Subchronic intake of arsenic at environmentally relevant concentrations causes histological lesions and oxidative stress in the prostate of adult Wistar rats.

The prostate gland is one of the main sites of hyperplasia and cancer in elderly men. Numerous factors have been demonstrated to disrupt prostate homeostasis, including exposure to environmental pollutants. Arsenic is a metalloid found ubiquitously in soil, air, and water, which favors human poisoning through the involuntary intake of contaminated drinking water and food and has harmful effects by increasing the oxidative stress response. This study aimed to investigate the effects of prolonged exposure to arsenic at environmentally relevant concentrations on the prostate biology of adult Wistar rats. Thirty 80-day-old male rats were divided into three experimental groups. Rats from the control group received filtered water, whereas animals from the arsenic groups ingested 1 mg L-1 and 10 mg L-1 of arsenic, in the form of sodium arsenite, daily. The arsenic solutions were provided ad libitum in the drinking water for eight weeks. Our results showed that 1 mg L-1 and 10 mg L-1 of arsenic made the prostate susceptible to evolving benign and premalignant histopathological changes. While the ingestion of 1 mg L-1 of arsenic reduced SOD activity only, 10 mg L-1 diminished SOD and CAT activity in the prostate tissue, culminating in high MDA production. These doses, however, did not affect the intraprostatic levels of DHT and estradiol. In conclusion, exposure to arsenic at environmentally relevant concentrations through drinking water induces histological and oxidative stress-related changes in the prostate of adult rats, strengthening the between arsenic exposure and prostate disorders.

Hepatoprotective effects of zingerone on sodium arsenite-induced hepatotoxicity in rats: Modulating the levels of caspase-3/Bax/Bcl-2, NLRP3/NF-κB/TNF-α and ATF6/IRE1/PERK/GRP78 signaling pathways.

OBJECTIVE: Long-term exposure to arsenic has been linked to several illnesses, including hypertension, diabetes, hepatic and renal diseases and cardiovascular malfunction. The aim of the current investigation was to determine whether zingerone (ZN) could shield rats against the hepatotoxicity that sodium arsenite (SA) causes. METHODS: The following five groups of thirty-five male Sprague Dawley rats were created: I) Control; received normal saline, II) ZN; received ZN, III) SA; received SA, IV) SA + ZN 25; received 10 mg/kg body weight SA + 25 mg/kg body weight ZN, and V) SA + ZN 50; received 10 mg/kg body weight SA + 50 mg/kg body weight ZN. The experiment lasted 14 days, and the rats were sacrificed on the 15th day. While oxidative stress parameters were studied by spectrophotometric method, apoptosis, inflammation and endoplasmic reticulum stress parameters were measured by RT-PCR method. RESULTS: The SA disrupted the histological architecture and integrity of the liver and enhanced oxidative damage by lowering antioxidant enzyme activity, such as those of glutathione peroxidase (GPx), catalase (CAT), superoxide dismutase (SOD), glutathione (GSH) level and increasing malondialdehyde (MDA) level in the liver tissue. Additionally, SA increased the mRNA transcript levels of Bcl2 associated x (Bax), caspases (-3, -6, -9), apoptotic protease-activating factor 1 (Apaf-1), p53, tumor necrosis factor-α (TNF-α), nuclear factor kappa B (NF-κB), interleukin-1ß (IL-1ß), interleukin-6 (IL-6), c-Jun NH2-terminal kinase (JNK), mitogen-activated protein kinase 14 (MAPK14), MAPK15, receptor for advanced glycation endproducts (RAGE) and nod-like receptor family pyrin domain-containing 3 (NLRP3) in the liver tissue. Also produced endoplasmic reticulum stress by raising the mRNA transcript levels of activating transcription factor 6 (ATF-6), protein kinase RNA-like ER kinase (PERK), inositol-requiring enzyme 1 (IRE1), and glucose-regulated protein 78 (GRP-78). These factors together led to inflammation, apoptosis, and endoplasmic reticulum stress. On the other hand, liver tissue treated with ZN at doses of 25 and 50 mg/kg showed significant improvement in oxidative stress, inflammation, apoptosis and endoplasmic reticulum stress. CONCLUSIONS: Overall, the study's data suggest that administering ZN may be able to lessen the liver damage caused by SA toxicity.

Protective Effects of Lactoferrin Treatment Against Sodium Arsenite Exposure-Induced Nephrotoxicity.

It is said that a wide range of renal functions are at risk from arsenic exposure. We examined how lactoferrin administration may mitigate inflammation, apoptosis, redox imbalance, and fibrosis in order to counteract arsenic-induced nephrotoxicity. Accordingly, male C57BL/6 mice (6 weeks) were divided into six experimental groups with six mice in each group. The first and second groups were intragastrically administered normal saline and sodium arsenite (NaAsO2) at 5 mg/kg body weight concentrations as the negative control (NC) and NaAsO2 groups. The third, fourth, and fifth groups were intragastrically administered lactoferrin at concentrations of 100, 200, and 400 mg/kg body weight in addition to NaAsO2 at concentrations of 5 mg/kg body weight. The sixth group was intragastrically administered lactoferrin at a concentration of 200 mg/kg body weight with the experimental group set as the lactoferrin group. After daily drug administration for 4 weeks, the lactoferrin concentrations were optimized based on the results of renal index and renal function. Histopathological, biochemical, and gene expression analyses were performed to evaluate the status of renal tissue architecture, redox imbalance, inflammation, apoptosis, and fibrosis to confirm the alleviative effect of lactoferrin treatment against the NaAsO2 exposure-induced nephrotoxicity. The results confirmed that the 200 mg/kg lactoferrin treatment mitigated these arsenic effects and maintained the normal renal frameworks. Conclusively, disrupting the renal redox balance and triggering inflammation, apoptosis, along with fibrosis is a milieu that arsenic, robustly exerts its nephrotoxic effect. Lactoferrin, probably by its direct and indirect control mechanism on these said pathways, can mitigate the nephrotoxicity and preserve the normal renal health.

Sodium arsenite induces hepatic stellate cells activation by m6A modification of TGF-ß1 during liver fibrosis.

The compound known as Sodium arsenite (NaAsO2), which is a prevalent type of inorganic arsenic found in the environment, has been strongly associated with liver fibrosis (LF), a key characteristic of nonalcoholic fatty liver disease (NAFLD), which has been demonstrated in our previous study. Our previous research has shown that exposure to NaAsO2 triggers the activation of hepatic stellate cells (HSCs), a crucial event in the development of LF. However, the molecular mechanism is still unknown. N6-methyladenosine (m6A) modification is the most crucial post-transcriptional modification in liver disease. Nevertheless, the precise function of m6A alteration in triggering HSCs and initiating LF caused by NaAsO2 remains unknown. Here, we found that NaAsO2 induced LF and HSCs activation through TGF-ß/Smad signaling, which could be reversed by TGF-ß1 knockdown. Furthermore, NaAsO2 treatment enhanced the m6A modification level both in vivo and in vitro. Significantly, NaAsO2 promoted the specific interaction of METTL14 and IGF2BP2 with TGF-ß1 and enhanced the TGF-ß1 mRNA stability. Notably, NaAsO2-induced TGF-ß/Smad pathway and HSC-t6 cells activation might be avoided by limiting METTL14/IGF2BP2-mediated m6A modification. Our findings showed that the NaAsO2-induced activation of HSCs and LF is made possible by the METTL14/IGF2BP2-mediated m6A methylation of TGF-ß1, which may open up new therapeutic options for LF brought on by environmental hazards.

mTORC1 - TFEB pathway was involved in sodium arsenite induced lysosomal alteration, oxidative stress and genetic damage in BEAS-2B cells.

The mechanistic target of rapamycin (RAPA) complex 1 (mTORC1) - transcription factor EB (TFEB) pathway plays a crucial role in response to nutritional status, energy and environmental stress for maintaining cellular homeostasis. But there is few reports on its role in the toxic effects of arsenic exposure and the related mechanisms. Here, we show that the exposure of bronchial epithelial cells (BEAS-2B) to sodium arsenite promoted the activation of mTORC1 (p-mTORC1) and the inactivation of TFEB (p-TFEB), the number and activity of lysosomes decreased, the content of reduced glutathione (GSH) and superoxide dismutase (SOD) decreased, the content of malondialdehyde (MDA) increased, the DNA and chromosome damage elevated. Further, when mTORC1 was inhibited with RAPA, p-mTORC1 and p-TFEB down-regulated, GSH and SOD increased, MDA decreased, the DNA and chromosome damage reduced significantly, as compared with the control group. Our data revealed for the first time that mTORC1 - TFEB pathway was involved in sodium arsenite induced lysosomal alteration, oxidative stress and genetic damage in BEAS-2B cells, and it may be a potential intervention target for the toxic effects of arsenic.

Nod-like receptor protein 3 inflammasome-mediated pyroptosis contributes to chronic NaAsO2 exposure-induced fibrotic changes and dysfunction in the liver of SD rats.

The metalloid arsenic, known for its toxic properties, is widespread presence in the environment. Our previous research has confirmed that prolonged exposure to arsenic can lead to liver fibrosis injury in rats, while the precise pathogenic mechanism still requires further investigation. In the past few years, the Nod-like receptor protein 3 (NLRP3) inflammasome has been found to play a pivotal role in the occurrence and development of liver injury. In this study, we administered varying doses of sodium arsenite (NaAsO2) and 10 mg/kg.bw MCC950 (a particular tiny molecular inhibitor targeting NLRP3) to Sprague-Dawley (SD) rats for 36 weeks to explore the involvement of NLRP3 inflammasome in NaAsO2-induced liver injury. The findings suggested that prolonged exposure to NaAsO2 resulted in pyroptosis in liver tissue of SD rats, accompanied by the fibrotic injury, extracellular matrix (ECM) deposition and liver dysfunction. Moreover, long-term NaAsO2 exposure activated NLRP3 inflammasome, leading to the release of pro-inflammatory cytokines in liver tissue. After treatment with MCC950, the induction of NLRP3-mediated pyroptosis and release of pro-inflammatory cytokines were significantly attenuated, leading to a decrease in the severity of liver fibrosis and an improvement in liver function. To summarize, those results clearly indicate that hepatic fibrosis and liver dysfunction induced by NaAsO2 occur through the activation of NLRP3 inflammasome-mediated pyroptosis, shedding new light on the potential mechanisms underlying arsenic-induced liver damage.

Effects of zingerone on rat induced testicular toxicity by sodium arsenite via oxidative stress, endoplasmic reticulum stress, inflammation, apoptosis, and autophagy pathways.

Objectives: This study aimed to investigate the effects of zingerone (ZNG) treatment on testicular toxicity in rats induced by sodium arsenite (SA). Materials and Methods: In the study, five groups were formed (n=7) and the experimental groups were designated as follows; Vehicle group, ZNG group, SA group, SA+ZNG 25 group, and SA+ZNG 50 group. While SA was administered orally to rats at 10 mg/kg/bw, ZNG was given to rats orally at 25 and 50 mg/kg/bw doses for 14 days. Results: As a result of the presented study, an increase was observed in the MDA contents of the testicular tissue of the rats administered SA, while significant decreases were observed in GSH levels, SOD, CAT, and GPx activities. The mRNA transcript levels of the pro-inflammatory genes NF-κB, TNF-α, IL-1ß, and IL-6 were triggered after SA administration. Additionally, SA administration caused inflammation by increasing RAGE, NLRP3, and JAK-2/STAT3 gene expression. Moreover, endoplasmic reticulum (ER) stress occurred in the testicular tissues of SA-treated rats and thus ATF-6, PERK, IRE1, and GRP78 genes were up-regulated. SA caused apoptosis by up-regulating Bax and Caspase-3 expressions and inhibiting Bcl-2 expression in testicles. SA caused histological irregularities in the testicles, resulting in decreased sperm quality. Conclusion: ZNG treatment reduced SA-induced oxidative stress, ER stress, inflammation, apoptosis, and histological irregularities in the testicles while increasing sperm quality. As a result, it was observed that ZNG could alleviate the toxicity caused by SA in the testicles.

Zingerone attenuates sciatic nerve damage caused by sodium arsenite by inhibiting NF-κB, caspase-3, and ATF-6/CHOP pathways and activating the Akt2/FOXO1 pathway.

Objectives: In the present study, the potential protective effects of zingerone (ZNG) against sciatic nerve damage caused by sodium arsenite (SA), a common environmental pollutant, were evaluated by various biochemical, molecular, and histological methods. Materials and Methods: In the study, SA and ZNG were given to 35 male Sprague Dawley rats for 14 days. At the end of the period, the sciatic nerve tissues were taken and the markers involved in oxidative stress, endoplasmic reticulum stress, inflammation, and apoptosis were analyzed. Results: The data obtained showed that SA decreased glutathione (GSH) levels and increased malondialdehyde (MDA) levels in the sciatic nerve tissue. However, it was determined that these markers approached the control group levels due to the anti-oxidant properties of ZNG. While SA triggered endoplasmic reticulum stress and apoptosis pathways, ZNG suppressed them. Moreover, SA up-regulated inflammatory markers such as nuclear factor kappa-B (NF-κB), tumor necrosis factor-alpha (TNF-α), interleukin-1-beta (IL-1ß), and neuronal nitric oxide synthases (nNOS) in the sciatic nerves and caused neuro-inflammation and inhibited cell survival by suppressing serine/threonine-protein kinase 2 (Akt2) and forkhead box protein O1 (FOXO1) genes. It has also been shown histopathologically that SA causes degeneration in the sciatic nerves. In contrast, ZNG suppressed neuro-inflammation, activated Akt2/FOXO1 signaling, and repaired histological irregularities. Conclusion: In general, SA caused oxidative stress, inflammation, ER stress, and apoptosis in the sciatic nerves of rats, causing damage to the tissues, however, ZNG suppressed these pathways and protected the sciatic nerves from the destructive effect of SA.

Proteomic-miRNA Biomics Profile Reveals 2D Cultures of Human iPSC-Derived Neural Progenitor Cells More Sensitive than 3D Spheroid System Against the Experimental Exposure to Arsenic.

The iPSC-derived 3D models are considered to be a connective link between 2D culture and in vivo studies. However, the sensitivity of such 3D models is yet to be established. We assessed the sensitivity of the hiPSC-derived 3D spheroids against 2D cultures of neural progenitor cells. The sub-toxic dose of Sodium Arsenite (SA) was used to investigate the alterations in miRNA-proteins in both systems. Though SA exposure induced significant alterations in the proteins in both 2D and 3D systems, these proteins were uncommon except for 20 proteins. The number and magnitude of altered proteins were higher in the 2D system compared to 3D. The association of dysregulated miRNAs with the target proteins showed their involvement primarily in mitochondrial bioenergetics, oxidative and ER stress, transcription and translation mechanism, cytostructure, etc., in both culture systems. Further, the impact of dysregulated miRNAs and associated proteins on these functions and ultrastructural changes was compared in both culture systems. The ultrastructural studies revealed a similar pattern of mitochondrial damage, while the cellular bioenergetics studies confirm a significantly higher energy failure in the 2D system than to 3D. Such a higher magnitude of changes could be correlated with a higher amount of internalization of SA in 2D cultures than in 3D spheroids. Our findings demonstrate that a 2D culture system seems better responsive than a 3D spheroid system against SA exposure.

Evaluation of Salvia hispanica as a Therapeutic Agent against Sodium Arsenic-Induced Testicular Toxicity in a Male Rats Model.

Chia seeds offer therapeutic properties that aid in the prevention of a variety of ailments, including cardiovascular disease, diabetes, obesity, and other risk factors. Arsenite, a common environmental chemical, has been identified as a reproductive toxin owing to its negative effects on male reproductive health. It has been shown to inhibit spermatogenesis and generate androgenic effects in men. The primary goal of this research was to look into the effect of Salvia hispanica on testicular toxicity caused by sodium arsenite in male rats. A set of 36 male albino rats was allocated to a negative control cohort. The individuals in this group were given a basic meal and orally given distilled water for a duration of 28 days. The other five groups were given a regular meal and received intra-peritoneal injections of sodium arsenite (NaAsO2) at a concentration of 4 mg/kg body weight that was diluted in a 0.9% NaCl solution. The injections were administered consecutively, with two doses given within a two-day period. Subsequently, the rats were categorized into several groups using the following classification: Group 2 consisted of a positive control cohort, in which the rats were given a typical baseline diet. Groups 3, 4, 5, and 6 were given a basic diet that included varying proportions of ground chia seeds, namely 5%, 10%, 15%, and 20% per 100 g of the diet. After the trial was completed, the rats were euthanized, and further biological examination was conducted. The measurements of the reproductive organs were documented and reported. The research assessed the following characteristics: sperm count, motility, progressive motility, and normal morphology. The research included examining serum sex hormones, namely luteinizing hormone (LH), follicle-stimulating hormone (FSH), and testosterone. An evaluation of the activity of antioxidant enzymes was performed in the tissue of the testicles. There were statistically significant improvements in the sperm parameters, serum sex hormone levels, and the activity of antioxidant enzymes, such as GPX, SOD, and CAT, in the therapy groups. The levels of malondialdehyde (MDA) exhibited a noteworthy decrease (p ≤ 0.05) when compared to the positive control group. Salvia hispanica seeds have demonstrated a significant level of effectiveness in reducing sodium arsenite-induced testicular toxicity, which leads to the conclusion. The flavonoid content and antioxidant properties of Salvia hispanica seeds may be to blame for the observed behavior. These indicated characteristics may have therapeutic significance in treating testicular harm induced by arsenite exposure.

Hydrogen sulfide regulates arsenic-induced cell death in yeast cells by modulating the antioxidative system.

Arsenic (As) is a metal with potentially toxic effects on different organisms. Hydrogen sulfide (H2S) plays a vital role in mitigating heavy metal toxicity by reducing oxidative stress in plants and animals. However, the role of H2S in alleviating arsenic toxicity in yeast cells remains unclear. In this study, the role of NaHS (exogenous physiological H2S) in alleviating As-induced yeast cell death was investigated. Yeast cells in the logarithmic phase were pretreated with 0.05 mmol/L NaHS for 6 h, and then incubated in the YPD medium with or without 1 mmol/L As. After 12 h of treatment, relative survival rate, H2S content, oxidative stress biomarkers, and antioxidant machinery were measured. Our results showed that sodium arsenite-induced yeast cell death and pretreatment with 0.05 mmol/L NaHS significantly alleviated sodium arsenite-induced cell death. Under sodium arsenite conditions, the levels of intracellular reactive oxygen species (ROS) and malondialdehyde (MDA) increased, accompanied by the inhibition of the catalase (CAT) activity and the downregulation of CTT1 expression. However, the activities of the superoxide dismutase (SOD) and glutathion peroxidase (GPX) increased, and the expression of SOD1 and GPX2 was markedly upregulated in the group treated with sodium arsenite. When yeast cells were pretreated with NaHS, the intracellular ROS and MDA levels decreased significantly, and the activities of SOD, CAT, and GPX increased significantly. This was associated with a significant increase in relative survival rate and H2S content compared to the arsenic treatment alone. Our findings indicate that NaHS alleviates sodium arsenite-induced yeast cell death, mainly by enhancing the antioxidant defense system.

Baicalein Alleviates Arsenic-induced Oxidative Stress through Activation of the Keap1/Nrf2 Signalling Pathway in Normal Human Liver Cells.

BACKGROUND: Oxidative stress is a key mechanism underlying arsenicinduced liver injury, the Kelch-like epichlorohydrin-related protein 1 (Keap1)/nuclear factor E2 related factor 2 (Nrf2) pathway is the main regulatory pathway involved in antioxidant protein and phase II detoxification enzyme expression. The aim of the present study was to investigate the role and mechanism of baicalein in the alleviation of arsenic-induced oxidative stress in normal human liver cells. METHODS: Normal human liver cells (MIHA cells) were treated with NaAsO2 (0, 5, 10, 20 µM) to observe the effect of different doses of NaAsO2 on MIHA cells. In addition, the cells were treated with DMSO (0.1%), NaAsO2 (20 µM), or a combination of NaAsO2 (20 µM) and Baicalein (25, 50 or 100 µM) for 24 h to observe the antagonistic effect of Baicalein on NaAsO2. Cell viability was determined using a Cell Counting Kit- 8 (CCK-8 kit). The intervention doses of baicalein in subsequent experiments were determined to be 25, 50 and 100µM. The intracellular content of reactive oxygen species (ROS) was assessed using a 2',7'-dichlorodihydrofluorescein diacetate (DCFHDA) probe kit. The malonaldehyde (MDA), Cu-Zn superoxide dismutase (Cu-Zn SOD) and glutathione peroxidase (GSH-Px) activities were determined by a test kit. The expression levels of key genes and proteins were determined by real-time fluorescence quantitative polymerase chain reaction (qPCR) and Western blotting. RESULTS: Baicalein upregulated the protein expression levels of phosphorylated Nrf2 (p-Nrf2) and nuclear Nrf2, inhibited the downregulation of Nrf2 target genes induced by arsenic, and decreased the production of ROS and MDA. These results demonstrate that baicalein promotes Nrf2 nuclear translocation by upregulating p-Nrf2 and inhibiting the downregulation of Nrf2 target genes in arsenic-treated MIHA cells, thereby enhancing the antioxidant capacity of cells and reducing oxidative stress. CONCLUSION: Baicalein alleviated arsenic-induced oxidative stress through activation of the Keap1/Nrf2 signalling pathway in normal human liver cells.

Experimental study of Lentinan antagonizes against hepatic lipid deposition induced by sodium arsenite in mice / 公共卫生与预防医学

Objective To investigate the ameliorative effect of Lentinan (LNT) on sodium arsenite (SA)-induced hepatic lipid deposition in mice. Methods C57BL/6 mice were used as the experimental subjects, which were divided into control group, SA-exposed group, LNT + SA-exposed group and LNT control group. Blood and liver tissue samples were collected at the end of the experiment, and serum glutathione transaminase (ALT) and glutathione aminotransferase (AST) levels were detected by enzyme-linked immunosorbent assay (ELISA). A part of liver tissues was stained with hematoxylin-eosin (HE) or oil red O to observe the characteristics of liver pathological damage and lipid deposition, and another part of liver tissues was used to detect triglyceride (TG) and Adiponectin (APN) levels by ELISA. Results Compared with control group or LNT control group, SA-exposed group showed the increased levels of AST and ALT, showing the characteristics of liver histopathological damage and lipid deposition, and the APN level decreased while the TG level increased (P<0.05). Compared with SA-exposed group, the levels of AST and ALT decreased in LNT + SA-exposed group, showing the reduced degree of liver tissue damage and lipid deposition, and APN level upregulated while TG level downregulated (P<0.05). Conclusion Chronic SA exposure induces liver function damage, APN downregulation and lipid deposition in C57BL/6 mice, while LNT intervention leads to the significantly improvement of hepatic damage and lipid deposition, which may be related to the elevated APN level in liver.

A regulatory module comprising G3BP1-FBXL5-IRP2 axis determines sodium arsenite-induced ferroptosis.

Arsenic contamination is extremely threatening to the global public health. It was reported that sodium arsenite exposure induces serious kidney injury. However, the underlying mechanism is unclear. Ferroptosis is a newly characterized form of iron-dependent programmed cell death, which is implicated in the pathogenesis of various human diseases, including kidney injury. The lethal accumulation of iron-catalyzed lipid peroxidation is the fundamental biochemical characteristic of ferroptosis. Herein we report that sodium arsenite exposure initiates ferroptosis in mammalian HEK293, MEF and HT1080 cells, and induces ferroptosis-associated acute kidney injury in mice. RNA-binding protein G3BP1, the switch component of stress granules, is indispensable for sodium arsenite-induced ferroptosis in a stress granule-independent manner. Mechanistically, G3BP1 stabilizes IRP2, the master regulator of cellular iron homeostasis, through binding to and suppressing the translation of FBXL5 mRNA, which encodes the E3 ligase component to mediate IRP2 ubiquitination and proteasomal degradation. Sodium arsenite intoxication expedites this G3BP1-FBXL5-IRP2 axis and elevates cellular labile free iron, which is responsible for sodium arsenite exposure-induced lipid peroxidation and ferroptotic cell death. In summary, this study highlights a regulatory module comprising G3BP1-FBXL5-IRP2 axis in determining sodium arsenite-induced ferroptosis and ferroptosis-associated acute kidney injury in mice.

Promotion of transcription factor EB-dependent autophagic process by curcumin alleviates arsenic-caused lung oxidative stress and inflammation in mice.

Arsenic is a human carcinogen widely distributed in the environment, and arsenic exposure from drinking water has received widespread attention as a global public health problem. Curcumin is a natural bioactive substance with high efficiency and low toxicity extracted from turmeric, which has a variety of biological properties such as antioxidation, anti-inflammation, anticancer, and immuno-modulatory activities. Curcumin is widely used in daily life as a food additive and dietary supplement. However, its protective effects in lung injuries by chronic arsenic exposure orally remain unexplored. In this study, curcumin treatment not only significantly accelerated arsenic elimination and improved lung tissue morphology, but also decreased arsenic-generated ROS by activating Nrf2 and its down-stream antioxidants. Further, curcumin alleviated inflammatory changes in mice exposed to arsenic for 6 and 12 weeks, as manifested by lung MPO levels, total protein and cellular levels in bronchoalveolar lavage fluid (BALF), serum IL-4 levels, and MAPK/NF-κB expression in lung tissue. Notably, our study also confirmed that curcumin could promote the expression and nuclear translocation of the transcription factor EB (TFEB), as well as activate TFEB-regulated autophagy in lung tissue of arsenic-treated mice, accompanied by inhibition of the AKT-mTOR signaling pathway. Overall, our study here suggests that natural bioactive compound curcumin could alleviate arsenic-induced pulmonary oxidative stress and inflammation in vivo, which is closely related to enhanced TFEB activity and induction of the autophagic process.

A Novel Quinazoline Derivative Prevents and Treats Arsenic-Induced Liver Injury by Regulating the Expression of RecQ Family Helicase.

Arsenic is a carcinogenic metalloid toxicant widely found in the natural environment. Acute or prolonged exposure to arsenic causes a series of damages to the organs, mainly the liver, such as hepatomegaly, liver fibrosis, cirrhosis, and even hepatocellular carcinoma. Therefore, it is imperative to seek drugs to prevent arsenic-induced liver injury. Quinazolines are a class of nitrogen heterocyclic compounds with biological and pharmacological effects in vivo and in vitro. This study was designed to investigate the ameliorating effects of quinazoline derivatives on arsenic-induced liver injury and its molecular mechanism. We investigated the mechanism of the quinazoline derivative KZL-047 in preventing and ameliorating arsenic-induced liver injury in vitro by cell cycle and apoptosis. We performed real-time fluorescence quantitative polymerase chain reaction (qPCR) and Western blotting combined with molecular docking. In vivo, the experiments were performed to investigate the mechanism of KZL-047 in preventing and ameliorating arsenic-induced liver injury using arsenic-infected mice. Physiological and biochemical indices of liver function in mouse serum were measured, histopathological changes in liver tissue were observed, and immunohistochemical staining was used to detect changes in the expression of RecQ-family helicases in mouse liver tissue. The results of in vitro experiments showed that sodium arsenite (SA) inhibited the proliferation of L-02 cells, induced apoptosis, blocked the cell cycle at the G1 phase, and decreased the expression of RecQ family helicase; after KZL-047 treatment in arsenic-induced L-02 cells, the expression of RecQ family helicase was upregulated, and the apoptosis rate was slowed, leading to the restoration of the cell viability level. KZL-047 inhibited arsenic-induced oxidative stress, alleviated oxidative damage and lipid peroxidation in vivo, and ameliorated arsenic toxicity-induced liver injury. KZL-047 restored the expression of RecQ family helicase proteins, which is consistent with the results of in vitro studies. In summary, KZL-047 can be considered a potential candidate for the treatment of arsenic-induced liver injury.

Mild Oxidative Stress Induced by Sodium Arsenite Reduces Lipocalin-2 Expression Levels in Cortical Glial Cells.

Astrocytes and microglia, the most abundant glial cells in the central nervous system, are involved in maintaining homeostasis in the brain microenvironment and in the progression of various neurological disorders. Lipocalin-2 (LCN2) is a small secretory protein that can be transcriptionally upregulated via nuclear factor kappa B (NF-κB) signaling. It is synthesized and secreted by glial cells, resulting in either the restoration of damaged neural tissues or the induction of neuronal apoptosis in a context-dependent manner. It has recently been reported that when glial cells are under lipopolysaccharide-induced inflammatory stress, either reduced production or accelerated degradation of LCN2 can alleviate neurotoxicity. However, the regulatory mechanisms of LCN2 in glial cells are not yet fully understood. In this study, we used primary astroglial-enriched cells which produce LCN2 and found that the production of LCN2 could be reduced by sodium arsenite treatment. Surprisingly, the reduced LCN2 production was not due to the suppression of NF-κB signaling. Mild oxidative stress induced by sodium arsenite treatment activated antioxidant responses and downregulated Lcn2 expression without reducing the viability of astroglial-enriched cells. Intriguingly, reduced LCN2 production could not be achieved by simple activation of the nuclear factor erythroid-2-related factor 2 (Nrf2)-Kelch-like ECH-associated protein 1 (Keap1) pathway in astroglial-enriched cells. Thus, it appears that mild oxidative stress, occurring in an Nrf2-independent manner, is required for the downregulation of Lcn2 expression. Taken together, our findings provide new insights into the regulatory mechanisms of LCN2 and suggest that mild oxidative stress may alter LCN2 homeostasis, even under neuroinflammatory conditions.

Arsenic exposure caused male infertility indicated by testis and sperm metabolic dysfunction in SD rats.

Arsenic containment is one of the most severe environmental problems. It has been reported that arsenic exposure could cause male reproductive damage. However, the evidence chain from sodium arsenite (NaAsO2) exposure to adverse male fertility outcomes has not been completed by molecular events. In this study, adult male rats were exposed to NaAsO2 for eight weeks via drinking water for verifying their reproductive capacity by checking the phenotypes of testis damage, sperm quality, and female pregnancy rate. H&E staining indicated testicular cells had atrophied, and necrosis was observed under transmission electron microscopy. Sperm viability tended to decrease, and sperm malformation increased. Notably, metabolites in the testes and sperm showed substantial disruption, especially sperm metabolites. The pregnancy rate tests showed that arsenic decreased male rats' reproduction, with some adverse outcomes of the increased numbers of unpregnant females. However, the fetal crown-rump length remained unaltered, indicating that the pregnancy rate was impacted by arsenic exposure but not fetal growth. On arsenic toxicometabolomics analysis, docosahexaenoic acid (DHA) in sperm was the clearest metabolic sign to correlate with the unpregnant rate. In summary, arsenic exposure can cause male infertility via the injured sperm, which results in decreased female pregnancy. The DHA information may imply the dietary intervention for improving sperm quality. Although the fetal growth of the successful pregnancy has not been affected, the changes in epigenetic phenotypes carried by sperms still need to be verified.

m6A methylation-mediated PGC-1α contributes to ferroptosis via regulating GSTK1 in arsenic-induced hepatic insulin resistance.

Arsenic exposure has been closely linked to hepatic insulin resistance (IR) and ferroptosis with the mechanism elusive. Peroxisome proliferator γ-activated receptor coactivator 1-α (PGC-1α) is essential for glucose metabolism as well as for the production of reactive oxygen species (ROS). However, it was unclear whether there is a regulatory connection between PGC-1α and ferroptosis. Besides, the definitive mechanism of arsenic-induced hepatic IR progression remains to be determined. Here, we found that hepatic insulin sensitivity impaired by sodium arsenite (NaAsO2) could be reversed by inhibiting ferroptosis. Mechanistically, we found that PGC-1α suppression inhibited the protein expression of glutathione s-transferase kappa 1 (GSTK1) via nuclear respiratory factor 1 (NRF1), thereby increasing ROS accumulation and promoting ferroptosis. Furthermore, we showed that NaAsO2 induced hepatic IR and ferroptosis via methyltransferase-like 14 (METTL14) and YTH domain-containing family protein 2 (YTHDF2)-mediated N6-methyladenosine (m6A) of PGC-1α mRNA. In conclusion, NaAsO2-mediated PGC-1α suppression was m6A methylation-dependent and induced ferroptosis via the PGC-1α/NRF1/GSTK1 pathway in hepatic IR. The data might provide insight into potential targets for diabetes prevention and treatment.

Protective effects of zingerone against sodium arsenite-induced lung toxicity: A multi-biomarker approach.

Objectives: Sodium arsenite (SA) exposure is toxic to the body. Zingerone (ZNG) is a flavonoid with many biological properties found naturally in honey and plants. This study aimed to determine the effects of ZNG on SA-induced rat lung toxicity. Materials and Methods: Thirty-five male Sprague rats were divided into Control, SA, ZNG, SA+ZNG25, and SA+ZNG50 groups (n=7). SA 10 mg/kg and ZNG were administered at two doses (25 and 50 mg/kg) (orally, 14 days). Analysis of oxidative stress, inflammation damage, apoptosis damage, and autophagic damage markers in lung tissue were determined by biochemical and histological methods. Results: The administration of ZNG reduced oxidative stress by increasing SA-induced decreased antioxidant enzyme activities, increasing Nrf-2, HO-1, and NQO1, and decreasing MDA level. ZNG administration reduced inflammation marker levels. Anti-apoptotic Bcl-2 increased and apoptotic Bax and Caspase-3 decreased with ZNG. ZNG promoted the regression of autophagy by reducing Beclin-1, LC3A, and LC3B levels. Conclusion: Evaluating all data showed that SA caused toxic damage to lung tissue by increasing inflammation, apoptosis, autophagy, and oxidant levels, whereas ZNG had a protective effect by reducing this damage.