Arsenic induced blood and brain oxidative stress and its response to some thiol chelators in rats

Antioxidant activity of Mentha piperita phenolics on arsenic induced oxidative stress, biochemical alterations, and cyto-genotoxicity in fish, Channa punctatus

The study aims to investigate the synergistic antioxidant effects of the phenolics present in Mentha piperita (MP) against arsenic trioxide-induced oxidative stress, biochemical alteration, and cyto-genotoxicity in the fish, Channa punctatus. The phenolic composition of MP estimated by HPLC-PDA analysis reveals the presence of phenolics, viz., ascorbic acid (Rt = 2.763 min.), rutin (Rt = 12.597 min.), caffeic acid (Rt = 18.304 min.), quercetin (Rt = 26.731 min.), luteolin (Rt = 42.709 min.), and hesperetin (Rt = 49.525 min.). The experimental setup consists of four groups (G1-G4) with a density of 12 fish in each. The fishes in G1 served as the control group, whereas the fishes in G2 were exposed to 81.73 mg/L of As2O3. Fish in group G3 were subjected to 8 mg/L MP, whereas those in group G4 were treated to 8 mg/L MP plus 81.73 mg/L As2O3. The result showed a significantly (p < 0.05) increased GOT and GPT level, increased oxidative stress markers, SOD and CAT, and induction in cyto-genotoxic markers, viz., disintegrated nucleus (DN), microcyte (MC), echinocyte (EC), and nucleoplasmic bridges (NpBs). A significant (p < 0.05) decreased GSH level in the arsenic-exposed group for all exposure periods was observed. However, in G4, all parameters reduced significantly (p < 0.05) more than in G2. The results suggest that the phenolics present in MP are synergistically able to reduce arsenic-induced oxidative damages by improving antioxidant defence, thus improving fish health status.

New mechanistic insights into soil ecological risk assessment of arsenite (III) and arsenate (V)：Cellular and molecular toxicity responses in Eisenia fetida

Inorganic arsenic (iAs) is a persistent bioaccumulation carcinogen that is most abundant in soils in the form of arsenite-As (III) and arsenate-As (V). However, there is currently very little explicit evidence about cytotoxicity of As on soil organisms. Moreover, toxicological data for iAs and proteotoxicity is shortage. The purpose of the present work is to elucidate the cytotoxicity mechanism of As (III) and As (V) to earthworms, a soil ecological sentinel species, and the molecular mechanisms by which As (III)/As (V) directly bind to antioxidative enzyme Cu/Zn-superoxide dismutase (Cu/Zn-SOD). Results indicate that iAs triggered cell membrane injury and genotoxicity. As (V) (56.15 %) induced lower cell viability than As (III) (61.88 %). Higher ROS and lipid peroxidation level in As (V) support greater cytotoxicity. Differences in cellular uptake due to valence induced diverse levels of oxidative stress and cytotoxicity. At the molecular level, As (III) (129.33 %) induced higher Cu/Zn-SOD activity than As (V) (110.75 %). Changes in backbone, secondary structure, amino acid microenvironment and particle size of Cu/Zn-SOD further revealed the mechanisms of differential molecular toxicity of As (III) and As (V). Binding reactions with Cu/Zn-SOD explain differences in molecular toxicity. Collective research showed that iAs-induced oxidative stress and binding reactions determine the difference of SOD activity between As (III) and As (V) at the cellular level. This work offers new insights into the health risk assessment of As.

Cerebral Vascular Toxicity after Developmental Exposure to Arsenic (As) and Lead (Pb) Mixtures

Arsenic (As) and lead (Pb) are environmental pollutants found in common sites linked to similar adverse health effects. This study determined driving factors of neurotoxicity on the developing cerebral vasculature with As and Pb mixture exposures. Cerebral vascular toxicity was evaluated at mixture concentrations of As and Pb representing human exposures levels (10 or 100 parts per billion; ppb; µg/L) in developing zebrafish by assessing behavior, morphology, and gene expression. In the visual motor response assay, hyperactivity was observed in all three outcomes in dark phases in larvae with exposure (1-120 h post fertilization, hpf) to 10 ppb As, 10 ppb Pb, or 10 ppb mix treatment. Time spent moving exhibited hyperactivity in dark phases for 100 ppb As and 100 ppb mix treatment groups only. A decreased brain length and ratio of brain length to total length in the 10 ppb mix group was measured with no alterations in other treatment groups or other endpoints (i.e., total larval length, head length, or head width). Alternatively, measurements of cerebral vasculature in the midbrain and cerebellum uncovered decreased total vascularization at 72 hpf in all treatment groups in the mesencephalon and in all treatment groups, except the 100 ppb Pb and 10 ppb As groups, in the cerebellum. In addition, decreased sprouting and branching occurred in the mesencephalon, while only decreased branching was measured in the cerebellum. The 10 ppb Pb group showed several cerebral vasculature modifications that were aligned with a specific gene expression alteration pattern different from other treatment groups. Additionally, the 100 ppb As group drove gene alterations, along with several other endpoints, for changes observed in the 100 ppb mix treatment group. Perturbations assessed in this study displayed non-linear concentration-responses, which are important to consider in environmental health outcomes for As and Pb neurotoxicity.

Metals on the Menu-Analyzing the Presence, Importance, and Consequences

Metals are integral components of the natural environment, and their presence in the food supply is inevitable and complex. While essential metals such as sodium, potassium, magnesium, calcium, iron, zinc, and copper are crucial for various physiological functions and must be consumed through the diet, others, like lead, mercury, and cadmium, are toxic even at low concentrations and pose serious health risks. This study comprehensively analyzes the presence, importance, and consequences of metals in the food chain. We explore the pathways through which metals enter the food supply, their distribution across different food types, and the associated health implications. By examining current regulatory standards for maximum allowable levels of various metals, we highlight the importance of ensuring food safety and protecting public health. Furthermore, this research underscores the need for continuous monitoring and management of metal content in food, especially as global agricultural and food production practices evolve. Our findings aim to inform dietary recommendations, food fortification strategies, and regulatory policies, ultimately contributing to safer and more nutritionally balanced diets.

A Review of the Occurrence of Metals and Xenobiotics in European Hedgehogs (Erinaceus europaeus)

Monitoring data from several European countries indicate that European hedgehog (Erinaceus europaeus) populations are declining, and research exploring the causes of the decline, including exposure to potentially harmful xenobiotics and metals, may inform conservation initiatives to protect this species in the wild. Hedgehogs are ground-dwelling mammals, feeding on a range of insects, slugs, snails, and earthworms, as well as eggs, live vertebrates, and carrion, including carcasses of apex predator species representing higher levels of the food chain. Consequently, hedgehogs come into close contact with contaminants present in their habitats and prey. This review investigated the studies available on the subject of the occurrence of metals and organic xenobiotics in hedgehogs. This study found that a vast range of different pesticides; persistent organic pollutants (POPs), including organochlorine compounds and brominated flame retardants (BFRs); as well as toxic heavy metals could be detected. Some compounds occurred in lethal concentrations, and some were associated with a potential adverse effect on hedgehog health and survival. Due to their ecology, combined with the opportunity to apply non-invasive sampling techniques using spines as sampling material, we suggest that the European hedgehog is a relevant bioindicator species for monitoring the exposure of terrestrial wildlife to potential toxicants in urban and rural environments.

Chia seeds and coenzyme Q10 alleviate iron overload induced hepatorenal toxicity in mice via iron chelation and oxidative stress modulation

Iron overload (IOL) can cause hepatorenal damage due to iron-mediated oxidative and mitochondrial damage. Remarkably, combining a natural iron chelator with an antioxidant can exert greater efficacy than monotherapy. Thus, the present study aimed to evaluate the efficacy of Chia and CoQ10 to chelate excess iron and prevent hepatorenal oxidative damage in IOL mice. Male Swiss albino mice (n = 49) were randomly assigned to seven groups: control, dietary Chia, CoQ10, IOL, IOL + Chia, IOL + CoQ10, and IOL + Chia + CoQ10. Computational chemistry indicates that the phytic acid found in the Chia seeds is stable, reactive, and able to bind to up to three iron ions (both Fe2+ and Fe3+). IOL induced a significant (P < 0.05) increase in serum iron, ferritin, transferrin, TIBC, TSI, RBCs, Hb, MCV, MCH, WBCs, AST, ALT, creatinine, and MDA. IOL causes a significant (P < 0.05) decrease in UIBC, platelets, and antioxidant molecules (GSH, SOD, CAT, and GR). Also, IOL elicits mitochondrial membrane change depolarization, and DNA fragmentation and suppresses mitochondrial DNA copies. Furthermore, substantial changes in hepatic and renal tissue, including hepatocellular necrosis and apoptosis, glomerular degeneration, glomerular basement membrane thickening, and tubular degeneration, were observed in the IOL group. Dietary Chia and CoQ10 induced significant (P < 0.05) amelioration in all the mentioned parameters. They can mostly repair the abnormal architecture of hepatic and renal tissues induced by IOL, as signified by normal sinusoids, normal central veins, and neither glomerular damage nor degenerated tubules. In conclusion, the combined treatment with Chia + CoQ10 exerts more pronounced efficacy than monotherapy in hepatorenal protection via chelating excess iron and improved cellular antioxidant status and hepatorenal mitochondrial function in IOL mice.

Alternations of Fertility Parameters by Graded Dose of Inorganic Arsenic in Adult Male White Pekin Ducks

A significant health issue, reproductive toxicity is mostly linked to exposure to various environmental heavy metals. A pervasive toxin that occurs naturally in the environment is arsenic (As). This research was done to determine the effects of various doses of inorganic As supplements on the reproductive organs of adult male white Pekin ducks. A total of 240 numbers of 14-days-old male white Pekin ducks were weighed and randomly assigned into 4 experimental groups with six replicates (10 ducklings in each replicate). The experimental groups were as follows: (T-1) basal diet along with normal drinking water (control group); (T-2 to T-4) basal diet along with As in the form of sodium-meta-arsenite at 7, 14, and 28 ppm of drinking water respectively. The results showed reduction in body weight and testicular weight, disruption of spermatogenesis, reduction in follicular-stimulating hormone (FSH), leutinizing hormone (LH), and testosterone levels and histopathological alterations as compared to control. Additionally, there was not only a significant decrease in various antioxidant parameters in testis tissue, like catalase (CAT), reduced glutathione (GSH), super oxide dismutase (SOD), and ferric-reducing antioxidant power (FRAP), but also a significant increase in oxidative parameters of testis like lipid peroxidation (LPO), myloperoxidase (MPO), nitric oxide (NO), and super oxide anion radical (O2-) in As-treated groups, in comparison with T-1. A significantly higher level of As content in testis was observed in all the 3 As-treated groups, with highest level recorded in T-4 birds. Besides that, there was upregulation of nuclear factor kappa B (NF-κB), heat shock proteins (Hsps) and pro-inflammatory cytokines like interlukin (IL) series, i.e., IL-2, IL-6, IL-18, IL-1β and tumor necrosis factor- α (TNF-α) levels, whereas anti-inflammatory parameters like IL-4 and IL-10 levels showed downregulation in testis of As-treated groups. Together, these findings provide deeper understandings of the roles played by oxidative stress, NF-κB and Hsps in the progression of testicular injury, which may help to explain how the As induced male sterility, in ducks, due to exposure.

Activation of Nrf-2 Transcription Factor and Caspase Pathway with Royal Jelly Reduces Fluoride Induced Testicular Damage and Infertility in Rats

This study was carried out to investigate the protective properties of royal jelly on the testicular tissue of rats with testicular damage by giving fluoride. Sperm motility, epididymal sperm density and abnormal sperm ratios were examined and visualized with a light microscope. Expression levels of Caspase-3, Bcl-2, Nrf-2, NF-κB, COX-2, TNF-α and IL1-α proteins in testis tissue were determined by western blot technique. As a result of the study, MDA level, expression level of Bcl-2, NFҡB, COX-2, TNF-α and IL1-α proteins, abnormal sperm rates were found higher in Fluoride-50 and Fluoride100 groups compared to other groups. In addition GSH, Catalase enzyme levels, expression levels of Caspase-3 and Nrf-2 proteins were found to be higher in Fluoride + Royal Jelly groups compared to Fluoride-50 and Fluoride-100 groups. In addition, lower degeneration of testicular tissue was found in the histological evaluation in the Fluoride + Royal Jelly groups compared to the other groups. When the data are evaluated royal jelly provides effective protection against testicular damage. From this point of view, we hope that similar results will be obtained when royal jelly is tested on humans.

The protective effect of natural or chemical compounds against arsenic-induced neurotoxicity: Cellular and molecular mechanisms

Arsenic is a notorious metalloid that exists in the earth's crust and is considered toxic for humans and the environment. Both cancerous and non-cancerous complications are possible after arsenic exposure. Target organs include the liver, lungs, kidney, heart, and brain. Arsenic-induced neurotoxicity, the main focus of our study, can occur in central and peripheral nervous systems. Symptoms can develop in a few hours, weeks, or years depending on the quantity of arsenic and the duration of exposure. In this review, we aimed to gather all the compounds, natural and chemical, that have been studied as protective agents in cellular, animal, and human reports. Oxidative stress, apoptosis, and inflammation are frequently described as destructive mechanisms in heavy metal toxicity. Moreover, reduced activity of acetylcholinesterase, the altered release of monoamine neurotransmitters, down-regulation of N-methyl-D-aspartate receptors, and decreased brain-derived neurotrophic factor are important underlying mechanisms of arsenic-induced neurotoxicity. As for neuroprotection, though some compounds have yet limited data, there are others, such as curcumin, resveratrol, taurine, or melatonin which have been studied more deeply and might be closer to a reliable protective agent. We collected the available information on all protective agents and the mechanisms by which they fight against arsenic-induced neurotoxicity.

Effect of sulfonamide derivatives of phenylglycine on scopolamine-induced amnesia in rats

Alzheimer's disease is a neurodegenerative disease responsible for dementia and other neuropsychiatric symptoms. In the present study, compounds 30 and 33, developed earlier in our laboratory as selective butyrylcholinesterase inhibitors, were tested against scopolamine-induced amnesia to evaluate their pharmacodynamic effect. The efficacy of the compounds was determined by behavioral experiments using the Y-maze and the Barnes maze and neurochemical testing. Both compounds reduced the effect of scopolamine treatment in the behavioral tasks at a dose of 20 mg/kg. The results of the neurochemical experiment indicated a reduction in cholinesterase activity in the prefrontal cortex and the hippocampus. The levels of antioxidant enzymes superoxide dismutase and catalase were restored compared to the scopolamine-treated groups. The docking study on rat butyrylcholinesterase (BChE) indicated tight binding, with free energies of -9.66 and -10.23 kcal/mol for compounds 30 and 33, respectively. The two aromatic amide derivatives of 2-phenyl-2-(phenylsulfonamido) acetic acid produced stable complexes with rat BChE in the molecular dynamics investigation.

Mechanistic insights on the possible protective role of polyphenols extracted from Tamarix aphylla aerial parts against sodium arsenite-induced hepatotoxicity in rats

Arsenic exposure is associated with the induction of hepatotoxicity. Current study was aimed to investigate the hepato-protective ability of polyphenolic components of Tamarix aphylla (TA) ethanolic extract against sodium arsenite (SA)-induced liver injury of rats. Significantly higher quantities of phenolic (318.7±2.5 mgg-1GAE) and flavonoid (250.69 ±3.3 mgg-1QE) contents were present. Inhibitory concentration (IC50) exhibited an excellent potential for antioxidant (IC50= 25.99 μg/mL) assay. High performance liquid chromatography (HPLC) confirmed the existence of myercetin (10.40ppm), sinapic acid (2.131ppm), kaempferol (0.486ppm), caffeic acid (5.094 ppm). Forty-two rats were divided into 7 groups. Group 1 received normal saline (2 mL/kg/day, orally for 21 days), Group 2 received SA (10mg/kg/day for 21 days), and Group 3 received SA alone for 7 days (10mg/kg) and continues with silymarine for 21 days (25mg/kg orally). Group 4, 5, 6 received SA alone for 7 days and continue with TA extract up to 21 days (125mg/kg, 250mg/kg, and 500mg/kg orally) respectively, and Group 7 received TA extract (500mg/kg) for 21 days. SA was administered to all treated groups for 21 days. Treatment with polyphenolic ethanolic extract of TA restored the hepatic indices and oxidative markers in a dose-dependent manner. The upregulation in tumor necrosis factor-α, interleukin-6, and cyclooxygenase-2 upon SA treatment suggesting inflammation was normalized by the treatment of rats. Above mentioned biochemical findings were supported well with histopathological screening. Present findings suggest that TA polyphenolic ethanolic extract could mitigate the oxidative stress and inflammation induced by SA in liver tissue.

Ameliorative effect of Brassica oleracea var. Italica extract on oxidative damage of arsenic in the rat's brain: biochemical, pathological, and behavioral aspects

Brain damage caused by the metal accumulation may result in the permanent injuries including severe neurological disorders. Thus, the aim of this study was to determine the medicinal efficacy of broccoli extract in arsenic-induced brain poisoning. Twenty-eight female rats were classified into 4 groups; control, receiving sodium arsenate (As), As + broccoli extract (As + Bc), and (Bc). Then, the Elevated Plus-Maze and pathological-biochemical assessment of the brain tissue were performed. Moreover, the GC-MS was used to explore the quantity and quality of broccoli extract. The catalase had a significant decrease in the As group compared to that of the control group; As + Bc and Bc groups also showed a significant increase compared to that of the As group. Glutathione peroxidase was the lowest in the As group (1.84 ± 0.97) and the highest in the Bc group (5.51 ± 2.31). The Treatment significantly reduced pro-inflammatory cytokines in the As + Bc group. In addition, in terms of behavioral changes, the duration of presence in the open arm was reduced in the As group compared to that of the control group. Besides, the open arm duration increased significantly in the Bc group. Interestingly, there was a significant increase in estrogen and gonadotropin hormones in the Bc group compared to the other groups. Pathological findings showed that the condition of cortical neurons was improved and the surrounding space was reduced in As + Bc compared to that of the As group. In addition, more than 30% of the extract's compounds are made up Phytol,1-isothiocyanate-4-[methylsulfinyl] butane, and γ-Sitosterol. Thereby, the broccoli extract with active substances was highly effective in enhancing the behavioral and pathological parameters switch in rats with arsenic-induced poisoned brains.

Detection of Relevant Heavy Metal Concentrations in Human Placental Tissue: Relationship between the Concentrations of Hg, As, Pb and Cd and the Diet of the Pregnant Woman

Heavy metals can cross the placental barrier and reach the fetal compartment, threatening fetal development. Pregnant women can acquire these through food, drinking water, toxic habits or simply by breathing polluted air. The placenta has been described as a biomarker of maternal and fetal exposure to different toxic elements.

OBJECTIVES

The main objective of this study was to test the possible existence of heavy metal deposits (Pb, As, Cd and Hg) in the placentas of women who gave birth at term in our setting, analyzing the influence of daily life and dietary habits.

METHODS

We studied 103 placentas, obtained by consecutive sampling, of women that delivered in the Regional Maternity Hospital of Malaga between March and June, 2021. As, Cd and Pb concentrations were analyzed using mass spectrometry techniques. Hg concentration was studied according to US EPA method 7473. Women also answered a questionnaire with epidemiological variables.

RESULTS

Detectable concentrations were found in 14.56% [As], 44.6% [Cd], 81.5% [Pb] and 100% [Hg]. [Pb] and [As] correlated significantly (Spearman's Rho of 0.91 and <0.001), as did [Hg] and [Cd] (Spearman's Rho 0.256, p < 0.004). The [Pb] and [AS] concentrations were significantly higher in cases of tap water consumption. [Hg] concentrations predicted the birth weight of female newborns.

Mutagenic, Carcinogenic, and Teratogenic Effect of Heavy Metals

Heavy metal (HM)-induced toxicity and its associated complications have become a major issue in the medical world. HMs are not biodegradable, enter into the food chain, and gets accumulated in the living systems. Increased concentrations and accumulation of HMs can cause severely damaging effects and severe complications in living organisms and can even lead to the death of the organism. In Ayurvedic medicine, ingredients of natural origin, including whole plants or certain portions of the plant, animal sources, and minerals, are used for therapeutic purposes as medicine, both alone and in combination. HM such as cadmium, copper, zinc, lead, chromium, nickel, and arsenic cause hazardous effects on animals, human health, and the environment. This review focuses on mutagenic, carcinogenic, and teratogenic effects of HM , mechanism, organ toxicity, available remedies in the market, and their side effects. Also, emphasis is given to alternative systems of medicine to treat HM toxicity.

Arsenic-Induced Sex Hormone Disruption: An Insight into Male Infertility

Arsenic (As) is one of the most potent natural as well as anthropogenic metalloid toxicants that have various implications in the everyday life of humans. It is found in several chemical forms such as inorganic salt, organic salt, and arsine (gaseous form). Although it is mostly released via natural causes, there are many ways through which humans come in contact with As. Drinking water contamination by As is one of the major health concerns in various parts of the world. Arsenic exposure has the ability to induce adverse health effects including reproductive problems. Globally, around 15% of the couples are affected with infertility, of which about 20-30% are attributed to the male factor. Arsenic affects the normal development and function of sperm cells, tissue organization of the gonads, and also the sex hormone parameters. Stress induction is one of the implications of As exposure. Excessive stress leads to the release of glucocorticoids, which impact the oxidative balance in the body leading to overproduction of reactive oxygen species (ROS). This may in turn result in oxidative stress (OS) ultimately interfering with normal sperm and hormonal parameters. This study deals with As-induced OS and its association with sex hormone disruption as well as its effect on sperm and semen quality.

Arsenic (III) induces oxidative stress and inflammation in the gills of common carp, which is ameliorated by zinc (II)

Arsenic (As) is widely present in the environment in form of arsenite (As^III) and arsenate (As^V). Oxidative stress and inflammation are believed to be the dominant mechanisms of As^III toxicity in vivo and in vitro. The aim of this study was to investigate whether zinc (Zn²⁺) alleviates exogenous gill toxicity in carp induced by As^III and to gain insight into the underlying mechanisms. Exposure of carp to 2.83 mg As₂O₃/L for 30 days reduced superoxide dismutase activity by 4.0%, catalase by 41.0% and glutathione by 19.8%, while the concentration of malondialdehyde was increased by 16.4% compared to the control group, indicating oxidative stress. After the exposure of carp to As^III the expression of inflammatory markers, such as interleukin-6, interleukin-8, tumor necrosis factor α and inducible nitric oxide synthase in gill tissue were significantly increased. In addition, the phosphorylation of nuclear factor kappa-B (NF-κB) was increased by 225%. 1 mg ZnCl₂/L can relieve the toxicity of As^III based on histopathology, antioxidase activity, qRT-PCR and western results. Zn²⁺ attenuated As^III-induced gill toxicity that suppressed intracellular oxidative stress and NF-κB pathway by an upregulation of metallothionein. Therefore, the toxic effect of As^III on the gill cells of carp was reduced. This study provides a theoretical basis for exploring the alleviation of the toxic effects of metalloids on organisms by heavy metals and the biological assessment of the effects.

Effects of Moringa oleifera leaf extracts and its bioactive compound gallic acid on reducing toxicities of heavy metals and metalloid in Saccharomyces cerevisiae

Moringa oleifera leaf extract is rich in antioxidants and has high potential for use to alleviate metal toxicity. Previously, we have reported the roles of aqueous M. oleifera leaf extract in mitigating intracellular cadmium (Cd) accumulation and Cd-induced oxidative stress. In this study, we investigated the protective role of aqueous and/or ethanolic M. oleifera leaf extracts (AMOLE and/or EMOLE) against other metal(loid)s in the eukaryotic model Saccharomyces cerevisiae. Our results show that only the AMOLE remarkably promoted the growth of yeast cells grown in the presence of arsenite (As(III)), Cd, nickel (Ni), and lead (Pb). Although the AMOLE contained lower amount of total phenolic and flavonoid contents and displayed lower DPPH scavenging capacity than the EMOLE, both AMOLE and EMOLE had the same capacity for reducing intracellular ROS levels in yeast cells exposed to As(III), Cd, Ni, and Pb. Moreover, the AMOLE was more effective than the EMOLE in inhibiting intracellular accumulation of these toxic metal(loid)s. In addition, we found that gallic acid, one of important phenolic constituents present in both extracts, could protect yeast cells against As(III) toxicity, likely through its role in decreasing As(III) accumulation and As(III)-induced ROS production. Furthermore, the hydroxyl and carboxyl groups of gallic acid appear to play a critical role in chelating As(III). The present study suggests the promising applications of the AMOLE (and also gallic acid) as protective agents against hazardous metal(loid)s.

Coenzyme Q10 protected against arsenite and enhanced the capacity of 2,3-dimercaptosuccinic acid to ameliorate arsenite-induced toxicity in mice

BACKGROUND

Arsenic poisoning affects millions of people. The inorganic forms of arsenic are more toxic. Treatment for arsenic poisoning relies on chelation of extracellularly circulating arsenic molecules by 2,3-dimecaptosuccinic acid (DMSA). As a pharmacological intervention, DMSA is unable to chelate arsenic molecules from intracellular spaces. The consequence is continued toxicity and cell damage in the presence of DMSA. A two-pronged approach that removes extracellular arsenic, while protecting from the intracellular arsenic would provide a better pharmacotherapeutic outcome. In this study, Coenzyme Q10 (CoQ10), which has been shown to protect from intracellular organic arsenic, was administered separately or with DMSA; following oral exposure to sodium meta-arsenite (NaAsO2) - a very toxic trivalent form of inorganic arsenic. The aim was to determine if CoQ10 alone or when co-administered with DMSA would nullify arsenite-induced toxicity in mice.

METHODS

Group one represented the control; the second group was treated with NaAsO2 (15 mg/kg) daily for 30 days, the third, fourth and fifth groups of mice were given NaAsO2 and treated with 200 mg/kg CoQ10 (30 days) and 50 mg/kg DMSA (5 days) either alone or in combination.

RESULTS

Administration of CoQ10 and DMSA resulted in protection from arsenic-induced suppression of RBCs, haematocrit and hemoglobin levels. CoQ10 and DMSA protected from arsenic-induced alteration of WBCs, basophils, neutrophils, monocytes, eosinophils and platelets. Arsenite-induced dyslipidemia was nullified by administration of CoQ10 alone or in combination with DMSA. Arsenite induced a drastic depletion of the liver and brain GSH; that was significantly blocked by CoQ10 and DMSA alone or in combination. Exposure to arsenite resulted in significant elevation of liver and kidney damage markers. The histological analysis of respective organs confirmed arsenic-induced organ damage, which was ameliorated by CoQ10 alone or when co-administered with DMSA. When administered alone, DMSA did not prevent arsenic-driven tissue damage.

CONCLUSIONS

Findings from this study demonstrate that CoQ10 and DMSA separately or in a combination, significantly protect against arsenic-driven toxicity in mice. It is evident that with further pre-clinical and clinical studies, an adjunct therapy that incorporates CoQ10 alongside DMSA may find applications in nullifying arsenic-driven toxicity.

Sodium arsenite induces spatial learning and memory impairment associated with oxidative stress and activates the Nrf2/PPARγ pathway against oxidative injury in mice hippocampus

Arsenic (As) is a ubiquitous environmental and industrial toxin with known correlates of oxidative stress and cognitive deficits in the brain. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcriptional factor that represents a central cellular antioxidant defense mechanism and transcribes many antioxidant genes. Peroxisome proliferator-activated receptor-gamma (PPARγ) is a well-known nuclear receptor to regulate lipid metabolism in many tissues, and it has been also associated with the control of oxidative stress, neuronal death, neurogenesis and differentiation. The role of Nrf2 and PPARγ in As-induced neurotoxicity is still debated. The present study was designed to investigate the neurobehavioral toxic effect of sub-chronic and middle-dose sodium arsenite exposure in mice hippocampus, as well as the response of Nrf2/PPARγ expression and influence on protein expression levels of their downstream antioxidant genes. Our results showed that mice treated with intraperitoneal injection of sodium arsenite (50 mg/kg body wt.) twice a week for 7 weeks resulted in increased generation of reactive oxygen species and impairment of spatial cognitive function. The present study also found a positive association between Nrf2/PPARγ expression in hippocampus of mice, and activation of antioxidant defenses by the evidently upregulated expression of their downstream genes, including superoxide dismutase, heme oxygenase-1 and glutathione peroxidase-3. Therefore, our findings were helpful for further understanding the role of Nrf2/PPARγ feedback loop in As-induced neurobehavioral toxicity.

Effects of Selenium on Arsenic-Induced Liver Lesions in Broilers

The aim of the present study was to investigate the abilities of selenium to counteract the toxic damage of arsenic (As). Two hundred 1-day-old healthy male broilers were randomly divided into five groups and fed the following diets: control group (0.1 mg/kg As + 0.2 mg/kg Se), As group (3 mg/kg As + 0.2 mg/kg Se), As + Se group I (3 mg/kg As + 5 mg/kg Se), As + Se group II (3 mg/kg As + 10 mg/kg Se), and As + Se group III (3 mg/kg As + 15 mg/kg Se), respectively. The relative weight of the liver, hepatic protein content, GSH-Px levels, SOD activities, NO contents, iNOS and tNOS activities, and increased malondialdehyde contents, ALT and AST activities, and the apoptotic hepatocytes were analyzed. Adding 3 mg/kg arsenic to the diet caused the growth and development of chicken liver to be blocked, resulting in decrease of protein contents in liver tissue, decrease of SOD and GSH-Px activities, increase of MDA contents, decrease of NO contents, decrease of iNOS and TNOs activities, increase of ALT and AST activities, increase of apoptosis rates of liver cells. Compared to the 3-mg/kg arsenic group, adding 5 mg/kg and 10 mg/kg selenium, respectively, could repair the liver growth retardation and steatosis caused by arsenic, increase the protein contents in liver tissue, increase the activities of SOD and GSH-Px, reduce the contents of MDA, increase the contents of NO, enhance the activities of iNOS and TNOs, reduce the activities of ALT and AST, and reduce the rates of apoptosis of liver cells, in which the best effects are to add 10 mg/kg selenium. While 15 mg/kg of sodium selenite may induce progression of As-induced hepatic lesions, the results indicated that 5 and 10 mg/kg of sodium selenite supplied in the diet, through mechanisms of oxidative stress and apoptosis regulation, may ameliorate As-induced hepatic lesions in a dose-dependent manner.

Chronic exposure to multi-metals on testicular toxicity in rats

Despite the availability of sufficient data on the effects of individual metal exposure on living organisms, a critical knowledge gap still exists in predicting effects of multi-metals particularly on the pituitary-testicular axis. Thus, the aim of the present study was to check the effects of individual or combined (binary and ternary) exposure to aluminum, copper, and zinc on (i) sperm and testosterone levels (ii) oxidative stress and (iii) structural changes in testis of male Wistar rats. Animals were exposed to aluminum, copper, and zinc either individually (20 mg/kg, orally, once, daily), binary (10 mg/kg each, orally, once daily) or in ternary combination (5 mg/kg, each, orally, once daily) for 24 weeks. The exposure to aluminum, copper individually and in combination led to a significant decrease in sperm counts and an increased oxidative stress compared to the control group. Exposure to zinc caused significant decrease in oxidative stress and an increase in different sperm variables. The exposure to zinc with aluminum or copper had no toxic effects on testis while concomitant exposure to aluminum, copper, and zinc produced more pronounced testicular injury. In summary, while co-exposure to zinc with aluminum or copper produced reproductive toxicity the co-exposure to all the three metals may lead to a significant testicular toxicity and these changes were related to increase in oxidative stress in rats.

Mechanisms involved in the possible protective effect of chrysin against sodium arsenite-induced liver toxicity in rats

Arsenic as a one of the most important toxic metals could induce hepatotoxicity. Previous reports revealed the significance of oxidative stress in promoting of arsenic-induced liver toxicity. The aim of the present investigation is to evaluate the effect of chrysin (CHR), a natural flavonoid with potent antioxidant activity, against sodium arsenite (SA)-induced hepatotoxicity. Thirty male Wistar rats were divided into four groups: Group 1: received normal saline (2 ml/kg/day, orally for 21 days), Group 2: received SA (10 mg/kg/day, orally for 14 days), Group 3, 4 and 5: received CHR (25, 50 and 100 mg/kg/day, respectively, orally for 21 days) and SA (10 mg/kg/day, orally for 14 days) from the 7th day. Serum levels of alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase were evaluated. Moreover, liver glutathione peroxidase and myeloperoxidase activity as well as levels of protein carbonylation, malondialdehyde, glutathione, catalase, nitric oxide, superoxide dismutase, tumor necrosis factor-α and interleukin-1β were evaluated. Moreover, histological evaluation was done. Our results revealed that treatment with CHR (more potentially at the dose of 100 mg/kg/day) before and alongside with SA significantly mitigated the SA-induced hepatotoxicity. Also, the hepatoprotective effect of CHR was verified by the histological evaluation of the liver. The results of current study demonstrated that CHR (100 mg/kg/day) could mitigate the oxidative stress and inflammation induced by SA in liver tissue.

Mitigation of arsenic driven utero-ovarian malfunction and changes of apoptotic gene expression by dietary NAC

An oral painless dietary therapy is also indispensable in the management of arsenic toxicity despite of its conventional painful therapeutic management. The present study focused on the management of arsenic mediated female reproductive dysfunctions by dietary therapy of N-acetyl cysteine (NAC). Here, sodium arsenite was given at the dose of 10 mg/kg body weight orally for the first 8 day. Day 9 onwards up to day 16 these arsenicated rats were provided with NAC (250 mg/kg body weight) enriched basal diet once daily. Arsenic intoxicated group exhibited a comparable inactivation of antioxidant enzymes superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx) due to oxidative stress in reproductive organs along with a simultaneous elevation of lipid peroxidation state and decline in non-protein soluble thiols (NPSH) level in female reproductive organs. Arsenic intoxication also accomplished with the up-regulation of inflammatory markers tumour necrosis factor (TNF α) and nuclear factor κB (NF κB). Pro-apoptotic Bax gene and p53 gene expressions were also raised due to arsenic intoxication while anti-apoptotic Bcl-2 gene expression was suppressed. In fact, arsenication decreased the circulating level of vitamin B12 and folic acid. Dietary NAC supplementation significantly reversed back the activity of antioxidant enzymes in arsenite fed rats towards normalcy and also sustained the normal reproductive cyclicity, utero-ovarian histo-morphology and estradiol receptor α (ER-α) expression in these reproductive organs. Dietary NAC exerted its positive action against arsenic intoxication by up-regulation of Bcl-2 gene expression along with the suppression of pro-apoptotic Bax gene and p53 gene. Thus, dietary NAC also plays anti-apoptotic, anti-inflammatory, and anti-oxidative role against arsenic toxicity. NAC also regulates the components (vitamin B12 and folic acid) of S-adenosylmethionine pool in the way of probable removal of arsenic from the system.

MiADMSA ameliorate arsenic induced urinary bladder carcinogenesis in vivo and in vitro

BACKGROUND AND PURPOSE

Arsenicosis is a major threat to public health and is a major cause of the development of urinary bladder cancer. Oxidative/ nitrosative stress is one of the key factors for these effects but the involvement of other associated factors is less known. There is a lack of data for the efficacy of chelator against urinary bladder carcinogenesis. The present study demonstrates the early signs of arsenic exposed urinary bladder carcinogenesis and its attenuation by Monoisoamyl dimercaptosuccinic acid (MiADMSA).

METHODS

Male rats were exposed to 50 ppm of sodium arsenite and dimethylarsinic acid (DMA) via drinking water for 18 weeks and treated with MiADMSA (50 mg/kg, orally once daily for 5 days) for 3 weeks with a gap one week between the two courses of treatments. We compared in vivo data with in vitro by co-exposing 100 nM of sodium arsenite and DMA to rat (NBT-II) as well as human transitional epithelial carcinoma (T-24) cells with 100 nM of MiADMSA.

RESULTS

The data showed that sodium arsenite and DMA exposure significantly increased the tissue arsenic contents, ROS, TBARS levels, catalase, SOD activities and significantly decreased GSH level which might be responsible for an increased 8-OHdG level. These changes might have increased pro-oncogenic biomarkers like MMP-9 and survivin in serum, bladder tissues, NBT-II, and T-24 cells. High cell migration and clonogenic potential in NBT-II and T-24 cells exposed to arsenic suggest pronounced carcinogenic potential. Significant recovery in these biomarkers was noted on treatment with MiADMSA.

CONCLUSION

Early signs of urinary bladder carcinogenesis were observed in arsenic and DMA exposed rats which were linked to metal accumulation, oxidative/ nitrosative stress, 8-OHdG, MMP-9 and survivin which were reduced by MiADMSA possibly via its efficient chelation abilities in vivo and in vitro.

Graphene oxide and GST-omega enzyme: An interaction that affects arsenic metabolism in the shrimp Litopenaeus vannamei

Arsenic (As) is one of the most widespread contaminants; it is found in almost every environment. Its toxic effects on living organisms have been studied for decades, but the interaction of this metalloid with other contaminants is still relatively unknown, mainly whether this interaction occurs with emerging contaminants such as nanomaterials. To examine this relationship, the marine shrimp Litopenaeus vannamei was exposed for 48 h to As, graphene oxide (GO; two different concentrations) or a combination of both, and gills, hepatopancreas and muscle tissues were sampled. Glutathione S-transferase (GST)-omega gene expression and activity were assessed. As accumulation and speciation (metabolisation capacity) were also examined. Finally, a molecular docking simulation was performed to verify the possible interaction between the nanomaterial and GST-omega. The main finding was that GO modulated the As toxic effect: it decreased GST-omega activity, a consequence related to altered As accumulation and metabolism. Besides, the molecular docking simulation confirmed the capacity of GO to interact with the enzyme structure, which also can be related to the decreased GST-omega activity and subsequently to the altered As accumulation and metabolisation pattern.

Altered neurotransmission and neuroimaging biomarkers of chronic arsenic poisoning in wild muskrats (Ondatra zibethicus) and red squirrels (Tamiasciurus hudsonicus) breeding near the City of Yellowknife, Northwest Territories (Canada)

Chronic arsenic poisoning has been shown to be a risk factor for the development of intellectual disability. Numerous human and animal studies have also confirmed that low-level arsenic exposure has deleterious effects on neurotransmission and brain structures which have been further linked to neurobehavioral disorders. The aim of this present work was to comparatively assess structural brain volume changes and alteration of two (2) neurotransmitters, specifically dopamine (DA) and serotonin (5-HT) in the brains of wild muskrats and squirrels breeding in arsenic endemic areas, near the vicinity of the abandoned Giant mine site in Yellowknife and in reference locations between 52 and 105 km from the city of Yellowknife. The levels of DA and 5-HT were measured in the brain tissues, and Magnetic Resonance Imaging (MRI) was used to attempt brain volume measurements. The results revealed that the concentrations of DA and 5-HT were slightly increased in the brains of squirrels from the arsenic endemic areas compared to the reference site. Further, DA and 5-HT were slightly reduced in the brains of muskrats from the arsenic endemic areas compared to the reference location. In general, no statistically significant neurotransmission changes and differences were observed in the brain tissues of muskrats and squirrels from both arsenic endemic areas and non-endemic sites. Although MRI results showed that the brain volumes of squirrels and muskrats were not statistically different between sites after multiple comparison correction; it was noted that core brain regions were substantially affected in muskrats, in particular the hippocampal memory circuit, striatum and thalamus. Squirrel brains showed more extensive neuroanatomical changes, likely due to their relatively smaller body mass, with extensive shrinkage of the core brain structures, and the cortex, even after accounting for differences in overall brain size. The results of this present study constitute the first observation of neuroanatomical changes in wild small mammal species breeding in arsenic endemic areas of Canada.

Impact of chronic low dose exposure of monocrotophos in rat brain: Oxidative/ nitrosative stress, neuronal changes and cholinesterase activity

Monocrotophos (MCP) is an organophosphate mainly used as insecticides in agriculture, and veterinary practice to control pests. Exposure to MCP is known to induce significant systemic toxicity in animals and humans. Short term exposure to a high dose of MCP has been reported to cause systemic toxicity, however limited information is available regarding low dose long term exposure in rats. We studied the effects of low dose long term exposure to MCP on oxidative/nitrosative stress, cholinesterase activity and neuronal loss in rat. Male rats were exposed to MCP (0.1 μg or 1 μg/ml) via drinking water for 8 weeks. The pro-oxidant markers such as reactive oxygen species (ROS), lipid peroxidation (MDA), nitrite level and antioxidant markers such as reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CAT) and inhibition of cholinesterase activities were measured to evaluate the effects of MCP on brain along with plasma cholinesterase activity. Neuronal loss was analyzed in cortical region using H&E stained slices. The results suggested that exposure to MC even at the low dose, increased reactive oxygen species, thiobarbituric acid reactive substance levels and decreased glutathione, superoxide dismutase, catalase and cholinesterase activities in brain. No significant effect however, was observed on nitrite levels. Histological analysis revealed that low dose MCP exposure lead to structural changes in the cortical neurons in rats. It can be concluded from the study that low dose long term exposure (lower than No Observed Effect Level) of MCP may lead to the generation of oxidative stress by elevation of pro-oxidants markers and depletion of antioxidant enzymes markers along with inhibition of cholinesterase activity. These changes might thus be considered as the possible mechanism of cortical neuronal loss in these animals.

Zinc alleviates arsenism in common carp: Varied change profiles of cytokines and tight junction proteins among two intestinal segments

This study was designed to evaluate the effects of zinc on inflammation and tight junction (TJ) in different intestinal regions of common carp under sub-chronic arsenic insult. Fish were exposed to zinc (0, 1 mg/L) and arsenic trioxide (0, 2.83 mg/L) in individual or combination for a month. Inflammatory infiltration and TJ structure changes were displayed by H&E staining and transmission electron microscope. To further explore these changes, biochemical indicator (SOD), gene or protein expressions of inflammatory responses (NF-κB, IL-1β, IL-6 and IL-8) and TJ proteins (Occludin, Claudins and ZOs) were determined. In the anterior intestine, arsenic decreased activity of SOD, mRNA levels of Occludin, Claudins and ZOs, increased mRNA levels of ILs. However, unlike the anterior intestine, arsenic has an upregulation effects of Occludin and Claudin-4 in the mid intestine. These anomalies induced by arsenic, except IL-8, were completely or partially recovered by zinc co-administration. Furthermore, transcription factor (NF-κB) nuclear translocation paralleled with its downstream genes in both intestinal regions. In conclusion, our results unambiguously suggested that under arsenic stress, zinc can partly relieve intestinal inflammation and disruption of tight junction segment-dependently.

Impacts of acute toxicity of arsenic (III) alone and with high temperature on stress biomarkers, immunological status and cellular metabolism in fish

The water bodies are greatly influenced by heavy metal contamination and global increasing temperature. Arsenic (As) is one of the most dangerous widespread pollutants that pose health threats to human, animals and fishes. Considering the above, the study has been carried out to delineate 96 h median lethal concentration of arsenic alone and in combination with high temperature (As-T, 34 °C) by conducting static non-renewable bio-assay acute toxicity in Pangasianodon hypophthalmus (average weight 6.25 ± 0.69 g, length 5.32 cm). Effect of definitive doses such as 25, 26, 27, 28, 29 and 30 mg/L of As alone and in combination with high temperature (As-T) were evaluated on stress biomarkers and cellular metabolism of P. hypophthalmus. The lethal concentration (96 h LC₅₀) of As alone and in combination with high temperature was found to be 28.16 mg/L and 26.88 mg/L, respectively. The stress biomarkers in terms of catalase, superoxide dismutase (SOD) and glutathione-s-transferase (GST) in liver, gill, brain and kidney, blood glucose and NBT were remarkable higher (p < 0.01) in comparison to unexposed group (control group). Brain neurotransmitter enzyme, AChE, immunological status (blood glucose and NBT) and cellular metabolic enzymes (lactate dehydrogenase LDH, malate dehydrogenase MDH, aspartate aminotransferase AST, and alanine aminotransferase ALT, glucose-6-phosphate dehydrogenase G6PDH and ATPase) were noticeably (p < 0.01) altered by As and As-T exposure. The histopathological study exhibited devastating changes with exposure to As and As-T such as bile stagnation, hepatocyte with irregular nucleus, eosinophilic granules in the cytoplasm, necrosis, and nuclear hypertrophy in liver and curling of secondary lamellae, hypertrophy of lamellar epithelium, blood congestion, incomplete fusion of secondary lamellae, complete fusion of several lamellae and aneurysm in gill. Overall results clearly indicate that acute exposure of As and high temperature led to pronounced deleterious alterations on stress biomarkers and cellular and metabolic activities of P. hypophthalmus.

Characterization of the cellular effects and mechanism of arsenic trioxide-induced hepatotoxicity in broiler chickens

To characterize the cellular effects and mechanism of arsenic trioxide (ATO)-induced hepatotoxicity in broiler chickens, increasing concentrations of ATO (0, 0.6, 1.2, 2.4, and 4.8 μM) were added to chicken hepatocyte cultures in vitro. The changes in hepatocyte morphology, oxidative stress and apoptosis were evaluated using fluorescence microscopy and flow cytometry. The effects of ATO on mRNA or protein expression of antioxidant enzymes, especially methionine sulfoxide reductase (Msr), were analyzed using qRT-PCR and western blotting assays. Increased apoptosis were concomitant with increased reactive oxygen species (ROS) accumulation and upregulation of antioxidant enzymes such as catalase (CAT) and superoxide dismutase (SOD) with increasing ATO concentrations. Moreover, G₁ phase arrest and dysregulation of the balance between antiapoptotic versus proapoptotic factors were noted. Furthermore, upregulation of HO-1, SOD-1, and TRX in the ATO groups were consistent with ATO-induced oxidative damage. High Msr, SOD-1, TRX, Bak1, Bax, and p53 protein levels in the ATO groups indicate that these proteins may have accumulated to counter ATO-induced oxidative stress. ROS scavenger N-acetyl-l-cysteine (NAC) could reverse ATO-induced oxidative damage and restore hepatocyte viability, even with compromised Msr function. Our findings suggest that Msr can protect broiler hepatocytes against ATO-induced oxidative stress. Furthermore, NAC-mediated reversal of oxidative damage may represent a strategy to mitigate potential economic losses associated with arsenic poisoning in the poultry industry.

Developmental Neurotoxicity of Arsenic: Involvement of Oxidative Stress and Mitochondrial Functions

Over the last decade, there has been an increased concern about the health risks from exposure to arsenic at low doses, because of their neurotoxic effects on the developing brain. The exact mechanism underlying arsenic-induced neurotoxicity during sensitive periods of brain development remains unclear, although enhanced oxidative stresses, leading to mitochondrial dysfunctions might be involved. Here, we highlight the generation of reactive oxygen species (ROS) and oxidative stress which leads to mitochondrial dysfunctions and apoptosis in arsenic-induced developmental neurotoxicity. Here, the administration of sodium arsenite at doses of 2 or 4 mg/kg body weight in female rats from gestational to lactational (GD6-PD21) resulted to increased ROS, led to oxidative stress, and increased the apoptosis in the frontal cortex, hippocampus, and corpus striatum of developing rats on PD22, compared to controls. Enhanced levels of ROS were associated with decreased mitochondrial membrane potential and the activity of mitochondrial complexes, and hampered antioxidant levels. Further, neuronal apoptosis, as measured by changes in the expression of pro-apoptotic (Bax, Caspase-3), anti-apoptotic (Bcl2), and stress marker proteins (p-p38, pJNK) in arsenic-exposed rats, was discussed. The severities of changes were found to more persist in the corpus striatum than in other brain regions of arsenic-exposed rats even after the withdrawal of exposure on PD45 as compared to controls. Therefore, our results indicate that perinatal arsenic exposure leads to abrupt changes in ROS, oxidative stress, and mitochondrial functions and that apoptotic factor in different brain regions of rats might contribute to this arsenic-induced developmental neurotoxicity.

Arsenic-Induced Autophagy in the Developing Mouse Cerebellum: Involvement of the Blood-Brain Barrier's Tight-Junction Proteins and the PI3K-Akt-mTOR Signaling Pathway

This study was designed to determine whether the tight-junction (TJ) proteins of the blood-brain barrier (BBB) and the PI3K-Akt-mTOR signaling pathway are involved during arsenic (As)-induced autophagy in developing mouse cerebella after exposure to different As concentrations (0, 0.15, 1.5, and 15 mg/L As(III)) during gestational and lactational periods. The dosage was continually given to the pups until postnatal day (PND) 42. Studies conducted at different developmental age points, like PND21, 28, 35, and 42, showed that exposure to As led to a significant decrease in the mRNA-expression levels of TJ proteins (occludin, claudin, ZO-1, and ZO-2), PI3K, Akt, mTOR, and p62, with concomitant increases in Beclin1, LC3I, LC3II, Atg5, and Atg12. Also, As significantly downregulated occludin and mTOR protein-expression levels with concomitant upregulation of Beclin1, LC3, and Atg12 at all the developmental age points. However, no significant alterations were observed in low- and medium-dose-exposed groups at PND42. Histopathological analysis revealed the irregular arrangement of the Purkinje cell layer in the As-exposed mice. Ultrastructural analysis by transmission electron microscopy (TEM) revealed the occurrence of autophagosomes and vacuolated axons in the cerebella of the mice exposed to high doses of As at PND21 and 42, respectively. Finally, we conclude that developmental As exposure significantly alters TJ proteins, resulting an increase in BBB permeability, facilitating the ability of As to cross the BBB and induce autophagy, which might be partly the result of inhibition of the PI3K-Akt-mTOR signaling pathway, in an age-dependent manner (i.e., PND21 mice were found to be more vulnerable to As-induced neurotoxicity), which could be due to the immature BBB allowing As to cross through it. However, the effect was not significant in PND42, which could be due to the developed BBB.

Lithium Treatment Aggregates the Adverse Effects on Erythrocytes Subjected to Arsenic Exposure

The present study was designed to investigate the effects of lithium treatment on red blood cells which were given arsenic exposure. Long-term lithium therapy is being extensively used for the treatment of bipolar disorders. Arsenic is a group I carcinogen and a major toxic pollutant in drinking water that affects millions of people worldwide. Male SD rats were segregated into four groups, viz. normal control, lithium treated, arsenic treated, and lithium + arsenic treated. Lithium was supplemented as lithium carbonate at a dose level of 1.1 g/kg diet for a period of 8 weeks. Arsenic was given in the form of sodium arsenite at a dose level of 100 ppm in drinking water, ad libitum, for the same period. Lysates of red blood cells were used to investigate the effects of lithium and arsenic treatments on anti-oxidant enzymes, reduced glutathione (GSH), and lipid peroxidation (LPO) levels. Various hematological parameters, activities of Na⁺ K⁺ ATPase and delta-aminolevulinic acid dehydratase (δ-ALAD) were also assessed. A significant reduction was observed in the activities of antioxidant enzymes, GSH levels, total erythrocyte counts, Na⁺ K⁺ ATPase, and ALAD enzyme activities in lysates of red blood cells when exposed either to lithium or arsenic. In addition, a significant increase in the levels of malondialdehyde (MDA), lymphocytes, neutrophils, and total leukocytes was also observed following lithium as well as arsenic treatments. However, when arsenic-treated rats were subjected to lithium treatment, a pronounced alteration was noticed in all the above parameters. Therefore, we conclude that lithium supplementation to the arsenic-treated rats enhances the adverse effects on red blood cells and therefore use of lithium may not be medicated to patients who are vulnerable to arsenic exposure through drinking water. It can also be inferred that adverse effects of lithium therapy may get aggravated in patients thriving in the arsenic-contaminated area.

3,4-Dihydroxybenzaldehyde lowers ROS generation and protects human red blood cells from arsenic(III) induced oxidative damage

Arsenic (As) is a potent environmental toxicant and chronic exposure to it results in various malignancies in humans. Oxidative stress has been implicated in the etiopathogenesis of As-induced toxicity. This investigated the protective effect of plant antioxidant 3,4-dihydroxybenzaldehyde (DHB) on sodium meta-arsenite (SA), an As-(III) compound, induced oxidative damage in human red blood cells (RBC). The RBC were first incubated with different concentrations of DHB and then treated with SA at 37°C. Hemolysates were prepared and assayed for various biochemical parameters. Treatment of RBC with SA alone enhanced the generation of reactive oxygen species and increased lipid and protein oxidation. Reduced glutathione levels, total sulfhydryl content and cellular antioxidant power were significantly decreased in SA alone treated RBC, compared to the untreated control cells. This was accompanied by membrane damage, alterations in activities of antioxidant enzymes and deranged glucose metabolism. Incubation of RBC with DHB, prior to treatment with SA, significantly and dose-dependently attenuated the SA-induced changes in all these parameters. Scanning electron microscopy of RBC confirmed these biochemical results. Treatment of RBC with SA alone converted the biconcave discoids to echinocytes but the presence of DHB inhibited this conversion and the RBC retained their normal shape. These results show that DHB protects human RBC from SA-induced oxidative damage, most probably due to its antioxidant character.

A comparative study on subacute toxicity of arsenic trioxide and dimethylarsinic acid on antioxidant status in Crandell Rees feline kidney (CRFK), human hepatocellular carcinoma (PLC/PRF/5), and epithelioma papulosum cyprini (EPC) cell lines

Arsenic (As) is a global contaminant of terrestrial and aquatic environments posing concern for environmental and human health. The effects of subacute concentrations of arsenic trioxide (As^III) and dimethylarsinic acid (DMA^V) were examined using Crandell Rees feline kidney (CRFK), human hepatocellular carcinoma (PLC/PRF/5), and epithelioma papulosum cyprini (EPC). Whole monolayer with suffering cells (confluence 100%, pyknosis and refractive cells; value scale = 2) led to identification of subacute As concentrations for the three cell lines. The selected As^III concentrations were 1.33 µM for CRFK and 33.37 µM for PLC/PRF/5 and EPC, at 48 hr time point. The selected DMA^V concentrations were 0.67 mM for PLC/PRF/5, 1.33 mM for CRFK, and 2.67 mM for EPC for 48 hr. Unlike the As^III test, the three cell lines did not exhibit marked susceptibility to DMA^V-mediated toxicity. Several oxidative stress biomarker levels, directly or indirectly associated with reactive oxygen species (ROS) elimination including superoxide dismutase, catalase, glutathione peroxidases, glutathione reductase, glutathione S-transferase, glyoxalase I, glyoxalase II, and total glutathione, were determined in the three cell lines at 24 and 48 hr. Antioxidant responses in metal-treated cells were significantly altered compared to controls, suggesting a perturbation of redox state. The weakening of antioxidant pathway in either healthy or tumoral cells was greater using As^III than DMA^V. Differences in level of several oxidative stress biomarkers suggest that the oxidative stress mechanism induced by As^III is distinctly different from DMA^V. Multifaceted mechanisms of action underlying ROS generation in tumor and nontumor cells versus As^III and DMA^V exposure are thus involved. Since As-mediated toxicity is quite complex, more data regarding both oxidant-enhancement and oxidant-lowering strategies may be useful to improve knowledge regarding the influence of As on human and animal cells.

Protective Effect of Hydroxytyrosol Against Oxidative Stress Mediated by Arsenic-Induced Neurotoxicity in Rats

The present study reports beneficial effect of hydroxytyrosol (HT) against arsenic (As)-induced oxidative stress in the rat brain. Rats were orally administered with sodium arsenite dissolved in distilled water (25 ppm, by oral gavage) for 8 weeks or HT (10 mg/kg b. wt.) in combination with As. Results showed increase in protein oxidation and lipid peroxidation, while catalase and superoxide dismutase (SOD) activities as well as GSH content were decreased after As exposure in rat brain. Fourier transform infrared analysis showed significant alteration in peak area values that also validated the oxidative damage to lipids and proteins. In addition, As exposure caused increase in protein expression of caspase-3 and Bax, while Bcl-2 expression was downregulated resulting in translocation of cytochrome c from mitochondria to cytosol. Treatment of HT with As reversed protein oxidation, lipid peroxidation, and increased GSH content as well as catalase and SOD activities. Administration of HT also prevented translocation of cytochrome c from mitochondria and increased mitochondria/cytosol ratio of cytochrome c. Hence, treatment of HT with As improved antioxidant system and efficiently lowered the generation of oxidative stress in rat brain.

Chronic exposure to arsenic and high fat diet additively induced cardiotoxicity in male mice

Diet is one of the important risk factors that could potentially affect arsenic-induced cardiotoxicity. The present study was undertaken to investigate the effect of high fat diet on arsenic-induced cardiotoxicity in mice. Mice were divided into six different groups (n = 12), two control groups received either low fat diet (LFD) or high fat diet (HFD) along with deionized drinking water and four test groups given LFD + 25 ppm arsenic, LFD + 50 ppm arsenic, HFD + 25 ppm arsenic, and HFD + 50 ppm arsenic in drinking water for 5 months. The body weight, heart weight to body weight ratio, cardiac biochemical markers, lipid profile, and histological examination of heart were evaluated. The results demonstrated that arsenic exposure led to a significant decrease in heart glutathione level, catalase enzyme activity, and a significant increase in reactive oxygen species (ROS), malondialdehyde levels, and biochemical enzymes. The administration of HFD resulted in above-mentioned changes as well as an alteration in lipid profile; however, arsenic exposure alone or along with HFD caused a reduction in lipid profile factors, except HDL level. Our results revealed that HFD increased arsenic-induced heart injury in the mice. This effect may be because of reduction in antioxidant activities and/or increase in oxidative stress and ROS in mice heart tissues. These findings could be important for clinical intervention to protect against or prevent arsenic-induced cardiotoxicity in humans.

Analysis of 28 trace elements in the blood and serum antioxidant status in chickens under arsenic and/or copper exposure

This study aimed to evaluate the 28 trace elements in the blood and serum antioxidant status in chickens under arsenic (As) and/or copper (Cu) exposure. A total of 200 1-day-old male Hy-Line chickens were fed either a commercial diet (C-group) or arsenic trioxide (30 mg/kg) and/or cupric sulfate (300 mg/kg) for 90 days. The 28 trace element levels in the blood were analyzed by inductively coupled plasma mass spectrometry (ICP-MS). The concentrations of As in the blood of chickens were elevated approximately 17.15-fold, 2.30-fold, and 13.37-fold in the As-group, Cu-group, and As + Cu-group, respectively, at 90 days. The concentrations of Cu did not change in the As-group and increased approximately 29.53 and 23.37% in the Cu-group and As + Cu-group, respectively, at 90 days. Moreover, As exposure caused ion profile disorders in the blood, including increased concentrations of Na, Mg, Si, K, Cr, Fe, and Se and reduced B, Ca, Ti, V, Mn, Co, Ni, Zn, Sr, and Mo. Cu exposure increased the contents of Mg, Si, Ca, Ti, V, Cr, Mn, Fe, Co, Zn, and Se and decreased the content of B, Ca, Al, Ni, and Mo. As + Cu exposure increased the contents of Mg, Si, Cr, Fe, Zn, and Se and decreased the content of B, Ca, Ti, Co, Ni, Sr, and Mo. Moreover, As and/or Cu exposure induced oxidative stress in the blood of chickens. In conclusion, the results indicated that the mixture of As and Cu caused a synergistic effect via disturbing homeostasis of trace elements and oxidative stress in the blood of chickens.

Synergistic effect of copper and arsenic upon oxidative stress, inflammation and autophagy alterations in brain tissues of Gallus gallus

Arsenic or copper is one of the most highly toxic pollution that can cause dysfunction to brains, however, the exact mechanism remains unclear. The aim of the study is to investigate the mechanisms of arsenic or/and copper-induced oxidative stress, inflammation and autophagy in chicken brains and elucidate the interactions between arsenic and copper. A total of 72 1-day-old Hy-line chickens were divided into four groups (18 chickens per group) treated with 30mg/kg arsenic trioxide (As₂O₃) or/and 300mg/kg copper sulfate (CuSO₄) for 12weeks. Histological signs of inflammation were found in the cerebrum, cerebellum and brainstem exposure to arsenic or/and copper. The malondialdehyde (MDA) content were up-regulation, whereas oxidative damage parameters total antioxidant capacity (T-AOC), glutathione (GSH), the inhibition ability of hydroxyl radical (OH), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) were significantly decreased (P<0.05). The mRNA levels and protein expressions of inflammation markers, such as nuclear factor kappa B (NF-κB), tumor necrosis factor-α (TNF-α), cyclooxygenase-2 (COX-2) and prostaglandin E synthase (PTGEs) were significantly increased (P<0.05). The mRNA levels and protein expressions of autophagy markers including phosphatidylinositol 3-kinase (PI3K), Akt, autophagy-related gene 5 (ATG5), microtubule-associated protein light chains 3 (LC3), ATG4B, and Becline1 in different regions of brains were up-regulation (P<0.05), except the mammalian target of rapamycin complex (mTORC). In conclusion, we speculated that arsenic or copper could induce oxidative stress, inflammation and autophagy in chicken brains, and there may have a synergistic effect between copper and arsenic.

Differential toxicity of arsenic on renal oxidative damage and urinary metabolic profiles in normal and diabetic mice

Diabetes is a common metabolic disease, which might influence susceptibility of the kidney to arsenic toxicity. However, relative report is limited. In this study, we compared the influence of inorganic arsenic (iAs) on renal oxidative damage and urinary metabolic profiles of normal and diabetic mice. Results showed that iAs exposure increased renal lipid peroxidation in diabetic mice and oxidative DNA damage in normal mice, meaning different effects of iAs exposure on normal and diabetic individuals. Nuclear magnetic resonance (NMR)-based metabolome analyses found that diabetes significantly changed urinary metabolic profiles of mice. Oxidative stress-related metabolites, such as arginine, glutamine, methionine, and β-hydroxybutyrate, were found to be changed in diabetic mice. The iAs exposure altered amino acid metabolism, lipid metabolism, carbohydrate metabolism, and energy metabolism in normal and diabetic mice, but had higher influence on metabolic profiles of diabetic mice than normal mice, especially for oxidative stress-related metabolites and metabolisms. Above results indicate that diabetes increased susceptibility to iAs exposure. This study provides basic information on differential toxicity of iAs on renal toxicity and urinary metabolic profiles in normal and diabetic mice and suggests that diabetic individuals should be considered as susceptible population in toxicity assessment of arsenic.

Experimental Hypothyroidism Inhibits δ-Aminolevulinate Dehydratase Activity in Neonatal Rat Blood and Liver

The aim of this study was to investigate the potential relationship between hypothyroidism and δ-aminolevulinate dehydratase (δ-ALA-D) activity in rat blood and liver. Experimental hypothyroidism was induced in weanling rats by exposing their mothers to propylthiouracil (PTU) diluted in tap water (0.05% w/ v), ad libitum, during the lactational period (PTU group). Control (euthyroid) group included weanling rats whose mothers received just tap water, ad libitum, during the lactational period. Reverted-hypothyroid group (PTU + 3,3′,5-triiodo-L-thyronine [T3]) included weanling rats whose mothers were exposed to PTU similarly to those in the hypothyroid group, but pups received daily subcutaneous injections of T3(20 μg/kg, from Postnatal Days 2–20). After the treatment, serum T3levels were drastically decreased (around 70%) in the PTU group, and this phenomenon was almost reverted by exogenous T3. PTU decreased blood δ-ALA-D activity by 75%, and T3treatment prevented such phenomena. Erythrocytes and hemoglobin levels were increased by 10% in PTU-treated animals and higher increments (around 25%) were observed in these parameters when exogenous T3was coadministered. Dithiothreitol did not change blood δ-ALA-D activity of PTU-exposed animals when present in the reaction medium, suggesting no involvement of the enzyme’s essential thiol groups in PTU-induced δ-ALA-D inhibition. PTU did not affect blood δ-ALA-D activity in vitro. These results are the first to show a correlation between hypothyroidism and decreased δ-ALA-D activity and point to this enzyme as a potential molecule involved with hypothyroidism-related hematological changes.

N-acetylcysteine and meso-2,3-dimercaptosuccinic acid alleviate oxidative stress and hepatic dysfunction induced by sodium arsenite in male rats

Environmental exposure to arsenic represents a serious challenge to humans and other animals. The aim of the present study was to test the protective effect of antioxidant N-acetylcysteine (NAC) either individually or in combination with a chelating agent, meso-2,3-dimercaptosuccinic acid (DMSA), against sodium arsenite oral toxicity in male rats. Five groups were used: control; arsenic group (orally administrated in a concentration of 2 mg/kg body weight [b.w.]); the other three groups were orally administrated sodium arsenite in a concentration of 2 mg/kg b.w. followed by either NAC (10 mg/kg b.w., intraperitoneally [i.p.]), DMSA (50 mg/kg b.w., i.p.) or NAC plus DMSA. Arsenic toxicity caused significant rise in serum aspartate aminotransferase, alanine aminotransferase and total bilirubin, and a significant decrease in total protein (TP) and albumin levels after 3 weeks of experimental period. In addition, arsenic-treated rats showed significantly higher arsenic content in liver and significant rise in hepatic malondialdehyde level. By contrast, sharp decreases in glutathione content and catalase and glutathione reductase activities were discernible. NAC and/or DMSA counteracted most of these physiologic and biochemical defects. NAC monotherapy was more effective than DMSA in increasing TP, while DMSA was more effective in decreasing alanine aminotransferase. The combined treatment was superior over monotherapies in recovery of TP and glutathione. Biochemical data were well supported by histopathological and ultrastructural findings. In conclusion, the combination therapy of NAC and DMSA may be an ideal choice against oxidative insult induced by arsenic poisoning.

Arsenic and dichlorvos: Possible interaction between two environmental contaminants

Metals are ubiquitously present in the environment and pesticides are widely used throughout the world. Environmental and occupational exposure to metal along with pesticide is an area of great concern to both the public and regulatory authorities. Our major concern is that combination of these toxicant present in environment may elicit toxicity either due to additive or synergistic interactions or 'joint toxic actions' among these toxicants. It poses a rising threat to human health. Water contamination particularly ground water contamination with arsenic is a serious problem in today's scenario since arsenic is associated with several kinds of health problems, such arsenic associated health anomalies are commonly called as 'Arsenism'. Uncontrolled use and spillage of pesticides into the environment has resulted in alarming situation. Moreover serious concerns are being addressed due to their persistence in the environmental matrices such as air, soil and surface water runoff resulting in continuous exposure of these harmful chemicals to human beings and animals. Bio-availability of these environmental toxicants has been enhanced much due to anthropological activities. Dreadfully very few studies are available on combined exposures to these toxicants on the animal or human system. Studies on the acute and chronic exposure to arsenic and DDVP are well reported and well defined. Arsenic is a common global ground water contaminant while dichlorvos is one of the most commonly and widely employed organophosphate based insecticide used in agriculture, horticulture etc. There is thus a real situation where a human may get exposed to these toxicants while working in a field. This review highlights the individual and combined exposure to arsenic and dichlorvos on health.

Neurological Toxicity of Individual and Mixtures of Low Dose Arsenic, Mono and Di (n-butyl) Phthalates on Sub-Chronic Exposure to Mice

The objective of this study was to evaluate the toxicity of individual and mixtures of di(n-butyl) phthalates (DBP) and their active metabolite monobutyl phthalate (MBP) and arsenic (As) on spatial cognition associated with hippocampal apoptosis in mice. Mice were exposed, individually or in combination, to DBP (50 mg/kg body weight, intragastrically), MBP (50 mg/kg body weight, intragastrically), and As (10 mg/L, per os) for 8 weeks. The Morris water maze test showed that mice exposed to DBP/MBP combined with As exhibited longer escape latencies and the lower average number of crossing the platform. The As content in the hippocampus after As exposure increased as compared to those without As exposure. In mice exposed to DBP/MBP combined with As, pathological alterations and oxidative damage to the hippocampus were found. Expression of apoptosis-related protein: Bax and caspase-3 were significantly increased in the hippocampus, while there was no significant change in expression of Bcl-2. The results suggested that DBP and MBP combined with As can induce spatial cognitive deficits through altering the expression of apoptosis-related protein and As played a critical role in cognition impairments. And the joint exposure has antagonistic effect.