led to higher metallothionein (MT) levels and increased transport of metal ions into cells. Pretreatment of p-SWCNTs in cells significantly increased the cytotoxicity of Pb2+, Cu2+, and Cr(VI) by 2–4-fold, whereas SWCNT-COOHs pretreated cells showed no noteworthy changes in response to heavy metals, which were further confirmed by the cellular reactive oxygen species (ROS) assays. These findings indicate that understanding the effects of the exposure sequence of engineered nanomaterials and environmental pollutants on their toxicity provides an excellent complement to combined toxicity evaluation.

Multibiomarker approach in fish to assess a heavily polluted Brazilian estuary, Guanabara Bay

Brazil's Guanabara Bay (GB), located in Rio De Janeiro, is a deeply contaminated, eutrophic waterbody that challenges the understanding of the effects of pollutants on the biota. This paper presents a strategy to evaluate the impact of contamination utilizing a multibiomarker approach in two fish species: corvine (Micropogonias furnieri) and burrfish (Chilomycterus spinosus). The strategy is comprised of a general biomarker of fish' physical condition, the condition factor (CF), and specific biomarkers of pollutant exposure such as acetylcholinesterase (AChE), metallothionein (MT) activity and biliary polycyclic aromatic hydrocarbons (PAH) metabolites. Our results indicate that fish from GB are greatly affected by environmental pollution. CF values were lower in fishes from GB than in the reference site indicating that these fishes were under higher environmental stress. Lower AChE activity level in both species showed vulnerability to the presence of pesticide residues. Higher levels of MT in both species in GB reflect the consequences of heavy metal exposure in the bay, in spite of their bioavailability being restricted specially by the high organic matter content of GB. The levels of PAHs were higher in GB for both fish species, indicating exposure to these substances. However, the fish species showed different behavior regarding the origin of the PAHs. The multibiomarker approach used in this study evidently depicted effects on the health of fish in a waterbody with a complex polluted situation and further categorized the effects of anthropogenic activities in this aquatic system.

Salinity variation modulates cellular stress response to ZnO nanoparticles in a sentinel marine bivalve, the blue mussel Mytilussp.

Zinc oxide nanoparticles are released into marine environments from industrial, medical and consumer uses sparking concerns about their potential ecotoxicological effects. Ecological hazard assessment of nZnO in marine ecosystems is hindered by the lack of understanding of the potential interactive effects of nZnO toxicity with other common abiotic stressors, such as salinity fluctuations, in marine organisms. To close this gap in our knowledge, we carried out a comprehensive biomarker-based assessment of the combined effects of salinity and nZnO in a sentinel marine bivalve, the blue mussels Mytilus edulis. The mussels were exposed for 21 days to clean seawater (control), an environmentally relevant concentration (100 μg Zn l−1) of nZnO or dissolved Zn (to identify the toxic effects attributable to Zn2+ toxicity) under the normal (15), low (5) and fluctuating (5–15) salinity regimes. The selected molecular and biochemical markers focused on the oxidative stress, apoptosis, detoxification system and inflammation in the gills and the digestive gland of the mussels. Biomarker analysis showed different effects of nZnO and dissolved Zn on biomarkers of oxidative stress, xenobiotic detoxification and apoptosis but similar effects of both pollutants on the levels of metallothioneins and inflammatory markers. Exposure to nZnO led to elevated levels of lipid peroxidation, upregulation of p53 and p38 stress kinases and apoptosis-related genes, most notably in the gills. Exposure to dissolved Zn led to accumulation of protein carbonyls and activated redox-sensitive detoxification enzymes (NADPH-P450 reductase and glutathione-S-transferase) in the mussels. The ambient salinity had significant effects the cellular adverse effects of nZnO in the mussels. The nZnO-induced cellular stress was detectable under the normal (15) and fluctuating (5–15) salinity conditions in the studied brackish water population of the mussels. At low salinity (5), nZnO toxicity signal was almost completely dampened. These findings indicate that chronic osmotic stress close to the tolerance limits of M. edulis prevails over the effects of the environmentally relevant nZnO and dissolved Zn concentrations in combined exposures. These stressor interactions might ameliorate the cellular toxicity of nZnO in the mussels but limit applicability of cellular stress biomarkers for detecting the toxic effects of nanopollutants in low salinity habitats.

Metallothionein level in the larva of Cheumatopsyche sp. and the relationship between heavy metal concentration in Bone River, Gorontalo, Indonesia

Abstract. Kadim MK, Herawati FY, Arfiati D, Hertik AMS. 2022. Metallothionein level in the larva of Cheumatopsyche sp. and the relationship between heavy metal concentration in Bone River, Gorontalo, Indonesia. Biodiversitas 23: 5942-5950. This study aims to confirm that the larvae of Cheumatopsyche sp. contain a metal-binding protein, metallothionein, in their body and correlate it with heavy metal concentrations in the larval tissues and sediments in Bone River. Pb, Cd and Hg concentrations in sediment, tissue and Metallothionein (MT) levels were analyzed in several areas with different metal contamination. The Pb concentration in the sediment averaged 33.6 ppm; Hg 0.17 ppm; Cd 0.125 ppm. Total metals concentration in the whole body of Cheumatopsyche sp. ranged from 0.424 to 0.781, while the MT content ranged from 4637 to 6930 ng.g-1. The results revealed that the larvae could accumulate different metals and be more effective in accumulating Hg than Pb and Cd, regardless of the level of metal concentration in the sediment. Metal concentrations measured in Cheumatopsyche sp. showed a significant correlation with metals in the sediment. Metallothionein levels throughout the larval body showed differences in different areas of metal contamination and this correlated with the concentrations of Pb, Cd, and Hg measured in the larval tissue, thus reflecting their bioavailability in the environment. The results also showed that even under exposure to low metal concentrations, MT was still detectable in Cheumatopsyche sp. and proved to be a good predictor of metal accumulation.

Integrated physiological, biochemical, and transcriptomic analysis of thallium toxicity in zebrafish (Danio rerio) larvae

Although several studies have evaluated the effects of Thallium (Tl) in adult species of fish, the developmental toxicity of Tl has not been previously explored. In this study, zebrafish embryos (<4 h post fertilization (hpf)) were exposed to Tl at concentrations from 0.8 to 400 μg L−1 for 7 d. The results showed that the decreased hatching rate and increased malformation rate were observed in the larvae. The swimming velocity of larvae from 200 and 400 μg L−1 treatments was respectively reduced by ~26 % and 15 %. Histopathological analysis of liver indicated the number of cells of karyolysis (143 % and 202 %) and pyknosis (170 % and 131 %) were respectively increased in 200 and 400 μg L−1 Tl treatments. Meanwhile, the Tl body burden and metallothionein (MT) levels in the larvae were increased with elevated Tl concentrations. The level of malondialdehyde (MDA) was increased by ~20 to 51 % in all Tl treatments and total antioxidant capacity (TAC) was decreased by ~12 % at 200 μg L−1. The activities of Na+/K+-ATPase and protease were inhibited in 200 and 400 μg L−1 Tl treatments. Moreover, the transcripts of genes (Nrf2, HO-1, TNF-α, IL-1β, IL-8, IL-10, TGF) were significantly altered. In addition, a total of 930 differentially expressed genes (DEGs) and 1549 DEGs were found in the 200 and 400 μg L−1 treatments with 458 overlapped DEGs by transcriptomic analysis. The protein digestion and absorption, ECM-receptor interaction, and complement and coagulation cascades pathways were shown to be the most significantly enriched pathways. This study helps better understand the molecular mechanisms of Tl toxicity in fish.

Physiological and gene expression responses of diploid and triploid Pacific oyster ( Crassostrea gigas ) to heat acclimation

High temperature is considered to be one of the important causes of mass mortality of diploid and triploid oysters in summer. In order to compare the tolerance adaptability of diploid and triploid oysters to heat stress, the activities of superoxide dismutase activity (SOD), catalase activity (CAT) and contents of malondialdehyde (MDA) and the expression of Hsp70 and metallothionein (MT) genes in diploid and triploid oysters under acute and chronic heat stress were studied. The results showed that the survival rate of diploid oysters was significantly higher than that of triploid oysters under acute and chronic heat stress (p < 0.05). Under acute heat stress, the SOD levels in gills of both diploid and triploid oysters increased significantly from hour 3 (p < 0.05), but there was no significant difference in SOD levels between diploid and triploid oysters at all time points. The SOD level in hepatopancreas of triploid oysters was significantly higher than that of diploid oysters at all time points except 48 h (p < 0.05). The CAT level of diploid and triploid oysters decreased sharply at 48 h and that of diploid oysters was significantly higher than that of triploid oysters (p < 0.05). Under acute heat stress, the increase in MDA content in triploid oysters was significantly higher than that in diploid oysters (p < 0.05). Under acute heat stress, the expression levels of Hsp70 in the gills and hepatopancreas were significantly increased in diploid and triploid oysters (p < 0.05), but increased varies between gills and hepatopancreas. The expression levels of MT in the gills and hepatopancreas were significantly decreased in diploid and triploid oysters (p < 0.05). The results obtained in this study provide physiological and immunological evidence to explain differences in high-temperature tolerance between diploid and triploid oysters and help us better understand the mass mortality of oysters that occurs during high temperatures in summer.

The potential adverse effects of acrylamide on the oxidative stress response, fatty acids profile, and histopathological aspect of the Mediterranean Holothuria forskali respiratory tree.

Acrylamide (ACR), organic compound, has been widely used owing to its broad spectrum of chemical and industrial applications. This study aims at evaluating the response of the antioxidant defense system, fatty acid composition and histopathological aspect in the respiratory trees of Holothuria forskali against ACR exposure under laboratory conditions. Holothuries were exposed to 5, 10, and 20 mg L-1 ACR concentrations for 5 days. A significant increase in n-6 polyunsaturated fatty acids levels especially the arachidonic acid (ARA, C20:4n-6) and its precursor linoleic acid (LA, C18:2n-6) in ACR-treated organisms. Regarding the n-3 levels, eicosapentaenoic acid (EPA, C20:5n-3) levels were increased in treated groups despite an acute decrease in docosahexaenoic acid (DHA, C22:6n-3) levels was observed. Our results showed a significant increase in hydrogen peroxide, malondialdehyde, protein carbonyl, and metallothionein levels along with an alteration of the antioxidants status in all treated sea cucumbers. The exposure to ACR prompted the inhibition of Acetylcholinesterase activity in a concentration-dependent manner. The histopathological aspect was marked especially with the infiltration of coelomic cells which confirms our biochemical findings. Our study provided novel insights to create a link between redox status and fatty acid composition disruptions to better understand ACR-triggered toxicity.

Mercury pollution assessment and metallothionein gene expression in tilapia (Oreochromis mossambicus): a case study of Revuè River in Manica, Mozambique

Revuè River has been considered as one of the most threatened systems in Mozambique due to increased anthropogenic activities such as artisanal and industrial gold mining using mercury (Hg), a heavy metal known for its diverse effects including, bioaccumulation and biomagnification in the environment. The present study aims to determine the metallothionein (MT) expressions in the hepatic tissue of Oreochromis mossambicus (tilapia) exposed to Hg in the laboratory and tilapia collected in Chicamba reservoir. Tilapia juveniles were exposed to different concentrations of Hg (0.037 and 0.37 mg/L) in the laboratory. Water, sediment and fish samples were collected to quantify Total Hg (THg). Furthermore, liver samples in tilapia exposed to Hg and tilapia samples from Chicamba reservoir were collected to analyze the gene expression levels of MT using a quantitative PCR. Results from the study showed a low contamination of the waters and sediment from Revuè River, demonstrated by the Hg concentration in the sediment and water. Slightly high concentrations of Hg were detected in fish from Chicamba reservoir, confirmed by the overexpression of MT observed in liver samples from tilapia and were higher than those expressed in tilapia from the laboratory experiment. There is a correlation between Hg exposure and the MT expression in tilapia, suggesting that MT can be used as a biomarker to assess Hg pollution in the Revuè River.

Investigation of Biomarkers in Sub-Acute Hepatorenal Toxicity against Bulk and Zinc Oxide Nanoparticles Exposed Mice

Zinc oxide nanoparticles have been utilized and produced at a very large scale due to their wide range of applications. Nevertheless, its toxicity is one of the concerns addressed by various researchers. Widely used methods of measuring plasma zinc have poor sensitivity and impaired specificity. Currently, there is no specific biomarker for determination of excess zinc inside our body is explored well. Furthermore, it is vital to know the toxic effects of zinc oxide nanoparticles and their bulk counterparts at early exposure level on human health due to day to day increased use of zinc oxide nanoparticles in various applications. In current study we investigate the kidney and liver as the primary target organs for toxicity and their oxidative stress parameters. Twenty-four male mice were divided into three groups(n=8). Control (group I) served as vehicle control; group II:50mg/kg ZnO (bulk) and group III:ZnO NPs (50mg/kg nano). The mice were sacrificed after 14 days exposure, liver and kidney tissue toxicity biomarkers were performed. Our results demonstrate increased levels of GPx, metallothionein, GST, and decrease level of ceruloplasmin, GSH:GSSG ratio in bulk ZnO administered animals. The acute kidney toxicity was further confirmed by increased levels of their biomarkers i.e. Kim-1 and Clusterin. The levels of serum cytokines and caspase were also analyzed. Hence, this study investigated the comparative effect of early exposure of zinc oxide nanoparticles (nZnO) and its bulk form and we conclude that at 50mg/kg b.wt dose, ZnO NPs is comparatively safe to bulk ZnO.

Effects of Fructose and Stress on Rat Renal Copper Metabolism and Antioxidant Enzymes Function.

The effects of a fructose-rich diet and chronic stress on copper metabolism in the kidneys are still understudied. We investigated whether fructose and/or chronic unpredictable stress modulate copper metabolism in a way that affects redox homeostasis, thus contributing to progression of metabolic disturbances in the kidney. We determined protein level of copper transporters, chaperones, and cuproenzymes including cytochrome c oxidase, as well as antioxidant enzymes function in the kidneys of male Wistar rats subjected to 20% liquid fructose supplementation and/or chronic stress. Liquid fructose supplementation increased level of copper chaperone of superoxide dismutase and decreased metallothionein level, while rendering the level of copper importer and copper chaperones involved in copper delivery to mitochondria and trans Golgi network unaffected. Stress had no effect on renal copper metabolism. The activity and expression of renal antioxidant enzymes remained unaltered in all experimental groups. In conclusion, fructose, independently of stress, decreased renal copper level, and modulated renal copper metabolism as to preserve vital cellular function including mitochondrial energy production and antioxidative defense, at the expense of intracellular copper storage.

Heavy Metal Bioaccumulation and Oxidative Stress Profile in Brachidontes pharaonis (Bivalvia: Mytilidae) from the Tunisian Coast: Insight into Its Relevance as Bioindicator of Marine Pollution.

This study aims to verify the relevance of Brachidontes pharaonis to assess the ecotoxicological status of polluted sites. For this, the levels of some heavy metals (i.e. Zn, Cu, Pb, and Cd) and a battery of biomarkers including metallothionein (MT), malondialdehyde (MDA), reduced glutathione (GSH), glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT) were assessed in mussels collected from the harbor of Rades (North), and the harbor of Zarzis (South). Moreover, abiotic parameters including temperature, salinity, pH, and dissolved oxygen were assessed. Results from the ICP-OES showed that the southern population exhibited a higher metal pollution index with significantly higher Zn, Cu, and Pb concentrations. Moreover, the specimens from Zarzis displayed significantly higher levels of MDA, MT, GSH, GPx, SOD, and CAT reflecting higher levels of oxidative and chemical stress. These results emphasize the potential utility of B. pharaonis for the monitoring of heavily impacted sites.

HPLC Analysis and the Antioxidant and Preventive Actions of Opuntia stricta Juice Extract against Hepato-Nephrotoxicity and Testicular Injury Induced by Cadmium Exposure.

Opuntia stricta is a rich source of phenolic compounds. This species generally has strong antioxidant activities in vitro and in vivo. This study aimed to analyze the antioxidant properties of phenolic compounds isolated from Opuntia stricta, including its radical scavenging activities and preventive action against Cd-induced oxidative stress in rats. To assess the protection of prickly pear juice extract (PPJE) against Cd-induced hepato-nephrotoxicity and testicular damage, male albino rats received PPJE (250 mg kg−1) and/or Cd (1 mg kg−1) by oral administration and injection, respectively, for five consecutive weeks. The preventive action of PPJE was estimated using biochemical markers of kidney and liver tissues, antioxidant status, and histological examinations. In the present study, the lipid peroxidation, protein carbonyls, antioxidant status, and metallothionein levels were determined in different tissues. The chromatographic analysis indicated that PPJE extract is very rich in phenolic compounds such as verbascoside, catechin hydrate, and oleuropein. Our results showed that PPJE-treated rats had significantly (p < 0.05) decreased Cd levels in liver and kidney tissues. In addition, the administration of PPJE induced a significant (p < 0.05) decrease in lipid peroxidation of 30.5, 54.54, and 40.8 in the liver, kidney, and testicle, respectively, and an increase in antioxidant status in these tissues. Additionally, PPJE showed a strong ability to protect renal, hepatic, and testicular architectures against Cd exposure. This study revealed that PPJE protects against the toxic effects of Cd, possibly through its free radical scavenging and antioxidant activities.

Assessment of hazardous impact of nickel oxide nanoparticles on biochemical and histological parameters of gills and liver tissues of Heteropneustes fossilis

BackgroundThe aim of the present study was to assess the hazardous impact of nickel oxide nanoparticles (NiO NPs) on gills and liver of Heteropneustes fossilis. MethodsFishes were treated with four concentrations of NiO NPs for a period of 14 days. Nickel accumulation, lipid peroxidation, antioxidant enzymes activities (superoxide dismutase, catalase, glutathione s transferase & glutathione reductase), liver enzymes activities (aspartate amino transferase, alanine transaminase, & alkaline phosphatase), Na+/K+ ATPase activity, FTIR, metallothionein content, ethoxyresorufin-o-deethylase activity, immunohistochemistry, histology and scanning electron microscopy were analyzed in both gills and liver tissues. ResultsResults revealed increased accumulation of nickel in both the tissues of exposed fishes. Lipid peroxidation and activities of different antioxidant enzymes increased (except superoxide dismutase) in both the tissues after exposure. Fluctuations in liver enzymes activities and variation in the activity of Na+/K+ ATPase were also observed. FTIR data revealed shift in peaks position in both the tissues. Level of metallothionein and its expression as well as activity of ethoxyresorufin-o-deethylase and expression of CYP1A also increased in both the target tissues of treated fishes. Furthermore, histological investigation and scanning electron microscopy showed structural damages in gills as well as liver tissues of exposed fishes. ConclusionOur results suggest that NiO NPs cause deteriorating effects on the gill and liver tissues of fish, therefore effluents containing these nanoparticles should be treated before their release into water bodies.

LUHMES Dopaminergic Neurons Are Uniquely Susceptible to Ferroptosis.

Ferroptosis is a necrotic cell death caused by lipid oxidation that may be responsible for neural degeneration in Parkinson's disease. We assessed whether three neuronal cell lines are sensitive to killing by ferroptosis. Ferroptosis inducer erastin killed LUHMES neurons at sub-micromolar concentrations, whereas neuronal cells derived from SH-SY5Y cells or neural stem cells were at least 50-fold less sensitive. LUHMES differentiated neurons were likewise sensitive to killing by RSL3 or ML210, inhibitors of the glutathione peroxidase 4 enzyme (GPX4) that consumes GSH to detoxify lipid peroxides. Additional assays showed that erastin, RSL3, and ML210 increased lipid peroxide levels, and that LUHMES neurons were protected from both peroxide accumulation and cell death by ferrostatin-1. A possible role of iron was assessed by evaluating the effects of five metal chelators on cytotoxicity of erastin and RSL3. LUHMES neurons were protected from RSL3 by three of the chelators, 2,3-dimercapto-1-propanesulfonic acid (DMPS), deferoxiprone (DFX), and deferiprone (DFP). Collectively, these results demonstrate the vulnerability of LUHMES neurons to ferroptosis by chemical treatments that disrupt glutathione synthesis, lipid peroxide detoxification, or iron metabolism. The same vulnerabilities may occur in CNS neurons, which reportedly generate low levels of GSH and metallothioneins, limiting their ability to neutralize oxidative stresses and toxic metals. These results suggest a rationale and methods to search for environmental toxicants that may exploit these vulnerabilities and promote neurodegenerative diseases.

Histological alterations and oxidative stress in adult zebrafish muscle after aluminium exposure

Aluminium (Al) is among the most abundant metals in nature, and its presence in the environment is further increasing by anthropogenic activities. In water bodies, the Al concentrations ranged between 0.001 and 50 mg/L, raising concerns about the health of aquatic organisms. For this reason, zebrafish was chosen as the model, since it is well suited for ecotoxicological studies. Adult specimens were exposed to 11 mg/L of Al for 10, 15 and 20 days to assess both the morphology and the oxidative state of muscle tissue. Considering the involvement of ROS, the activity of the main antioxidant enzymes, metallothioneins contents, but also oxidative damage and enzymes involved in energy consumption and neuromuscular transmission were assessed. Collected data showed an increase in the thickness of the endomysium and resorbed myofibrils in the organisms exposed to Al for 10 days, and an increase of myotomes' size in the organisms exposed to Al for 15 days. Moreover, the organisms exposed for less time to Al, it was evident an activation of anaerobic metabolism and the increased activity of antioxidant enzymes such as superoxide dismutase, glutathione peroxidase and glutathione S-transferases. However, these effects stabilized with increasing exposure time. In addition, only after 20 days of treatment did the oxidative damage to the proteins and the activity of acetylcholinesterase increase while the levels of metallothioneins and the lipid peroxidation were lower for all treated animals when compared to the control group. Overall, the biochemical and histological changes induced by aluminium exposure in the muscular tissue represent a relevant contribution to understanding the environmental risk due to the diffusion of this metal within the aquatic compartment.

Metallothionein levels on the gill and liver of Mystus nigriceps (Valenciennes, 1840) in Welang River, Pasuruan City, East Java

This research was conducted in October 2021 using a survey method. Sampling was carried out three times with a span of every 2 weeks at 3 stations along the lower reaches of the Welang River Pasuruan Regency. Parameters observed included cadmium metal content in fish gills and liver, metallothionein levels in gills, and liver of M. nigriceps. Fish and the relationship between cadmium metal and metallothionein levels in the gills and liver of M. nigriceps in the Welang River. The average yield of cadmium metal content in the gills of M. nigriceps is 5.943-8.103 mg/l. Meanwhile, the average result of heavy metal content in the liver of M. nigriceps is 6.397-9.997 mg/l. Measurement of metallothionein levels showed that the average level of metallothionein in the gills of M. nigriceps was 5.860-8.688 ng/mL. Meanwhile, the average level of metallothionein in the liver of M. nigriceps is 7.110-8.334 ng/mL. And the results of the linear regression test showed that the average content of cadmium in the gills and liver with the average metallothionein levels in the gills and liver of catfish was significantly correlated.