Arsenic Toxicity in Male Reproduction and Development

Mitigating effect of gallic acid on zinc oxide nanoparticles and arsenic trioxide-induced spermatogenesis suppression, testicular injury, hormonal imbalance, and immunohistochemical changes in rats

The current study compared the effects of incorporated exposure to arsenic trioxide (As) and zinc oxide nanoparticles (ZnONPs) on male reproductive hormones, oxidative stress, and inflammatory biomarkers in adult rats to each metal alone. A defensive trial with gallic acid (GA) has also been studied. A total of 60 adult male Sprague Dawley rats were categorized into six groups: control, GA (20 mg/kg), ZnONPs (100 mg/kg), As (8 mg/kg), ZnONPs with As, and GA concurrently with ZnONPs and As at the same previous doses. The regimens were applied for 60 days in sequence. Current findings showed significant weight loss in all study groups, with testicular weights significantly decreased in the As and combined groups. Testosterone, follicular stimulating hormone, and luteinizing hormone serum levels were also considerably reduced, while serum levels of estradiol increased. Inducible nitric oxide synthase (iNOS) immunoexpression was significantly upregulated while proliferating cell nuclear antigen (PCNA) was downregulated. Moreover, there was a significant elevation of testicular malondialdehyde, reduction of testicular superoxide dismutase, and glutathione peroxidase with disruptive testes, prostate glands, and seminal vesicle alterations in all experimental groups with marked changes in the combined group. Additionally, the present results revealed the protective effects of GA on ZnONPs and As adverse alterations in rats. GA enhanced sperm picture, oxidant status, and hormonal profile. Also, it modulates iNOS and PCNA immunoexpression and recovers the histoarchitecture of the testes, prostate glands, and seminal vesicles. Ultimately, GA may be a promising safeguarding agent against ZnONPs and As-induced disturbances to reproductive parameters.

Unravelling the epigenetic impact: Oxidative stress and its role in male infertility-associated sperm dysfunction

Male infertility is a multifactorial condition influenced by epigenetic regulation, oxidative stress, and mitochondrial dysfunction. Oxidative stress-induced damage leads to epigenetic modifications, disrupting gene expression crucial for spermatogenesis and fertilization. Paternal exposure to oxidative stress induces transgenerational epigenetic alterations, potentially impacting male fertility in offspring. Mitochondrial dysfunction impairs sperm function, while leukocytospermia exacerbates oxidative stress-related sperm dysfunction. Therefore, this review focuses on understanding these mechanisms as vital for developing preventive strategies, including targeting oxidative stress-induced epigenetic changes and implementing lifestyle modifications to prevent male infertility. This study investigates how oxidative stress affects the epigenome and sperm production, function, and fertilization. Unravelling the molecular pathways provides valuable insights that can advance our scientific understanding. Additionally, these findings have clinical implications and can help to address the significant global health issue of male infertility.

Sustained effects of developmental exposure to inorganic arsenic on hepatic gsto2 expression and mating success in zebrafish

The impacts of exposure to the pervasive environmental toxicant, inorganic arsenic (iAs), on human and fish health are well characterized and several lines of evidence suggest that some impacts can manifest years after exposure cessation. Using a developmental exposure protocol whereby zebrafish embryos were exposed to 0.5 and 1.5 mM iAs from 4-120 hours post fertilization (hpf) and then removed, we investigated the sustained effects of iAs on gene expression in the liver, survival, reproductive success, and susceptibility to iAs toxicity in the subsequent generation. Persistent exposure to iAs during development had substantial effects on the hepatic transcriptome, with 23% of all expressed genes significantly changed following developmental exposure. The gsto2 gene is involved in iAs metabolism and this gene was significantly downregulated in female livers 9 months after iAs was removed. Developmental exposure to 1.5 mM iAs, but not 0.5 mM, decreased survival by over 50% at 3 months of age. Adults that were developmentally exposed to 0.5 mM iAs had reduced mating success, but their offspring had no differences in observable aspects of development or their susceptibility to iAs toxicity. This demonstrates that developmental exposure of zebrafish to iAs reduces long-term survival, reproductive success and causes sustained changes to gsto2 expression in the liver.

hnRNPA2B1 represses the disassembly of arsenite-induced stress granules and is essential for male fertility

Although the composition and assembly of stress granules (SGs) are well understood, the molecular mechanisms underlying SG disassembly remain unclear. Here, we identify that heterogeneous nuclear ribonucleoprotein A2/B1 (hnRNPA2B1) is associated with SGs and that its absence specifically enhances the disassembly of arsenite-induced SGs depending on the ubiquitination-proteasome system but not the autophagy pathway. hnRNPA2B1 interacts with many core SG proteins, including G3BP1, G3BP2, USP10, and Caprin-1; USP10 can deubiquitinate G3BP1; and hnRNPA2B1 depletion attenuates the G3BP1-USP10/Caprin-1 interaction but elevates the G3BP1 ubiquitination level under arsenite treatment. Moreover, the disease-causing mutation FUSR521C also disassembles faster from SGs in HNRNPA2B1 mutant cells. Furthermore, knockout of hnRNPA2B1 in mice leads to Sertoli cell-only syndrome (SCOS), causing complete male infertility. Consistent with this, arsenite-induced SGs disassemble faster in Hnrnpa2b1 knockout (KO) mouse Sertoli cells as well. These findings reveal the essential roles of hnRNPA2B1 in regulating SG disassembly and male mouse fertility.

Assessing the impact and mechanisms of environmental pollutants (heavy metals and pesticides) on the male reproductive system: a comprehensive review

The escalation of technological advancements, coupled with the increased use of hazardous chemicals, has emerged as a significant concern for human health. Exposure to environmental pollutants like heavy metals and pesticides (insecticides, herbicides and fungicides) is known to significantly contribute to various health problems, particularly affecting reproductive health. Disturbances in reproductive potential and reproductive toxicity in males are particularly worrisome. Existing literature suggests that exposure to these environmental pollutants significantly alters male reproductive parameters. Thus, it is imperative to thoroughly analyze, comprehend, and evaluate their impact on male reproductive toxicity. Oxidative stress and disruptions in redox equilibrium are major factors through which these pollutants induce changes in sperm parameters and affect the reproductive system. Insecticides, fungicides, and herbicides act as endocrine disruptors, interfering with the secretion and function of reproductive hormones such as testosterone and luteinizing hormone (LH), consequently impacting spermatogenesis. Additionally, heavy metals are reported to bio-accumulate in reproductive organs, acting as endocrine disruptors and triggering oxidative stress. The co-operative association of these pollutants can lead to severe damage. In this comprehensive review, we have conducted an in-depth analysis of the impact of these environmental pollutants on the male reproductive system, shedding light on the underlying mechanisms of action.

Sodium arsenite exposure enhances H3K14 acetylation and impairs male spermatogenesis in rat testes

Histone modifications play important roles in the epigenetic regulation of spermatogenesis via mediating gene transcription. Steroidogenic regulatory enzymes control testosterone biosynthesis, which are essential for spermatogenesis. Arsenic exposure inhibits the expression of steroidogenic genes by significantly increasing tri-methylation of H3K9 (H3K9me3) level in rat testis, finally diminishes testosterone release and lowers the rat sperm quality. Acetylation of H3K14 (H3K14ac) is associated with testosterone production and spermatogenesis. Co-occurrence of H3K9me3/H3K14ac has been identified previously by mass spectrometry in histone H3 isolated from different human cell types. H3K9me3/H3K14ac dually marked regions are in a poised inactive state to inhibit the gene expression. Whereas, whether inorganic arsenic exposure affects spermatogenesis and steroidogenic regulatory enzymes via mediating H3K14ac level has not been studied. Thereupon, the male Sprague-Dawley (SD) rats were exposed to (NaAsO2) for 6 weeks, then the sperm density and motility, testosterone level in serum, arsenic in rat testis were detected. mRNA expression of steroidogenic regulatory enzymes Star, Cyp11a1, Hsd3b and Hsd17b were determined by RT-PCR. H3K14ac level and the expression of histone acetylases of H3K14 (KAT2A and EP300), histone deacetylases of H3K14 (HDAC6 and HDAC3), the reader of H3K14ac (BAZ2A) were determined. The results suggested arsenic enhances H3K14ac in rat testis, which was associated with repression of steroidogenic regulatory genes expression, further reduced testosterone production, and impaired the spermatogenesis.

Evaluating the effects of geochemical and anthropogenic factors on the concentration and treatability of heavy metals in Awash River and Lake Beseka, Ethiopia: arsenic and molybdenum issues

In the Awash River basin (Ethiopia), massive urbanization and industrialization, driven by rapid development and human settlement, are detrimental to the environment and human health as pollutants such as heavy metals (HMs) find their way into water bodies without proper treatment. The purpose of this study was to assess the HMs content and pollution sources within the basin. In this context, a total of 205 samples were collected from 21 surface water sampling stations. Heavy metal concentrations were measured using the Perkin Elmer NexION 350 ICP-MS with inductively coupled plasma. Findings demonstrate that high levels of HMs, such as Al, Mn, Mo, As, V, Fe, and Ba were exhibited with the value of 1257 μg/L, 626.8 μg/L, 116.7 μg/L, 61.2 μg/L, 100.5 μg/L, 1082.7 μg/L, and 211.7 μg/L, respectively. Among 20 HMs analyzed, 20% of the parameters within the study area were above the WHO limit for drinking water; Al (157 μg/L), V (100.5 μg/L), Fe (1082.7 μg/L), Mn (626.8 μg/L), and Mo (103.8 μg/L) were exhibited at sites along the river system. Likewise, 57% of water samples showed high values of As at many stations down the river systems. In particular, high HM concentrations seen in the upper Awash are primarily controlled by anthropogenic activities such as untreated industrial, agricultural, and domestic discharges, while the high HM concentrations in the middle Awash samples were likely due to the influence from the Lake Beseka that has high HM concentrations due to geological process. In conclusion, securing potable water for the rapidly increasing population in Addis Ababa and in the watersheds of Awash is unsafe to sustain the environment and the human health.

Casein and pea enriched high-protein diet attenuates arsenic provoked apoptosis in testicles of adult rats

Arsenic toxicity is a major health issue that also threats male reproductive system leading to impairment of fertility. The antioxidant capacity of casein and pea enriched formulated high-protein diet (FHPD) is found to be effective in different toxicity management. The present study was endeavored to investigate the mitigatory aspect of FHPD on arsenic stimulated testicular apoptosis. Adult male rats were maintained on either normal diet as control (Gr I, n = 8) and arsenic (As2O3) treated at a dose of 3 mg/kg/rat/day (Gr II, n = 8) or on isocaloric FHPD as supplemented (Gr III, n = 8) with same dose of arsenic for 30 consecutive days. Testicular histomorphometry, spermatokinetics, testicular functional marker enzymes, serum gonadotrophins, oxidative stress markers, testicular deoxyribonucleic acid (DNA) damage, and apoptosis markers were evaluated to assess the reprotoxicity of arsenic and subsequent protection by FHPD. FHPD protected the histopathological alterations and also restored normal spermatogenesis. Altered enzymatic activities of testicular functional markers like lactate dehydrogenase, γ-glutamyl transferase, acid phosphatase, and alkaline phosphatase were also regularized. FHPD also reinstated the normal level of follicle stimulating hormone (FSH), luteinising hormone (LH), and also normalized the enzymatic activities of testicular glutathione peroxidase and glutathione reductase. Testicular DNA damage was also prevented by FHPD supplementation. Testicular apoptosis marked by the altered messenger ribonucleic acid and protein expression of apoptotic markers like Bax, Bcl-2, caspase 9, and caspase 3 were also attenuated upon FHPD supplementation along with diminution of arsenic accumulation in testicular tissues. FHPD not only mitigated the adverse effects of arsenic induced gonadotoxicity but also helped in sustaining the normal reproductive functions.

The Protective Effects of Trametes Versicolor on Arsenic-Induced Male Reproductive Toxicity through Regulation of Oxidative Stress: A Biochemical and Histopathological Survey

Exposure to arsenic is linked to a wide range of diseases, in particular male reproductive toxicities. Trametes versicolor is a traditional medicinal fungus with a remarkable potential for antioxidant activity. The purpose of this study was to examine the ameliorating effects of water and methanol extracts of T. versicolor on arsenic-induced male reproductive toxicities via the abrogation of oxidative stress. The mice were divided as follows: control: normal saline, As: arsenic (15 mg/kg), WE: water extract (400 mg/kg), ME: methanol extract (400 mg/kg), As + WE: arsenic (15 mg/kg) + water extract (100, 200, 400 mg/kg), As + ME: arsenic (15 mg/kg) + methanol extract (100, 200, 400 mg/kg), and positive control: arsenic (15 mg/kg) + vitamin C (500 mg/kg). Animals were treated via the intraperitoneal route. About 24 hr later, the mice were euthanized, and oxidative stress parameters (reactive oxygen species [ROS], lipid peroxidation, glutathione concentration, protein carbonylation, glutathione peroxidase, and superoxide dismutase activity), histopathological changes and sperm parameters (count, motility, and morphology) were examined in the testicular tissue. Arsenic caused significant pathological changes in the testicular tissue and sperm morphology and significantly reduced sperm count and motility. Moreover, arsenic mediated oxidative stress via significant increases in ROS generation, lipid peroxidation, and protein carbonyl content, as well as significant depletion in glutathione concentration and superoxide dismutase and glutathione peroxidase activities. Although, coadministration of water and methanol extracts of T. versicolor at 200 and 400 mg/kg counteracted arsenic-induced oxidative and histopathological damages and improved sperm parameters. Our study indicated that T. versicolor ameliorated arsenic-induced testis toxicity and sperm dysfunction via attenuation of oxidative damage.

Origin, dietary exposure, and toxicity of endocrine-disrupting food chemical contaminants: A comprehensive review

Endocrine-disrupting chemicals (EDCs) are a growing public health concern worldwide. Consumption of foodstuffs is currently thought to be one of the principal exposure routes to EDCs. However, alternative ways of human exposure are through inhalation of chemicals and dermal contact. These compounds in food products such as canned food, bottled water, dairy products, fish, meat, egg, and vegetables are a ubiquitous concern to the general population. Therefore, understanding EDCs' properties, such as origin, exposure, toxicological impact, and legal aspects are vital to control their release to the environment and food. The present paper provides an overview of the EDCs and their possible disrupting impact on the endocrine system and other organs.

Arsenite exposure disturbs maternal-to-zygote transition by attenuating H3K27ac during mouse preimplantation development

Arsenite is commonly used as an insecticide, antiseptic and herbicide. It can enter the food chain via through soil contamination, and harm human health, including the reproductive systems. Early embryos, as the initial stage of mammalian life, are very sensitive to the environmental toxins and pollutants. However, whether and how arsenite disturbs the early embryo development remains unclear. Our study used mouse early embryos as a model and revealed that arsenite exposure did not cause reactive oxygen species production, DNA damage or apoptosis. However, arsenite exposure arrested embryonic development at the 2-cell stage by altering gene expression patterns. The transcriptional profile in the disrupted embryos showed abnormal maternal-to-zygote transition (MZT). More importantly, arsenite exposure attenuated H3K27ac modification enrichment at the promoter region of Brg1, a key gene for MZT, which inhibited its transcription, and further affected MZT and early embryonic development. In conclusion our study highlights arsenite exposure affects MZT by reducing the enrichment of H3K27ac on the embryonic genome, and ultimately induces early embryonic development arrest at the 2-cell stage.

Arsenic interferes with spermatogenesis involving Rictor/mTORC2-mediated blood-testis barrier disruption in mice

Ingestion of arsenic interferes with spermatogenesis and increases the risk of male infertility, but the underlying mechanism remines unclear. In this study, we investigated spermatogenic injury with a focus on blood-testis barrier (BTB) disruption by administrating 5 mg/L and 15 mg/L arsenic orally to adult male mice for 60 d. Our results showed that arsenic exposure reduced sperm quality, altered testicular architecture, and impaired Sertoli cell junctions at the BTB. Analysis of BTB junctional proteins revealed that arsenic intake downregulated Claudin-11 expression and increased protein levels of β-catenin, N-cadherin, and Connexin-43. Aberrant localization of these membrane proteins was also observed in arsenic-treated mice. Meanwhile, arsenic exposure altered the components of Rictor/mTORC2 pathway in mouse testis, including inhibition of Rictor expression, reduced phosphorylation of protein kinase Cα (PKCα) and protein kinase B (PKB), and elevated matrix metalloproteinase-9 (MMP-9) levels. Furthermore, arsenic also induced testicular lipid peroxidative damage, inhibited antioxidant enzyme (T-SOD) activity, and caused glutathione (GSH) depletion. Our findings suggest that disruption of BTB integrity is one of the main factors responsible for the decline in sperm quality caused by arsenic. PKCα-mediated rearrangement of actin filaments and PKB/MMP-9-increased barrier permeability jointly contribute to arsenic-induced BTB disruption.

The interplay of arsenic, silymarin, and NF-ĸB pathway in male reproductive toxicity: A review

Arsenic toxicity is one of the most trending reasons for several malfunctions, particularly reproductive toxicity. The exact mechanism of arsenic poisoning is a big question mark. Exposure to arsenic reduces sperm count, impairs fertilization, and causes inflammation and genotoxicity through interfering with autophagy, epigenetics, ROS generation, downregulation of essential protein expression, metabolite changes, and hampering several signaling cascades, particularly by the alteration of NF-ĸB pathway. This work tries to give a clear idea about the different aspects of arsenic resulting in male reproductive complications, often leading to infertility. The first part of this article explains the implications of arsenic poisoning and the crosstalk of the NF-ĸB pathway in male reproductive toxicity. Silymarin is a bioactive compound that exerts anti-cancer and anti-inflammatory properties and has demonstrated hopeful outcomes in several cancers, including colon cancer, breast cancer, and skin cancer, by downregulating the hyperactive NF-ĸB pathway. The next half of this article thus sheds light on silymarin's therapeutic potential in inhibiting the NF-ĸB signaling cascade, thus offering protection against arsenic-induced male reproductive toxicity.

Does environmental pollution affect male reproductive system in naturally exposed vertebrates? A systematic review

Due to environmental contamination, the environment constantly receives pollutants from various anthropic actions. These pollutants put ecological health at risk due to contamination and accumulation in living organisms, including wild animals and humans. Exposure can cause physiological, morphological, and behavioral changes in living beings. In this context, laboratory studies have frequently investigated how environmental contaminants affect the male reproductive system and gametes. However, few studies have examined how these contaminants affect male reproduction in naturally exposed animals. To better understand this topic, we conducted a systematic review of the effects of exposing male vertebrate animals to polluted environments on their reproductive functions. After an extensive search using the PubMed/MEDLINE, Scopus, and Web of Science databases, 39 studies met our inclusion criteria and were eligible for this review. This study showed that reproductive damages were frequent in fishes, amphibians, reptiles, birds, and mammals exposed to contaminated environments. Wild animals are exposed mainly to endocrine-disrupting compounds (EDCs), toxic metals, and radiation. Exposure to pollutants causes a reduction in androgen levels, impaired spermatogenesis, morphological damage to reproductive organs, and decreased sperm quality, leading to reduced fertility and population decline. Although several species have been studied, the number of studies is limited for some groups of vertebrates. Wildlife has proven valuable to our understanding of the potential effects of environmental contaminants on human and ecosystem health. Thus, some recommendations for future investigations are provided. This review also creates a baseline for the understanding state of the art in reproductive toxicology studies.

Arsenic-induced toxicity and the ameliorative role of antioxidants and natural compounds

Arsenic (As) poisoning has proven to be a major threat worldwide because of its toxic effects on the human body. As toxicity through drinking water is a global health concern. The toxicity of As is known to affect the liver, kidney, lungs, muscles, cardiovascular system, and nervous system and can even induce diabetes. Further As can cause skin lesions leading to notable diseases in the skin like Bowen's disease. Chronic exposure to As has caused many tragedies in Eastern, and several Southeast Asian and Latin American countries. Long-term exposure to As makes it an immediate threat that should be dealt with as a priority, and one of the ways to handle it may be with the use of antioxidants. In this review, we have discussed the natural and anthropogenic sources of As, its metabolism, pathophysiology, and mechanism of toxicity. Besides, we have also discussed some of the synthetic chelators and the ameliorative role of antioxidants and natural compounds in reducing As toxicity.

Arsenic exposure and its implications in male fertility

Arsenic exposure is a global health concern. This toxic metalloid is ubiquitous in the environment and contaminates food and drinking water. Once ingested, it undergoes a complex metabolic process within the body, which contributes to its accumulation and reactivity. Arsenic toxicity stems from the induction of oxidative stress, inhibition of thiol-containing proteins, and mimicry of inorganic phosphates. Arsenic poisoning is associated with the development of reproductive disorders. In males, arsenic causes a reduction in testicular weight and alterations in steroidogenesis and spermatogenesis. Moreover, it reduces the number and quality of spermatozoa harvested from the cauda epididymis. The mitochondria are targets of arsenic toxicity because of the production of free radicals and their high content of cysteine-rich proteins and fatty acids. Mitochondrial dysfunction may contribute to reproductive disorders because this organelle is crucial for controlling testicular and epididymal events related to sperm production and maturation. All of these alterations mediated by arsenic exposure contribute to the failure of male reproductive competence by reducing gamete viability. This review describes the potential mechanisms of arsenic toxicity, its detrimental effects on male reproductive organs, and consequences on sperm fertility.

Mechanistic insight into the protective effects of fisetin against arsenic-induced reproductive toxicity in male rats

Arsenic is one of the most hazardous environmental contaminants, which adversely affects the dynamics of male reproductive system. Fisetin (FIS) is a bioactive flavonoid, which is known to exert strong antioxidative effects. Therefore, the current research was planned to evaluate the alleviative efficacy of FIS against arsenic-induced reproductive damages. Forty-eight male albino rats were divided into 4 groups (n = 12), which were treated as follows: (1) Control, (2) Arsenic-intoxicated group (8 mg kg^-1), (3) Arsenic + FIS-treated group (8 mg kg^-1 + 10 mg kg^-1), and (4) FIS-treated group (10 mgkg^-1). After 56 days of treatment, the biochemical, lipidemic, steroidogenic, hormonal, spermatological, apoptotic and histoarchitectural profiles of rats were analyzed. Arsenic intoxication reduced the enzymatic activities of catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione reductase (GSR), in addition to glutathione (GSH) level. Conversely, the levels of thiobarbituric acid reactive substance (TBARS) and reactive oxygen species (ROS) were increased. Moreover, it escalated the level of low-density lipoprotein (LDL), triglycerides and total cholesterol, while declining the level of high-density lipoprotein (HDL). Furthermore, steroidogenic enzymes expressions, 3β-hydroxysteroid dehydrogenase (HSD), 17β-HSD, steroidogenic acute regulatory protein (StAR), cholesterol side-chain cleavage enzyme (CYP11A1) and 17α-hydroxylase/17, 20-lyase (CYP17A1), were found to be reduced, which brought down the level of testosterone. Besides, the levels of gonadotropins (LH and FSH) were decreased. Additionally, a decline in sperm mitochondrial membrane potential (MMP), motility, epididymal sperm count and hypo-osmotic swelling (HOS) coil-tailed sperms was observed, whereas the dead sperms and structural damages (head, midpiece and tail) of sperms were escalated. Moreover, arsenic exposure up-regulated the mRNA expressions of apoptotic markers, namely Bax and caspase-3, whereas lowered the expression of anti-apoptotic marker, Bcl-2. In addition, it induced histoarchitectural changes in testes of rats. However, FIS treatment resulted in remarkable improvements in testicular and sperm parameters. Therefore, it was inferred that FIS could serve as a therapeutic candidate against arsenic-generated male reproductive toxicity attributing to its anti-oxidant, anti-lipoperoxidative, anti-apoptotic, and androgenic efficacy.

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

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

Speciation and source changes of atmospheric arsenic in Qingdao from 2016 to 2020 - Response to control policies in China

Arsenic (As) is a toxic pollutant in the atmosphere. The atmospheric As concentration is high over the East Asian continent. At present, there is less research on the long-term trend of atmospheric arsenic pollution, which is not conducive to understanding its behavior. Total suspended particulate matter (TSP) samples were collected in Qingdao in autumn and winter from 2016 to 2020 to analyze total arsenic (TAs), As(V) and As(III). The interannual variation patterns, influencing factors and health risks of arsenic concentrations in aerosols were discussed. The results showed that As(V) is the dominant species of arsenic in aerosols. The average concentration of TAs gradually decreased and the proportion of As(III) increased during autumn and winter from 2016 to 2020. The levels of TAs, As(V) and As(III) in aerosols increased during the heating period and on polluted days. Negative correlation between TAs/TSP and TSP indicated that higher concentrations of TSP in the atmosphere would reduce the content of TAs in particulate matter. The increase of secondary aerosol particles played a dilution effect. Mobile source emissions, biomass and coal combustion were main sources of atmospheric arsenic. The distribution range of large potential sources of atmospheric arsenic decreased from 2016 to 2020, and concentrated, mainly in parts of Shandong province and its offshore areas. Local sources contributed the most to atmospheric arsenic pollution in Qingdao in autumn and winter. TAs, As(V) and As(III) posed a low non-carcinogenic risk and a negligible carcinogenic risk to adults and children. This study reveals the influence of strict air pollution control policies on the speciation and source of arsenic in aerosols.

Ameliorating effect of Mucuna pruriens seed extract on sodium arsenite-induced testicular toxicity and hepato-renal histopathology in rats

Background and Aim

A significant cause of arsenic poisoning is polluted groundwater. Arsenic poisoning results in the suppression of spermatogenesis and the liver and kidneys are vulnerable to the toxic effects as well. Mucuna pruriens has been identified to have fertility-enhancing and anti-lipid peroxidation properties. Based on these properties of M. pruriens, this study aimed to investigate the efficacy of M. pruriens seed extract in reducing sodium arsenite-induced testicular impairment and hepato-renal histopathology in rats.

Materials and Methods

The study was divided into two groups; short-term (45 days) and long-term (90 days) treatment groups and each group was divided into nine subgroups. Subgroups 1 and 2 served as normal and N-acetyl cysteine (NAC) controls, respectively. Subgroups 3-9 received sodium arsenite in the drinking water (50 mg/L). Subgroup-4 received NAC (210 mg/kg body weight [BW]) orally once daily. Subgroups 5-7 received aqueous seed extract of M. pruriens (350, 530, and 700 mg/kg BW, respectively) orally once daily. Subgroups 8 and 9 received a combination of NAC and aqueous seed extract (350 and 530 mg/kg BW, respectively) orally once daily. Following the treatment, animals were sacrificed and sperm parameters and DNA damage were evaluated. Testis, liver, and kidneys were analyzed for histopathology.

Results

Sodium arsenite-induced a significant reduction in sperm parameters and increase in the abnormal architecture of spermatozoa. Histology revealed tissue necrosis. The M. pruriens seed extract ameliorated the damaging effects of sodium arsenite with respect to tissue architecture and sperm parameters when coadministered.

Conclusion

Mucuna pruriens has beneficial effects against the deleterious effects of sodium arsenite on various tissues. Thus, M. pruriens (530 and 700 mg/kg BW) supplementation would reduce the adverse changes observed with sodium arsenite exposure.

Integrated review of the nexus between toxic elements in the environment and human health

Emerging pollutants in the environment due to economic development have become a global challenge for environmental and human health management. Potentially toxic elements (PTEs), a major group of pollutants, have been detected in soil, air, water and food crops. Humans are exposed to PTEs through soil ingestion, consumption of water, uptake of food crop products originating from polluted fields, breathing of dust and fumes, and direct contact of the skin with contaminated soil and water. The dose absorbed by humans, the exposure route and the duration (i.e., acute or chronic) determine the toxicity of PTEs. Poisoning by PTEs can lead to excessive damage to health as a consequence of oxidative stress produced by the formation of free radicals and, as a consequence, to various disorders. The toxicity of certain organs includes neurotoxicity, nephrotoxicity, hepatotoxicity, skin toxicity, and cardiovascular toxicity. In the treatment of PTE toxicity, synthetic chelating agents and symptomatic supportive procedures have been conventionally used. In addition, there are new insights concerning natural products which may be a powerful option to treat several adverse consequences. Health policy implications need to include monitoring air, water, soil, food products, and individuals at risk, as well as environmental manipulation of soil, water, and sewage. The overall goal of this review is to present an integrated view of human exposure, risk assessment, clinical effects, as well as therapy, including new treatment options, related to highly toxic PTEs.

Contemporary Comprehensive Review on Arsenic-Induced Male Reproductive Toxicity and Mechanisms of Phytonutrient Intervention

Arsenic (As) is a poisonous metalloid that is toxic to both humans and animals. Drinking water contamination has been linked to the development of cancer (skin, lung, urinary bladder, and liver), as well as other disorders such as diabetes and cardiovascular, gastrointestinal, neurological, and developmental damage. According to epidemiological studies, As contributes to male infertility, sexual dysfunction, poor sperm quality, and developmental consequences such as low birth weight, spontaneous abortion, and small for gestational age (SGA). Arsenic exposure negatively affected male reproductive systems by lowering testicular and accessory organ weights, and sperm counts, increasing sperm abnormalities and causing apoptotic cell death in Leydig and Sertoli cells, which resulted in decreased testosterone synthesis. Furthermore, during male reproductive toxicity, several molecular signalling pathways, such as apoptosis, inflammation, and autophagy are involved. Phytonutrient intervention in arsenic-induced male reproductive toxicity in various species has received a lot of attention over the years. The current review provides an in-depth summary of the available literature on arsenic-induced male toxicity, as well as therapeutic approaches and future directions.

Study on the Mechanism of Arsenic-Induced Lung Injury Based on SWATH Proteomics Technology

Chronic arsenic poisoning is a global health problem that affects millions of people, and studies have found that long-term ingestion of arsenic-containing compounds can lead to lung damage, but the exact mechanism is unknown. In this study, Sprague-Dawley (SD) rats were used as the research object, and the proteomic analysis method based on sequential window acquisition of all theoretical fragment ions (SWATH) was used to detect the changes in the expression levels of related proteins in the lung tissue of arsenic-exposed rats, and to explore the mechanism of arsenic compound-induced lung injury. The results showed that arsenic exposure resulted in the abnormal expression of collagen type III and proteins involved in metabolic, immune, and cellular processes, leading to the dysfunction of important pathways associated with these proteins, resulting in lung injury. It suggested that the underlying mechanism of arsenic-induced lung injury may be related to oxidative stress, immune injury, cell junction, and collagen type III. This result provides a new research idea for revealing the mechanism of lung injury caused by arsenic exposure.

Comparison between Macro and Trace Element Concentrations in Human Semen and Blood Serum in Highly Polluted Areas in Italy

Macro and trace elements are important regulators of biological processes, including those ones linked to reproduction. Among them, Ca, Cu, Fe, K, Mg, Mn, Na, Se, and Zn ensure normal spermatic functions. Hence, the aim of this study was to evaluate the concentrations of 26 macro and trace elements (Al, As, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Li, Mg, Mn, Na, Ni, Pb, Rb, Sb, Se, Sn, Sr, U, V, and Zn) in blood serum and also in semen of healthy young men, homogeneous for age, anthropometric characteristics, and lifestyle, living in three highly polluted areas in Italy. Furthermore, a comparison among three geographical areas was performed to highlight any difference in the investigated parameters and, overall, to speculate any correlations between chemical elements and semen quality. Statistically significant differences (p < 0.05) among the three areas were found for each investigated element, in both semen and serum samples, where inter-area differences were more evident in semen than in blood serum, suggesting human semen as an early environmental marker. Considering the homogeneity of three cohorts, these differences could be due more to environmental conditions in the recruiting areas, suggesting that variations in those involved in reproductive-associated pathways can have an impact on male fertility. Nevertheless, more research is needed to evaluate threshold values for sperm dysfunction and male infertility. Actually, the role of different dietary intake and environmental exposure underlying the observed differences in the recruiting areas is under further investigation for the same cohort.

Arsenic exposure during juvenile and puberty significantly affected reproductive system development of female SD rats

Infertility affects about 10-15% couples over the world, among which a large number of cases the underlying causes are still unclear. Recent studies suggest that environmental factors may play an important role in these idiopathic infertilities. Arsenic is a heavy metal found in drinking water over the world. Its effect on the development of female reproductive system at the environmental-relevant levels is still largely unknown. To test the hypothesis that arsenic exposure during juvenile and puberty may affect sex maturation and female reproductive system development, SD rats of 3 weeks of age were exposed to arsenic with environmental-relevant levels (0, 0.02, 0.2, or 2 mg/L, n = 16/group) through drinking water for about 44 days until the rats reached adulthood (65 days of age). Arsenic exposure significantly reduced the weights of both ovary and uterus without affecting the body weight. Also, arsenic exposure disturbed estrus cycles and reduced the numbers of primordial follicles and corpora lutea while increased atretic follicles. In addition, arsenic reduced serum levels of estradiol, progesterone and testosterone but increased LH and FSH levels in dose-dependent manners. QPCR and Western blot experiments indicated arsenic selectively down-regulated ovarian steroidogenic-related proteins FSHR, STAR, CYP17A1, HSD3B1 and CYP19A1 and signaling molecules PKA-ERK-JNK-cJUN, without affecting AKT and CREB. As about reproductive capacity, arsenic-exposed dams had smaller pups, reduced litter size and lower number of male pups without a change in female pups. In conclusion, juvenile and pubertal arsenic exposures at environmental-relevant levels significantly reduced reproductive functions and capacity by adult. Since the lowest effective dose is very close to the government safety standards, the relevancy of arsenic over exposure to reproductive defects in human deserves further study.

Eugenol reduces serum testosterone levels and sperm viability in adult Wistar rats

Eugenol is the main constituent of clove extract. It is a remarkably versatile molecule incorporated as a functional ingredient in several food products and widely applied in the pharmaceutical industry. Men consume natural products enriched with eugenol for treating sexual disorders and using as aphrodisiacs. Nevertheless, there is no information about the impact of eugenol intake on the reproductive parameters of healthy males. Therefore, we provided 10, 20, and 40 mg kg^-1 pure eugenol to adult Wistar rats for 60 days. Testis, epididymis, and spermatozoa were analyzed under microscopic, biochemical, and functional approaches. This phenolic compound did not alter testicular and epididymal biometry and microscopy. However, 20 and 40 mg kg^-1 eugenol reduced serum testosterone levels. The highest dose altered lactate and glucose concentrations in the epididymis. All the eugenol concentrations diminished CAT activity and MDA levels in the testis and increased FRAP and CAT activity in the epididymis. Epididymal sperm from rats receiving 10, 20, and 40 mg kg^-1 eugenol presented high Ca²⁺ ATPase activity and low motility. In conclusion, eugenol at low and high doses negatively impacted the competence of epididymal sperm and modified oxidative parameters in male organs, with no influence on their microscopy.

Transgenerational male reproductive effect of prenatal arsenic exposure: abnormal spermatogenesis with Igf2/H19 epigenetic alteration in CD1 mouse

Developmental exposure to environmental toxicants can induce transgenerational reproductive disease phenotypes through epigenetic mechanisms. We treated pregnant CD-1 (F0) mice with drinking water containing sodium arsenite (85 ppm) from days 8 to 18 of gestation. Male offspring were bred with untreated female mice until the F3 generation was produced. Our results revealed that F0 transient exposure to arsenic can cause decreased sperm quality and histological abnormalities in the F1 and F3. The overall methylation status of Igf2 DMR2 and H19 DMR was significantly lower in the arsenic-exposed group than that of the control group in both F1 and F3. The relative mRNA expression levels of Igf2 and H19 in arsenic-exposed males were significantly increased in both F1 and F3. This study indicates that ancestral exposure to arsenic may result in transgenerational inheritance of an impaired spermatogenesis phenotyping involving both epigenetic alterations and the abnormal expression of Igf2 and H19.

Arsenic intake-induced gastric toxicity is blocked by grape skin extract by modulating inflammation and oxidative stress in a mouse model

Arsenic (As) is known to induce toxic responses in many organs of human beings and animals. However, research concerning toxicity in the stomach is limited. In this study, arsenic-induced gastric toxicity was investigated in a mouse model, and grape skin extract (GSE) was confirmed to have protective effects against arsenic toxicity. Our experimental results showed that exposure to 10 mg/l arsenic via drinking water for 56 days caused oxidative damage and inflammatory responses. The H₂O₂ and malondialdehyde (MDA) contents were significantly increased, accompanied by significant decreases in total superoxide dismutase (T-SOD) activity and glutathione (GSH) content in the gastric tissue of arsenic-treated mice. Two inflammatory signalling pathways, i.e., TLR2/MyD88/NF-κB and IL-6/STAT-3, were activated, along with inflammatory cell infiltration and the elevated mRNA expression of pro-inflammatory cytokines (TNF-α, IL-1β and IFN-γ) and myeloperoxidase (MPO) in the gastric tissue of mice exposed to arsenic. Meanwhile, the mRNA levels of the ZO-1, ZO-2 and occludin genes, which encode the key components of tight junction (TJ) complexes, were downregulated. However, the application of GSE (300 mg/kg bw) significantly inhibited the arsenic-induced increases in H₂O₂ and MDA contents and the decreases in T-SOD activity and GSH content. The arsenic-mediated gene expression of pro-inflammatory cytokines (TNF-α, IL-1β and IFN-γ), MPO and IL-6/STAT3 and TLR2/MyD88/NF-κB pathways was found down-regulated. Moreover, the arsenic-induced inflammatory cell infiltration and inhibition of TJ genes transcription were markedly attenuated in the As+GSE (300 mg/kg bw) group. Based on the present findings, arsenic intake appears to cause gastric toxicity via oxidative stress and inflammation, and the application of GSE offers significant protection against arsenic toxicity in a mouse model by attenuating the oxidative stress and inflammatory response. Our results suggest that GSE by oral administration might function as a candidate therapeutic supplement to antagonize arsenic toxicity.

Effect of heavy metals on epididymal morphology and function: An integrative review

Male fertility has deteriorated over the last decades, and environmental risk factors are among the possible causes of this phenomenon. Pollutants such as heavy metals might accumulate in male reproductive organs to levels that are associated with reproductive disorders. Several studies reported detrimental effects of inorganic arsenic (iAs⁺³/iAs⁺⁵), cadmium (Cd⁺²), lead (Pb⁺²), and mercury (Hg⁺²/CH₃Hg⁺²) on the epididymis, which plays a crucial role in sperm maturation. However, the magnitude of their effects and the consequences on the physiology of the epididymis are still unclear. Therefore, an integrative review with meta-analyses was conducted examining 138 studies to determine how exposure to arsenic, cadmium, lead, and mercury affects epididymal morphology and functions, using primarily murine data from experimental studies as a source. This study showed that exposure to metal(loids) reduced epididymal weight, sperm motility, and sperm number. Inorganic arsenic, cadmium, and lead damaged sperm structures within the epididymal duct. While sodium arsenite, sodium arsenate, and lead acetate generate oxidative stress by an imbalance between ROS production and scavenging, cadmium chloride causes an increase in the pH level of the luminal fluid (from 6.5 to 7.37) that diminishes sperm viability. Inorganic arsenic induced a delay in the sperm transit time by modulating noradrenaline and dopamine secretion. Subacute exposure to heavy metals at concentrations < 0.1 mg L^-1 initiates a dyshomeostasis of calcium, copper, iron, and zinc that disturbs sperm parameters and reduces epididymal weight. These alterations worsen with prolonged exposure time and higher doses. Most studies evaluated the effects of concentrations > 1.1 mg L^-1 of heavy metals on the epididymis rather than doses with relevant importance for human health risk. This meta-analytical study faced limitations regarding a deeper analysis of epididymis physiology. Hence, several recommendations for future investigations are provided. This review creates a baseline for the comprehension of epididymal toxicology.

Multi-omics analyses reveal the mechanisms of Arsenic-induced male reproductive toxicity in mice

Arsenic (As), a widespread environmental contaminant, can induce serious male reproductive injury; however, the underlying mechanisms remain unclear. Multi-omics analyses, including transcriptome, proteome, and phosphoproteome could promote our understanding of As-induced male reproductive toxicity. Here, we established the reproductive injured mice model by intraperitoneal injection of NaAsO2 (8 mg/kg body weight), which was validated by reduced reproductive cells, sperm motility, and litter size. The followed multi-omics analyses of mice revealed that As exposure inhibited ATP production by decreasing the expression of proteins HK1, and GAPDHS, and the enzymatic activities of PDH and SDH. The inhibition of mitochondrial activity and increase in HDAC2 and MTA3 dysregulated the lysine acetylation levels of histone and global proteins. Specifically, the downregulated histones H4K5ac and H4K12ac and upregulated histone H3K9ac disordered the distribution of TP1 to interfere with spermatogenesis. Moreover, As could reduce the expression of COL1A1, RAB13, and LSR to disrupt the junctions between seminiferous tubules, and thereinto, the inhibition of RAB13 increased PKA-dependent phosphorylation. Our study reveals that As causes male reproductive toxicity through decreasing energy production, altering histone acetylation, and impairing cell junctions. Our findings provide basic data for further studies on As reproductive toxicity.

Soluble arsenic species in total suspended particles and their health risk and origin implication: A case study in Taiyuan, China

The inhalation is one of important exposure ways to arsenic. Traditionally, the health risk of arsenic exposure from particulate matter (PM) was assessed by using total arsenic, which may erroneously estimate the health risk of arsenic since the toxicity of arsenic depends on its chemical species and not all arsenic in PM is bio-accessible. Herein, total suspended particles (TSP) were collected from Taiyuan in China during whole year of 2018, and the species and concentrations of arsenic in TSP were investigated in order to more accurately assess the health risk of arsenic exposure from TSP and evaluate the possible sources of arsenic in TSP. Total arsenic varied within 1.16-28.4 ng/m³ with a mean value of 7.40 ng/m³, which exceeded the standard limit of China (6 ng/m³). Two arsenic species, As⁵⁺ and As³⁺, were detected out in soluble fractions of TSP, with As⁵⁺ as dominant species. Total arsenic, soluble arsenic and soluble As⁵⁺ in TSP revealed closed correlation each other, indicating that they may originate from similar anthropogenic and crust sources. Soluble As³⁺ showed no obvious correlations with total arsenic, implying that soluble As³⁺ has different dominant sources. The ratio of As⁵⁺/As³⁺ significantly varied within 1.08-32.5 and the percentages of soluble arsenic in total arsenic varied within 50%-93%, implying that arsenic in TSP of Taiyuan has multiple sources and none of them stably dominated during 2018. Non-carcinogenic risk and carcinogenic risk indicators calculated with soluble arsenic species showed significant difference to that calculated with total arsenic or soluble arsenic when TSP contained equivalent As⁵⁺ and As³⁺, verifying that it is necessary and more accurate to assess the health risk of arsenic exposure from TSP by using soluble arsenic species, rather than total arsenic or soluble arsenic.

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

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

OUP accepted manuscript

Objective

The central objective of this study was to investigate the cumulative effects restraint stress and sodium arsenite on reproductive health in male rats.

Methods

Healthy male Wistar rats were allocated into 4 groups (n = 8). Animals in group 1 served as controls and did not subjected to any stress. Rats in groups 2, 3, and 4 were subjected to either restraint stress (5 h/day) or maintained on arsenic (25 ppm) via drinking water or both for 65 days. After completion of the experimental period, all the rats were analyzed for selected reproductive endpoints.

Results

Restraint stress or sodium arsenite treatment increased serum corticosterone levels, reduced testicular daily sperm count, epididymal sperm viability, motility, membrane integrity, and decreased testicular steroidogenic enzymes such as 3β- and 17β-hydroxysteroid dehydrogenases associated with reduced serum testosterone levels, deteriorated testicular architecture, and reduced activity levels of testicular superoxide dismutase and catalase accompanied by elevated lipid peroxidation levels. In rats subjected to restraint stress and sodium arsenite, a significant decrease in selected sperm qualitative and quantitative parameters, serum testosterone levels were observed as compared with rats subjected to sodium arsenite alone. A significant increase in the levels of lipid peroxidation with a concomitant decrease in the activities of antioxidant enzymes was observed in the testis of rats subjected to both restraint stress and sodium arsenite treatment as compared with sodium arsenite alone intoxicated rats. Surprisingly, serum corticosterone levels were significantly elevated in rats following both stressors as compared with arsenic alone treated rats. Analysis of atomic absorption spectroscopy revealed that the accumulation of arsenic in the testis of arsenic-treated and arsenic plus immobilization stress groups was significant as compared with controls.

Conclusions

Based on the findings, it can be concluded that deterioration of male reproductive health could be accelerated in arsenic intoxicated rats following restraint stress.

Intraperitoneal kisspeptin-10 administration ameliorates sodium arsenite-induced reproductive toxicity in adult male mice

The current study investigated the protective ameliorative effect of intraperitoneally administered kisspeptin-10 (50 nmol/day) against reproductive toxicity in adult male mice challenged with 35 days of exposure to sodium arsenite in drinking water. Mice were divided into tap water control, sodium arsenite-alone (4 ppm and 10 ppm), kisspeptin-alone (intermittent and continuous) and combined (sodium arsenite +kisspeptin-10 intermittent and continuous) treatment groups. Results revealed protective effect of both intermittent and continuous kisspeptin doses on reproductive organs against sodium arsenite-induced toxicity. This was indicated by an increase (p < 0.001) in the activity of antioxidant enzymes and a decrease (p < 0.001) in the levels of oxidative stress biomarkers. Concomitant significant increase was noticeable in the relative organ weight (p < 0.01), and serum testosterone and seminal fructose (p < 0.001), and a significant improvement in sperm parameters was also observed. A significant downregulation of lactate dehydrogenase concentration demonstrated further the protective effect of kisspeptin against tissue damage. Histologically, both treatment regimens of kisspeptin combined with sodium arsenite exposure prevented massive germ cell loss and tissue damage, a condition prominent in sodium arsenite-alone-treated mice. The study demonstrates for the first time kisspeptin's potential to mitigate the biochemical and histotoxic effects of arsenic on male reproductive system.

Lead and lead-arsenic combined exposure induces mortality and developmental impairments in zebrafish embryos: a study using wild-caught zebrafish from Bangladesh

Heavy metal toxicity has become a global health burden, exerting various physiological effects on aquatic animals and humans. Zebrafish (Danio rerio) has emerged as a real-time model system for toxicological study. We previously reported the effects of arsenic on the embryonic development of zebrafish. The current study aimed to get deep insights into the toxic effects of another heavy metal, lead, on the early embryonic development of wild-caught zebrafish. We exposed freshly collected zebrafish embryos to different lead concentrations and studied different developmental and morphological changes using an inverted microscope. In a separate experiment, embryos were exposed to a combination of lead and arsenic to evaluate the combined effects of the elements. Lead concentration of as low as 0.25 mM resulted in developmental and morphological abnormalities in the zebrafish embryos. Exposure to different concentrations (0.25 mM, 0.5 mM, and 0.75 mM) caused a higher mortality rate of the embryos. Besides, an increased rate of arrested hatching, irregularities in size and shape of the yolk sac, deformed otic vesicle, and body curvature were observed in a dose-dependent manner. Lead exposure also resulted in reduced heart rate and severe pericardial edema. The combined effect of minimum concentrations of lead and arsenic that causes toxicity individually (0.25 mM and 1.0 mM, respectively) revealed a more severe effect than the individual treatments. This study's findings explain the association of heavy metal exposure with an increased rate of miscarriage/abortion incidences in highly polluted areas assisting in proper management and creating public awareness.

Protective Effect of Nano-Vitamin C on Infertility due to Oxidative Stress Induced by Lead and Arsenic in Male Rats

Occupational and environmental exposure to heavy metals such as arsenic (As) and lead (Pb) by inducing oxidative damage may impair male fertility. However, there is a new view that shows that the nano form of vitamins such as vitamin C, which have antioxidant activity, can be effective in improving this disorder. Therefore, this study aimed to evaluate the effect of NVC (NVC) on reproductive toxicity caused by the combination of Pb and As on testicular histology, sperm morphology, oxidative stress parameters, and hormonal changes in male rats. In this experimental study, forty-two male Wistar rats were randomly divided into six groups: control, NVC (200 mg/kg), As (50 ppm sodium arsenate), Pb (500 ppm Pb acetate), As + NVC, and Pb + NVC. FSH, LH, and testosterone levels were measured in serum. The activity of glutathione peroxidase (GPx), superoxide dismutase (SOD), catalase (CAT), carbonyl protein, malondialdehyde (MDA), and total antioxidant capacity (TAC) was measured in testis. Histological examination and sperm parameters were also evaluated. FSH, LH, and testosterone levels and sperm parameters significantly decreased, and levels of protein carbonyl, MDA, and DNA fragmentation increased in the As and Pb groups, while treatment with NVC could improve them. Histological evaluation and sperm parameters in As and Pb groups showed damage in the process of spermatogenesis and sperm parameters. The treatment with NVC could significantly improve these parameters. The activity of GPx, SOD, and CAT in testis decreased in As and Pb groups, while treatment with NVC could enhance them. It can be concluded that NVC by inhibiting oxidative damage and improving serum level of testosterone, LH, and FSH could overcome As- and Pb-induced reproductive dysfunction.

Molecular Mechanism of Arsenic-Induced Neurotoxicity including Neuronal Dysfunctions

Arsenic is a key environmental toxicant having significant impacts on human health. Millions of people in developing countries such as Bangladesh, Mexico, Taiwan, and India are affected by arsenic contamination through groundwater. Environmental contamination of arsenic leads to leads to various types of cancers, coronary and neurological ailments in human. There are several sources of arsenic exposure such as drinking water, diet, wood preservatives, smoking, air and cosmetics, while, drinking water is the most explored route. Inorganic arsenic exhibits higher levels of toxicity compared its organic forms. Exposure to inorganic arsenic is known to cause major neurological effects such as cytotoxicity, chromosomal aberration, damage to cellular DNA and genotoxicity. On the other hand, long-term exposure to arsenic may cause neurobehavioral effects in the juvenile stage, which may have detrimental effects in the later stages of life. Thus, it is important to understand the toxicology and underlying molecular mechanism of arsenic which will help to mitigate its detrimental effects. The present review focuses on the epidemiology, and the toxic mechanisms responsible for arsenic induced neurobehavioral diseases, including strategies for its management from water, community and household premises. The review also provides a critical analysis of epigenetic and transgenerational modifications, mitochondrial oxidative stress, molecular mechanisms of arsenic-induced oxidative stress, and neuronal dysfunction.

Effects of arsenic and heavy metals on metabolic pathways in cells of human origin: Similarities and differences

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There are distinctive overlaps in different heavy metal affected metabolic pathways.

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Affected pathways vary according to the tissue origin and maturity of the cell.

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Arsenic appears to have relatively more pleiotropic effects on metabolic pathways.

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Some of the arsenic affected pathways are associated with diabetes.

Various anthropogenic and natural events over the years have gradually increased human exposure to various heavy metals. Several of these heavy metals including cadmium, mercury, nickel, chromium, and the metalloid arsenic among others, have created major public health concerns for their high level of toxicities. Identification of the general as well as the differentially affected cellular metabolic pathways will help understanding the molecular mechanism of different heavy metal-induced toxicities. In this study, we analyzed 25 paired (control vs. treated) transcriptomic datasets derived following treatment of various human cells with different heavy metals and metalloid (arsenic, cadmium, chromium, iron, mercury, nickel and vanadium) to identify the affected metabolic pathways. The effects of these metals on metabolic pathways depend not only on the metals per se, but also on the nature of the treated cells. Tissue of origin, therefore, must be considered while assessing the effects of any particular heavy metal or metalloid. Among the metals and metalloid, arsenic appears to have relatively more pleiotropic influences on cellular metabolic pathways including those known to have association with diabetes. Although only two stem cell derived datasets are included in the current study, effects of heavy metals on these cells appear to be different from other mature cells of similar tissue origin. This study provides useful information about different heavy metal affected pathways, which may be useful in further exploration using wet-lab based techniques.

Transgenerational effects in DNA methylation, genotoxicity and reproductive phenotype by chronic arsenic exposure

An emerging concern is the influences of early life exposure to environmental toxicants on offspring characteristics in later life. Since recent evidence suggests a transgenerational transference of aberrant phenotypes from exposed-parents to non-exposed offspring related to adult-onset diseases including reproductive phenotype. The transgenerational potential of arsenic a well know genotoxic and epigenetic modifier agent has not been assessed in mammals until now. In this experimental study, we evaluated the transgenerational effects of arsenic in a rat model with chronic exposure to arsenic. Rats chronically exposed to arsenic in drinking water (1 mg As₂O₃/mL) (F0) were mated to produce the arsenic lineage (F1, F2, and F3). The arsenic toxic effects on were evaluated over the four generations by analyzing the DNA methylation percentage, genotoxicity in WBC and physical and reproductive parameters, including sperm quality parameters and histopathological evaluation of the gonads. Chronic exposure to arsenic caused genotoxic damage (F0-F3) different methylation patterns, alterations in physical and reproductive parameters, aberrant morphology in the ovaries (F0 and F1) and testicles (F1-F3), and a decrease in the quality of sperm (F0-F3, except F2). Parental chronic arsenic exposure causes transgenerational genotoxicity and changes in global DNA methylation which might be associated with reproductive defects in rats. Combined with recent studies reveal that disturbances in the early life of an individual can affect the health of later generations.

Zingiber officinale ethanolic extract attenuates oxidative stress, steroidogenic gene expression alterations, and testicular histopathology induced by sodium arsenite in male rats

Arsenic (As) indelibly exists in the environment and may reach to a food chain. Flavors and herbs are recognized sources of natural antioxidants that play imperative against harmful chemical pollutants. Ginger is utilized around the world as a zesty condiment. This study assessed the ability of ginger extract (GE) as a protector to improve regenerative disabilities initiated by sodium arsenate in reproductive functions in male rats. Thirty-two Sprague-Dawley male rats weighted 240 ± 10 g were arbitrarily relegated into four experimental groups (n = 8): the control group; the GE-treated group received at 100 mg/kg BW; the As-treated group received sodium arsenite at 10 mg/kg BW; the fourth group received sodium arsenite additionally GE at mentioned doses for 4 weeks. Phytochemical results of GE revealed that GE had good antioxidative characteristics and high content of total flavonoid, tannins, alkaloids, and total phenolic components. Simultaneously, treatment of GE showed protection against oxidative stress induced by As and restoration of the serum cholesterol, testosterone, LH, and sperm parameter to normal levels. GE significantly improved the antioxidant activities (GSH, SOD, and CAT) as well as H2O2 and MDA in rats received concurrently the GE and As compared with control group. Moreover, the expression of genes controlling the cholesterol transportation and testosterone synthesis (SR-B1, StAR, CYP11A1, 3b-HSD, 17b-HSD, and CYP17a) as well as LHR showed a meaningful improvement in rats treated by GE plus As compared with their expression in the As-treated group. Besides, GE treatment exhibited significant recovered testis histopathological alterations, reduced the arsenic content in testes, and improved the sperm parameters.

Impact of environmental toxin exposure on male fertility potential

Idiopathic infertility is the most common individual diagnosis in male infertility, representing nearly 44% of cases. Research studies dating over the last half-century consistently demonstrate a decline in male fertility that is incompletely explained by obesity, known genetic causes, or diet and lifestyle changes alone. Human exposures have changed dramatically over the same time course as this fertility decline. Synthetic chemicals surround us. Some are benevolent; however, many are known to cause disruption of the hypothalamic-pituitary-gonadal axis and impair spermatogenesis. More than 80,000 chemicals are registered with the United States National Toxicology Program and nearly 2,000 new chemicals are introduced each year. Many of these are known toxins, such as phthalates, polycyclic aromatic hydrocarbons, aromatic amines, and organophosphate esters, and have been banned or significantly restricted by other countries as they carry known carcinogenic effects and are reproductively toxic. In the United States, many of these chemicals are still permissible in exposure levels known to cause reproductive harm. This contrasts to other chemical regulatory legislature, such as the European Union’s REACH (Registration, Evaluation, Authorization and Restriction of Chemicals) regulations which are more comprehensive and restrictive. Quantification of these diverse exposures on an individual level has proven challenging, although forthcoming technologies may soon make this data available to consumers. Establishing causality and the proportion of idiopathic infertility attributable to environmental toxin exposures remains elusive, however, continued investigation, avoidance of exposure, and mitigation of risk is essential to our reproductive health. The aim of this review is to examine the literature linking changes in male fertility to some of the most common environmental exposures. Specifically, pesticides and herbicides such as dichlorodiphenyltrichloroethane (DDT), dibromochloropropane (DBCP), organophosphates and atrazine, endocrine disrupting compounds including plastic compounds phthalates and bisphenol A (BPA), heavy metals, natural gas/oil, non-ionizing radiation, air and noise pollution, lifestyle factors including diet, obesity, caffeine use, smoking, alcohol and drug use, as well as commonly prescribed medications will be discussed.

Correlations between Basal Trace Minerals and Hormones in Middle and Long-Distance High-Level Male Runners

Several essential trace minerals play an important role in the endocrine system; however, toxic trace minerals have a disruptive effect. The aim of this research was to determine basal concentrations and the possible correlations between trace minerals in plasma and several plasma hormones in runners. Sixty high-level male endurance runners (21 ± 3 years; 1.77 ± 0.05 m; 64.97 ± 7.36 kg) participated in the present study. Plasma hormones were analyzed using an enzyme-linked immunosorbent assay (ELISA) and plasma trace minerals were analyzed with inductively coupled plasma mass spectrometry (ICP-MS). Correlations and simple linear regression were used to assess the association between trace minerals and hormones. Plasma testosterone concentrations were inversely correlated with manganese (r = -0.543; β = -0.410; p < 0.01), selenium (r = -0.292; β = -0.024; p < 0.05), vanadium (r = -0.406; β = -1.278; p < 0.01), arsenic (r = -0.336; β = -0.142; p < 0.05), and lead (r = -0.385; β = -0.418; p < 0.01). Plasma luteinizing hormone (LH) levels were positively correlated with arsenic (r = 0.298; β = 0.327; p < 0.05) and cesium (r = 0.305; β = 2.272; p < 0.05), and negatively correlated with vanadium (r = -0.303; β = -2.467; p < 0.05). Moreover, cortisol concentrations showed significant positive correlations with cadmium (r = 0.291; β = 209.01; p < 0.05). Finally, insulin concentrations were inversely related to vanadium (r = -0.359; β = -3.982; p < 0.05). In conclusion, endurance runners living in areas with high environmental levels of toxic minerals should check their concentrations of anabolic hormones.

Generating adverse outcome pathway (AOP) of inorganic arsenic-induced adult male reproductive impairment via integration of phenotypic analysis in comparative toxicogenomics database (CTD) and AOP wiki

BACKGROUND

Inorganic arsenic (iAs) is a worldwide environmental pollutant which exerts complicated and various toxic effects in organisms. Increasingly epidemic studies have revealed the association between iAs exposure and adult male reproductive impairment. Consistent with the proposal for toxicity testing in the 21st century (TT21C), the adverse outcome pathway (AOP) framework may help unravel the iAs-caused molecular and functional changes leading to male reproductive impairment.

METHOD

Combining CTD's phenotype-disease inference data, iAs-phenotypes were anchored to five male reproductive diseases induced by iAs, and local network topological algorithm was applied in prioritizing their interference significance. Through integrating analysis in AOP Wiki knowledge base, filtered phenotypes were linked to key events consisting of AOPs and assembled together based on evidentially upstream and downstream relationships.

RESULTS

A subset of 655 phenotypes were filtered from CTD as potential key events and showed a significant coherence in five reproductive diseases wherein 39 significant phenotypes showed a good clustering features involving cell cycle, ROS and mitochondria function. Two AOP subnetworks were enriched in AOP Wiki where testosterone reduction and apoptosis of sperm served as focus events respectively. Besides, a candidates list of molecular initialing events was provided of which glucocorticoid receptor activation was overall assessed as an example.

CONCLUSION

This study applied computational and bioinformatics methods in generating AOPs for arsenic reproductive toxicity, which identified the imperative roles of testosterone reduction, response to ROS, spermatogenesis and provided a global view about their internal association. Furthermore, this study helped address the existing knowledge gaps for future experimental verification.

Response of male reproductive function to environmental heavy metal pollution in a free-living passerine bird, Passer montanus

Heavy metals affect male reproductive function by impairing reproductive organs, disturbing reproductive hormone levels or directly affecting sperm quality. However, little attention has been given to the effect of environmental heavy metals on reproductive function in wild male birds. The present study investigated the alterations of reproductive function in male tree sparrows (Passer montanus) exposed to environments contaminated by heavy metals in terms of testis parameters, reproductive hormone levels and sperm movement characteristics. Two plots, Baiyin (BY, mainly polluted by copper, zinc, lead and cadmium) and Liujiaxia (LJX, a relatively unpolluted area) were selected as sampling sites. The results showed that tree sparrows from BY (1) accumulated higher levels of cadmium in the testes, (2) showed lower superoxide dismutase (SOD) activity and malondialdehyde level, with higher total antioxidant capacity and apoptosis level in the testes, (3) showed higher plasma levels of estrogen, follicle stimulating hormone and luteinizing hormone (LH), and (4) had better sperm movement performance. Additionally, we found that testis size, SOD activity in testes and LH levels were decisive factors in sperm movement performance in tree sparrows. Heavy metal concentrations in testes negatively correlated with testis size, SOD activity in testes, and estrogen levels in tree sparrows. The present study indicates that heavy metals accumulating in testes of tree sparrows adversely affected some key indicators of male reproductive function. However, testicular function, reproductive hormone levels and sperm quality showed adaptive responses that tended to partially compensate for the negative effects in the heavy metal polluted area. This study further indicated that the regulation of testicular function and reproductive hormone levels was the main factor for better sperm quality in tree sparrows exposed to environments contaminated by heavy metals.

Inorganic arsenic and its methylated metabolites as endocrine disruptors in the placenta: Mechanisms underpinning glucocorticoid receptor (GR) pathway perturbations

Exposure to inorganic arsenic (iAs) is a significant public health concern with individuals around the globe exposed to harmful levels through contaminated drinking water. Exposure to iAs during pregnancy is of particular concern and has been associated with pregnancy complications and adverse child health later in life. Effects of in utero exposure may be mediated through alterations in key signaling pathways in the placenta that regulate fetal growth and development. A pathway of interest is the glucocorticoid receptor (GR)- signaling pathway, which is known to regulate fetal and placental development. While prior research has shown that iAs alters GR-associated gene expression in trophoblasts, the mechanisms that underlie these perturbations remain unknown. In the present study, we set out to elucidate the molecular mechanisms that underpin observed alterations in GR-associated gene expression. We also aimed to determine whether the methylated metabolites of iAs, namely monomethyl‑arsenic (MMA) and dimethyl‑arsenic (DMA), also influence GR-associated signaling in the placenta. The data indicate that iAs alters GR activation in a dose-dependent manner, reduces nuclear translocation, and reduces DNA binding. Additionally, the results demonstrate that MMA and DMA alter the expression of eight GR-associated genes, modulate GR activation, and alter DNA binding. These data are significant as they highlight the role of iAs as an endocrine disruptor and for the first time explore the effects of MMA and DMA on endocrine signaling in the placenta.

Polyphenol-rich fraction of Alchornea cordifolia leaf ameliorates arsenite-induced infertility in male rats

Alchornea cordifolia is used traditionally for the treatment of infertility and venereal diseases. Thirty rats were randomly divided into five groups of six rats each: Group 1 (distilled water), group 2 (7 mg/kg sodium arsenite), group 3 (7 mg/kg sodium arsenite and 100 µg/kg polyphenol-rich fraction 1 of A. cordifolia), group 4 (7 mg/kg sodium arsenite + 100 µg/kg polyphenol-rich fraction 2) and group 5 (7 mg/kg sodium arsenite + α-tocopherol). The experiment lasted 30 consecutive days. Biochemical markers of oxidative stress and antioxidants, male reproductive hormones, spermatozoa function tests, histopathology, immunoreactivity of androgen receptor binding protein (ARBP) and anti-apoptotic B-cell lymphoma-2 protein expressions were estimated. Data were analysed using descriptive statistics and ANOVA at p < .05. Treatment with AF1 significantly decreased markers of oxidative stress, but increased the systemic antioxidants, testosterone, FSH, spermatozoa count and motility. Histopathological lesions of necrosis and germinal epithelial sloughing observed in sodium arsenite group were absent in sodium arsenite + 100 µg/kg polyphenol-rich fraction 1 group. Expressions of androgen receptor binding protein and anti-apoptotic B-cell lymphoma-2 were highest in sodium arsenite + 100 µg/kg polyphenol-rich fraction 1 group. In conclusion, the polyphenol-rich fraction of A. cordifolia is protective against sodium arsenite-induced infertility in male rats through the inhibition of oxidative and apoptotic mechanisms.