Investigating the protective actions of D-pinitol against arsenic-induced toxicity in PC12 cells and the underlying mechanism

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.

Morin attenuates arsenic-induced toxicity in 3T3 embryonic fibroblast cells by suppressing oxidative stress, inflammation, and apoptosis: In vitro and silico evaluations

This study aims to investigate the curative effects of Morin, a flavonoid, against arsenic toxicity in 3T3 embryonic fibroblast cells and its effect on the molecular mechanisms of cells. The cytotoxicity and viability of the cells were measured by MTT and LDH tests. Arsenic (0.74 μM) was used to trigger toxicity and Morin (50 μM) was used for treatment. The levels of oxidative stress biomarkers and the activities of antioxidant enzymes were measured by spectrophotometric method, and inflammatory markers were measured by ELISA method. While mRNA expression levels of Bax, Bcl-2 levels, and Caspase-3 activity were measured by qRT-PCR technique, TUNEL staining was performed to detect DNA breaks and DAPI staining to visualize nuclear changes. Protein structures were retrieved from the protein data bank. OpenBabel and Autodock programs were used for the molecular docking study. Morin rescued the 3T3 embryonic fibroblast cells exposed to arsenic. However, Arsenic decreased the activities of antioxidant enzymes in cells and significantly increased oxidative stress, inflammation, and apoptosis. Morin treatment reduced oxidative damage and TNF-α and IL-1β levels. Arsenic-induced Caspase-3 mRNA expression level and Bax protein mRNA expression level were significantly increased, while Bcl-2 mRNA expression level was significantly decreased. While Caspase-3 mRNA expression level and Bax protein mRNA expression level decreased with morin treatment, Bcl-2 mRNA expression level increased significantly. Molecular docking study results showed good binding affinity of morin in SOD, GSH-Px, Bax, Bcl-2, Caspase-3, TNF-α, and IL-1β structures. Morin showed antioxidant, anti-inflammatory, and anti-apoptotic effects against Arsenic-induced cellular toxicity.

The role of thioredoxin and glutathione systems in arsenic-induced liver injury in rats under glutathione depletion

Antioxidant systems like thioredoxin (Trx) and glutaredoxin (Grx) maintain oxidative stress balance. These systems have cross-talk supported by some in vitro studies. We investigated the underlying mechanisms of arsenic-induced liver injury in glutathione-deficient rats and whether there was any cross-talk between the Trx and Grx systems. The rats in arsenic-treated groups were administered with sodium arsenite (10, 20 mg/kg b w/d) for four weeks. In buthionine sulfoximine (BSO, an inhibitor of GSH) and 20 mg/kg arsenic combined groups, rats were injected with 2 mmol/kg BSO intraperitoneally twice per week. BSO exacerbated arsenic-induced liver injury by increasing arsenic accumulation in urine, serum, and liver while decreasing glutathione activity and resulting in upregulated mRNA expression of the Trx system and downregulation of Grx mRNA expression. The impact of Trx lasted longer than that of the Grx. The Trx system remained highly expressed, while GSH, Grx1, and Grx2 levels were decreased. The inhibitory effect of only BSO treatment on Grx1 and Grx2 was not pronounced. However, the combined impact of arsenic and BSO upregulated Trx expression, primarily related to further reduction of GSH. As a result, the suppressed Grxs were protected by the upregulated Trxs, which serve as a backup antioxidant defense system in the liver.

D-pinitol ameliorated H2O2-induced oxidative damage in PC12 cells and prolonged the lifespan by IIS pathway in Caenorhabditis elegans

D-pinitol (DP) has been extensively regarded as the main active component of legumes for anti-aging. In this study, we intended to explore the anti-aging mechanism of DP, utilizing computer modeling techniques. The results demonstrated that DP significantly delayed H2O2-induced cellular senescence. Model PC12 cells treated with DP exhibited increased cell viability, increased antioxidant enzyme activity (SOD, CAT), and reduced ROS and MDA levels. Furthermore, DP was discovered to have a positive effect on healthy longevity. In C. elegans, DP treatment enhanced lifespan, stress capacity, antioxidant capacity (T-SOD/CAT/GSH-Px/MDA/ROS), and altered aging-related indicators of lipofuscin accumulation, pharyngeal pump rate, motility, and reproduction. Moreover, DP could reduce the toxicity Aβ in transgenic C. elegans CL4176, CL2355, and CL2331. Further mechanistic studies indicated DP increased transcription factor (daf-16, skn-1, hsf-1) expression of insulin/insulin-like growth factor-1 signaling (IIS) pathway. As expected, DP also extended the downstream target genes of the three transcription factors (sod-3, ctl-1, ctl-2, gst-4, hsp-16.1, and hsp-16.2). Further mutant lifespan experiments, network pharmacology, and molecular docking revealed that DP might be life-extending through the IIS pathway. DP deserves extensive investigation and development as a potential anti-aging drug in the future.

The protective effect of apigenin against inorganic arsenic salt-induced toxicity in PC12 cells

Poisoning by arsenic affects people worldwide, and many human illnesses and health issues, including neurotoxicity, have been linked to chronic exposure to arsenic. When exposed to arsenic, the body produces intracellular reactive oxygen species (ROS), which influence a variety of alterations in cellular activity and directly harm molecules through oxidation. Arsenic-induced lesions are improved by antioxidants with the ability to lower ROS levels. Therefore, the current research aimed to assess how well apigenin protected PC12 cells from the toxicity caused by inorganic arsenic salt (iAs). For 24 and 48 h, iAs and/or apigenin were applied to PC12 cells. Then, oxidative stress indicators like malondialdehyde (MDA), nitric oxide (NO), and ROS in addition to the enzymatic and non-enzymatic antioxidant molecules such as catalase (CAT), glutathione (GSH), and superoxide dismutase (SOD) were assessed. Moreover, after exposure to iAs, PC12 was examined for nuclear factor erythroid 2-related factor 2 (Nrf2) expression to clarify how apigenin manifests its neuroprotection. Furthermore, NF-kB p65 concentration and IL-1B, IL-6, and TNF-α mRNA expression were measured to assess neuroinflammation. Bax, caspase-3, and Bcl-2 levels were measured to investigate apigenin's potential to protect PC12 cells from iAs poisoning. The obtained results revealed that, the cell survival rate in the iAs group was significantly lower (P < 0.05), and the number of viable cells steadily increased after apigenin treatment. Furthermore, the study found that iAs decreased GSH, CAT, and SOD in the PC12 cells while increasing ROS, MDA, and NO levels. In PC12 cells, the capacity of iAs to cause oxidative stress was linked to the induction of neuroinflammation and apoptosis. Interestingly, apigenin pre-treatment of PC12 cells resulted in exceptional protection against iAs-induced neuroinflammation, oxidative stress, and apoptotic cell death. Nrf2 upregulation in PC12 cells may explain the neuroprotection effect of apigenin against iAs toxicity. In conclusion, the obtained results of the present study have clinical significance and indicate that apigenin is a promising candidate for shielding the nervous system from toxic effects caused by arsenic. These findings require further investigation using in vivo experimental models.

Antihyperglycemic Properties of Extracts and Isolated Compounds from Australian Acacia saligna on 3T3-L1 Adipocytes

Our early work indicated that methanolic extracts from the flowers, leaves, bark, and isolated compounds of Acacia saligna exhibited significant antioxidant activities in vitro. The overproduction of reactive oxygen species (ROS) in the mitochondria (mt-ROS) interfered with glucose uptake, metabolism, and its AMPK-dependent pathway, contributing to hyperglycemia and diabetes. This study aimed to screen the ability of these extracts and isolated compounds to attenuate the production of ROS and maintain mitochondrial function via the restoration of mitochondrial membrane potential (MMP) in 3T3-L1 adipocytes. Downstream effects were investigated via an immunoblot analysis of the AMPK signalling pathway and glucose uptake assays. All methanolic extracts effectively reduced cellular ROS and mt-ROS levels, restored the MMP, activated AMPK-α, and enhanced cellular glucose uptake. At 10 µM, (-)-epicatechin-6 (from methanolic leaf and bark extracts) markedly reduced ROS and mt-ROS levels by almost 30% and 50%, respectively, with an MMP potential ratio 2.2-fold higher compared to the vehicle control. (-)-Epicatechin 6 increased the phosphorylation of AMPK-α by 43%, with an 88% higher glucose uptake than the control. Other isolated compounds include naringenin 1, naringenin-7-O-α-L-arabinopyranoside 2, isosalipurposide 3, D-(+)-pinitol 5a, and (-)-pinitol 5b, which also performed relatively well across all assays. Australian A. saligna active extracts and compounds can reduce ROS oxidative stress, improve mitochondrial function, and enhance glucose uptake through AMPK-α activation in adipocytes, supporting its potential antidiabetic application.

A review of mechanisms underlying the protective effects of natural compounds against arsenic-induced neurotoxicity

Arsenic (As) is a toxic metalloid that is widely distributed in the earth's crust. People are continuously exposed to this toxicant in their food and drinking water. Inorganic arsenic occurs in two oxidation states, arsenite 3⁺ (iAs³⁺) and arsenate 5⁺ (iAs⁵⁺). The most toxic form is its trivalent form which interferes with the electron transfer cycle and induces overproduction of reactive oxygen species, leading to depletion of the antioxidant defense system, as well as altering fatty acid levels and mitochondrial action. Since arsenic crosses the blood-brain barrier, it can damage cells in different regions of the brain, causing neurological disorders through the induction of oxidative stress, inflammation, DNA damage, and cell death. Hydroxytyrosol, taurine, alpha-lipoic acid, ellagic acid, and thymoquinone have been shown to effectively alleviate arsenic-induced neurotoxicity. The protective effects are the result of the anti-oxidative and anti-inflammatory properties of the phytochemicals and in particular their anti-apoptotic function via the Nrf2 and PI3/Akt/SIRT1 signaling pathways.

Alpha-mangostin Protects PC12 Cells Against Neurotoxicity Induced by Cadmium and Arsenic

Arsenic and cadmium are nonessential elements that are of importance in public health due to their high toxicity. Contact with these toxic elements, even in very small amounts, can induce various side effects, including neurotoxicity. Oxidative stress and apoptosis are part of the main mechanisms of arsenic- and cadmium-induced toxicity. Alpha-mangostin is the main xanthone derived from mangosteen, Garcinia mangostana, with anti-oxidative properties.In this study, PC12 cells were selected as a nerve cell model, and the protective effects of alpha-mangostin against neurotoxicity induced by arsenic and cadmium were investigated. PC12 cells were exposed to cadmium (5-80 µM) and arsenic (2.5-180 µM) for 24 h. Cytotoxicity, reactive oxygen species (ROS) production, and the protein expression of Bax, Bcl2, and cleaved caspase 3 were determined using MTT assay, fluorimetry, and western blot, respectively.Arsenic (10-180 µM) and cadmium (50-80 µM) significantly reduced cell viability. IC₅₀ values were 10.3 ± 1.09 and 45 ± 4.63 µM, respectively. Significant increases in ROS, Bax/Bcl-2 ratio, and cleaved caspase-3 were observed after arsenic and cadmium exposures. Cell viability increased and ROS production decreased when cells were pretreated with alpha-mangostin for 2 h. Alpha-mangostin reduced the increased level of cleaved caspase-3 induced by cadmium and decreased the elevated level of the Bax/Bcl-2 ratio after arsenic exposure.Alpha-mangostin significantly increased cell viability and reduced oxidative stress caused by cadmium and arsenic in PC12 cells. Moreover, alpha-mangostin reduced cadmium-induced apoptosis through the reduction in the level of cleaved caspase 3. Further studies are required to determine the different mechanisms of alpha-mangostin against neurotoxicity induced by these elements.

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.

Assessing the Role of Nrf2/GPX4-Mediated Oxidative Stress in Arsenic-Induced Liver Damage and the Potential Application Value of Rosa roxburghii Tratt [Rosaceae]

Arsenic poisoning is a geochemical disease that seriously endangers human health. The liver is one of the important target organs for arsenic poisoning, several studies have shown that oxidative stress plays an important role in arsenic-induced liver damage. However, the specific mechanism of arsenic-induced oxidative stress has not yet been fully elucidated, and currently, there are no effective intervention measures for the prevention and treatment of arsenic-induced liver damage. In this study, the effect of the Nrf2/GPX4 signaling pathway and oxidative stress in the arsenic-induced liver damage was first evaluated. The results show that arsenic can activate the Nrf2/GPX4 signaling pathway and increase the oxidative stress, which in turn promotes arsenic-induced liver damage in MIHA cells. Moreover, when we applied the Nrf2 inhibitor, the promoting effect of arsenic on liver damage was alleviated by inhibiting the activation of the Nrf2/GPX4 signaling pathway. Subsequently, the Rosa roxburghii Tratt [Rosaceae] (RRT) intervention experiments in cells and arsenic poisoning population were designed. The results revealed that RRT can inhibit Nrf2/GPX4 signaling pathway to reduce oxidative stress, thereby alleviates arsenic-induced liver damage. This study provides some limited evidence that arsenite can activate Nrf2/GPX4 signaling pathway to induce oxidative stress, which in turn promotes arsenic-induced liver damage in MIHA cells. The second major finding was that Kaji-ichigoside F1 may be a potential bioactive compound of RRT, which can inhibit Nrf2/GPX4 signaling pathway to reduce oxidative stress, thereby alleviates arsenic-induced liver damage. Our study will contribute to a deeper understanding of the mechanisms in arsenic-induced liver damage, these findings will identify a possible natural medicinal food dual-purpose fruit, RRT, as a more effective prevention and control strategies for arsenic poisoning.

The effects of lead exposure on the expression of IGF1R, IGFBP3, Aβ40, and Aβ42 in PC12 cells

BACKGROUND

To investigate the effects of lead exposure and IGF1R inhibitor AG1024 on the expression of IGF1R and IGFBP3 in PC12 cells. It is clear that the mechanism of the related proteins inducing AD is regulated by them, thus providing theoretical guidance for the prevention and treatment of lead poisoning.

METHODS

This study is mainly used PC12 neuron cell to cultivate and establish a corresponding lead exposure model, deal with cells with different concentrations of lead acetate respectively, divide the experiment into control group, 1 μmoL/L PbAc, 10 μmoL/L PbAc group, IGF1R inhibitor (AG1024) group, IGF1R inhibitor group (AG1024) + 1 μmoL/L PbAc group, IGF1R inhibitor group (AG1024) + 10 μmoL/L PbAc group, respective contamination's three periods of time 24 h, 48 h, and 72 h. Lead exposure dose on cell proliferation was examined by MTT. The protein expression of IGF1R and IGFBP3 in PC12 cells were tested by western blotting and immunohistochemistry, The expression of Aβ40 and Aβ42 in cell supernatant was determined by ELISA.

RESULTS

Compared with the control group, the proliferation of the cells in the high-dose lead-exposed group was significantly inhibited (P < 0.05), and the expression of IGF1R and IGFBP3 was significantly decreased (P < 0.05); the contents of Aβ40 and Aβ42 were not statistically significant among the groups (P > 0.05).

CONCLUSION

This study shows that lead can obviously down-regulate the expression of IGF1R and IGFBP3, lead and inhibitor can inhibit the proliferation of cells, promote the tendency of apoptosis, and damage the nervous system.

Environmental arsenic exposure and its contribution to human diseases, toxicity mechanism and management

Arsenic is a well-recognized environmental contaminant that occurs naturally through geogenic processes in the aquifer. More than 200 million people around the world are potentially exposed to the elevated level of arsenic mostly from Asia and Latin America. Many adverse health effects including skin diseases (i.e., arsenicosis, hyperkeratosis, pigmentation changes), carcinogenesis, and neurological diseases have been reported due to arsenic exposure. In addition, arsenic has recently been shown to contribute to the onset of non-communicable diseases, such as diabetes mellitus and cardiovascular diseases. The mechanisms involved in arsenic-induced diabetes are pancreatic β-cell dysfunction and death, impaired insulin secretion, insulin resistance and reduced cellular glucose transport. Whereas, the most proposed mechanisms of arsenic-induced hypertension are oxidative stress, disruption of nitric oxide signaling, altered vascular response to neurotransmitters and impaired vascular muscle calcium (Ca²⁺) signaling, damage of renal, and interference with the renin-angiotensin system (RAS). However, the contributions of arsenic exposure to non-communicable diseases are complex and multifaceted, and little information is available about the molecular mechanisms involved in arsenic-induced non-communicable diseases and also no suitable therapeutic target identified yet. Therefore, in the future, more basic research is necessary to identify the appropriate therapeutic target for the treatment and management of arsenic-induced non-communicable diseases. Several reports demonstrated that a daily balanced diet with proper nutrient supplements (vitamins, micronutrients, natural antioxidants) has shown effective to reduce the damages caused by arsenic exposure. Arsenic detoxication through natural compounds or nutraceuticals is considered a cost-effective treatment/management and researchers should focus on these alternative options. This review paper explores the scenarios of arsenic contamination in groundwater with an emphasis on public health concerns. It also demonstrated arsenic sources, biogeochemistry, toxicity mechanisms with therapeutic targets, arsenic exposure-related human diseases, and onsets of cardiovascular diseases as well as feasible management options for arsenic toxicity.

Metallothionein Attenuated Arsenic-Induced Cytotoxicity: The Underlying Mechanism Reflected by Metabolomics and Lipidomics

Arsenic ions (As³⁺) have been recognized as a hazard that threatens the health of humans. Metallothionein (MT) rich in cysteine may provide favorable binding sites for chelation of As³⁺. However, the influence of MT on As³⁺-induced toxicity and the underlying mechanism are poorly understood, especially at the metabolic level. Herein, the effects of MT on As³⁺-induced toxicity were evaluated. Cell viability analysis suggested that MT alleviated As³⁺-induced cytotoxicity. The metabolic response of PC12 cells to As³⁺ investigated by lipidomics and metabolomics indicated that the presence of As³⁺ disrupted phospholipids metabolism and induced cell membrane damage. Moreover, energy and amino acid metabolism were perturbed by As³⁺. The perturbation of As³⁺ on metabolism was further illustrated by the decrease of the mitochondrial membrane potential and the rise of cellular reactive oxygen species (ROS). On the contrary, MT rescued As³⁺-induced metabolic disorder and suppressed ROS accumulation. In addition, the binding process between As³⁺ and MT was characterized. The results proved that the As³⁺-MT complex was formed and chelated As³⁺-scavenged ROS, thus alleviating the toxic effects of As³⁺. These results revealed that MT would be a potential agent to reduce As³⁺-induced cytotoxicity.

Combined effect of arsenic and fluoride at environmentally relevant concentrations in zebrafish (Danio rerio) brain: Alterations in stress marker and apoptotic gene expression

Arsenic and fluoride are two naturally occurring toxicants to which various organisms including a major part of the human populations are co-exposed to. However, interactions between them inside body are quite complicated and needs proper evaluation. Inconclusive reports regarding their combined effects on brain prompted us to conduct this study where we investigated their individual as well as combined effects on female zebrafish brain at environmentally relevant concentrations (50 μgL^-1 arsenic trioxide and 15 mgL^-1 sodium fluoride) after different time intervals (15, 30 and 60 days). Persistent near-basal level of GSH, least increased MDA content and catalase activity portrayed arsenic and fluoride co-exposure as less toxic which was corroborated with far less damage caused in the histoarchitecture of optic tectum region in midbrain. Stress-responsive genes viz., Nrf2 and Hsp70 were overexpressed after individual as well as combined exposures, indicating a common cellular response to combat the formed oxidative stresses. Biphasic response of AChE upon individual exposure confirmed their neurotoxic effects too. Expression profile of p53 (unaltered), Bax (lower or near-basal) and Bcl2 (comparatively higher), along with absence of DNA fragmentation indicated no induction of apoptosis in the co-exposed group. Tissue accumulation of arsenic and fluoride was significantly less in the brain of co-exposed zebrafish when compared to their individual exposures. This preliminary study indicates an antagonistic effect of these two toxicants in zebrafish brain and needs further studies involving oxidative stress independent markers to understand the detailed molecular mechanism.

Arsenic-induced autophagy regulates apoptosis in AML-12 cells

Arsenic (As), a potent toxicant, is known to be a hepatotoxicant. Although As induced liver apoptosis and autophagy, the relationship between apoptosis and autophagy of hepatocytes caused by As remains largely unknown. 3-methyladenine (3-MA) and rapamycin can inhibit and promote autophagy of AML-12 cells, respectively. Hence, in this study, AML-12 cells were treated with different concentrations (0, 2, 4, 6, 8, 10 and 12 μmol/L) of As₂O₃, and 5 mmol/L 3-MA or 100 nmol/L rapamycin were applied to distinguish the effect of autophagy on apoptosis in AML-12. Results showed that exposure to As induced cell apoptosis and autophagy, which were mediated by the significantly altered expression levels of autophagy markers (mTOR, LC3, PI3K and P62), and apoptosis markers (Bcl-2 and caspase-3). Further analysis indicated that a certain dosage of 3-MA and rapamycin decreased apoptosis and the caspase-3 expression, which suggested that As-induced autophagy regulated AML-12 cells apoptosis through the expressions of PI3K, mTOR, P62 and Bcl-2.

Curcumin alleviates arsenic-induced toxicity in PC12 cells via modulating autophagy/apoptosis

Arsenic is a recognized highly toxic contaminant, responsible for numerous human diseases and affecting many millions of people in different parts of the world. Contrarily, curcumin is a natural dietary polyphenolic compound and the main active ingredient in turmeric. Recently it has drawn great attention due to its diverse biological activities, strong antioxidant properties and therapeutic potential against many human ailments. In this study, we aimed to explore the protective effects and the regulatory role of curcumin on arsenic-induced toxicity and gain insights into biomolecular mechanism/s. Arsenic (10 μM) treatment in PC12 cells for 24 h induced cytotoxicity by decreasing cell viability and intracellular glutathione level and increasing lactate dehydrogenase activity and DNA fragmentation. In addition, arsenic caused apoptotic cell death in PC12 cells, which were confirmed from flow cytometry results. Moreover, arsenic (10 μM) treatment significantly down-regulated the inhibition factors of autophagy/apoptosis; mTOR, Akt, Nrf2, ERK1, Bcl-x, Xiap protein expressions, up-regulated the enhanced factors of autophagy/apoptosis; ULK, LC3, p53, Bax, cytochrome c, caspase 9, cleaved caspase 3 proteins and eventually caused autophagic and apoptotic cell death. However, curcumin (2.5 μM) pretreatment with arsenic (10 μM) effectively saves PC12 cells against arsenic-induced cytotoxicity through increasing cell viability, intracellular GSH level and boosting the antioxidant defense system, and limiting the LDH activity and DNA damage. Furthermore, pretreatment of curcumin with arsenic expressively alleviated arsenic-induced toxicity and cell death by reversing the expressions of proteins; mTOR, Akt, Nrf2, ERK1, Bcl-x, Xiap, ULK, LC3, p53, Bax, cytochrome c, caspase 9 and cleaved caspase 3. Our findings indicated that curcumin showed antioxidant properties through the Nrf2 antioxidant signaling pathway and alleviates arsenic-triggered toxicity in PC12 cells by regulating autophagy/apoptosis.

Arsenic Uptake and Accumulation Mechanisms in Rice Species

Rice consumption is a source of arsenic (As) exposure, which poses serious health risks. In this study, the accumulation of As in rice was studied. Research shows that As accumulation in rice in Taiwan and Bangladesh is higher than that in other countries. In addition, the critical factors influencing the uptake of As into rice crops are defined. Furthermore, determining the feasibility of using effective ways to reduce the accumulation of As in rice was studied. AsV and AsIII are transported to the root through phosphate transporters and nodulin 26-like intrinsic channels. The silicic acid transporter may have a vital role in the entry of methylated As, dimethylarsinic acid (DMA) and monomethylarsonic acid (MMA), into the root. Amongst As species, DMA(V) is particularly mobile in plants and can easily transfer from root to shoot. The OsPTR7 gene has a key role in moving DMA in the xylem or phloem. Soil properties can affect the uptake of As by plants. An increase in organic matter and in the concentrations of sulphur, iron, and manganese reduces the uptake of As by plants. Amongst the agronomic strategies in diminishing the uptake and accumulation of As in rice, using microalgae and bacteria is the most efficient.