Toxicity of inorganic arsenic to animals and its treatment strategies.

In nature, arsenic is mostly found in the form of inorganic compounds. Inorganic arsenic compounds have a variety of uses and are currently used in the manufacture of pesticides, preservatives, pharmaceuticals, etc. While inorganic arsenic is widely used, arsenic pollution is increasing worldwide. Public hazards caused by arsenic contamination of drinking water and soil are becoming increasingly evident. Epidemiological and experimental studies have linked inorganic arsenic exposure to the development of many diseases, including cognitive impairment, cardiovascular failure, cancer, etc. Several mechanisms have been proposed to explain the effects caused by arsenic, such as oxidative damage, DNA methylation, and protein misfolding. Understanding the toxicology and potential molecular mechanisms of arsenic can help mitigate its harmful effects. Therefore, this paper reviews the multiple organ toxicity of inorganic arsenic in animals, focusing on the various toxicity mechanisms of arsenic-induced diseases in animals. In addition, we have summarized several drugs that can have therapeutic effects on arsenic poisoning in pursuit of reducing the harm of arsenic contamination from different pathways.

Dimercaptosuccinic Acid: Summary of Evidence.

Dimercaptosuccinic acid, or succimer, is an oral, heavy-metal chelating agent used to treat lead and heavy-metal poisoning. Although the drug is mainly used for the treatment of lead intoxication, initial data has shown encouraging results for the treatment of mercury and arsenic poisoning as well. This article focuses on the use of dimercaptosuccinic acid as a chelating agent and provides some general information on dimercaptosuccinic acid.

Flavonoids and stilbenoids as a promising arsenal for the management of chronic arsenic toxicity.

Rapid industrial and technological development has impacted ecosystem homeostasis strongly. Arsenic is one of the most detrimental environmental toxins and its management with chelating agents remains a matter of concern due to associated adverse effects. Thus, safer and more effective alternative therapy is required to manage arsenic toxicity. Based on existing evidence, native and indigenous plant-based active biomolecules appear as a promising strategy to mitigate arsenic-induced toxicity with an acceptable safety profile. In this regard, various phytochemicals (flavonoids and stilbenoids) are considered important classes of polyphenolic compounds with antioxidant and chelation effects, which may facilitate the removal of arsenic from the body more effectively and safely with regard to conventional approaches. This review presents an overview of conventional chelating agents and the potential role of flavonoids and stilbenoids in ameliorating arsenic toxicity. This report may provide a roadmap for identifying novel prophylactic/therapeutic strategies for managing arsenic toxicity.

Chemistry, Pharmacology, and Toxicology of Monoisoamyl Dimercaptosuccinic Acid: A Chelating Agent for Chronic Metal Poisoning.

Arsenic, a metalloid, is known to cause deleterious effects in various body organs, particularly the liver, urinary bladder, and brain, and these effects are primarily mediated through oxidative stress. Chelation therapy has been considered one of the promising medical treatments for arsenic poisoning. Meso 2,3- dimercaptosuccinic acid (DMSA) has been recognized as one of the most effective chelating drugs to treat arsenic poisoning. However, the drug is compromised with a number of shortcomings, including the inability to treat chronic arsenic poisoning due to its extracellular distribution. Monoisoamyl 2,3-dimercaptosuccinic acid, one of the analogues of meso 2,3-dimeraptosuccinic acid (DMSA), is a lipophilic chelator and has shown promise to be considered as a potential future chelating agent/antidote not only for arsenic but also for a few other heavy metals like lead, mercury, cadmium, and gallium arsenide. The results from numerous studies carried out in the recent past, mainly from our group, strongly support the clinical application of MiADMSA. This review paper summarizes most of the scientific details including the chemistry, pharmacology, and safety profile of MiADMSA. The efficacy of MiADMSA mainly against arsenic toxicity but also a few other heavy metals was also discussed. We also reviewed a few other strategies in order to achieve the optimum effects of MiADMSA, like combination therapy using two chelating agents or coadministration of a natural and synthetic antioxidant (including phytomedicine) along with MiADMSA for treatment of metal/metalloid poisoning. We also briefly discussed the use of nanotechnology (nano form of MiADMSA i.e. nano-MiADMSA) and compared it with bulk MiADMSA. All these strategies have been shown to be beneficial in getting more pronounced therapeutic efficacy of MiADMSA, as an adjuvant or as a complementary agent, by significantly increasing the chelating efficacy of MiADMSA.

Natural Dietary Compounds in the Treatment of Arsenic Toxicity.

Chronic exposure to arsenic (As) compounds leads to its accumulation in the body, with skin lesions and cancer being the most typical outcomes. Treating As-induced diseases continues to be challenging as there is no specific, safe, and efficacious therapeutic management. Therapeutic and preventive measures available to combat As toxicity refer to chelation therapy, antioxidant therapy, and the intake of natural dietary compounds. Although chelation therapy is the most commonly used method for detoxifying As, it has several side effects resulting in various toxicities such as hepatotoxicity, neurotoxicity, and other adverse consequences. Drugs of plant origin and natural dietary compounds show efficient and progressive relief from As-mediated toxicity without any particular side effects. These natural compounds have also been found to aid the elimination of As from the body and, therefore, can be more effective than conventional therapeutic agents in ameliorating As toxicity. This review provides an overview of the recently updated knowledge on treating As poisoning through natural dietary compounds. This updated information may serve as a basis for defining novel prophylactic and therapeutic formulations.

Phytochemicals in the Management of Arsenic Toxicity.

Arsenic toxicity is a major concern due to its deleterious consequences for human health. Rapid industrialization also has weakened the quality of the environment by introducing pollutants that may disrupt balanced ecosystems, adversely and irreversibly impacting humans, plants, and animals. Arsenic, an important toxicant among all environmental hazards, can lead to several detrimental effects on cells and organs, impacting the overall quality of life. Nevertheless, arsenic also has a rich history as a chemotherapeutic agent used in ancient days for the treatment of diseases such as malaria, cancer, plague, and syphilis when other chemotherapeutic agents were yet to be discovered. Arsenicosis-mediated disorders remain a serious problem due to the lack of effective therapeutic options. Initially, chelation therapy was used to metabolically eliminate arsenic by forming a complex, but adverse effects limited their pharmacological use. More recently, plant-based products have been found to provide significant relief from the toxic effects of arsenic poisoning. They act by different mechanisms affecting various cellular processes. Phytoconstituents such as curcumin, quercetin, diallyl trisulfide, thymoquinone, and others act via various molecular pathways, primarily by attenuating oxidative damage, membrane damage, DNA damage, and proteinopathies. Nonetheless, most of the phytochemicals reviewed here protect against the adverse effects of metal or metalloid exposure, supporting their consideration as alternatives to chelation therapy. These agents, if used prophylactically and in conjunction with other chemotherapeutic agents, may provide an effective approach for management of arsenic toxicity. In a few instances, such strategies like coadministration of phytochemicals with a known chelating agent have led to more pronounced elimination of arsenic from the body with lesser off-site adverse effects. This is possible because combination treatment ensures the use of a reduced dose of chelating agent with a phytochemical without compromising treatment. Thus, these therapies are more practical than conventional therapeutic agents in ameliorating arsenic-mediated toxicity. This review summarizes the potential of phytochemicals in alleviating arsenic toxicity on the basis of available experimental and clinical evidence.

Polyphenolics with Strong Antioxidant Activity from Acacia nilotica Ameliorate Some Biochemical Signs of Arsenic-Induced Neurotoxicity and Oxidative Stress in Mice.

Neurotoxicity is a serious health problem of patients chronically exposed to arsenic. There is no specific treatment of this problem. Oxidative stress has been implicated in the pathological process of neurotoxicity. Polyphenolics have proven antioxidant activity, thereby offering protection against oxidative stress. In this study, we have isolated the polyphenolics from Acacia nilotica and investigated its effect against arsenic-induced neurotoxicity and oxidative stress in mice. Acacia nilotica polyphenolics prepared from column chromatography of the crude methanol extract using diaion resin contained a phenolic content of 452.185 ± 7.879 mg gallic acid equivalent/gm of sample and flavonoid content of 200.075 ± 0.755 mg catechin equivalent/gm of sample. The polyphenolics exhibited potent antioxidant activity with respect to free radical scavenging ability, total antioxidant activity and inhibition of lipid peroxidation. Administration of arsenic in mice showed a reduction of acetylcholinesterase activity in the brain which was counteracted by Acacia nilotica polyphenolics. Similarly, elevation of lipid peroxidation and depletion of glutathione in the brain of mice was effectively restored to normal level by Acacia nilotica polyphenolics. Gallic acid methyl ester, catechin and catechin-7-gallate were identified in the polyphenolics as the major active compounds. These results suggest that Acacia nilotica polyphenolics due to its strong antioxidant potential might be effective in the management of arsenic induced neurotoxicity.

Effect of Selenium on Brain Injury in Chickens with Subacute Arsenic Poisoning.

The aim of this study was to investigate the effects of different doses of selenium (Se) on oxidative damage and neurotransmitter-related parameters in arsenic (As)-induced broiler brain tissue damage. Two hundred 1-day-old avian broilers were randomly divided into five groups and fed the following diets: control group (As 0.1 mg/kg + Se 0.2 mg/kg), As group (As 3 mg/kg + Se 0.2 mg/kg), low-Se group (As 3 mg/kg + Se 5 mg/kg), medium-Se group (As 3 mg/kg + Se 10 mg/kg), and high-Se group (As 3 mg/kg + Se 15 mg/kg). Glutathione (GSH), glutathione peroxidase (GSH-PX), nitric oxide (NO), nitric oxide synthase (NOS) activity, glutamate (Glu) concentration, glutamine synthetase (GS) activity, acetylcholinesterase (TchE) activity, and the apoptosis rate of brain cells were measured. The results showed that 3 mg/kg dietary As could induce oxidative damage and neurotransmitter disorder of brain tissue, increase the apoptosis rate of brain cells and cause damage to brain tissue, decrease activities of GSH and GSH-PX, decrease the contents of NO, decrease the activities of iNOS and tNOS, increase contents of Glu, and decrease activities of Gs and TchE. Compared with the As group, the Se addition of the low-Se and medium-Se groups protected against As-induced oxidative damage, neurotransmitter disorders, and the apoptosis rate of brain cells, with the addition of 10 mg/kg Se having the best effect. However, 15 mg/kg Se not only did not produce a protective effect against As damage but actually caused similar or severe damage.

Chemopreventive Role of Black Tea Extract in Swiss Albino Mice Exposed to Inorganic Arsenic.

OBJECTIVE: Chronic exposure to inorganic arsenic (iAs) may cause a number of health problems including skin cancer. Present study is aimed to look into the potential of black tea extract (BTE) to prevent the development of skin carcinoma in Swiss albino mice. METHODS: The study was done on Swiss albino mice, chronically exposed to inorganic arsenic. 150 mice were housed in different cages, 5 in each cage. The control mice did not receive any treatment. Mice were sacrificed at 30, 90, 180, 270 and 330 days. Development of carcinogenesis was assessed by histological studies. Generation of Reactive Oxygen Species (ROS) and Reactive Oxygen Species (RNS) were estimated using 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA) and Greiss reagent respectively, and their consequences on DNA (by Micronuclei and Comet assay), protein (by protein carbonyl assay kit) and lipid (by lipid peroxidation) were estimated. Activity of antioxidant enzymes, along with total antioxidant capacity were measured by respective kits. Repair percentage was obtained by Comet assay. Western blotting was employed to study the expression of repair enzymes and expression of cytokines. Sandwich Enzyme-linked Immunosorbent Assay (ELISA) technique was employed to study the activity of various cytokines. RESULTS: At 330 days, invasive squamous cell carcinoma of the skin developed. With increasing time generation of ROS and RNS increased, causing damage to DNA, protein and lipid. Antioxidant defence system gets repressed with time. Capacity to repair the DNA damage is inhibited by iAs, due to alteration in repair enzymes - XRCC I, DNA Ligase I, PARP I, ERCC1, ERCC2, XPA, DNA Ligase IV, DNA PKc and Ku-70. Another consequence of iAs exposure is chronic inflammation due to disrupted cytokine level. Intervention with BTE reverses these deleterious effects, preventing development of skin carcinogenesis.

Melatonin: a pleiotropic hormone as a novel potent therapeutic candidate in arsenic toxicity.

BACKGROUND: Arsenic is a natural element which exists in the environment in inorganic and organic forms. In humans, the main reason for the toxicity of arsenic is its uptake via water sources. As polluted water and the problems associated with it can be found in many countries. Therefore, considering all these positive effects of melatonin, this review is aimed at melatonin supplementation therapy on arsenic toxicity which seems to be a suitable therapeutic agent to eliminate the adverse effects of arsenic. METHODS AND RESULTS: It is seen in previous studies that chronic exposure to arsenic could cause serious dys functions of organs and induce different degrees of toxicities that is one of the first hazardous materials in the classification of substances by the United States Environmental Protection Agency so leads to costly cleanup operations burdening the economy. Arsenic harmfulness degree depends on the bioavailability, chemical form, valence state, detoxification, and metabolism of human body. The oxidative stress has a major role in arsenic-induced toxicity; on the other hand, it was discovered that melatonin is a powerful scavenger for free radical and it's an extensive-spectrum antioxidant. CONCLUSION: Due to its highly lipophilic and small size properties, melatonin accesses all intracellular organs by easily passing via the cell membrane and prevents protein, DNA damage, and lipid peroxidation. In particular, melatonin, by protecting and reducing oxidative stress in mitochondria, can normalize homeostasis and mitochondrial function and ultimately prevent apoptosis and cell death.

Assessing the potential value and mechanism of Ginkgo biloba L. On coal-fired arsenic-induced skin damage: In vitro and human evidence.

Exposure through arsenic-contaminated air and food caused by the burning of coal is a major environmental public health concern in Guizhou Province of China. Previous studies have shown that immunological dysfunction is involved in the pathogenesis and carcinogenesis of arsenic; however, knowledge regarding effective prevention measures have not been fully examined. The effect of Ginkgo biloba extract (EGb761) on arsenic-induced skin damage of human immortalized keratinocyte cells (HaCaT) was first evaluated in this study. The results showed that 200 µg/mL EGb761 can reduce the expression of miR-155-5p, and the indicators reflecting arsenic-induced skin damage (Krt1, Krt6c and Krt10) in arsenic-exposed cells (P < 0.05), the expression levels of NF-AT1; the indicators reflecting arsenic-induced immunological dysfunction (IL-2, IFN-γ) in cells; and the levels of secreted IL-2 and IFN-γ in cell supernatants were significantly increased (P < 0.05). Further randomized controlled double-blind experiments showed that compared to the placebo control group, the expression level of miR-155-5p in the plasma of the Ginkgo biloba intervention group, the indicators in the serum reflecting arsenic-induced skin damage (Krt1, Krt6c, and Krt10) and the epithelial-mesenchymal transformation (EMT) vimentin were significantly reduced (P < 0.05), but the levels of NF-AT1 and the indicators reflecting arsenic-induced immunological dysfunction (IL-2, IFN-γ) and EMT (E-cadherin) in serum were significantly increased (P < 0.05). Our study provides some limited evidence that Ginkgo biloba L. can increase the expression of NF-AT1 by downregulating the level of miR-155-5p, alleviating immunological dysfunction, and decreasing the expression of EMT biomarkers, thus indirectly improving arsenic-induced skin damage.

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.

Role of inhibiting Chk1-p53 pathway in hepatotoxicity caused by chronic arsenic exposure from coal-burning.

Arsenic is a naturally occurring environmental toxicant, chronic exposure to arsenic can cause multiorgan damage, except for typical skin lesions, liver damage is the main problem for health concern in population with arsenic poisoning. Abnormal apoptosis is closely related to liver-related diseases, and p53 is one of the important hallmark proteins in apoptosis progression. This study was to investigate whether arsenic poisoning-induced hepatocyte apoptosis and the underlying role of p53 signaling pathway. A rat model of arsenic poisoning was established by feeding corn powder for 90 days, which was baked with high arsenic coal, then were treated with Ginkgo biloba extract (GBE) for 45 days by gavage. The results showed that arsenic induced liver damage, increased hepatocyte apoptosis and elevated the expression level of Chk1 and the ratios of p-p53/p53 and Bax/Bcl-2 in liver tissues, which were significantly attenuated by GBE. Additionally, to further demonstrate the potential apoptosis-associated mechanism, L-02 cells were pre-incubated with p53 inhibitor pifithrin-α (PFTα), ataxia telangiectasia-mutated (ATM)/ataxia telangiectasia-mutated and Rad3-related (ATR) inhibitor (CGK733) or GBE, then treated with sodium arsenite (NaAsO2) for 24 h. The results showed that GBE, PFTα or CGK733 significantly reduced arsenic-induced Chk1 expression and the ratios of p-p53/p53 and Bax/Bcl-2. In conclusion, Chk1-p53 pathway was involved in arsenic poisoning-induced hepatotoxicity, and inhibiting of Chk1-p53 pathway ameliorated hepatocyte apoptosis caused by coal-burning arsenic poisoning. The study provides a pivotal clue for understanding of the mechanism of arsenic poisoning-induced liver damage, and possible intervention strategies.

Effects of Selenium on the Immunotoxicity of Subacute Arsenic Poisoning in Chickens.

This study aimed to determine the effects of selenium on the immune toxicity of subacute arsenic poisoning in chickens. Two hundred 8-day-old broilers were randomly divided into 5 groups: the control group (0.1 mg/kg As + 0.2 mg/kg Se), the 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). The conclusions were drawn based on the following measurements: 3.0 mg/kg added to feed led to a decrease in the growth performance of the broilers, reduced the level and conversion rate of ANAE, reduced the blood protein content of the broilers but had no effect on the albumin/globulin ratio, and had an inhibitory effect on erythrocyte immunity. Selenium-added of 5 and 10 mg/kg in daily feed leads to increased growth performance, increases the positive rate and conversion rate of ANAE, increases the hemoglobin content of broilers, and promotes erythrocyte immunity, which indicates that the selenium-added reduces the toxic effects of arsenic; 3.0 mg/kg arsenic with 15 mg/kg selenium had the most severe toxic effects. Fifteen milligrams per kilogram of selenium added in daily feed increases the toxicity of arsenic to broilers. The dose of 10 mg/kg selenium showed the best inhibitory effect on subacute arsenic poisoning in the broilers.

Curcumin Has Protective Effect on the Eye Lens Against Arsenic Toxicity.

Arsenic is a highly carcinogenic environmental contaminant. Curcumin, the bioactive component of turmeric, exhibits therapeutic efficacy against several chronic inflammatory and infectious diseases. The present study was carried out to investigate the impact of arsenic on eye lens and evaluate the ameliorative potential of curcumin against arsenic toxicity. Gene expression analysis of α, ß, and γ-crystallins and fatty acid profile of lens tissues of arsenic-exposed Labeo rohita was examined and the protective effect of curcumin as diet supplement was evaluated. Curcumin-supplemented diet was prepared at 1.5% and 3% and fed to four groups of fish for 7 days prior to arsenic exposure (at 5 ppm and 15 ppm) for 15 days. Gene expression analysis showed downregulation of α and ß-crystallins in the eye lens of arsenic-exposed groups (fed basal diet), whereas the groups fed a curcumin-supplemented diet showed insignificant alterations. Similarly, fatty acid fingerprint of lens lipids arsenic-exposed group exhibited reduction in saturated fatty acid and docosahexaenoic acid (DHA) content. However, in 3% curcumin-supplemented diet-fed and arsenic exposed group group, fatty acid profile remained unchanged. Interestingly, concentration of one non-fatty acid, an antioxidant compound (phenol 2,4-bis 1,1 dimethyl; PD) that was identified in the GC-MS fingerprinting through NIST library (version 2.2, 2014), decreased in response to arsenic exposure which was restored to normal level in curcumin-supplemented groups proving the therapeutic potential of curcumin. The findings of the study suggest that curcumin has a protective effect on eye lens against arsenic toxicity.

Ameliorative effects and mechanism of crocetin in arsenic trioxide­induced cardiotoxicity in rats.

Arsenic trioxide (ATO) is commonly used to treat patients with acute promyelocytic leukemia since it was authorized by the U.S. Food and Drug Administration in the 1970s, but its applicability has been limited by its cardiotoxic effects. Therefore, the aim of the present study was to investigate the cardioprotective effects and underlying mechanism of crocetin (CRT), the critical ingredient of saffron. Sprague­Dawley rats were then randomly divided into four groups (n=10/group): i) Control group; ii) ATO group, iii) CRT­low (20 mg/kg) group; and iv) CRT­high (40 mg/kg) group. Rats in the Control and ATO groups were intraperitoneally injected with equal volumes of 0.9% sodium chloride solution, and CRT groups were administered with either 20 and 40 mg/kg CRT. Following 6 h, all groups except the Control group were intraperitoneally injected with 5 mg/kg ATO over 10 days. Cardiotoxicity was indicated by changes in electrocardiographic (ECG) patterns, morphology and marker enzymes. Histomorphological changes in the heart tissue were observed by pathological staining. The levels of superoxide dismutase, glutathione peroxidase, malondialdehyde and catalase in the serum were analyzed using colometric commercial assay kits, and the levels of reactive oxygen species in the heart tissue were detected using the fluorescent probe dihydroethidium. The expression levels of inflammatory factors and activities of apoptosis­related proteins were analyzed using immunohistochemistry. The protein expression levels of silent information regulator of transcription 1 were measured using western blotting. Cardiotoxicity was induced in male Sprague­Dawley rats with ATO (5 mg/kg). CRT (20 and 40 mg/kg) and ATO were co­administered to evaluate possible cardioprotective effects. CRT significantly reduced the heart rate and J­point elevation induced by ATO in rats. Histological changes were evaluated via hematoxylin and eosin staining. CRT decreased the levels of creatine kinase and lactate dehydrogenase, increased the activities of superoxide dismutase, glutathione­peroxidase and catalase, and decreased the levels of malondialdehyde and reactive oxygen species. Moreover, CRT downregulated the expression levels of the pro­inflammatory factors IL­1, TNF­α, IL­6, Bax and p65, as well as increased the expression of Bcl­2. It was also identified that CRT enhanced silent information regulator of transcription 1 protein expression. Thus, the present study demonstrated that CRT treatment effectively ameliorated ATO­induced cardiotoxicity. The protective effects of CRT can be attributed to the inhibition of oxidative stress, inflammation and apoptosis. Therefore, CRT represents a promising therapeutic method for improving the cardiotoxic side effects caused by ATO treatment, and additional clinical applications are possible, but warrant further investigation.

Comparative efficacy of Nano and Bulk Monoisoamyl DMSA against arsenic-induced neurotoxicity in rats.

Chelation therapy is considered as a safe and effective strategy to combat metal poisoning. Arsenic is known to cause neurological dysfunctions such as impaired memory, encephalopathy, and peripheral neuropathy as it easily crosses the blood-brain barrier. Oxidative stress is one of the mechanisms suggested for arsenic-induced neurotoxicity. We prepared Solid Lipid nanoparticles loaded with Monoisoamyl 2, 3-dimercaptosuccinic acid (Nano-MiADMSA), and compared their efficacy with bulk MiADMSA for treating arsenic-induced neurological and other biochemical effects. Solid lipid nanoparticles entrapping MiADMSA were synthesized and particle characterization was carried out by transmission electron microscopy (TEM) and dynamic light scattering (DLS). An in vivo study was planned to investigate the therapeutic efficacy of MiADMSA-encapsulated solid lipid nanoparticles (Nano-MiADMSA; 50 mg/kg orally for 5 days) and compared it with bulk MiADMSA against sodium meta-arsenite exposed rats (25 ppm in drinking water, for 12 weeks) in male rats. The results suggested the size of Nano-MiADMSA was between 100-120 nm ranges. We noted enhanced chelating properties of Nano-MiADMSA compared with bulk MiADMSA as evident by the reversal of oxidative stress variables like blood δ-aminolevulinic acid dehydratase (δ-ALAD), Reactive Oxygen Species (ROS), Catalase activity, Superoxide Dismutase (SOD), Thiobarbituric Acid Reactive Substances (TBARS), Reduced Glutathione (GSH) and Oxidized Glutathione (GSSG), Glutathione Peroxidase (GPx), Glutathione-S-transferase (GST) and efficient removal of arsenic from the blood and tissues. Recoveries in neurobehavioral parameters further confirmed nano-MiADMSA to be more effective than bulk MiADMSA. We conclude that treatment with Nano-MiADMSA is a better therapeutic strategy than bulk MiADMSA in reducing the effects of arsenic-induced oxidative stress and associated neurobehavioral changes.

Phytoremedial effect of Tinospora cordifolia against arsenic induced toxicity in Charles Foster rats.

Arsenic poisoning is one of the most serious health hazards of recent times. It has been estimated that more than 200 million people of about 105 countries in the world are affected due to arsenic poisoning. Except mitigation, there is no such mode by which the population can be prevented from being exposed to arsenic. Tinospora cordifolia (T. cordifolia) is widely used in the folk medicine system for the treatment of various diseases. Hence, the aim of the present study was to investigate the antidote effects of ethanolic extract of T. cordifolia stem against arsenic induced hepato-renal toxicity in rat model. Twenty-four male Charles Foster rats (weighing 160-180 g) were randomly divided into two groups, where six rats were used as control group. Eighteen rats were orally treated with arsenic at the dose of 8 mg/kg body weight for 90 days daily and then further divided into three sub groups (n = 6 each). Sub group I-arsenic treated rats, were sacrificed after treatment; sub group II rats were used as arsenic control and the sub group III rats were administrated with T. cordifolia at the dose of 400 mg/kg body weight/day for 90 days. After the completion of dose duration, all the control and treatment group rats were sacrificed to evaluate the various parameters. Arsenic induced rats had significantly (p < 0.0001) altered biochemical serum levels of SGPT, SGOT, ALP, total bilirubin, urea, uric acid, creatinine and albumin; But, after the administration of T. cordifolia there was significant (p < 0.0001) restoration observed in these liver and kidney function parameters. The T. cordifolia administration also significantly (p < 0.0001) restored the serum MDA levels and arsenic concentration in blood, liver and kidney tissues, as well as significant (p < 0.0001) improvement in haematological variables. In histopathological study, the arsenic treated rats showed degenerative changes in the liver and kidney tissues such as lesions and vacuolizations in hepatocytes and nephrocytes respectively. However, after the administration with T. cordifolia rats, there was considerably significant restoration in liver and kidney tissues. The entire study suggests that arsenic caused severe damage to the liver and kidney at haematological, biochemical and histopathological levels in rats. However, T. cordifolia played the vital role to combat the arsenic induced toxicity in rats. Hence, T. cordifolia might be used as a nutritional supplement to combat the arsenic led toxicity among the exposed population.

A strategy for repression of arsenic toxicity through nuclear factor E2 related factor 2 activation mediated by the (E)-2-alkenals in Coriandrum sativum L. leaf extract.

Activation of the Kelch-like ECH-associated protein 1 (Keap1)/nuclear factor E2 related factor 2 (Nrf2) system plays a role in repression of xenobiotic toxicity. The Coriandrum sativum L. leaf extract (CSLE) contains various aliphatic electrophiles such as (E)-2-decenal and (E)-2-dodecenal. In the present study, we examined the activation of Nrf2 coupled to chemical modification of Keap1 mediated by (E)-2-alkenals in CSLE, and the protective role of CSLE and (E)-2-alkenals against inorganic arsenite (iAsIII) cytotoxicity. Ultra-performance liquid chromatography-elevated collision energy mass spectrometry analysis revealed that (E)-2-decenal modified recombinant Keap1 at Cys241, Cys249, Cys257 and His274. Exposure of HepG2 cells to CSLE, (E)-2-decenal, or (E)-2-dodecenal upregulated Nrf2-related downstream signaling such as expression of phase-II xenobiotic-metabolizing enzymes and phase-III transporters involved in cytoprotection against iAsIII. Pretreatment with CSLE or (E)-2-butenal, a prototype of (E)-2-alkenal, prior to iAsIII exposure suppressed accumulation of iAsIII significantly and reduced iAsIII-induced cytotoxicity in cells. Oral administration of CSLE to C57BL/6 mice upregulated downstream proteins of Nrf2 and reduced accumulation of arsenic in liver tissue. The present study indicates that CSLE containing (E)-2-alkenals activates Nrf2, leading to a reduction in arsenic accumulation in vivo.

Counteracting arsenic toxicity: Curcumin to the rescue?

Arsenicosis leads to various irreversible damages in several organs and is considered to be a carcinogen. The effects of chronic arsenic poisoning are a result of an imbalance between pro- and antioxidant homeostasis, oxidative stress, as well as DNA and protein damage. Curcumin, the polyphenolic pigment extracted from the rhizome of Curcuma longa, is well-known for its pleiotropic medicinal effects. Curcumin has been shown to have ameliorative effects in arsenic-induced genotoxicity, nephrotoxicity, hepatotoxicity, angiogenesis, skin diseases, reproductive toxicity, neurotoxicity, and immunotoxicity. This review aims to summarize the scientific evidence on arsenic toxicity in various organs and the ameliorative effects of curcumin on the arsenic toxicity.