Selenium prevent cadmium-induced hepatotoxicity through modulation of endoplasmic reticulum-resident selenoproteins and attenuation of endoplasmic reticulum stress

Joint associations among non-essential heavy metal mixtures and nutritional factors on glucose metabolism indexes in US adults: evidence from the NHANES 2011-2016

Dietary intake can modify the impact of metals on human health, and is also closely related to glucose metabolism in human bodies. However, research on their interaction is limited. We used data based on 1738 adults aged ≥20 years from the National Health and Nutrition Examination Survey 2011-2016. We combined linear regression and restricted cubic splines with Bayesian kernel machine regression (BKMR) to identify metals associated with each glucose metabolism index (P < 0.05 and the posterior inclusion probabilities of BKMR >0.5) in eight non-essential heavy metals (barium, cadmium, antimony, tungsten, uranium, arsenic, lead, and thallium) and glucose metabolism indexes [fasting plasma glucose (FPG), blood hemoglobin A1c (HbA1c) and homeostatic model assessment of insulin resistance (HOMA-IR)]. We identified two pairs of metals associated with glucose metabolism indexes: cadmium and tungsten to HbA1c and barium and thallium to HOMA-IR. Then, the cross-validated kernel ensemble (CVEK) approach was applied to identify the specific nutrient group (nutrients) that interacted with the association. By using the CVEK model, we identified significant interactions between the energy-adjusted diet inflammatory index (E-DII) and cadmium, tungsten and barium (all P < 0.05); macro-nutrients and cadmium, tungsten and barium (all P < 0.05); minerals and cadmium, tungsten, barium and thallium (all P < 0.05); and A vitamins and thallium (P = 0.043). Furthermore, a lower E-DII, a lower intake of carbohydrates and phosphorus, and a higher consumption of magnesium seem to attenuate the positive association between metals and glucose metabolism indexes. Our finding identifying the nutrients that interact with non-essential heavy metals could provide a feasible nutritional guideline for the general population to protect against the adverse effects of non-essential heavy metals on glucose metabolism.

Vitamin E: An assistant for black soldier fly to reduce cadmium accumulation and toxicity

Cadmium (Cd) is a toxic heavy metal associated with osteoporosis, liver, and kidney disease. The black soldier fly (BSF) Hermetia illucens may be exposed to Cd during the transformation of livestock manure. The BSF has a high tolerance to Cd. In the previous work of the laboratory, we found that vitamin E (VE) may play a role in the tolerance of BSF to Cd exposure. The main findings are as follows: The BSF larvae pretreated with exogenous VE had heavier body weight, lower content and toxicity of Cd under similar Cd exposure. Even in high Cd exposure at the concentrations of 300 and 700 mg/kg, the BSF larvae pretreated with exogenous VE at a concentration of 100 mg/kg still reduced the Cd toxicity to 85.33 % and 84.43 %, respectively. The best-fitting models showed that metallothionein (MT) content, oxidative damage (8-hydroxydeoxyguanosine content, malondialdehyde content), antioxidant power (total antioxidant power, peroxidase activity) had a great influence on content and toxicity of Cd bioaccumulated in the larvae. The degree of oxidative damage was reduced in the larvae with exogenous VE pretreatments. This variation can be explained by their changed MT content and increased antioxidant power because of exogenous VE. These results reveal the roles of VE in insects defense against Cd exposure and provide a new option for the prevention and therapy of damage caused by Cd exposure.

Nano-selenium alleviates cadmium-induced neurotoxicity in cerebrum via inhibiting gap junction protein connexin 43 phosphorylation

Cadmium (Cd) as a ubiquitous toxic heavy metal is reported to affect the nervous system. Selenium (Se) has been shown to have antagonistic effects against heavy metal toxicity. In addition, it shows potential antioxidant and anti-inflammatory properties. Thus, the purpose of this study was to determine the possible mechanism of brain injury after high Cd exposure and the mitigation of Nano-selenium (Nano-Se) against Cd-induced brain injury. In this study, the Cd-treated group showed a decrease in the number of neurons in brain tissue, swelling of the endoplasmic reticulum and mitochondria, and the formation of autophagosomes. Nano-Se intervention restored Cd-caused alterations in neuronal morphology, endoplasmic reticulum, and mitochondrial structure, thereby reducing neuronal damage. Furthermore, we found that some differentially expressed genes were involved in cell junction and molecular functions. Subsequently, we selected eleven (11) related differentially expressed genes for verification. The qRT-PCR results revealed the same trend of results as determined by RNA-Seq. Our findings also showed that Nano-Se supplementation alleviated Cx43 phosphorylation induced by Cd exposure. Based on immunofluorescence colocalization it was demonstrated that higher expression of GFAP and lower expressions of Cx43 were restored by Nano-Se supplementation. In conclusion, the data presented in this study establish a direct association between the phosphorylation of Cx43 and the occurrence of autophagy and neuroinflammation. However, it is noteworthy that the introduction of Nano-Se supplementation has been observed to mitigate these alterations. These results elucidate the relieving effect of Nano-Se on Cd exposure-induced brain injury.

Machine learning-based prediction of cadmium bioaccumulation capacity and associated analysis of driving factors in tobacco grown in Zunyi City, China

Tobacco grown in areas with high-geochemical backgrounds exhibits considerably different cadmium (Cd) bioaccumulation abilities due to regional disparities and environmental changes. However, the impact of key factors on the Cd bioaccumulation ability of tobacco grown in the karst regions with high selenium (Se) geochemical backgrounds is unclear. Herein, 365 paired rhizospheric soil-grown tobacco samples and 321 topsoil samples were collected from typical karst tobacco-growing soil in southwestern China and analyzed for Cd and Se. XGBoost was used to predict and evaluate the Cd bioaccumulation ability of tobacco and potential influencing factors. Results showed that regional geochemical characteristics, such as soil Cd and Se contents, soil type, and lithology, have the highest influence on the Cd bioaccumulation ability of tobacco, accounting for 46.5% of the overall variation. Moreover, soil Se contents in high-geochemical background areas considerably affect Cd bioaccumulation in tobacco, with a threshold for the mutual suppression effects of Cd and Se at a soil Se content of 0.8 mg/kg. According to the results of bivariate local indicators of spatial association analysis, tobacco cultivated in the central, northeast, and southeast regions of Zunyi City carries a lower risk of soil Cd contamination. This study provides new insights for managing tobacco cultivation in karst regions.

Selenium - An environmentally friendly micronutrient in agroecosystem in the modern era: An overview of 50-year findings

Agricultural productivity is constantly being forced to maintain yield stability to feed the enormously growing world population. However, shrinking arable and nutrient-deprived soil and abiotic and biotic stressor (s) in different magnitudes put additional challenges to achieving global food security. Though well-defined, the concept of macro, micronutrients, and beneficial elements is from a plant nutritional perspective. Among various micronutrients, selenium (Se) is essential in small amounts for the life cycle of organisms, including crops. Selenium has the potential to improve soil health, leading to the improvement of productivity and crop quality. However, Se possesses an immense encouraging phenomenon when supplied within the threshold limit, also having wide variations. The supplementation of Se has exhibited promising outcomes in lessening biotic and abiotic stress in various crops. Besides, bulk form, nano-Se, and biogenic-Se also revealed some merits and limitations. Literature suggests that the possibilities of biogenic-Se in stress alleviation and fortifying foods are encouraging. In this article, apart from adopting a combination of a conventional extensive review of the literature and bibliometric analysis, the authors have assessed the journey of Se in the "soil to spoon" perspective in a diverse agroecosystem to highlight the research gap area. There is no doubt that the time has come to seriously consider the tag of beneficial elements associated with Se, especially in the drastic global climate change era.

Silver Nanoparticles Loaded with Oleuropein Reduce Doxorubicin-Induced Testicular Damage by Regulating Endoplasmic Reticulum Stress, and Apoptosis

Doxorubicin (DOX) is the most used chemotherapeutic agent for treating solid tumors. DOX treatment may lead to testicular damage using oxidative stress, resulting in infertility. These adverse effects may be prevented by the activation of antioxidant systems. Oleuropein (OLE) is a powerful flavonoid with several ameliorative effects, including antioxidative, antiproliferative, and anti-inflammatory. It would be more efficient and applicable in treating chronic human diseases if its poor bioavailability improves with a nano-delivery system. The current study aims to assess the histopathological changes and antioxidative effects of OLE loaded with silver nanoparticles oleuropein (OLE-AgNP) on the testicular injury triggered by DOX in rats. Forty-eight male albino rats were randomly divided into six groups as follows: the control, DOX (2.5 mg/kg), OLE (50 mg/kg), AgNP (100 mg/kg), OLE + AgNP (50 mg/kg), OLE (50 mg/kg) + DOX (2.5 mg/kg), AgNP (100 mg/kg) + DOX (2.5 mg/kg), and OLE-AgNP (50 mg/kg) + DOX (2.5 mg/kg) for 11 days. Oxidative stress, inflammation, apoptosis, endoplasmic reticulum stress markers, sperm analysis, and histopathological analyses were performed on testicular tissues taken from rats decapitated after the applications and compared between the experimental groups. The tissue MDA level was lower in the OLE and OLE+AgNP-treated groups than in the DOX-treated group. In addition, SOD and GSH levels significantly increased in both the OLE and OLE+AgNP-treated groups compared to the DOX group. Both OLE and OLE+AgNP, particularly OLE+AgNP, ameliorated DOX-induced testicular tissue injury, as evidenced by reduced injury and improved seminiferous tubules and spermatocyte area. In addition, OLE and OLE+AgNP, especially OLE+AgNP, inhibited DOX-induced testicular tissue inflammation, apoptosis, and endoplasmic reticulum stress. The findings suggest that nanotechnology and the production of OLE+AgNP can ameliorate DOX-induced testicular damage.

Antagonistic effect of selenium on programmed necrosis of testicular Leydig cells caused by cadmium through endoplasmic reticulum stress in chicken

Cadmium (Cd) is a widely distributed environmental contaminant that is highly toxic to animals and humans. However, detailed reports on Cd-induced programmed necrosis have not been seen in chicken testicular Leydig cells. Selenium (Se) is a trace element in the human body that has cytoprotective effects in a variety of pathological damages caused by heavy metals. This study investigated the potential mechanisms of Cd-induced programmed cell necrosis and the antagonistic effect of Se on Cd toxicity. Chicken testis Leydig cells were divided into six groups, namely, control, Se (5 µmol/L Na2SeO3), Cd (20 µmol/L CdCl2), Se + Cd (5 µmol/L Na2SeO3 and 20 µmol/L CdCl2), 4-phenylbutyric acid (4-PBA) + Cd (10 mmol/L 4-phenylbutyric acid and 20 µmol/L CdCl2), and Necrostatin-1 (Nec-1) + Cd (60 µmol/L Necrostatin-1 and 20 µmol/L CdCl2). The results showed that Cd exposure decreased the activity of CAT, GSH-Px, and SOD and the concentration of GSH, and increased the concentration of MDA and the content of ROS. Relative mRNA and protein expression of GRP78, PERK, ATF6, IRE1, CHOP, and JNK increased in the Cd group, and mRNA and protein expression of TNF-α, TNFR1, RIP1, RIP3, MLKL, and PARP1 significantly increased in the Cd group, while Caspase-8 mRNA and protein expression significantly decreased. The abnormal expression of endoplasmic reticulum stress-related proteins was significantly reduced by 4-PBA pretreatment; the increased expression of TNF-α, TNFR1, RIP1, RIP3, MLKL, and PARP1 caused by Cd toxicity was alleviated; and the expression of caspase-8 was upregulated. Conversely, the increased mRNA and protein expression of endoplasmic reticulum stress marker genes (GRP78, ATF6, PERK, IRE1, CHOP, JNK) caused by Cd was not affected after pretreatment with Nec-1. We also found that these Cd-induced changes were significantly attenuated in the Se + Cd group. We clarified that Cd can cause programmed necrosis of chicken testicular Leydig cells through endoplasmic reticulum stress, and Se can antagonize Cd-induced programmed necrosis of chicken testicular Leydig cells.

Implication of ferroptosis in hepatic toxicity upon single or combined exposure to polystyrene microplastics and cadmium

Microplastics (MPs) are a newly emerging type of pollutants. To date, MPs have been found in the atmosphere, soil, water, and even in human samples, posing a non-negligible threat to humans. Furthermore, multiple heavy metals have been found to co-exist with MPs or be absorbed by MPs. This leads to a widespread concern about their combined toxicity, which is currently elusive. Herein, we investigated the single or combined toxic effects of polystyrene MPs (PS-MPs) and cadmium chloride (CdCl2) on the liver and hepatocytes. After co-incubation, cadmium (Cd) can be absorbed by PS-MPs, resulting in physiochemical alterations of PS-MPs. In vivo and in vitro experiments revealed that PS-MPs solely or together with CdCl2 induced ferroptosis in hepatocytes, a newly defined programmed cell death characterized by lipid oxidation and iron accumulation. PS-MPs exerted more ferroptotic effect on hepatocytes than CdCl2, and combined exposure to PS-MPs and CdCl2 enhanced their ferroptotic effect, mainly by stimulating reactive oxygen species (ROS) production and inhibiting antioxidant activity. Upon single or combined exposure to PS-MPs and CdCl2, the induction of ferroptosis in hepatocytes can be inhibited by N-acetyl-cysteine (NAC, an ROS scavenger), deferoxamine (DFO, an iron chelator), and particularly ferrostatin-1 (Fer-1, a specific ferroptosis inhibitor). Fer-1 efficiently rescued the cell viability of hepatocytes upon exposure to PS-MPs and CdCl2 through enhancing the antioxidant system via upregulating GPX4 and SLC7A11. These findings would contribute to an in-depth understanding of the single and combined toxicity of microplastics and cadmium.

Modulation of inflammatory and oxidative stress biomarkers due to dexamethasone exposure in chicken splenocytes

Dexamethasone (DEXA) is a potent corticosteroid, commonly used for treating inflammatory, hypersensitive and allergic conditions. It is administered to birds with tumours. Many studies were conducted on its immunosuppressive effects; however none of the similar study is available employing chicken splenocytes culture system. The present study was conducted to assess DEXA induced alterations in inflammatory and oxidative stress biomarkers in chicken splenocytes due to its in vitro exposure. The maximum non-cytotoxic dose (MNCD) was evaluated and was further used for conducting lymphocytes proliferation assay (LPA), antioxidant assays (lipid peroxidation, GSH, superoxide dismutase and nitric oxide assays) and assessment of mRNA levels of various genes (IL-1β, IL-6, IL-10, LITAF, iNOS, NF-κB1, Nrf-2, Caspase-3 and -9) through qPCR. The MNCD was determined to be 30 ng/ml in chicken splenocytes culture system. DEXA caused reduction in B and T lymphocytes proliferation indicating its immunosuppressive effects, however improved the antioxidant status of the exposed splenocytes. The expression levels of IL-1β, IL-6, iNOS, LITAF and NF-κB1 were significantly reduced while IL-10 was enhanced, which signify potent anti-inflammatory potential of DEXA. NF-κB is a major transcription factor that regulates genes responsible for both, innate and adaptive immune responses and elicits inflammation. The nuclear factor erythroid 2-related factor 2 (Nrf-2) level was found to be up-regulated. Nrf-2 plays important role in combating the oxidant stress and its increased expression could be the reason of improved antioxidant status of DEXA exposed cells. Present findings indicated that DEXA exhibited modulation in anti-inflammatory, immunomodulatory and antioxidant mediators in chicken splenocytes.

Selenium alleviates cadmium and copper toxicity in Gracilaria lemaneiformis (rhodophyta) with contrasting detoxification strategies

Selenium (Se) is a beneficial element for plants, and can be used to mitigate the toxicity of heavy metals. However, the detoxification of Se in macroalgae, a crucial part of aquatic ecosystem productivity, has rarely been reported. In the present study, a red macroalga Gracilaria lemaneiformis was exposed to non-essential metal cadmium (Cd) or essential metal copper (Cu) with addition of different levels of Se. We then examined the changes in growth rate, metal accumulation, metal uptake rate, subcellular distribution, as well as thiol compound induction in this alga. Se addition alleviated Cd/Cu-induced stress in G. lemaneiformis by regulating cellular metal accumulation and intracellular detoxification. Specifically, supplementation of low-level Se displayed a significant decrease in Cd accumulation, and thus alleviated the growth inhibition induced by Cd. This may be caused by the inhibitory effect of endogenous Se instead of exogenous Se on Cd uptake. Although Se addition increased bioaccumulation of Cu in G. lemaneiformis, the important intracellular metal chelators, phytochelatins (PCs), were massively induced to alleviate Cu-induced growth inhibition. High-dose Se addition did not deteriorate but failed to normalize the growth of algae under metal stress conditions. Reduction in Cd accumulation or induction of PCs by Cu could not suppress the toxicity of Se above safe levels. Se addition also altered metal subcellular distribution in G. lemaneiformis, which might affect the subsequent metal trophic transfer. Our results demonstrated that the detoxification strategies of Se between Cd and Cu were different in macroalgae. Elucidating the protective mechanisms of Se against metal stress may help us better apply Se to regulate metal accumulation, toxicity, and transfer in aquatic environment.

Autophagy protects against Cd-induced cell damage in primary chicken hepatocytes via mitigation of oxidative stress and endoplasmic reticulum stress

Cadmium (Cd) is widespread globally in the environment as a toxic metal. Although it is well known to induce hepatotoxicity in the cells, defense mechanisms against the detrimental effects of Cd are still unknown. We examined the role of autophagy (a cellular defense mechanism) on Cd-induced cytotoxicity in bird hepatocytes. Primary chicken hepatocytes were cultured with different concentrations (0, 1, 2.5, 5, and 10 μM) of cadmium chloride (CdCl₂) for 12 h. We assessed the effects of CdCl₂ on the cell viability, antioxidant status, reactive oxygen species (ROS) generation, autophagy response and endoplasmic reticulum (ER) stress. Further, it is also evaluated that insight into underling molecular mechanisms involved in the study. In this study, CdCl₂-induce hepatotoxicity was caused by drastically increased ROS generation as well as a reduction level of antioxidant enzymes. It was also demonstrated that marked activation of ER stress markers (GRP78, IRE1, PERK, ATF4, ATF6 and XBP-1 s) was observed. Simultaneously, increased activation of autophagy in low-dose CdCl₂ (1 μM) exposed group was observed, but high-dose CdCl₂ (10 μM) inhibited autophagy and significantly promoted apoptosis, as indicated by the expression of the autophagy related genes for P62, Beclin-1, ATG3, ATG5, ATG9, and the detection of autophagic vacuoles. Pretreatment with autophagy agonist Rapamycin (RAP) has successfully reduced ROS production, attenuated ER stress and enhanced hepatocytes viability, while the autophagy inhibitor 3-Methyladenine (3-MA) had the opposite effect. Hence, these findings stipulate that Cd could inhibit viability of hepatocytes in a dose-dependent manner. Autophagy relieves hepatotoxicity of Cd via reducing ROS generation and regulating ER stress. We identified autophagy as a novel protective mechanism involved in Cd-mediated chicken hepatotoxicity.

Endoplasmic Reticulum Stress: A Key Regulator of Cardiovascular Disease

The problems associated with economic development and social progress have led to an increase in the occurrence of cardiovascular diseases (CVDs), which affect the health of an increasing number of people and are a leading cause of disease and population mortality worldwide. Endoplasmic reticulum stress (ERS), a hot topic of interest for scholars in recent years, has been confirmed in numerous studies to be an important pathogenetic basis for many metabolic diseases and play an important role in maintaining physiological processes. The endoplasmic reticulum (ER) is a major organelle that is involved in protein folding and modification synthesis, and ERS occurs when several physiological and pathological factors allow excessive amounts of unfolded/misfolded proteins to accumulate. ERS often leads to initiation of the unfolded protein response (UPR) in a bid to re-establish tissue homeostasis; however, UPR has been documented to induce vascular remodeling and cardiomyocyte damage under various pathological conditions, leading to or accelerating the development of CVDs such as hypertension, atherosclerosis, and heart failure. In this review, we summarize the latest knowledge gained concerning ERS in terms of cardiovascular system pathophysiology, and discuss the feasibility of targeting ERS as a novel therapeutic target for the treatment of CVDs. Investigation of ERS has immense potential as a new direction for future research involving lifestyle intervention, the use of existing drugs, and the development of novel drugs that target and inhibit ERS.

Resveratrol protects against cadmium-induced cerebrum toxicity through modifications of the cytochrome P450 enzyme system in microsomes

BACKGROUND

Cadmium (Cd), known as a vital contaminant in the environment, penetrates the blood-brain barrier and accumulates in the cerebrum. Acute toxicosis of Cd, which leads to lethal cerebral edema, intracellular accumulation and cellular dysfunction, remains to be illuminated with regard to the exact molecular mechanism of cerebral toxicity. Resveratrol (RES), present in the edible portions of numerous plants, is a simply acquirable and correspondingly less toxic natural compound with neuroprotective potential, which provides some theoretical bases for antagonizing Cd-induced cerebral toxicity.

RESULTS

This work was executed to research the protective effects of RES against Cd-induced toxicity in chicken cerebrum. Markedly, these lesions were increased in the Cd group, which also exhibited a thinner cortex, reduced granule cells, vacuolar degeneration, and an enlarged medullary space in the cerebrum. Furthermore, Cd induced CYP450 enzyme metabolism disorders by disrupting the nuclear xenobiotic receptor response (NXRs), enabling the cerebrum to reduce the ability to metabolize exogenous substances, eventually leading to Cd accumulation. Meanwhile, accumulated Cd promoted oxidative damage and synergistically promoted the damage to neurons and glial cells.

CONCLUSION

RES initiated NXRs (especially for aromatic receptor and pregnancy alkane X receptor), decreasing the expression of CYP450 genes, changing the content of CYP450, maintaining CYP450 enzyme normal activities, and exerting antagonistic action against the Cd-induced abnormal response of nuclear receptors. These results suggest that the cerebrum toxicity caused by Cd was reduced by pretreatment with RES. © 2023 Society of Chemical Industry.

Selenium alleviates cadmium-induced oxidative stress, endoplasmic reticulum stress and programmed necrosis in chicken testes

Cadmium (Cd) is a common heavy metal pollutant, and one of the important target organs of its toxicity is the testis. Selenium (Se) has the ability to antagonize the toxicity of Cd. However, the mechanism of the alleviating effects of Se on Cd in chicken testis injury through oxidative stress, endoplasmic reticulum stress (ERS), and programmed necrosis remained unclear. To explore this, 80 7-day-old chickens were divided into the Control group, the Se group (1.00 mg/kg Se), the Cd group (150.00 mg/kg Cd), and the CdSe group. On the 30th and 60th days, serum and chicken testis tissue samples were collected for testing. The results showed that Cd exposure resulted in swelling and deformation of seminiferous tubules, and thinning of the seminiferous epithelium. The ROS and MDA increased, and the SOD, CAT, GSH, GSH-Px decreased. The expression of GRP78, PERK, IRE1, ATF6, CHOP, and JNK in the Cd group increased. The expression of TNF-α, TNFR1, RIP1, RIP3, MLKL, and PARP1 increased, while the expression of Caspase-8 decreased. Histopathological changes, oxidative stress, ERS, and programmed necrosis were improved after CdSe treatment. In conclusion, Se antagonized the toxicity of Cd, and Se could alleviate Cd-induced oxidative stress, ERS, and programmed necrosis in chicken testis.

Hepatoprotective Effects of Taurine Against Cadmium-Induced Liver Injury in Female Mice

Cadmium (Cd), a heavy metal contaminant, seriously threatens human and animal health. Taurine (Tau) has been used against hepatotoxicity caused by different environmental toxins. However, it has not been elucidated whether Tau exerts its protective function against Cd-induced hepatotoxicity. The aim of this study was thus to evaluate the ameliorative function of Tau (500 mg/kg body weight intraperitoneally) on Cd-induced (2 mg/kg body weight intraperitoneally) liver toxicity in mice for 14 days. The histopathologic and ultrastructure changes as well as alterations in indexes related to liver function, antioxidant biomarkers, inflammatory, and apoptosis were evaluated. The results showed that Tau alleviated the vacuolar degeneration, nuclear condensation, mitochondria swelling, and cristae lysis of hepatocytes induced by Cd. In addition, Tau treatment significantly reduced the ALT, AST levels in serum, and inflammatory factor TNF-α and IL-1β in liver tissue. Furthermore, Tau treatment decreased the Bax/Bcl-2 ratio and cleaved caspase-3 protein expression levels. Taken together, these observations demonstrate that Tau has an important hepatic protective function against the inflammation and apoptosis induced by Cd.

Associations of blood metals with liver function: Analysis of NHANES from 2011 to 2018

BACKGROUND

Heavy metals have been reported to affect liver function. However, there is currently little and inconsistent knowledge about the effects of combined and individual blood metals on specific parameters of liver function in the general population. Hence, this study aimed to elucidate their associations.

METHODS

Data from National Health and Nutrition Examination Survey (NHANES) 2011-2018 were used in this cross-sectional study. Multivariate linear, and a quantile-based g-computation (qgcomp) were applied to explore the associations between blood metals [mercury (Hg), manganese (Mn), lead (Pb), cadmium (Cd), selenium (Se)], alone and in combination, and liver function parameters [alanine transaminase (ALT), aspartate transaminase (AST), ALT/AST, alkaline phosphatase (ALP), gamma-glutamyl transferase (GGT) and serum total bilirubin (TBIL)].

RESULTS

A total of 15,328 were included. Multivariate linear models indicated that liver function was significantly associated with blood heavy metals. The most significant relationship was found between Se and AST (β 5.09, 95%CI (3.28,6.91), p＜0.001), Mn and ALT (β 1.24, 95%CI (0.57, 1.91), p＜0.001). Furthermore, the qgcomp analysis showed that the combination of five blood metals was positively associated with AST, ALT, GGT, TBIL and HSI. Cd contributed the most to the correlation of AST (weight = 0.447), Se contributed the most to the association of ALT (weight = 0.438) and HSI (weight = 0.570), Pb contributed the most to the association of GGT (weight = 0.421) and Hg contributed the most to the correlation of TBIL (weight = 0.331).

CONCLUSIONS

Blood heavy metal levels were significantly associated with liver function parameters. Further studies are required to clarify the relationship between heavy metals and liver function.

Non-Lethal Concentrations of CdCl2 Cause Marked Alternations in Cellular Stress Responses within Exposed Sertoli Cell Line

Cadmium is a component of ambient metal pollution, which is linked to diverse health issues globally, including male reproductive impairment. Assessments of the acute effects of cadmium on male reproduction systems, such as testes, tend to be based on frank adverse effects, with particular molecular pathways also involved. The relationship between cytotoxicity potential and cellular stress response has been suggested to be one of the many possible drivers of the acute effects of cadmium, but the link remains uncertain. In consequence, there is still much to be learned about the cellular stress response induced by a non-lethal concentration of cadmium in male reproductive cells. The present study used temporal assays to evaluate cellular stress response upon exposure to non-lethal concentrations of Cadmium chloride (CdCl₂) in the Sertoli cell line (TM4). The data showed alternations in the expression of genes intimated involved in various cellular stress responses, including endoplasmic reticulum (ER) stress, endoplasmic unfolded protein stress (UPRmt), endoplasmic dynamics, Nrf2-related antioxidative response, autophagy, and metallothionein (MT) expression. Furthermore, these cellular responses interacted and were tightly related to oxidative stress. Thus, the non-lethal concentration of cadmium perturbed the homeostasis of the Sertoli cell line by inducing pleiotropic cellular stresses.

Cerebellar injury induced by cadmium via disrupting the heat-shock response

Cadmium (Cd) is a food contaminant that poses serious threats to animal health, including birds. It is also an air pollutant with well-known neurotoxic effects on humans. However, knowledge on the neurotoxic effects of chronic Cd exposure on chicken is limited. Thus, this study assessed the neurotoxic effects of chronic Cd on chicken cerebellum. Chicks were exposed to 0 (control), 35 (low), and 70 (high) mg/kg of Cd for 90 days, and the expression of genes related to the heat-shock response was investigated. The chickens showed clinical symptoms of ataxia, and histopathology revealed that Cd exposure decreased the number of Purkinje cells and induced degeneration of Purkinje cells with pyknosis, and some dendrites were missing. Moreover, Cd exposure increased the expression of heat-shock factors, HSF1, HSF2, and HSF3, and heat-shock proteins, HSP60, HSP70, HSP90, and HSP110. These changes indicate that HSPs improve the tolerance of the cerebellum to Cd. Conversely, the expressions of HSP10, HSP25, and HSP40 were decreased significantly, which indicated that Cd inhibits the expression of small heat-shock proteins. However, HSP27 and HSP47 were upregulated following low-dose Cd exposure, but downregulated under high-dose Cd exposure. This work sheds light on the toxic effects of Cd on the cerebellum, and it may provide evidence for health risks posed by Cd. Additionally, this work also identified a novel target of Cd exposure in that Cd induces cerebellar injury by disrupting the heat-shock response. Cd can be absorbed into chicken's cerebellum through the food chain, which eventually caused cerebellar injury. This study provided a new insight that chronic Cd-induced neurotoxicity in the cerebellum is associated with alterations in heat-shock response-related genes, which indicated that Cd through disturbing heat-shock response induced cerebellar injury.

Nano-Selenium Antagonized Cadmium-Induced Liver Fibrosis in Chicken

Cadmium is a global ecological toxic pollutant; in animals, hepatotoxic fibrosis is caused by bioaccumulation of Cd through food chains. We determined the path of nano-Se antagonism in Cd-induced hepatocyte pyroptosis by targeting the APJ-AMPK-PGC1α pathway, using an in vivo model of hepatotoxicity. All 1-day-old chicks were treated with Cd (140 mg/kg BW/day) and/or nano-Se (0.3 or 0.6 mg/kg BW/day) for 90 days. The result showed that Cd (1.55 ± 0.148) activated NLRP3 inflammasome 49.903% as compared to the Con group (1.034 ± 0.008) to release the inflammasome as a result of hepatocyte pyroptosis (2.824 ± 0.057). Compared with the Con group (1.010 ± 0.021), Kupffer cells were 219.109% more to activate astrocytes through the APJ-AMPK-PGC1α pathway, resulting in 185.149% more hepatic fibrosis. However, the fibrosis degree of the H-Se + Cd group (1.252 ± 0.056) was 56.5278% (p < 0.001) lower than that of the Cd group (2.880 ± 0.124). Therefore, this study established that pyroptotic hepatocytes and Kupffer cells could be targeted for nano-Se antagonizing Cd toxicity, which reveals a potential new approach targeting astrocytes for the treatment of liver fibrosis triggered by Cd pollution.

Selenite Ameliorates Cadmium-induced Cytotoxicity Through Downregulation of ROS Levels and Upregulation of Selenoprotein Thioredoxin Reductase 1 in SH-SY5Y Cells

Cadmium (Cd) as a ubiquitous toxic heavy metal in the environment, causes severe hazards to human health, such as cellular stress and organ injury. Selenium (Se) was reported to reduce Cd toxicity and the mechanisms have been intensively studied so far. However, it is not yet crystal clear whether the protective effect of Se against Cd-induced cytotoxicity is related to selenoproteins in nerve cells or not. In this study, we found that Cd inhibited selenoprotein thioredoxin reductase 1 (TrxR1; TXNRD1) and decreased the expression level of TrxR1, resulting in cellular oxidative stress, and Se supplements ameliorated Cd-induced cytotoxicity in SH-SY5Y cells. Mechanistically, the detoxification of Se against Cd is attributed to the increase of the cellular TrxR activity and upregulated TrxR1 protein level, culminating in strengthened antioxidant capacity. Results showed that Se supplements attenuated the ROS production and apoptosis in SH-SY5Y cells, and significantly mitigated Cd-induced SH-SY5Y cell death. This study may be a valuable reference for shedding light on the mechanism of Cd-induced cytotoxicity and the role of TrxR1 in Se-mitigated cytotoxicity of Cd in neuroblast cells, which may be helpful for understanding the therapeutic potential of Cd and Se in treating or preventing neurodegenerative diseases, like Alzheimer's disease (AD) and Parkinson's disease (PD).

Role of Endoplasmic Reticulum Stress in Nano-Selenium Alleviating Prehierarchical Follicular Atresia Induced by Mercury in Laying Hens

This study investigated that the effect of nano-selenium (nano-Se) addition preventing prehierarchical follicular atresia induced by mercury (Hg) exposure in laying hens. Furthermore, endoplasmic reticulum (ER) stress pathway was explored to reveal the protective mechanism of nano-Se in vitro. The results revealed that Hg could significantly reduce laying performance (P < 0.05) and egg quality (P < 0.05), whereas nano-Se addition partially reversed the reductions. Besides, Hg significantly induced the deposition of Hg in prehierarchical follicles (P < 0.05) and prehierarchical follicular atresia (P < 0.05), whereas nano-Se addition could alleviate these toxicities in vitro. In addition, Hg exposure could significantly reduce cell viability (P < 0.05) and induce pyknotic nucleus in prehierarchical granulosa cells, while nano-Se addition reversed these effects. The levels of follicle-stimulating hormone (P < 0.05), luteinizing hormone (P < 0.05), progesterone (P < 0.05), and estradiol (P < 0.05) were significantly decreased after Hg exposure in vitro. However, nano-Se addition reversed the decreases of sex hormone levels. Furthermore, Hg exposure significantly increased the gene expressions of CHOP (P < 0.05), PERK (P < 0.05), ATF4 (P < 0.05), ATF6 (P < 0.05), ASK1 (P < 0.05), IRE1α (P < 0.05), TRAF2 (P < 0.05), caspase-9 (P < 0.05), caspase-3 (P < 0.05), and Bax/Bcl-2 (P < 0.05), whereas nano-Se addition reversed these increases of gene expressions in vitro. In summary, this study provides that Hg can induce prehierarchical follicular atresia, whereas nano-Se addition can ameliorate it, and elucidates an important role of ER stress in nano-Se alleviating prehierarchical follicular atresia induced by Hg in laying hens.

Nano-selenium alleviates cadmium-induced cerebellar injury by activating metal regulatory transcription factor 1 mediated metal response

This study aims to investigate the role of metal regulatory transcription factor 1 (MTF1)-mediated metal response in cadmium (Cd)-induced cerebellar injury, and to evaluate the antagonistic effects of nano-selenium (Nano-Se) against Cd toxicity. A total of 80 chicks (1 d old, male, Hy-Line Variety White) were randomly allocated to 4 treatment groups for 3 months: the control group (fed with a basic diet, n = 20), the Nano-Se group (basic diet with 1 mg/kg nano-Se 1 mg/kg Nano-Se in basic diet, n = 20), the Nano-Se + Cd group (basic diet with 1 mg/kg Nano-Se and 140 mg/kg CdCl₂, n = 20) and the Cd group (basic diet with 140 mg/kg CdCl₂ , n = 20). The results of the experiment showed that the Purkinje cells were significantly decreased with their degradation and indistinct nucleoli after Cd exposure. Moreover, exposure to Cd caused a significant accumulation of Cd and cupper. However, the contents of Se, iron, and zinc were decreased, thereby disturbing the metal homeostasis in the cerebellum. The Cd exposure also resulted in high levels of malondialdehyde (MDA) and down regulation of selenoprotein transcriptome. Furthermore, the expressions of MTF1, metallothionein 1 (MT1), MT2, zinc transporter 3 (ZNT3), ZNT5, ZNT10, zrt, irt-like protein 8 (ZIP8), ZIP10, transferrin (TF), ferroportin 1 (FPN1), ATPase copper transporting beta (ATP7B), and copper uptake protein 1 (CTR1) were inhibited by Cd exposure. However, all these changes were significantly alleviated by the supplementation of Nano-Se. This study proved that Cd could disorder metal homeostasis and induce oxidative stress, whereas Nano-Se could relieve all these negative effects caused by Cd via activating the MTF1-mediated metal response in the cerebellum of chicken.

Association between plasma selenium and risk of ischemic stroke: A community-based, nested, and case-control study

Background

The prospective association between plasma Se and stroke risk remains inconclusive. The relationship between Se and ischemic stroke among a low circulating Se status population deserves more attention, especially for Chinese people who were a high-risk group for Se deficiency.

Objective

The relationship between plasma Se concentration and ischemic stroke risk in a large-scale Chinese community-based population and any potential effect modifiers were investigated.

Methods

A nested, case-control study, using data from the “China H-type Hypertension Registry Study” were conducted. A total of 1,904 first ischemic stroke cases and 1,904 controls matched for age, sex, and village were included in this study. The association between plasma Se and first ischemic stroke was evaluated by conditional logistic regression analyses.

Results

The median value of plasma Se was 65.8 μg/L among total participants. Overall, a significant inverse relationship between plasma Se and first ischemic stroke risk was found (per SD increment; adjusted OR: 0.87; 95% CI: 0.80 and 0.95). Accordingly, a significantly lower risk of first ischemic stroke was found in participants in quartile 3 (65.8−&lt;77.8 μg/L) (adjusted OR: 0.78; 95% CI: 0.63 and 0.96) and quartile 4 (≥77.8 μg/L) (adjusted OR: 0.76; 95% CI: 0.59 and 0.96), compared with those in quartile 1 (&lt;56.0 μg/L). Furthermore, a significantly lower ischemic stroke risk was found in those with lower low-density lipoprotein cholesterol (LDL-C) levels (&lt;3.4 vs. ≥3.4 mmol/L; P for interaction = 0.015) or those with lower homocysteine levels (&lt;12.1 (median) vs. ≥12.1 μmol/L; P for interaction = 0.027) at baseline.

Conclusion

Plasma Se was significantly inversely associated with the risk of first ischemic stroke among a large-scale Chinese community-based population (most adults with hypertension and elevated total homocysteine), especially among those with lower LDL-C and lower homocysteine levels.

Oligochaeta ramosa (Roxb.) Extract Regulates Lipid Metabolism and Exerts Hepatoprotective Effects in Cadmium-Induced Hepatic Injury in Rats

Environmental pollutants present a potential source of toxicity when exposed to humans. The study was aimed at investigating the potential of Oligochaeta ramosa (Roxb.) as a hepatoprotective agent in cadmium-induced hepatotoxicity causing lipid profile disturbance. The aqueous methanolic (30 : 70 v/v) extract of O. ramosa Roxb. (AME.Or) was subjected to preliminary phytochemical analysis, whereas the antioxidant activity of its constituents was investigated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The hepatoprotective and antihyperlipidemic effects of AME.Or was investigated by dividing animals into five groups (A-E). Animals were either treated with normal saline or CdCl₂ (6.5 mg/kg, intraperitoneally) followed by treatment with silymarin (100 mg/kg), or AME.Or (200 mg/kg) and AME.Or (400 mg/kg) for consecutive three weeks. Blood samples were collected, and the serum lipid profile was assessed on the 11^th and 21^st day of treatment. Histopathological analysis was performed after euthanization. In vitro analysis of AME.Or revealed 64% inhibition as free radicals scavenging potential during DPPH, total phenolic content (TPC) (79.92 mgGAE/g), and total flavonoids content (TFC) (38.75 mgRE/g). The group intoxicated with CdCl₂ showed significantly high (p ≤ 0.05) levels of the liver function indicators and lipid profile than in the control group. The higher dose of AME.Or (400 mg/kg) significantly decreased the aspartate aminotransferase (AST), alanine transferase (ALT), alkaline phosphatase (ALP), total bilirubin (p ≤ 0.001), decreased total cholesterol and triglycerides (p ≤ 0.01) while significantly increased high density lipoprotein (HDL; p ≤ 0.01) as compared to the intoxicated group. The histopathological analysis of the liver revealed signs of necrosis in the intoxicated group, while AME.Or treated groups showed marked improvement. The findings accentuate the therapeutic importance of O. ramosa (Roxb.) as a hepatoprotective remedy.

Molluscicidal and biochemical effects of green-synthesized F-doped ZnO nanoparticles against land snail Monacha cartusiana under laboratory and field conditions

The glass clover snail, Monacha cartusiana (M. cartusiana) is one of the most seriously impacting economic animal pests spreading across Egypt which inflicts severe damages to the agriculture. A green route is developed by deploying an abundant Rosemary plant leaves aqueous extract to synthesize ZnO and F-doped ZnO (F-ZnO) nanoparticles (NPs) that display high molluscicidal activities against the M. cartusiana land snails via leaf dipping and contact techniques. The effect of lethal concentrations, that kills 50% of exposed snails (LC50) value of the treatments, is examined on the activity of alkaline phosphatase (ALP), aspartate aminotransferase (AST), alanine aminotransferase (ALT), enzymes, total protein (TP), total lipids (TL) and cholesterol level of snails, including the histopathological evaluation of the digestive gland and foot of M. Cartusiana. Their molluscicidal activity as poisonous baits under field conditions is also evaluated and compared to the recommended molluscicide, Neomyl. The results show that F^- doping dramatically improves the snail control capability of ZnO NPs, and promotes a considerable increase in both ALT and AST enzymes with an enhancement of TL and Cholesterol levels, but a significant decrease in TP content and ALP activity in treated snails compared to the control group. The LC₅₀ values are found to be 1381.55 and 2197.59 ppm using the leaf dipping for F-ZnO and ZnO, while 237.51 and 245.90 ppm can be achieved using the contact technique, respectively. The greenly synthesized F-ZnO and ZnO NPs induce severe histological alterations in the digestive gland and foot of M. cartusiana, including a complete destruction of the digestive tubules. The histological evaluation of the foot of M. cartusiana exposed to ZnO, shows a rupture of the epithelial layer of the foot sole, while F- ZnO NPs causes the folds of the foot becoming deeper and the rupture of epithelial layer. Our field experiments further demonstrate that F-ZnO achieves 60.08% reduction, while ZnO attains 56.39% diminution in snail population compared to the commercial, Neomyl (69.55%), exhibiting great potentials in controlling the harmful land snail populations.

Protective role of selenium on ammonia-mediated nephrotoxicity via PI3K/AKT/mTOR pathway: Crosstalk between autophagy and cytokine release

Ammonia (NH₃) is a hazardous substance to human and animal health. Selenium (Se) is an essential micronutrient with multiple health benefits. The present study aimed to verify whether and how Se supplementation has a protective role against NH₃ mediated-nephrotoxicity in pigs. A Se-NH₃ interaction model was established in pigs and the kidney samples were collected after a 30-day treatment period. The results showed that NH₃ exposure inhibited the PI3K/AKT/mTOR pathway and enhanced the secretion of inflammatory cytokines to induce autophagy and inflammation. Se can regulate the PI3K/AKT/mTOR pathway and attenuate the secretion of inflammatory cytokines altered by NH₃ to reduce autophagy and inflammation. In addition, Se co-treatment inhibited ROS production, elevated the activities of antioxidant systems, and increased the expression of 13 selenoproteins in pig kidneys caused by NH₃ exposure. These results implied that L-selenomethionine can moderate NH₃-induced nephrotoxicity in pigs. Our study gives new ideas for the specific mechanism of NH₃ nephrotoxicity and provides a reference for comparative medicine and clinical medication.

Protective effect of nano-selenium on mercury-induced prehierarchical follicular atresia in laying hens

This study investigated the effect of nano-selenium (nano-Se) in protecting laying hens from mercury (Hg)-induced prehierarchical follicular atresia. Furthermore, the endoplasmic reticulum stress (ERS) was explored to reveal the molecular mechanism. In vivo, 720 Hyline-Brown laying hens were treated with Hg and nano-Se alone or in combination. In vitro, the prehierarchical follicles were treated with Hg, nano-Se and 4-phenyl butyric acid (4-PBA) alone or in combination (Control, 25 μM Hg group, 10 μM nano-Se group, 20 μM nano-Se group, 25 μM Hg + 10 μM nano-Se group, 25 μM Hg + 20 μM nano-Se group, 25 μM Hg + 4-PBA group, and 25 μM Hg + 20 μM nano-Se + 4-PBA group). The GCs were treated with Hg and nano-Se alone or in combination (Control, 15 μM Hg group, 6 μM nano-Se group, 12 μM nano-Se group, 15 μM Hg + 6 μM nano-Se group, 15 μM Hg + 12 μM nano-Se group). The results revealed that dietary Hg significantly reduced laying performance (P < 0.05) and egg quality (P < 0.05), whereas nano-Se addition prevented these reductions (P < 0.05). Hg exposure significantly induced the accumulation of Hg in PHFs (P < 0.05), prehierarchical follicular atresia (P < 0.05) and apoptosis in PHFs, whereas nano-Se addition significantly prevented these effects (P < 0.05). The levels of sex hormones (P < 0.05) were significantly decreased after Hg exposure in vivo and in vitro, while nano-Se addition prevented the reductions. Furthermore, the RNA-Seq results showed that the key factors of the ERS presented differential expression, including C/EBP homologous protein, protein kinase RNA-like endoplasmic reticulum kinase (PERK) and activating transcription factor 6 (ATF6) in GCs. Hg exposure significantly increased the key gene expression of endoplasmic reticulum stress in GCs, whereas nano-Se addition prevented the induction of expression of these genes. In addition, the protein levels of PERK, inositol requiring protein 1α (IRE1α) and ATF6 were significantly increased, whereas nano-Se addition prevented the enhancements of protein expression in GCs. In conclusion, this study shows that Hg exposure can reduce induce prehierarchical follicular atresia, whereas nano-Se can prevent these effects. Our results also elucidate a key role of ERS in these protective effects of nano-Se in laying hens.

Effects of the Gut Microbiota and Barrier Function on Melatonin Efficacy in Alleviating Liver Injury

Environmental cadmium (Cd) exposure has been associated with severe liver injury. In contrast, melatonin (Mel) is a candidate drug therapy for Cd-induced liver injury due to its diverse hepatoprotective activities. However, the precise molecular mechanism by which Mel alleviates the Cd-induced liver injury, as well as the Mel–gut microbiota interaction in liver health, remains unknown. In this study, mice were given oral gavage CdCl2 and Mel for 10 weeks before the collection of liver tissues and colonic contents. The role of the gut microbiota in Mel’s efficacy in alleviating the Cd-induced liver injury was evaluated by the gut microbiota depletion technique in the presence of antibiotic treatment and gut microbiota transplantation (GMT). Our results revealed that the oral administration of Mel supplementation mitigated liver inflammation, endoplasmic reticulum (ER) stress and mitophagy, improved the oxidation of fatty acids, and counteracted intestinal microbial dysbiosis in mice suffering from liver injury. It was interesting to find that neither Mel nor Cd administration induced any changes in the liver of antibiotic-treated mice. By adopting the GMT approach where gut microbiota collected from mice in the control (CON), Cd, or Mel + Cd treatment groups was colonized in mice, it was found that gut microbiota was involved in Cd-induced liver injury. Therefore, the gut microbiota is involved in the Mel-mediated mitigation of ER stress, liver inflammation and mitophagy, and the improved oxidation of fatty acids in mice suffering from Cd-induced liver injury.

Protective Effect of Nanoselenium on Renal Oxidative Damage Induced by Mercury in Laying Hens

This study investigated the effects of dietary nanoselenium (nano-Se) supplementation protecting from renal oxidative damages induced by mercury (Hg) exposure in laying hens. Furthermore, endoplasmic reticulum (ER) stress pathway was explored to reveal the protective mechanism of nano-Se. A total of 576 40-week-old Hyline-White laying hens were randomly allocated to 4 groups with 6 pens per group and 24 hens per pen. The experimental groups were as follows: control (basal diet), control + 27.0 mg/kg Hg, control + 5.0 mg/kg nano-Se, and Hg27.0 + 5.0 mg/kg nano-Se. The results revealed that dietary Hg exposure significantly reduced laying performance (P < 0.05) and egg quality (P < 0.05), whereas nano-Se supplementation partially reversed the reductions. Besides, dietary Hg exposure could induce histopathology damages and apoptosis in kidney, whereas nano-Se addition could alleviate these toxicities effectively. After Hg exposure, the activities and gene expressions of superoxidative dismutase (SOD) (P < 0.05), catalase (CAT) (P < 0.01), glutathione reductase (GR) (P < 0.05) and glutathione peroxidase (GSH-Px) (P < 0.05), and glutathione (GSH) content (P < 0.05) were significantly decreased, while the malondialdehyde (MDA) level was significantly increased (P < 0.05) in kidney. However, nano-Se supplementation partially reversed the levels and gene expressions of these antioxidant biomarkers in kidney. Furthermore, dietary Hg exposure significantly increased the gene expressions of PERK (P < 0.05), ATF4 (P < 0.05), CHOP (P < 0.05), IRE1α (P < 0.05), TRAF2 (P < 0.05), ASK1 (P < 0.05), Caspase-9 (P < 0.05), Caspase-8 (P < 0.05), Caspase-3 (P < 0.05), and Bax/Bcl-2 (P < 0.05), whereas nano-Se supplementation partially reversed these increases of gene expressions. In summary, this study provides evidence that dietary Hg exposure can induce renal oxidative damages, and elucidates an important role of ER stress pathway in nano-Se alleviating renal apoptosis in laying hens.

Lycopene alleviates di(2-ethylhexyl) phthalate-induced splenic injury by activating P62-Keap1-NRF2 signaling

Di(2-ethylhexyl) phthalate (DEHP) is an omnipresent environmental pollutant. It has been determined that DEHP is involved in multiple health disorders. Lycopene (Lyc) is a natural carotenoid pigment, with anti-inflammatory and antioxidant properties. However, it is not clear whether Lyc can protect the spleen from DEHP-induced oxidative damage. A total of 140 mice were randomly divided into seven groups (n = 20) and continuously gavaged with corn oil, distilled water, DEHP (500 or 1000 mg/kg BW/day) and/or Lyc (5 mg/kg BW/day) for 28 days. Histopathological and ultrastructural results showed a DEHP-induced inflammatory response and mitochondrial injuries. Moreover, DEHP exposure induced redox imbalance, which resulted in the up-regulation of ROS activity and MDA content, and the down-regulation of T-AOC, T-SOD and CAT in the DEHP groups. Simultaneously, our results also demonstrated that DEHP-induced kelch-like ECH-associated protein 1 (Keap1) expression was downregulated, and the expression levels of P62, nuclear factor erythroid 2-related factor (NRF2) and their downstream target genes were up-regulated. However, the supplementary Lyc reverted these changes to normal levels. Together, Lyc prevented DEHP-induced splenic injuries by regulating the P62-Keap1-NRF2 signaling pathway. Hence, the protective effects of Lyc might be a therapeutic strategy to ameliorate DEHP-induced splenic damage.

Effects of exposure to cadmium (Cd) and selenium-enriched Lactobacillus plantarum in Luciobarbus capito: Bioaccumulation, antioxidant responses and intestinal microflora

Cadmium (Cd) is a dangerous pollutant with multiple toxic effects on aquatic animals, and it exists widely in the environment. Selenium (Se) is a biologically essential trace element. Interactions between heavy metals and selenium can significantly affect their biological toxicity, although little is known about the mechanism of this antagonism. Lactobacillus is one of the dominant probiotics, given that a certain dose promotes host health. In this study, we evaluated the protective effect of a dietary probiotic supplementation, Se-enriched Lactobacillus plantarum (L. plantarum), on the bioaccumulation, oxidative stress and gut microflora of Luciobarbus capito exposed to waterborne Cd. Fish were exposed for 28 days to waterborne Cd at 0.05 mg/L and/or dietary Se-enriched L. plantarum. Exposure to Cd in water leads to Cd accumulation in tissues, oxidative stress and significant changes in gut microflora composition. Adding Se-enriched L. plantarum to the diet can reduce the accumulation of Cd in tissues, enhance the activity of antioxidant enzymes, and reverse changes in intestinal microbial composition after Cd exposure. The results obtained indicate that Se-enriched L. plantarum provides significant protection against the toxicity of Cd by inhibiting bioaccumulation. Selenium reduced oxidative stress by increasing the activity of glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX) and malondialdehyde (MDA). Se-enriched L. plantarum can reduce the increase in the number of pathogenic Aeromonas caviae bacteria in the intestine caused by Cd stress and increase the number of Gemmobacter to regulate the microbial population. The results of this study show that Se-enriched L. plantarum dietary supplements can effectively protect Luciobarbus capito against Cd toxicity at subchronic levels.

Trace metal concentrations, fluxes, and potential human health risks in West Africa rivers: a case study on the Bia, Tanoé, and Comoé rivers (Cote d'Ivoire)

Downstream water pollution resulting from anthropogenic pressures on upstream water can cause conflicts, especially in transboundary rivers basins. This study assessed trace metals cadmium, lead, copper, and iron total concentrations, fluxes, and the potential human health risks through ingestion or dermal contact of waters at the mouth of three West African transboundary rivers: the Comoé, Bia, and Tanoé rivers. The results showed highest total concentrations during the months of May and October and statistically comparable concentrations in the rivers. The fluxes discharged to the Atlantic Ocean through the Aby and Ebrie Lagoons are as high as average values found elsewhere in the World. Trace metals lead, copper, and iron fluxes were highest during the month of October in the Bia, Tanoé, and Comoé rivers. The cadmium flux was highest during the month of October in the Bia and Comoé rivers, and during the months of February and December in the Tanoé River, indicating that contamination came mainly from upstream waters and the draining of the river basins. The Pearson correlation analysis showed that the trace metals were mainly from anthropogenic sources including gold mining and agriculture. The total concentrations were lower than international guidelines set by the World Health Organization (WHO). However, the potential human health risk assessment results suggest a significant likelihood of community exposure to harmful effects but not to cancers through water ingestion. This work recommends including small rivers when assessing global river metal fluxes to the ocean and also reducing upstream inputs from human activities to mitigate downstream river water pollution.

Antagonistic Interaction of Selenium and Cadmium in Human Hepatic Cells Through Selenoproteins

Cadmium (Cd) is a highly toxic heavy metal for humans and animals, which is associated with acute hepatotoxicity. Selenium (Se) confers protection against Cd-induced toxicity in cells, diminishing the levels of ROS and increasing the activity of antioxidant selenoproteins such as glutathione peroxidase (GPx). The aim of this study was to evaluate the antagonistic effect of selenomethionine (SeMet) against Cd toxicity in HepG2 cells, through the modulation of selenoproteins. To this end, the cells were cultured in the presence of 100 µM SeMet and 5 μM, 15 µM, and 25 µM CdCl₂ and a combination of both species for 24 h. At the end of the experiment, cell viability was determined by MTT assay. The total metal content of Cd and Se was analyzed by triple-quadrupole inductively coupled plasma–mass spectrometry (ICP-QqQ-MS). To quantify the concentration of three selenoproteins [GPx, selenoprotein P (SELENOP), and selenoalbumin (SeAlb)] and selenometabolites, an analytical methodology based on column switching and a species-unspecific isotopic dilution approach using two-dimensional size exclusion and affinity chromatography coupled to ICP-QqQ-MS was applied. The co-exposure of SeMet and Cd in HepG2 cells enhanced the cell viability and diminished the Cd accumulation in cells. Se supplementation increased the levels of selenometabolites, GPx, SELENOP, and SeAlb; however, the presence of Cd resulted in a significant diminution of selenometabolites and SELENOP. These results suggested that SeMet may affect the accumulation of Cd in cells, as well as the suppression of selenoprotein synthesis induced by Cd.

Alterations at biochemical, proteomic and transcriptomic levels in liver of tilapia (Oreochromis niloticus) under chronic exposure to environmentally relevant level of glyphosate

The toxicity of glyphosate (Gly) on aquatic animals has received attention from many researchers. However, the chronic toxicity mechanism of Gly on fish has not yet been clarified entirely. Thus, this study aimed to explore the potential toxicity mechanism of Gly at 2 mg/L, a possibly existing concentration in the aquatic environment, via biochemical, transcriptomic and proteomic analyses in the liver of tilapia. Long-term Gly exposure increased lipid content, and altered redox status in liver. Transcriptomic analysis revealed that Gly exposure changed dramatically the expression of 225 genes in liver, including 94 up-regulated genes and 131 down-regulated genes. GO (Gene Ontology) and KEGG (Kyoto Encyclopedia of Genes and Genomes) enrichment analyses showed that these genes were predominantly enriched in ion transport, lipid metabolism and PPAR (peroxisome proliferator-activated receptor) signaling pathway. Meanwhile, at proteomic level, long-term Gly exposure resulted in alteration of 21 proteins, which were principally related to hepatic metabolism function. In conclusion, our data displayed a potential toxicity, mainly manifested as redox imbalance and dysregulation of metabolism function, in the liver of tilapia after long-term Gly exposure at 2 mg/L. This study provided novel insight into underlying toxicity mechanism of long-term Gly exposure at an environmentally relevant concentration in fish.

Selenium protects against cadmium-induced cardiac injury by attenuating programmed cell death via PI3K/AKT/PTEN signaling

Cadmium (Cd) is an environmental pollutant that has an enormous influence on agricultural production, but selenium (Se) can alleviate its toxicity. The present study aimed to illustrate the effects of Se on Cd-induced heart injury. All 40 rabbits were randomly divided into four groups: control group, Se [0.5 mg kg^-1 ·body weight (BW)] group, Cd (1 mg kg^-1 ·BW) group, and Se + Cd group. After 30 days of feeding, morphological changes, the levels of oxidative stress and myocardial enzyme, the content of cardiac troponin T, programmed cell death (pyroptosis, autophagy and apoptosis), and PI3K/AKT/PTEN transduction capacity were observed. The results showed that Cd destroyed the physiological balance of trace elements and caused myocardial damage, increased the cardiac oxidative damage and led to programmed cell death. Coadministration of Se prominently ameliorated histological lesions and improved cardiac function of hearts in Cd-induced rabbits. Furthermore, Se exerted detoxification and oxidation resistance, maintained trace element homeostasis, and alleviated the changes of mRNA and protein levels of pyroptosis-, autophagy- and apoptosis-controlling factors and PI3K/AKT/PTEN signal molecules caused by Cd. In conclusion, Se might protect against Cd-induced pyroptosis, autophagy and apoptosis by interfering with PI3K/AKT/PTEN signaling in heart.

Hydroxy Selenomethionine Alleviates Hepatic Lipid Metabolism Disorder of Pigs Induced by Dietary Oxidative Stress via Relieving the Endoplasmic Reticulum Stress

This study used 40 castrated male pigs to determine the protective effects of a new selenium molecule (hydroxy selenomethionine, OH-SeMet) on dietary oxidative stress (DOS) induced hepatic lipid metabolism disorder, and corresponding response of selenotranscriptome. The pigs were randomly grouped into 5 dietary treatments and fed a basal diet formulated with either normal corn and oils or oxidized diet in which the normal corn and oils were replaced by aged corn and oxidized oils, and supplemented with OH-SeMet at 0.0, 0.3, 0.6 and 0.9 mg Se/kg for a period of 16 weeks (n = 8). The results showed that DOS induced liver damage, increased serum alanine aminotransferase (ALT) and alkaline phosphatase (ALP) levels, decreased serum triacylglycerol (TG) level, suppressed antioxidant capacity in the liver, and changed lipid metabolism enzyme activity, thus causing lipid metabolism disorder in the liver. The DOS-induced lipid metabolism disorder was accompanied with endoplasmic reticulum (ER) stress, changes in lipid metabolism-related genes and selenotranscriptome in the liver. Dietary Se supplementation partially alleviated the negative impact of DOS on the lipid metabolism. These improvements were accompanied by increases in Se concentration, liver index, anti-oxidative capacity, selenotranscriptome especially 11 selenoprotein-encoding genes, and protein abundance of GPX1, GPX4 and SelS in the liver, as well as the decrease in SelF abundance. The Se supplementation also alleviated ER stress, restored liver lipid metabolism enzyme activity, increased the mRNA expression of lipid synthesis-related genes, and decreased the mRNA levels of lipidolysis-related genes. In conclusion, the dietary Se supplementation restored antioxidant capacity and mitigated ER stress induced by DOS, thus resisting hepatic lipid metabolism disorders that are associated with regulation of selenotranscriptome.

Environmental pollution, a hidden culprit for health issues

The environmental and health impacts from the massive discharge of chemicals and subsequent pollution have been gaining increasing public concern. The unintended exposure to different pollutants, such as heavy metals, air pollutants and organic chemicals, may cause diverse deleterious effects on human bodies, resulting in the incidence and progression of different diseases. The article reviewed the outbreak of environmental pollution-related public health emergencies, the epidemiological evidence on certain pollution-correlated health effects, and the pathological studies on specific pollutant exposure. By recalling the notable historical life-threatening disasters incurred by local chemical pollution, the damning evidence was presented to criminate certain pollutants as the main culprit for the given health issues. The epidemiological data on the prevalence of some common diseases revealed a variety of environmental pollutants to blame, such as endocrine-disrupting chemicals (EDCs), fine particulate matters (PMs) and heavy metals. The retrospection of toxicological studies provided illustrative clues for evaluating ambient pollutant-induced health risks. Overall, environmental pollution, as the hidden culprit, should answer for the increasing public health burden, and more efforts are highly encouraged to strive to explore the cause-and-effect relationships through extensive epidemiological and pathological studies.

Endoplasmic Reticulum Stress Contributes to Copper-Induced Pyroptosis via Regulating the IRE1α-XBP1 Pathway in Pig Jejunal Epithelial Cells

Copper (Cu) is a common additive in food products, which poses a potential concern to animal and human health when it is in excess. Here, we investigated the relationship between endoplasmic reticulum (ER) stress and pyroptosis in Cu-induced toxicity of jejunum in vivo and in vitro. In in vivo experiments, excess intake of dietary Cu caused ER cavity expansion, elevated fluorescence signals of GRP78 and Caspase-1, and increased the mRNA and protein expression levels related to ER stress and pyroptosis in pig jejunal epithelium. Simultaneously, similar effects were observed in IPEC-J2 cells under excess Cu treatment. Importantly, 4-phenylbutyric acid (ER stress inhibitor) and MKC-3946 (IRE1α inhibitor) significantly inhibited the ER stress-triggered IRE1α-XBP1 pathway, which also alleviated the Cu-induced pyroptosis in IPEC-J2 cells. In general, these results suggested that ER stress participated in regulating Cu-induced pyroptosis in jejunal epithelial cells via the IRE1α-XBP1 pathway, which provided a novel view into the toxicology of Cu.

Plasma selenium and the risk of first stroke in adults with hypertension: a secondary analysis of the China Stroke Primary Prevention Trial

BACKGROUND

Previous studies have indicated that selenium (Se) may play an important role in cardio-cerebrovascular disease. However, the relation between circulating selenium and risk of first stroke remains inconclusive.

OBJECTIVES

We conducted a secondary analysis of the China Stroke Primary Prevention Trial (CSPPT), using a nested case-control design, and aimed to investigate the correlation between Se concentration and first stroke risk in adults with hypertension and examine the potential effect modifiers.

METHODS

In the CSPPT, a total of 20,702 adults with hypertension were randomly assigned to a double-blind daily treatment with either 10 mg enalapril and 0.8 mg folic acid or 10 mg enalapril alone. A total of 618 first stroke cases and 618 controls matched for age, sex, treatment group, and study site were included in this study.

RESULTS

During a median follow-up duration of 4.5 y (IQR: 4.2-4.6 y), there was a significant inverse association between plasma Se and the risk of first stroke (per SD increment; adjusted OR: 0.81; 95% CI: 0.68, 0.96) and ischemic stroke (per SD increment; adjusted OR: 0.76; 95% CI: 0.62, 0.93). Furthermore, a stronger inverse association between plasma Se and first stroke was observed in participants with higher folate concentrations at baseline [≥7.7 ng/mL (median), adjusted OR: 0.67; 95% CI: 0.54, 0.85, compared with <7.7 ng/mL, adjusted OR: 0.98; 95% CI: 0.80, 1.21; P-interaction = 0.008] and those with higher time-averaged systolic blood pressure (SBP) over the treatment period (≥140 mm Hg, adjusted OR: 0.71; 95% CI: 0.58, 0.86, compared with <140 mm Hg, adjusted OR: 0.96; 95% CI: 0.77, 1.20; P-interaction = 0.023).

CONCLUSIONS

There was a significant inverse association between plasma Se and risk of first stroke in Chinese adults with hypertension, especially among those with higher baseline folate concentrations and those with higher time-averaged SBP over the treatment period. This trial was registered at clinicaltrials.gov as NCT00794885.

Cadmium induced oxidative stress, endoplasmic reticulum (ER) stress and apoptosis with compensative responses towards the up-regulation of ribosome, protein processing in the ER, and protein export pathways in the liver of zebrafish

The present study identified that exposure to 5, 10, and 20 µg/L Cd for 48 days reduced growth, increased Cd accumulation and levels of reactive oxygen species (ROS) and lipid peroxidation, and induced ER stress and cellular apoptosis in the liver in a dose-dependent manner. However, the survival rate was not affected by Cd. The increased production of ROS might result from reduced catalase (CAT) and copper/zinc-superoxide dismutase (Cu/Zn-SOD) activities, which might trigger ER stress pathways and subsequently induce apoptotic responses, ultimately leading to growth inhibition. Transcriptomic analyses indicated that the differentially expressed genes (DEGs) involved in metabolic pathways were significantly enriched and dysregulated by Cd, suggesting that metabolic disturbances may contribute to Cd toxicity. However, there were increases in glutathione peroxidase (GPX) activity, protein levels of metallothioneins (MTs) and heat shock protein 70 (HSP70), and mRNA levels of sod1, cat, gpx, mt2, and hsp70. Furthermore, DEGs related to ribosome, protein processing in the ER, and protein export pathways were significantly enriched and up-regulated by Cd. These increases may be compensatory responses following oxidative stress, ER stress, and apoptosis to resist negative effects. Taken together, we demonstrated that environmentally relevant levels of Cd induced adaptive responses with compensatory mechanisms in fish, which may help to maintain fish survival at the cost of growth.

Cadmium induced Fak -mediated anoikis activation in kidney via nuclear receptors (AHR/CAR/PXR)-mediated xenobiotic detoxification pathway

Cadmium (Cd) is a toxic heavy metal of considerable toxicity, possessing a serious environmental problem that threatening food safety and human health. However, the underlying mechanisms of Cd-induced nephrotoxicity and detoxification response remain largely unclear. Cd was administered at doses of 35, 70, and 140 mg/kg diet with feed for 90 days and produced potential damage to chickens' kidneys. The results showed that Cd exposure induced renal anatomical and histopathological injuries. Cd exposure up-regulated cytochrome P450 enzymes (CYP450s), activated nuclear xenobiotic receptors (NXRs) response, including aryl hydro-carbon receptor (AHR), constitutive androstane receptor (CAR), and pregnane X receptor (PXR) by low and moderate doses of Cd, and induced an increase in CYP isoforms expression. Cd exposure down-regulated phase II detoxification enzymes (glutathione-S-transferase (GST), glutathione peroxidase (GSH-PX) activities, and glutathione (GSH) content), and GST isoforms transcription . Furthermore, ATP-binding cassette (ABC) transporters, multidrug resistance protein (MRP1), and P-glycoprotein (P-GP) levels were elevated by low dose, but high dose inhibited the P-GP expression. Activation of detoxification enzymes lost their ability of resistance as increasing dose of Cd, afterwards brought into severe renal injury. Additionally, Cd suppressed focal adhesion kinase (Fak) and integrins protein expression as well as activated extrinsic pathway and intrinsic pathways, thereby producing anoikis. In conclusion, these results indicated that Cd induced Fak-mediated anoikis activation in the kidney via nuclear receptors (AHR/CAR/PXR)-mediated xenobiotic detoxification pathway.

ER Stress in Cardiometabolic Diseases: From Molecular Mechanisms to Therapeutics

The endoplasmic reticulum (ER) hosts linear polypeptides and fosters natural folding of proteins through ER-residing chaperones and enzymes. Failure of the ER to align and compose proper protein architecture leads to accumulation of misfolded/unfolded proteins in the ER lumen, which disturbs ER homeostasis to provoke ER stress. Presence of ER stress initiates the cytoprotective unfolded protein response (UPR) to restore ER homeostasis or instigates a rather maladaptive UPR to promote cell death. Although a wide array of cellular processes such as persistent autophagy, dysregulated mitophagy, and secretion of proinflammatory cytokines may contribute to the onset and progression of cardiometabolic diseases, it is well perceived that ER stress also evokes the onset and development of cardiometabolic diseases, particularly cardiovascular diseases (CVDs), diabetes mellitus, obesity, and chronic kidney disease (CKD). Meanwhile, these pathological conditions further aggravate ER stress, creating a rather vicious cycle. Here in this review, we aimed at summarizing and updating the available information on ER stress in CVDs, diabetes mellitus, obesity, and CKD, hoping to offer novel insights for the management of these cardiometabolic comorbidities through regulation of ER stress.

Vanadium Induces Oxidative Stress and Mitochondrial Quality Control Disorder in the Heart of Ducks

Vanadium (V) is an ultra-trace element presenting in humans and animals, but excessive V can cause toxic effects. Mitochondrial quality control (MQC) is an essential process for maintaining mitochondrial functions, but the relationship between V toxicity and MQC is unclear. To investigate the effects of excessive V on oxidative stress and MQC in duck hearts, 72 ducks were randomly divided into two groups, including the control group and the V group (30 mg of V/kg dry matter). The cardiac tissues were collected for the histomorphology observation and oxidative stress status evaluation at 22 and 44 days. In addition, the mRNA and protein levels of MQC-related factors were also analyzed. The results showed that excessive V could trigger vacuolar degeneration, granular degeneration, as well as mitochondrial vacuolization and swelling in myocardial cells. In addition, CAT activity was elevated in two time points, while T-SOD activity was increased in 22 days but decreased in 44 days after V treatment. Meanwhile, excessive V intake could also increase the number of Drp1 puncta, the mRNA levels of mitochondrial fission–related factors (Drp1and MFF), and protein (MFF) level, but decrease the number of Parkin puncta and the mitochondrial biogenesis (PGC-1α, NRF-1, and TFAM), mitochondrial fusion (OPA1, Mfn1, and Mfn2), and mitophagy (Parkin, PINK1, P62, and LC3B) related mRNA levels and protein (PGC-1α, Mfn1, Mfn2, PINK1) levels. Collectively, our results suggested that excessive V could induce oxidative stress and MQC disorder in the heart of ducks.

The Impact of ZIP8 Disease-Associated Variants G38R, C113S, G204C, and S335T on Selenium and Cadmium Accumulations: The First Characterization

The metal cation symporter ZIP8 (SLC39A8) is a transmembrane protein that imports the essential micronutrients iron, manganese, and zinc, as well as heavy toxic metal cadmium (Cd). It has been recently suggested that selenium (Se), another essential micronutrient that has long been known for its role in human health and cancer risk, may also be transported by the ZIP8 protein. Several mutations in the ZIP8 gene are associated with the aberrant ion homeostasis of cells and can lead to human diseases. However, the intricate relationships between ZIP8 mutations, cellular Se homeostasis, and human diseases (including cancers and illnesses associated with Cd exposure) have not been explored. To further verify if ZIP8 is involved in cellular Se transportation, we first knockout (KO) the endogenous expression of ZIP8 in the HeLa cells using the CRISPR/Cas9 system. The elimination of ZIP8 expression was examined by PCR, DNA sequencing, immunoblot, and immunofluorescence analyses. Inductively coupled plasma mass spectrometry indicated that reduced uptake of Se, along with other micronutrients and Cd, was observed in the ZIP8-KO cells. In contrast, when ZIP8 was overexpressed, increased Se uptake could be detected in the ZIP8-overexpressing cells. Additionally, we found that ZIP8 with disease-associated single-point mutations G38R, G204C, and S335T, but not C113S, showed reduced Se transport ability. We then evaluated the potential of Se on Cd cytotoxicity prevention and therapy of cancers. Results indicated that Se could suppress Cd-induced cytotoxicity via decreasing the intracellular Cd transported by ZIP8, and Se exhibited excellent anticancer activity against not all but only selected cancer cell lines, under restricted experimental conditions. Moreover, clinical-based bioinformatic analyses revealed that up-regulated ZIP8 gene expression was common across multiple cancer types, and selenoproteins that were significantly co-expressed with ZIP8 in these cancers had been identified. Taken together, this study concludes that ZIP8 is an important protein in modulating cellular Se levels and provides insights into the roles of ZIP8 and Se in disease prevention and therapy.