Oral exposure of mice to cadmium (II), chromium (VI) and their mixture induce oxidative- and endoplasmic reticulum-stress mediated apoptosis in the livers

Nanoparticles toxicity: an overview of its mechanism and plausible mitigation strategies

Over the last decade, nanoparticles have found great interest among scientists and researchers working in various fields within the realm of biomedicine including drug delivery, gene delivery, diagnostics, targeted therapy and biomarker mapping. While their physical and chemical properties are impressive, there is growing concern about the toxicological potential of nanoparticles and possible adverse health effects as enhanced exposure of biological systems to nanoparticles may result in toxic effects leading to serious contraindications. Toxicity associated with nanoparticles (nanotoxicity) may include the undesired response of several physiological mechanisms including the distressing of cells by external and internal interaction with nanoparticles. However, comprehensive knowledge of nanotoxicity mechanisms and mitigation strategies may be useful to overcome the hazardous situation while treating diseases with therapeutic nanoparticles. With the same objectives, this review discusses various mechanisms of nanotoxicity and provides an overview of the current state of knowledge on the impact of nanotoxicity on biological control systems and organs including liver, brain, kidneys and lungs. An attempt also been made to present various approaches of scientific research and strategies that could be useful to overcome the effect of nanotoxicity during the development of nanoparticle-based systems including coating, doping, grafting, ligation and addition of antioxidants.

Chronic low-dose chromium VI exposure induces oxidative stress and apoptosis with altered expressions of DNA repair genes and promoter hypermethylation in the liver of Swiss albino mice

The present investigation dealt with harmful effects of hexavalent chromium (Cr [VI]) on liver of Swiss albino mice. This variant exhibited cytotoxicity, mutagenicity, and carcinogenicity. Our study focused on elucidating the hepatotoxic effects of chronic low-dose exposure to Cr (VI) (2, 5, and 10 ppm) administered via drinking water for 4 and 8 months. The observed elevation in SGPT, ALP, and SGOT and increased oxidative stress markers unequivocally confirmed the severe disruption of liver homeostasis at these low treatment doses. Noteworthy alterations in histoarchitecture, body weight, and water intake provided further evidences of the harmful effects of Cr (VI). Production of reactive oxygen species (ROS) during metabolism led to DNA damages. Immunohistochemistry and qRT-PCR analyses revealed that chronic low-dose exposure of Cr (VI) induced apoptosis in liver tissue. Our study exhibited alterations in the expression pattern of DNA repair genes (Rad51, Mutyh, Mlh1, and Ogg1), coupled with promoter hypermethylation of Mutyh and Rad51, leading to transcriptional inhibition. Our findings underscored the potential of low-dose Cr (VI) exposure on hepatotoxicity by the intricate interplay between apoptosis induction and epigenetic alterations of DNA repair genes.

Cadmium as an ovarian toxicant: A review

Cadmium (Cd) is a ubiquitous heavy metal toxicant with no biological function in the human body. Considerably, because of its long biological half-life and very low excretion rate, Cd is inclined to accumulate and cause deleterious effects on various body organs (e.g., liver, kidney, and ovary) in humans and animals. Ovaries are the most vulnerable targets of Cd toxicity. Cd has been shown to induce oxidative stress, follicular atresia, hormonal imbalance, and impairment of oocyte growth and development. Moreover, Cd toxicity has been associated with increasing incidences of menstrual disorders, pregnancy loss, preterm births, delayed puberty, and female infertility. Therefore, it is crucial to understand how Cd poisoning impacts specific ovarian processes for the development of preventive interventions to enhance female fertility. The current review attempts to collate the recent findings on Cd-induced oxidative stress, follicular apoptosis, steroid synthesis inhibition, and teratogenic toxicity, along with their possible mechanisms in the ovarian tissue of different animal species. Additionally, the review also summarizes the studies related to the use of many antioxidants, medicinal herbs, and other compounds as remedial approaches for managing Cd-induced ovarian toxicity.

Coenzyme Q10, Biochanin A and Phloretin Attenuate Cr(VI)-Induced Oxidative Stress and DNA Damage by Stimulating Nrf2/HO-1 Pathway in the Experimental Model

Hexavalent chromium [Cr(VI)] has emerged as a prevailing environmental and occupational contaminant over the past few decades. However, the knowledge is sparse regarding Cr(VI)-induced neurological aberrations, and its remediation through natural bioactive compounds has not been fully explored. This study intended to probe the possible invigorative effects of nutraceuticals such as coenzyme Q10 (CoQ10), biochanin A (BCA), and phloretin (PHL) on Cr(VI) intoxicated Swiss albino mice with special emphasis on Nrf2/HO-1/NQO1 gene expressions. Mice received potassium dichromate (75 ppm) through drinking water and were simultaneously co-treated intraperitoneally with CoQ10 (10 mg/kg), BCA, and PHL (50 mg/kg) each for 30-day treatment period. The statistics highlight the elevated levels of lipid peroxidation (LPO) and protein carbonyl content (PCC) with a concomitant reduction in the superoxide dismutase (SOD), glutathione-S-transferase (GST), reduced glutathione (GSH), total thiols (TT), catalase (CAT), and cholinesterase activities in the Cr(VI)-exposed mice. The collateral assessment of DNA fragmentation, DNA breakages, and induced histological alterations was in conformity with the above findings in conjugation with the dysregulation in the Nrf2 and associated downstream HO-1 and NQO1 gene expressions. Co-treatment with the selected natural compounds reversed the above-altered parameters significantly, thereby bringing cellular homeostasis in alleviating the Cr(VI)-induced conciliated impairments. Our study demonstrated that the combination of different bioactive compounds shields the brain better against Cr(VI)-induced neurotoxicity by revoking the oxidative stress-associated manifestations. These compounds may represent a new potential combination therapy due to their ability to modulate the cellular antioxidant responses by upregulating the Nrf2/HO-1/NQO1 signaling pathway against Cr(VI)-exposed population. HIGHLIGHTS: Cr(VI)-associated heavy metal exposure poses a significant threat to the environment, especially to living organisms. Cr(VI) exposure for 30 days resulted in the free radical's generation that caused neurotoxicity in the Swiss albino mice. Natural compounds such as coenzyme Q10, biochanin A, and phloretin counteracted the neurotoxic effect due to Cr(VI) exposure in scavenging of free radicals by enhancing Nrf2/HO-1/NQO1 gene expressions in maintaining the cellular homeostasis.

The relationship between co-exposure to multiple heavy metals and liver damage

BACKGROUND

The impact of heavy metal exposure on human health has attracted widespread attention of researchers, and the impact of heavy metal exposure on liver function has also been confirmed, however, more attention is paid to the impact of single or two heavy metal exposures, and most epidemiological studies focus on heavy metal pollution areas. In this study, rural residents in non-heavy metal-contaminated areas in Northwest China were selected as the research objects to explore the comprehensive effects of co-exposure to multiple heavy metals on the liver, which can provide certain reference and support for related research.

OBJECTIVES

This study used a Bayesian nuclear machine model (BKMR) to evaluate the relationship between exposure to heavy metal mixtures and indicators of liver function in a population in rural Northwest China.

RESULTS

Exposure to higher concentrations of metal mixtures was positively correlated with total bilirubin, direct bilirubin, and aspartate aminotransferase, and negatively correlated with alanine aminotransferase, with Pb contributing the most to indicators of liver function. We also observed a possible interaction of Cd with other heavy metals in the effect of heavy metal mixtures on DB levels.

CONCLUSIONS

Concurrent exposure to higher concentrations of heavy metal mixtures (Cr, Co, Cd, and Pb) in rural China was associated with indicators representing poor liver function, of which the effect of lead on liver function should be focused. More prospective epidemiological studies and animal experiments need to be carried out to determine this relationship and possible mechanism.

Toxic and carcinogenic effects of hexavalent chromium in mammalian cells in vivo and in vitro: a recent update

Chromium VI (Cr (VI)) can cross cell membranes readily and causes the formation of Cr-DNA adducts, genomic damages, elevation of reactive oxygen species (ROS) and alteration of survival signaling pathways, as evidenced by the modulation in p53 signaling pathway. Mammals, including humans are exposed to Cr, including Cr (VI), frequently through inhalation, drinking water, and food. Several studies demonstrated that Cr (VI) induces cellular death through apoptosis and autophagy, genotoxicity, functional alteration of mitochondria, endocrine and reproductive impairments. In the present review, studies on deleterious effects of Cr (VI) exposure to mammalian cells (in vivo and in vitro) have been documented. Special attention is paid to the underlying molecular mechanism of Cr (VI) toxicity.

Molybdenum and cadmium co-exposure promotes M1 macrophage polarization through oxidative stress-mediated inflammatory response and induces pulmonary fibrosis in Shaoxing ducks (Anas platyrhyncha)

High molybdenum (Mo) and cadmium (Cd) are harmful to the body, but pulmonary toxicity induced by Mo and Cd co-exposure is unknown. To assess the combined impacts of Mo and Cd on fibrosis through M1 polarization in the lung of ducks, 80 healthy 8-day-old Shaoxing ducks (Anas platyrhyncha) were randomly assigned to 4 groups and fed with containing unequal doses of Mo or/and Cd diet. Lung tissues were collected on the 16th week. Results indicated that Mo or/and Cd significantly increased their contents in the lungs, and led to trace elements disorder and histological abnormality, and oxidative stress accompanied by promoting contents of H₂ O₂ and MDA and decreasing activities of T-SOD, GSH-Px, and CAT, then activated the TLR4/NF-κB/NLRP3 pathway accompanied by upregulating Caspase-1, ASC, IL-18, IL-1β, TLR4, NF-κB, and NLRP3 expression levels, and disrupted M1/M2 balance to divert toward M1, which evoked the TGF-β/Smad2/3-mediated fibrosis by elevating TGF-β1, Smad2, Smad3, COL1A1, α-SMA, and MMP2 expression levels, and decreasing Smad7 and TIMP2 expression levels. The changes of the combined group were most obvious. To sum up, the research demonstrated that Mo or/and Cd may cause macrophages to polarize toward M1 by oxidative stress-mediated the TLR4/NF-κB/NLRP3 pathway, then result in fibrosis through the TGF-β1/Smad2/3 pathway in duck lungs. Mo and Cd may worsen lung damage.

Graphene Oxide Enhances Biogenesis and Release of Exosomes in Human Ovarian Cancer Cells

BACKGROUND

Exosomes, which are nanovesicles secreted by almost all the cells, mediate intercellular communication and are involved in various physiological and pathological processes. We aimed to investigate the effects of graphene oxide (GO) on the biogenesis and release of exosomes in human ovarian cancer (SKOV3) cells.

METHODS

Exosomes were isolated using ultracentrifugation and ExoQuick and characterized by various analytical techniques. The expression levels of exosome markers were analyzed via quantitative reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay.

RESULTS

Graphene oxide (10-50 μg/mL), cisplatin (2-10 μg/mL), and C6-ceramide (5-25 μM) inhibited the cell viability, proliferation, and cytotoxicity in a dose-dependent manner. We observed that graphene oxide (GO), cisplatin (CIS), and C6-Ceramide (C6-Cer) stimulated acetylcholine esterase and neutral sphingomyelinase activity, total exosome protein concentration, and exosome counts associated with increased level of apoptosis, oxidative stress and endoplasmic reticulum stress. In contrast, GW4869 treatment inhibits biogenesis and release of exosomes. We observed that the human ovarian cancer cells secreted exosomes with typical cup-shaped morphology and surface protein biomarkers. The expression levels of TSG101, CD9, CD63, and CD81 were significantly higher in GO-treated cells than in control cells. Further, cytokine and chemokine levels were significantly higher in exosomes isolated from GO-treated SKOV3 cells than in those isolated from control cells. SKOV3 cells pre-treated with N-acetylcysteine or GW4869 displayed a significant reduction in GO-induced exosome biogenesis and release. Furthermore, endocytic inhibitors decrease exosome biogenesis and release by impairing endocytic pathways.

CONCLUSION

This study identifies GO as a potential tool for targeting the exosome pathway and stimulating exosome biogenesis and release. We believe that the knowledge acquired in this study can be potentially extended to other exosome-dominated pathologies and model systems. Furthermore, these nanoparticles can provide a promising means to enhance exosome production in SKOV3 cells.

Anchoring of Nanocomposites Based on Novel Metal Nanocomplexes/Nanocarbonaceous Surfaces and Assessing Their In Vivo Anticancer Effects on Ehrlich Ascites Tumor

Nanotechnology is the study of materials' unique properties at the nanoscale. Nanomedicine is the application of nanotechnology in medicine, which has been utilized to treat some common diseases, such as cancer. The aim of the present work is to synthesize the cadmium (Cd) nanocomplex using paracetamol as a ligand with a molar ratio of 1:2 M/L that was characterized by different physicochemical methods and to explore the effect of the synthesized Cd nanocomplex on the immune system and the redox status of the body and their anticancer effects on Ehrlich ascites carcinoma (EAC) induced in mice. Eighty female albino mice were separated into Group I: control; Group II: EAC; Group III: EAC treated with a low-dose Cd nanocomplex; and Group IV: EAC treated with a high-dose Cd nanocomplex. Interleukin-6 (IL-6), NLR family pyrin domain containing 3 (NLRP3), and 8-hydroxy 2-deoxyguanosine (8-OHdG) levels were assessed by enzyme-linked immunosorbent assay (ELISA). Peroxynitrite level and glutathione peroxidase activity were assessed by spectrophotometry. NRF2 mRNA expression, cadmium content, and liver and renal toxicity were estimated. Results: There was a significant increase in IL-6, NLRP3, 8-OHdG, peroxynitrite, and NRF2 mRNA expressions and in the glutathione peroxidase activity in EAC treated with low- and high-dose Cd nanocomplexes. However, the EAC treated with high-dose Cd nanocomplex group showed significant liver and renal toxicity. Conclusion: Cadmium nanocomplex has anticancer effects on EAC induced in mice via its effects on the immune system and redox status as well as pyroptosis and epigenetic instability of the body, while high doses of Cd nanocomplex can cause liver and renal toxicity.

Role of ER Stress in Xenobiotic-Induced Liver Diseases and Hepatotoxicity

The liver is a highly metabolic organ and plays a crucial role in the transportation, storage, and/or detoxication of xenobiotics. Liver damage induced by xenobiotics (e.g., heavy metal, endocrine disrupting chemicals, Chinese herbal medicine, or nanoparticles) has become a pivotal reason for liver diseases, leading to great clinical challenge and much attention for the past decades. Given that endoplasmic reticulum (ER) is the prominent organelle involved in hepatic metabolism, ER dysfunction, namely, ER stress, is clearly observed in various liver diseases. In response to ER stress, a conserved adaptive signaling pathway known as unfolded protein response (UPR) is activated to restore ER homeostasis. However, the prolonged ER stress with UPR eventually leads to the death of hepatocytes, which is a pathogenic event in many hepatic diseases. Therefore, analyzing the perturbation in the activation or inhibition of ER stress and the UPR signaling pathway is likely an effective marker for investigating the molecular mechanisms behind the toxic effects of xenobiotics on the liver. We review the role of ER stress in hepatic diseases and xenobiotic-induced hepatotoxicity, which not only provides a theoretical basis for further understanding the pathogenesis of liver diseases and the mechanisms of hepatotoxicity induced by xenobiotics but also presents a potential target for the prevention and treatment of xenobiotic-related liver diseases.

A comprehensive review on human health effects of chromium: insights on induced toxicity

The growing use of heavy metals in most industrial activities has led to it being considered as the most important environmental pollutant that may cause harm and toxicity to animals and humans. Chromium has been found in the environment in different oxidation states such as Cr⁰, Cr(III), and Cr(VI) and is released from a variety of anthropogenic and natural activities. At among, trivalent and hexavalent chromium are the most stable forms. Considerably, Cr(VI) is frequently more toxic than Cr(III) because of its particular solubility and high mobility. Chronic exposure and bioaccumulation of chromium, as a heavy metal, can cause toxicity and numerous pathophysiological defects, including allergic reactions, anemia, burns, and sores especially in the stomach and small intestine, damage to sperm along with the male reproductive system, and affect various biological systems. Chromium pollution can have severe consequences for water and the soil environment. This article reviews the toxicological effects of Cr(VI) and Cr(III) and their mechanisms of toxicity and carcinogenicity.

Protective Effects of Astilbin Against Cadmium-Induced Apoptosis in Chicken Kidneys via Endoplasmic Reticulum Stress Signaling Pathway

Cadmium (Cd) can cause endoplasmic reticulum stress (ERS) and apoptosis in animals. The kidney is an organ seriously affected by Cd because it can accumulate metal ions. Astilbin (ASB) is a dihydroflavonol rhamnoside, which has an anti-renal injury effect. This study aimed to evaluate the protective effect of ASB on Cd-induced ERS and apoptosis in the chicken kidney. In this study, a total of 120 1-day-old chickens were randomly divided into 4 groups. Chickens were fed with a basic diet (Con group), ASB 40 mg/kg (ASB group), CdCl₂ 150 mg/kg + ASB 40 mg/kg (ASB/Cd group), and CdCl₂ 150 mg/kg (Cd group) for 90 days. The results showed that Cd exposure induced pathological and ultrastructural damages and apoptosis in chicken kidneys. Compared with the Con group, metallothionein (MT1/MT2) level, nitric oxide (NO) content, inducible nitric oxide synthase (iNOS) activity, ERS-related genes 78-kDa glucose-regulated protein (Grp78), protein kinase PKR-like endoplasmic reticulum kinase (Perk), activating transcription factor 4 (Atf4) and CAAT/enhancer-binding protein (C/EBP) homologous protein (Chop), and pro-apoptotic gene B-cell lymphoma 2 (Bcl-2)-associated X (Bax), caspase-12, caspase-9, caspase-3 expression levels, and apoptotic rate were significantly increased in the Cd group. The expression level of Bcl-2 was significantly decreased in the Cd group. ASB/Cd combined treatment significantly improves the damage of chicken kidneys by ameliorating Cd-induced kidney ERS and apoptosis. Cd can cause the disorder of the GRP78 signal axis, activate the PERK-ATF4-CHOP pathway, aggravate the structural damage and dysfunction of ER, and promote the apoptosis of chicken kidneys, while the above changes were significantly alleviated in the ASB/Cd group. The results showed that ASB antagonizes the negative effects of Cd and against Cd-induced apoptosis in chicken kidneys via ERS signaling pathway.

Improvement of the antioxidant activity of thyme essential oil against biosynthesized titanium dioxide nanoparticles-induced oxidative stress, DNA damage, and disturbances in gene expression in vivo

BACKGROUND

Titanium dioxide nanoparticles (TiO₂-NPs) are widely utilized in medicine and industry; however, their safety in biological organisms is still unclear. In this study, we determined the bioactive constitutes of thyme essential oil (TEO) and utilized the nanoemulsion technique to improve its protective efficiency against oxidative stress, genotoxicity, and DNA damage of biosynthesized titanium dioxide nanoparticles (TiO₂-NPs).

METHODS

TEO nanoemulsion (TEON) was prepared using whey protein isolate (WPI). Sixty male Sprague-Dawley rats were divided into six groups and treated orally for 21 days including the control group, TEO, or TEON- treated groups (5 mg/kg b.w), TiO₂-NPs-treated group (50 mg/kg b.w) and the groups received TiO₂-NPs plus TEO or TEON. Blood and tissues samples were collected for different assays.

RESULTS

The GC-MS analysis identified 17 bioactive compounds in TEO and thymol and carvacrol were the major compounds. TEON was irregular with average particles size of 230 ± 3.7 nm and ζ-potential of -24.17 mV. However, TiO2-NPs showed a polygonal shape with an average size of 50 ± 2.4 nm and ζ-potential of -30.44 mV. Animals that received TiO2-NPs showed severe disturbances in liver and kidney indices, lipid profile, oxidant/antioxidant indices, inflammatory cytokines, gene expressions, increased DNA damage, and pathological changes in hepatic tissue. Both TEO and TEON showed potential protection against these hazards and TEON was more effective than TEO.

CONCLUSION

The nanoemulsion of TEO enhances the oil bioactivity, improves its antioxidant characteristics, and protects against oxidative damage and genotoxicity of TiO2-NPs.

Mechanism of chromium-induced toxicity in lungs, liver, and kidney and their ameliorative agents

Heavy metal Chromium (Cr), can adversely affect humans and their health if accumulated in organs of the body, such as the lungs, liver, and kidneys. Cr (VI) is highly toxic and has a higher solubility in water than Cr (III). One of the most common routes for Cr exposure is through inhalation and is associated with liver, lung, kidney damage, widespread dermatitis, GI tract damage, human lung cancer, cardiomyopathies, and cardiovascular disease. The increase in ROS production has been attributed to most of the damage caused by Cr toxicity. Cr-induced ROS-mediated oxidative stress has been seen to cause a redox imbalance affecting the antioxidant system balance in the body. The Nrf2 pathway dysregulation has been implicated in the same. Deregulation of histone acetylation and methylation has been observed, together with gene methylation in genes such as p16, MGMT, APC, hMLH1, and also miR-143 repression. Several ultra-structural changes have been observed following Cr (VI)-toxicity, including rough ER dilation, alteration in the mitochondrial membrane and nuclear membrane, pycnotic nuclei formation, and cytoplasm vacuolization. A significant change was observed in the metabolism of lipid, glucose, and the metabolism of protein after exposure to Cr. Cr-toxicity also leads to immune system dysregulations with changes seen in the expression of IL-8, IL-4, IgM, lymphocytes, and leukocytes among others. P53, as well as pro-and anti-apoptotic proteins, are involved in apoptosis. These Cr-induced damages can be alleviated via agents that restore antioxidant balance, regulate Nrf-2 levels, or increase anti-apoptotic proteins while decreasing pro-apoptotic proteins.

Assessment of 2-Pentadecyl-2-oxazoline Role on Lipopolysaccharide-Induced Inflammation on Early Stage Development of Zebrafish (Danio rerio)

Lipopolysaccharide (LPS), or bacterial endotoxin, is an important virulence factor in several human and animal pathologies. Oxazoline of Palmitoylethanolamide (PEAOXA) has shown strong anti-inflammatory activity in several animal models. LPS was applied for 24 h to zebrafish embryos to induce inflammation, and then the anti-inflammatory action of PEAOXA was evaluated for the first time in the zebrafish model (Danio rerio). Different concentrations of PEAOXA were tested for toxicity on zebrafish embryonic development; only the highest concentration of 30 mg/L showed toxic effects. Quantitative RT-PCR was applied to detect Tumor necrosis factor-α, Interleukin 1β, 6, and 8, and members of the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB). Exposure to LPS induced an increase in pro-inflammatory cytokines (tumor necrosis factor and interleukin 1, 6, and 8) in both gene and protein expression, as well as an increase of the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) and the nuclear factor kappa light polypeptide enhancer in B-cells inhibitor (IκBα) gene expression. Furthermore, acute LPS exposure also induced an increase in tryptase release, related to mast cell activity, and in the production of apoptosis-related proteins (caspase 3, bax, and bcl-2). Treatment with PEAOXA 10 mg/L significantly counteracts LPS-induced inflammation in terms of cytokine expression and decreases tryptase release and the apoptosis pathway.

Intestinal Disorder in Zebrafish Larvae (Danio rerio): The Protective Action of N-Palmitoylethanolamide-oxazoline

IBD (Inflammatory Bowel Disease) is an inflammatory disease affecting the gastrointestinal tract that is common in both humans and veterinarians. Several studies have revealed the pharmacological properties of the oxazoline of palmitoylethanolamide (PEAOXA). Zebrafish larvae were exposed to sodium dextran sulphate (DSS) to induce enterocolitis and study the protective action of PEAOXA. After repetitive exposure with 0.25% DSS, larvae presented gut alteration with an increase in mucus production. Furthermore, DSS exposure induced an increase in the inflammatory pathway in the intestine, related to an increase in the Endoplasmic-reticulum (ER) stress genes. PEAOXA exposure at a concentration of 10 mg/L decreased the DSS-induced gut damage and mucus production, as well as being able to reduce the inflammatory and ER stress-related genes expression. In conclusion, our results demonstrate that the alterations induced by repeated exposure to DSS were counteracted by PEAOXA action that was able to inhibit the increase in inflammation and ER stress involved in the progression of enterocolitis.

Nano-selenium alleviating the lipid metabolism disorder of LMH cells induced by potassium dichromate via down-regulating ACACA and FASN

Chromium (Cr) VI is a common environmental contaminant highly toxic to livers. To explore the protective effect of nano-selenium (NANO-Se) on broiler liver damage caused by Cr (VI), this experiment was conducted with chicken hepatocellular carcinoma cell line (LMH) as the research object, using potassium dichromate (PDC) and NANO-Se gel for culturing cells. The results indicated that: (1) in the PDC-exposure group, LMH cells being treated with 20 μmol/L PDC for 24 h, IC50 (median inhibition concentration) = 23.427 could significantly reduce cell activity (p < 0.01) which decreased over time. PDC markedly increased the concentration of triglycerides (TG) and low-density lipoprotein cholesterol (LDL-C) in LMH cells (p < 0.01), which increased over time. In addition, PDC could substantially augment the transcription and protein levels of acetyl-CoA carboxylases alpha (ACACA) and fatty acid synthase (FASN) in LMH cells (p < 0.01). (2) Compared with the PDC-exposure group, the addition of 8 μmol/L NANO-Se after 12 h of PDC treatment could significantly increase the cell viability (p < 0.01) but decreased over time; the levels of TG and LDL-C in LMH cells declined markedly (p < 0.01). In addition, the transcription and protein levels of ACACA and FASN in LMH cells were significantly reduced (p < 0.01). (3) The LMH cells were cultured in advance with 8 μmol/L NANO-Se for 12 h and then with PDC for 24 h. The obtained results were similar to the above. There were no obvious differences in TG and LDL-C levels (p > 0.05). However, significant differences were found in the activity of LMH cells and the expression of genes related to lipid metabolism (p < 0.05).All these results suggest that the exposure to PDC promotes the increase of lipid synthesis in LMH cells and causes disorders in the lipid metabolism. Moreover, NANO-Se can partially attenuate the damage caused by PDC through down-regulating of the lipid metabolism-related genes (ACACA and FASN) in LMH cells.

Combined inhibition of AURKA and HSF1 suppresses proliferation and promotes apoptosis in hepatocellular carcinoma by activating endoplasmic reticulum stress

PURPOSE

In this study we aimed to assess the anti-tumor effect of co-inhibition of Aurora kinase A (AURKA) and heat shock transcription factor 1 (HSF1) on hepatocellular carcinoma (HCC), as well as to explore the mechanism involved.

METHODS

Expression of AURKA and HSF1 in primary HCC tissues and cell lines was detected by immunohistochemistry (IHC), qRT-PCR and Western blotting. AURKA was knocked down in HepG2 and BEL-7402 HCC cells using lentivirus-mediated RNA interference. Next, CCK-8, clone formation, transwell and flow cytometry assays were used to assess their viability, migration, invasion and apoptosis, respectively. The expression of proteins related to cell cycle progression, apoptosis and endoplasmic reticulum stress (ERS) was analyzed using Western blotting. In addition, in vivo tumor growth of HCC cells was assessed using a nude mouse xenograft model, and the resulting tumors were evaluated using HE staining and IHC.

RESULTS

Both AURKA and HSF1 were highly expressed in HCC tissues and cells, while being negatively related to HCC prognosis. Knockdown of AURKA significantly inhibited the colony forming and migrating capacities of HCC cells. In addition, we found that treatment with an AURKA inhibitor (Danusertib) led to marked reductions in the proliferation and migration capacities of the HCC cells, and promoted their apoptosis. Notably, combined inhibition of AURKA and HSF1 induced HCC cell apoptosis, while increasing the expression of ERS-associated proteins, including p-eIF2α, ATF4 and CHOP. Finally, we found that co-inhibition of AURKA and HSF1 elicited an excellent in vivo antitumor effect in a HCC mouse model with a relatively low cytotoxicity.

CONCLUSIONS

Combined inhibition of AURKA and HSF1 shows an excellent anti-tumor effect on HCC cells in vitro and in vivo, which may be mediated by ERS. These findings suggest that both AURKA and HSF1 may serve as targets for HCC treatment.

Co-exposures of TiO2 nanoparticles and cadmium ions at non-lethal doses aggravates liver injury in mice with ConA-induced hepatitis

The wide applications of titanium dioxide nanoparticles (TNP) and ubiquitous cadmium (Cd) pollution increase the chances of their co-existence in the environment and also pose potential health risks to humans. However, toxicological understanding of effects of co-exposures of TNP and Cd to mammals is still lacking. In this study, non-lethal doses of TNP and CdCl2 were intravenously co-administered to healthy or Concanavalin A (ConA)-induced acute hepatitis mice. Co-exposures of TNP and CdCl2 increased the accumulation of Cd2+ in the liver of hepatitis mice, which was 1.42-fold higher than that of healthy mice. Co-exposures also caused liver damage only in hepatitis mice on the basis of histopathological and biochemical evidence. Further study showed that co-exposure upregulated hepatic oxidative stress, which further induced autophagy and apoptosis only in the liver of hepatitis mice. This finding underlines the potential toxicological consequences of co-exposures of TNP and CdCl2 in hepatitis sufferers.

Grape seed proanthocyanidin extract ameliorates cisplatin-induced testicular apoptosis via PI3K/Akt/mTOR and endoplasmic reticulum stress pathways in rats

Testicular toxicity is an adverse reaction of the effective chemotherapy drug cisplatin (CIS). Our previous study found that grape seed proanthocyanidin extract (GSPE) had a protective effect on CIS-induced testicular toxicity. However, the protective mechanism of GSPE against CIS-induced testicular toxicity remains unknown. In this study, we aimed to investigate whether GSPE can reduce CIS-induced testicular toxicity and its potential mechanism in rats. The results showed that GSPE ameliorated CIS-induced the apoptosis of testicular cells and inhibited the protein levels of Bad, Cyt c, caspase-9, caspase-3, caspase-12, GRP78, CHOP, IRE1α, p-IRE1α, XBP-1S, PERK, p-PERK, eIF2α, and p-eIF2α. Besides, GSPE reversed the downregulation of PI3K, p-PI3K, Akt, p-Akt, mTOR, and p-mTOR protein expression induced by CIS. These results indicated that GSPE can improve CIS-induced testicular cells apoptosis via activating PI3K/Akt/mTOR and inhibiting Bad/Cyt c/caspase-9/caspase-3 pathways. And GSPE relieved endoplasmic reticulum stress-mediated apoptosis via inhibiting PREK/eIF2α and IRE1α/XBP-1S/caspase-12 pathways. In conclusion, the evidence suggested that GSPE can act as a protective agent against testicular toxicity induced by CIS. PRACTICAL APPLICATIONS: Testicular toxicity was a well-known adverse effect of cisplatin (CIS) in cancer treatment. Grape seed proanthocyanidin extract (GSPE) has been reported to serve as one of the most therapeutic potentials agents. In present study, we explored the regulatory effects of GSPE on the apoptosis induced by CIS, which involved testicular apoptosis mechanisms in rats. Our results indicated that CIS caused testicular toxicity via PI3K/AKT/mTOR and ERS mediated apoptosis pathway in rats. This toxicity was attenuated by GSPE treatment via activated PI3K/Akt/mTOR pathway, and inhibiting Bad/CytC/caspase-9/caspase-3 as well as PREK/eIF2α, IRE1α/XBP-1S/caspase-12 pathways. Our findings suggest that GSPE may be a novel protective agent against testicular toxicity induced by CIS.

Microcystin-leucine arginine induced the apoptosis of GnRH neurons by activating the endoplasmic reticulum stress resulting in a decrease of serum testosterone level in mice

Microcystin-leucine arginine (MC-LR) is a kind of toxin produced by cyanobacterial, resulting in decrease of testosterone levels in serum and leading to impaired spermatogenesis. Gonadotropin-releasing hormone (GnRH) neurons play crucial roles in the regulation of testosterone release. Meanwhile, it has been demonstrated that MC-LR is capable of entering the GnRH neurons and inducing apoptosis. Nevertheless, the molecular mechanism of MC-LR induced apoptosis of GnRH neurons remains elusive. In present study, we found that MC-LR inhibited the cell viability of GT1-7 cells. In addition, we discovered apoptosis of GnRH neurons and GT1-7 cells treated with MC-LR. And increased intracellular ROS production and the release of intracellular Ca²⁺ were all observed following exposure to MC-LR. Furthermore, we also found the endoplasmic reticulum stress (ERs) and autophagy were activated by MC-LR. Additionally, pretreatment of the ERs inhibitor (4-Phenyl butyric acid) reduced the apoptotic rate of GT1-7 cells comparing with MC-LR exposure alone. Comparing with MC-LR treatment alone, apoptotic cell death was increased by pretreatment of GT1-7 cells with an autophagy inhibitor (3-methyladenine). Together, our data implicated that the treatment of MC-LR induced the apoptosis of GnRH neurons by activating the ERs resulting in a decrease of serum testosterone level in mice. Autophagy is a protective cellular process which was activated by ER stress and thus protected cells from apoptosis upon MC-LR exposure.

Copper Induces Apoptosis Through Endoplasmic Reticulum Stress in Skeletal Muscle of Broilers

The purpose of this research was to investigate whether copper (Cu) exposure could induce apoptosis via endoplasmic reticulum stress (ERS) in skeletal muscle of broilers. A total of 240 one-day-old chickens were randomly divided into four groups by free access; the diets are as follows: control diet (Cu 11 mg/kg, control group) and high level of Cu diets (Cu 110 mg/kg, group I; Cu 220 mg/kg, group II; Cu 330 mg/kg, group III). The skeletal muscle tissues were collected on day 49 for further examination. The content of Cu, histopathology, and the expression levels of the genes and proteins related to ERS and apoptosis were detected. Results showed that the Cu levels in skeletal muscle were increased in a dose-dependent manner. Meanwhile, the spaces between the muscle fibers were wider with the increase of Cu content, and the myolysis was observed in group III. Besides, the mRNA expression levels of GRP78, GRP94, eIF2α, ATF6, XBP1, CHOP, Caspase-12, and Caspase3 were markedly increased in treated groups compared with control group, and the protein expression levels of GRP78, Caspase3, Active-Caspase3 and JNK were significantly elevated with the increase of dietary Cu. In summary, these findings suggested that Cu could induce apoptosis through ERS in skeletal muscle of broilers.

Mitochondrial connection to ginsenosides

Mitochondria play an essential role in energy synthesis and supply, thereby maintaining cellular function, survival, and energy homeostasis via mitochondria-mediated pathways, including apoptosis and mitophagy. Ginsenosides are responsible for most immunological and pharmacological activities of ginseng, a highly beneficial herb with antioxidant, anti-inflammatory, anti-apoptotic, and neuroprotective properties. Studies have shown that ginsenosides assist in regulating mitochondrial energy metabolism, oxidative stress, biosynthesis, apoptosis, mitophagy, and the status of membrane channels, establishing mitochondria as one of their most important targets. This article reviews the regulatory effects of ginsenosides on the mitochondria and highlights their beneficial role in treating mitochondrial diseases.

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

Cadmium (Cd), a heavy metal contaminant, exists in humans and animals throughout life and closely associate with severe hepatotoxicity. Selenium (Se) has been recognized as an effective chemo-protectant of Cd, but the underlying mechanisms remain unclear. The objective of the present study is to illustrate the antagonistic effect of Se against Cd-induced hepatotoxicity. Primary hepatocytes were cultured in the presence of 5 μM Cd, 1 μM Se and the mixture of 1 μM Se and 5 μM Cd for 24 h. Cell viability and morphology, antioxidant status, endoplasmic reticulum (ER) stress response and selenotranscriptome were assessed. It was observed that Se treatment dramatically alleviated Cd-induced hepatocytes death and morphological change. Simultaneously, Se mitigated Cd-induced oxidative stress by reducing ROS production, increasing reduced glutathione (GSH) level and increasing selenoenzyme (glutathione peroxidase, GPX) activity. Cd induced hepatotoxicity via disordering ER-resident selenoproteins transcription and triggering ER stress and unfolded protein response. Supplementary Se evidently relieved hepatocytes injury via modulating ER-resident selenoproteins transcription to inhibit ER stress. Collectively, our findings showed a potential protection of Se against Cd-induced hepatotoxicity via suppressing ER stress response.

Ginsenoside Rb 1: A novel therapeutic agent in Staphylococcusaureus-induced Acute Lung Injury with special reference to Oxidative stress and Apoptosis

Acute lung injury (ALI) is considered as an uncontrolled inflammatory response that can leads to acute respiratory distress syndrome (ARDS), which limits the therapeutic strategies. Ginsenosides Rb1 (Rb1), an active ingredient obtained from Panax ginseng, possesses a broad range of pharmacological and medicinal properties, comprising the anti-inflammatory, anti-oxidant, and anti-tumor activities. Therefore, the purpose of the present study was to investigate the protective effects of Rb1 against S. aureus-induced (ALI) through regulation of Nuclear factor erythroid 2-related factor 2 (Nrf2) and mitochondrial-mediated apoptotic pathways in mice (in-vivo), and RAW264.7 cells (in-vitro). For that purpose, forty Kunming mice were randomly assigned into four treatment groups; (1) Control group (phosphate buffer saline (PBS); (2) S. aureus group; (3) S. aureus + Rb1 (20 mg/kg) group; and (4) Rb1 (20 mg/kg) group. The 20 μg/mL dose of Rb1 was used in RAW264.7 cells. In the present study, we found that Rb1 treatment reduced ALI-induced oxidative stress via suppressing the accumulation of malondialdehyde (MDA) and myeloperoxidase (MPO) and increase the antioxidant enzyme activities of superoxidase dismutase 1 (SOD1), Catalase (CAT), and glutathione peroxidase 1 (Gpx1). Similarly, Rb1 markedly increased messenger RNA (mRNA) expression of antioxidant genes (SOD1, CAT and Gpx1) in comparison with ALI group. The histopathological results showed that Rb1 treatment ameliorated ALI-induced hemorrhages, hyperemia, perivascular edema and neutrophilic infiltration in the lungs of mice. Furthermore, Rb1 enhanced the antioxidant defense system through activating the Nrf2 signaling pathway. Our findings showed that Rb1 treated group significantly up-regulated mRNA and protein expression of Nrf2 and its downstream associated genes down-regulated by ALI in vivo and in vitro. Moreover, ALI significantly increased the both mRNA and protein expression of mitochondrial-apoptosis-related genes (Bax, caspase-3, caspase-9, cytochrome c and p53), while decreased the Bcl-2. In addition, Rb1 therapy significantly reversed the mRNA and protein expression of these mitochondrial-apoptosis-related genes, as compared to the ALI group in vivo and in vitro. Taken together, Rb1 alleviates ALI-induced oxidative injury and apoptosis by modulating the Nrf2 and mitochondrial signaling pathways in the lungs of mice.

Histological changes, lipid metabolism, and oxidative and endoplasmic reticulum stress in the liver of laying hens exposed to cadmium concentrations

The objective of this study was to determine the effects of cadmium (Cd) on histological changes, lipid metabolism, and oxidative and endoplasmic reticulum (ER) stress in the liver of layers. A total of 480 hens at 38 wk of age were randomly assigned in 5 groups that were fed a basal diet or basal diet supplemented with CdCl₂ 2.5H₂O at 7.5, 15, 30, and 60 mg Cd/kg feed for 9 wk. The results showed that accumulation of Cd was the greatest in the kidney, followed by the liver, pancreas, and lung. Diet contaminated with 30 mg Cd/kg induced antioxidant defenses accompanied by the increase of the activities of antioxidant enzymes in the liver, while dietary supplementation with 60 mg Cd/kg decreased the antioxidant levels significantly (P < 0.05). Immunofluorescence assay showed Cd induced reactive oxygen species production and endoplasmic reticulum stress in hepatocytes. Exposure to 60 mg Cd/kg significantly upregulated the expression of cytochrome C, caspase 3, caspase 9, caspase 7, Grp78, and Chop (P < 0.05). Histopathology and quantitative real-time PCR results presented periportal fibrosis, bile duct hyperplasia, and periportal inflammatory cell infiltration in the liver accompanied by upregulating the expression of tumor necrosis factor-α, IL-6 and IL-10 in the 30- or 60-mg Cd/kg groups. Oil Red O staining and RT-qPCR results showed dietary supplementation with 7.5, 15, and 30 mg Cd/kg promoted the synthesis of lipid droplets and upregulated the expression of fatty acid synthase, while dietary supplementation with 60 mg Cd/kg attenuated the synthesis of lipid droplets and downregulated the expression of acyl-CoA oxidase 1, carnitine palmitoyltransferase-1, and perixisome proliferation-activated receptor α (P < 0.05). Besides, the expression of vitellogenin (VTG) II and microsomal triglyceride transfer protein were upregulated in the 7.5-mg Cd/kg group, and the expressions of apolipoprotein B, vitellogenin II, and apolipoprotein very-low-density lipoprotein-II were downregulated in the 30- and/or 60-mg Cd/kg groups (P < 0.05). Conclusively, although low-dose Cd exposure promoted the synthesis of lipids and lipoproteins in the liver, the increase of Cd exposure could trigger liver injury through inducing oxidative and endoplasmic reticulum stress and negatively affect lipid metabolism and yolk formation in laying hens.

Removal of dental alloys and titanium attenuates trace metals and biological effects on liver and kidney

To determine whether the potential effects on liver and kidney caused by dental alloys could be reduced or terminated by the removal of nickel-chromium (Ni-Cr) alloy, cobalt-chromium (Co-Cr) alloy, and commercially pure titanium (CP-Ti), they were placed in the cheek pouches of Syrian hamsters according to ISO 10993-10. Then, the peak/plateau and end times of trace metals in the blood were determined with or without the removal of the dental alloys. Based on these time points, the trace metals and their effects on liver and kidney were examined. We found that trace metals released from these dental alloys and titanium were accumulated transiently in the blood, liver, and kidney but had no effect on the histopathology of the liver or kidney. Although the functions of the liver and kidney were compromised, the function of these tissues seemed to be clinically acceptable compared to those in control Syrian hamsters. In addition, the apoptotic effect on renal cells was terminated by removing the Ni-Cr and Co-Cr alloys, and that on hepatocytes was also eliminated by removing the Ni-Cr alloy. In contrast, the effect of the Co-Cr alloy on hepatocytes was temporary and recovered by itself. Taken together, Ni- and Co-based dental alloys and titanium have no effect on the histopathology or function of liver and kidney. Moreover, Ni-Cr and Co-Cr alloys induce transient trace metal accumulation and apoptotic effects in liver and kidney, which can be reduced or terminated by the removal of the alloys, while CP-Ti shows favorable biocompatibility.

Cadmium induces ovarian granulosa cell damage by activating PERK-eIF2α-ATF4 through endoplasmic reticulum stress

This study aimed to investigate whether cadmium induces ovarian granulosa cell damage by activating protein kinase R-like endoplasmic reticulum kinase (PERK)-eIF2α-ATF4 through endoplasmic reticulum (ER) stress and to elucidate the underlying regulation mechanism. Two models of cadmium exposure were established. In one model, ovarian granulosa cells isolated from 21-day-old female Sprague Dawley rats were cultured in vitro for 36 h and exposed to CdCl2 (0, 5, 10, and 20 μM), and in another model, a human ovarian granulosa tumor cell line (COV434) was used to construct the binding immunoglobulin protein (BIP)-knockdown cell line sh-BIP and exposed to 0 and 20 μM CdCl2. After exposure to cadmium for 12 h, the expression mRNA and protein levels of BIP, p-PERK, and p-eIF2α were determined in the two models. miRNAs related to BIP were also detected in granulosa cells after cadmium exposure. We found that mRNA and protein levels of all factors were upregulated in each cadmium-dose group, except for BIP mRNA expression in the 5 μM Cd group. The BIP gene was knocked down in COV434 cells before exposure to cadmium. All factors were upregulated in COV434 cells exposed to Cd, and the expression of the p-eIF2α protein was downregulated in sh-BIP cells exposed to Cd. In addition, no differences in BIP-related miRNAs were detected in cadmium-exposed rat ovarian granulosa cells versus the control group. Cadmium induces ovarian granulosa cell damage by inducing ER stress.

Mechanisms of titanium dioxide nanoparticle-induced oxidative stress and modulation of plasma glucose in mice

Titanium dioxide nanoparticles (TiO₂ NPs) are reported to increase plasma glucose levels in mice at specific doses. The production and accumulation of reactive oxygen species (ROS) is potentially the most important factor underlying the biological toxicity of TiO₂ NPs but the underlying mechanisms are unclear at present. Data from genome-wide analyses showed that TiO₂ NPs induce endoplasmic reticulum (ER) stress and ROS generation, leading to the inference that TiO₂ NP-induced ER stress contributes to enhancement of ROS in mice. Resveratrol (Res) effectively relieved TiO₂ NP-induced ER stress and ROS generation by ameliorating expression of a common set of activated genes for both processes, signifying that ER stress and ROS are closely related. TiO₂ NP-induced ER stress occurred earlier than ROS generation. Upon treatment with 4-phenylbutyric acid to relieve ER stress, plasma glucose levels tended toward normal and TiO₂ NP increased ROS production was inhibited. These results suggest that TiO2 NP-induced ER stress promotes the generation of ROS, in turn, triggering increased plasma glucose levels in mice. In addition, Res that displays the ability to reduce ER stress presents a dietary polyphenol antioxidant that can effectively prevent the toxicological effects of TiO₂ NPs on plasma glucose metabolism.

Knockdown of CREB3 activates endoplasmic reticulum stress and induces apoptosis in glioblastoma

Glioblastoma is a highly malignant type of central nervous system tumor. In the present study, the results of RNA sequencing indicated that cAMP responsive element binding protein 3 (CREB3) was upregulated in tumor tissues from patients with GBM. The cAMP responsive element binding protein 3 (CREB3) pathway is a major contributor to the malignant progression of glioblastoma. In this study, we explored the mechanisms by which CREB3 regulates the proliferation, invasion and apoptosis of glioblastoma. Pairs of glioblastoma and normal tissues were subjected to RNA sequencing. Then, qRT-PCR and Western blotting were used to detect CREB3 levels in glioblastoma tissues and cell lines, respectively. CREB3 was upregulated in glioblastoma tissues and cell lines. Overexpression of CREB3 promoted the proliferation and invasion of SHG-44 cells, while downregulation of CREB3 inhibited the invasion of U251MG cells. Knockdown of CREB3 also induced apoptosis in U251MG cells and increased the protein levels of BAX, active caspase 3, p-PERK, p-eIF2α and ATF4. An in vivo study in nude mice bearing U251MG cell xenografts confirmed these results. Our findings indicate that CREB3 functions as a tumor promoter in glioblastoma, and thus could serve as a treatment target in glioblastoma patients.

Effects of Cadmium and /or Chromium on reproductive organs and semen profiles of male albino rats

Objective: To evaluate the potential hazards of cadmium and/or chromium on the reproductive system of adult male albino rat. Design: Randomized controlled study. Animals: Forty mature male albino rats weighing 260 ± 10 g. Procedures: Rats were allocated into four groups (ten animals each). Control group (group 1), group 2 received 4.4 mg kg-1 cadmium chloride, group 3 was given 2.5 mg kg-1 sodium dichromate and group 4 received combination of Cd (2.2 mg kg-1) and Cr (1.25mg kg-1) orally, once daily for 65 consecutive days. Results: Exposure to Cd or Cr, in particular their combination, caused a reduction in the index weights of testes, epididymis, seminal vesicle and prostate glands. They induced a reduction of sperm count and viability with an increase of abnormal sperm morphology. Interestingly, in the combination group (Cd and Cr together), the deleterious effects were more noticeable. Pathologically, both Cd and Cr produced degenerative changes in seminiferous tubules, necrosis of spermatogenic epithelium within the testis. Moreover, the interstitial tissue of epididymis showed marked edema and prostate showed necrosis and serous exudate of lining epithelium. In the interaction group, testis showed complete degenerative changes and necrosis of spermatogenic epithelium, with marked interstitial edema and hyperplastic epithelial lining of epididymal tubules. Conclusion and clinical relevance: The present results support the hypothesis that the testis is one of the most sensitive organs to Cd and/or Cr and that the exposure to any of them or to their combination lead to testicular damage and thereby male infertility.

Chronic exposure to low doses of Pb induces hepatotoxicity at the physiological, biochemical, and transcriptomic levels of mice

Lead (Pb), a non-essential heavy metal, is a major global environmental contaminant with serious toxicological consequences. In the present study, the effects on hepatotoxicity of mice with chronic exposure to low doses of Pb were evaluated. While oral exposure to 0.03 or 0.1 mg/L Pb for 15 weeks in male adult mice had no significant effect on body weights, Pb exposure resulted in liver histopathological effects and increase of hepatic activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP). In addition, hepatic reactive oxygen species (ROS) and malondialdehyde (MDA) significantly accumulated after treatment. Conversely, glutathione (GSH) decreased significantly in both 0.03 and 0.1 mg/L Pb-treated groups. Moreover, the hepatic activities of superoxide dismutase 1 (SOD) and catalase (CAT) increased significantly following treatment with 0.1 mg/L Pb for 15 weeks, concomitant with increases in transcriptions of hepatic Sod, Cat, and Gpx. Furthermore, transcriptions of hepatic metallothionein (MT), zinc transporter 5 (Znt5) and copper transporter 1 (Ctr1), and subsequent protein levels were also increased in liver of mice when exposed to 0.1 mg/L Pb for 15 weeks. In addition, the transcriptome data showed that Pb has substantial influence on several pathways, including PPAR signaling pathways, AMPK signaling pathways, fatty acid metabolism, and drug metabolism. Our data suggested that chronic Pb exposure could induce hepatotoxicity at the physiological, biochemical, and transcriptomic levels in mice.

Proanthocyanidins Alleviates AflatoxinB₁-Induced Oxidative Stress and Apoptosis through Mitochondrial Pathway in the Bursa of Fabricius of Broilers

Aflatoxin B₁ (AFB₁) is a serious threat to the poultry industry. Proanthocyanidins (PCs) demonstrates a broad range of biological, pharmacological, therapeutic, and chemoprotective properties. The aim of this study was to investigate the ameliorative effects of PCs against AFB₁-induced histopathology, oxidative stress, and apoptosis via the mitochondrial pathway in the bursa of Fabricius (BF) of broilers. One hundred forty-four one-day old Cobb chicks were randomly assigned into four treatment groups of six replicates (6 birds each replicate) for 28 days. Groups were fed on the following four diets; (1) Basal diet without addition of PCs or AFB₁ (Control); (2) basal diet supplemented with 1 mg/kg AFB₁ from contaminated corn (AFB₁); (3) basal diet supplemented with 250 mg/kg PCs (PCs); and (4) basal diet supplemented with 1 mg/kg AFB₁ + 250 mg/kg PCs (AFB₁+ PCs). The present study results showed that antioxidant enzymes activities of total superoxide dismutase (T-SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and glutathione S-transferase (GST) in AFB₁ treated group were (p < 0.05) decreased, whereas malondialdehyde (MDA) contents were significantly increased in comparison with the control group. Furthermore, we found that dietary PCs treatment ameliorated AFB₁-induced oxidative stress in the BF through inhibiting the accumulation of MDA content and enhancing the antioxidant enzymes activities (T-SOD, CAT, GSH-Px, and GST). Similarly, PCs markedly enhanced messenger RNA (mRNA) expression of antioxidant genes (SOD, CAT, GPx1, and GST) in comparison with AFB₁ group. Moreover, histological results showed that PCs alleviated AFB₁-induced apoptotic cells in the BF of broilers. In addition, both mRNA and protein expression results manifested that mitochondrial-apoptosis-associated genes (Bax, caspase-9, caspase-3, and p53 and cytochrome c) showed up-regulation, while (Bcl-2) showed down-regulation in AFB₁ fed group. The supplementation of PCs to AFB₁ diet significantly reversed the mRNA and protein expression of these apoptosis-associated genes, as compared to the AFB₁ group. Our results demonstrated that PCs ameliorated AFB₁-induced oxidative stress by modulating the antioxidant defense system and apoptosis in the BF through mitochondrial pathway in broilers.

Chromium(VI) removal by mechanochemically sulfidated zero valent iron and its effect on dechlorination of trichloroethene as a co-contaminant

Mechanochemically sulfidated microscale zero valent iron (S-mZVI^bm) is a promising groundwater remediation material as it has been proven to be not only efficient in dechlorinating chlorinated compounds but also amenable to up-scaling. Yet, its efficiency in treating metal contaminants remains barely studied. In this study, we investigated the mechanism and efficiencies of Cr(VI) removal by S-mZVI^bm and its effect on TCE dechlorination as a co-contaminant. The Cr(VI) removal by S-mZVI^bm was mainly a chemisorption process and its kinetics was well fitted by a pseudo-second-order model. Alkaline pH inhibited Cr(VI) removal while dissolved oxygen slightly depressed the Cr(VI) removal. The Cr(VI) removal rapidly formed a non-conductive layer on S-mZVI^bm surface to hinder further electron transfer from Fe⁰ core before H⁺ was able to accept any electrons to produce H₂, which resulted in 100% electron efficiencies of Cr(VI) removal but <1% of Fe⁰ utilization efficiency. The presence of Cr(VI) also dramatically inhibited the dechlorination of TCE and its electron efficiency as a co-contaminant by passivating the FeS surface. Therefore, Cr(VI) is likely to be an electron sink if present for remediation of other contaminants in groundwater.

Kaempferol Attenuates ROS-Induced Hemolysis and the Molecular Mechanism of Its Induction of Apoptosis on Bladder Cancer

Bladder cancer has become the most common malignant urinary carcinoma. Studies have shown that significant antioxidant and bladder cancer-fighting properties of several plant-based diets like Psidium guajava, ginger and amomum, are associated with their high kaempferol content. In this paper, we evaluated the antioxidant and anticancer activities of kaempferol and its mechanism of induction to apoptosis on bladder cancer cells. Our findings demonstrated that kaempferol showed an obvious radical scavenging activity in erythrocytes damaged by oxygen. Kaempferol promoted antioxidant enzymes, inhibited ROS generation and lipid peroxidation and finally prevented the occurrence of hemolysis. Additionally, kaempferol exhibited a strong inhibitory effect on bladder cancer cells and high safety on normal bladder cells. At the molecular level, kaempferol suppressed EJ bladder cancer cell proliferation by inhibiting the function of phosphorylated AKT (p-AKT), CyclinD1, CDK4, Bid, Mcl-1 and Bcl-xL, and promoting p-BRCA1, p-ATM, p53, p21, p38, Bax and Bid expression, and finally triggering apoptosis and S phase arrest. We found that Kaempferol exhibited strong anti-oxidant activity on erythrocyte and inhibitory effects on the growth of cancerous bladder cells through inducing apoptosis and S phase arrest. These findings suggested that kaempferol might be regarded as a bioactive food ingredient to prevent oxidative damage and treat bladder cancer.

Ameliorative Effects of Selenium on Cadmium-Induced Injury in the Chicken Ovary: Mechanisms of Oxidative Stress and Endoplasmic Reticulum Stress in Cadmium-Induced Apoptosis

Despite the well-established toxicity of cadmium (Cd) to animals and the ameliorative effects of selenium (Se), some specific mechanisms in the chicken ovary are not yet clarified. To explore the mechanism by which the toxicity effect of Cd is induced and explore the effect of supranutritional Se on Cd toxicity in female bird reproduction, forty-eight 50-day-old Isa Brown female chickens were divided randomly into four groups. Group I (control group) was fed the basic diet containing 0.2 mg/kg Se. Group II (Se-treated group) was fed the basic diet supplemented with sodium selenite (Na₂SeO₃), and the total Se content was 2 mg/kg. Group III (Se + Cd-treated group) was fed the basic diet supplemented with Na₂SeO₃; the total Se content was 2 mg/kg, and it was supplemented with 150 mg/kg cadmium chloride (CdCl₂). Group IV (Cd-treated group) was with the basic diet supplemented with 150 mg/kg CdCl₂. The Cd, estradiol (E2), and progestogen (P4) contents changed after subchronic Cd exposure in chicken ovarian tissue; subsequently, oxidative stress occurred and activated the endoplasmic reticulum (ER) pathway to induce apoptosis. Further, Se decreased the accumulation of Cd in ovarian tissue, increased the E2 and P4 contents, alleviated oxidative stress, and reduced apoptosis via the ER stress pathway. The present results demonstrated that Cd could induce apoptosis via the ER stress pathway in chicken ovarian tissue and that Se had a significant antagonistic effect. These results are potentially valuable for finding a strategy to prevent Cd poisoning.

Protective Effect of Agaricus blazei Polysaccharide Against Cadmium-Induced Damage on the Testis of Chicken

Cadmium (Cd) exposure can cause reproductive toxicity through oxidative stress and inflammatory response. A polysaccharide extract of the edible mushroom Agaricus blazei Murill has been isolated and exhibits antioxidant activity and immunoregulatory effect. The aim of this study was to investigate the protective role of Agaricus blazei polysaccharide (ABP) against Cd-induced damage in chicken testis through enhancing antioxidant activity and alleviating inflammatory response. One hundred twenty healthy 7-day-old Hy-Line male chickens (Harbin, China) were randomly divided into four groups, and each group consisted of 30 chickens: Normal control was fed daily with full feed and 0.2 mL distilled water per day via oral gavage; Cd-treated group was fed daily with full feed that contained 140 mg/kg CdCl₂ and 0.2 mL distilled water per day by gavage; Polysaccharide-treated group was fed daily with full feed with 0.2 mL ABP(30 mg/ml) solution per day via oral gavage; Cd/polysaccharide-treated group was fed daily with full feed containing 140 mg/kg CdCl₂ and 0.2 mL ABP(30 mg/ml) solution per day by gavage. On the 20, 40, and 60 days, the testis was immediately removed. The contents of Cd in the testis, activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), malondialdehyde (MDA) production, messenger RNA (m RNA) levels of tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), and interleukin-6 (IL-6), protein expressions of heat shock proteins (HSPs) (HSP60, HSP70, and HSP90), and the histopathological changes of the testis were determined. The results indicated that ABP improved Cd-caused testicular tissue damage by increasing the SOD and GSH-Px activities: decreasing the Cd accumulation and MDA content, mRNA levels of TNF-α, IL-1β, and IL-6, and protein expressions of HSP60, HSP70, and HSP90. Results suggest that ABP for the mitigation of damage induced by cadmium in chicken testis through enhancing antioxidant activity and alleviating Inflammatory response.

Effects of short term lead exposure on gut microbiota and hepatic metabolism in adult zebrafish

Lead (Pb) is one of the most prevalent toxic, nonessential heavy metals that has been associated with a wide range of toxic effects in humans and environmental animals. Here, effects of short time exposure to 10 and 30 μg/L Pb on gut microbiota and hepatic metabolism were analyzed in adult male zebrafish. We observed that both 10 and 30 μg/L Pb increased the volume of mucus in the gut. At phylum level, the abundance of α-Proteobacteria decreased significantly and the abundance of Firmicutes increased significantly in the gut when treated with 30 μg/L Pb for 7 days. In addition, the 16S rRNA gene sequencing for V3-V4 region revealed a significant change in the richness and diversity of gut microbiota in 30 μg/L Pb exposed group. A more depth analysis, at the genus level, discovered that 52 gut microbes identified by operational taxonomic unit analysis were changed significantly in 30 μg/L Pb treated group. Based on GC/MS metabolomics analysis, a total of 41 metabolites were significantly altered in 30 μg/L Pb treatment group. These changed metabolites were mainly associated with the pathways of glucose and lipid metabolism, amino acid metabolism, nucleotide metabolism. In addition, we also confirmed that the transcription of some genes related to glycolysis and lipid metabolism, including Gk, Aco, Acc1, Fas, Apo and Dgat, decreased significantly in the liver of zebrafish when exposed to 30 μg/L Pb for 7 days. Our results observed that Pb could cause gut microbiota dysbiosis and hepatic metabolic disorder in zebrafish.

Alterations of mitochondrial antioxidant indexes and apoptosis in duck livers caused by Molybdenum or/and cadmium

Cadmium (Cd) and high Molybdenum (Mo) can lead to adverse reactions on animals, but the co-induced toxicity of Mo and Cd to liver in ducks was not well understood. To investigate the co-induced toxic effects of Mo combined with Cd on mitochondrial oxidative stress and apoptosis in duck livers. 240 healthy 11-day-old ducks were randomly divided into 6 groups (control, LMo group, HMo group, Cd group, LMoCd group and HMoCd group). After being treated for 30, 60, 90 and 120 days, liver mitochondrial antioxidant indexes, ceruloplasmin (CP), metallothionein (MT), Bak-1 and Caspase-3 genes mRNA expression levels, and ultrastructural changes were evaluated. The results showed that total antioxidative capacity (T-AOC), catalase (CAT), superoxide dismutase (SOD) and xanthine oxidase (XOD) activities in experimental groups were decreased, whereas malondialdehyde (MDA) content and nitric oxide synthase (NOS) activity were increased compared with control group, and these changes of co-treated groups were more obvious in the later period of the experiment. The mRNA expression levels of CP, Bak-1 and Caspase-3 were up-regulated in experimental groups compared with control group and showed significant difference between co-treated groups and single treated groups. The mRNA expression level of MT in Cd group was higher than that in co-treated groups. Additionally, ultrastructural changes showed karyopyknosis, mitochondrial swelling, vacuolation and disruption of mitochondrial cristae in co-treated groups. Taken together, it was suggested that dietary Mo and Cd might lead to mitochondrial oxidative stress and apoptosis in duck livers, and it showed a possible synergistic relationship between the two elements.

Nickel oxide nanoparticles induce hepatocyte apoptosis via activating endoplasmic reticulum stress pathways in rats

Nickel oxide nanoparticles (nano NiO) could induce hepatocyte apoptosis, while its potential mechanisms are unclear. This study aimed to explore the role of endoplasmic reticulum (ER) stress pathways in hepatocyte apoptosis induced by nano NiO. Male Wistar rats were administrated with nano NiO (0.015, 0.06, and 0.24 mg/kg b.w.) and micro NiO (0.24 mg/kg b.w.) by intratracheal instillation twice a week for 6 weeks. We measured the hepatocyte apoptosis levels by TdT-mediated dUTP nick-end labeling (TUNEL) staining, ER stress related gene and protein expression levels in rat liver. The results showed that the TUNEL positive cells increased after exposure nano NiO, hinting hepatocyte apoptosis. The up-regulated gene and protein levels of 78 kD glucose regulated protein and CCAAT/enhancer binding protein homologous protein suggested that nano NiO triggered ER stress. Nano NiO exposure contributed to the increased protein contents of inositol-requiring enzyme 1 (IRE-1)α, p-IRE-1α, X box protein-1S, pancreatic ER kinase (PERK), p-PERK, eukaryotic initiation factor-2 alpha (eIF-2α), p-eIF-2α, caspase-12, -9, and -3, implicating that nano NiO can activate the pathways of ER stress-mediated apoptosis. These findings indicate that the ER stress pathways may play an important role in hepatocyte apoptosis induced by nano NiO.

The critical role of autophagy in cadmium-induced immunosuppression regulated by endoplasmic reticulum stress-mediated calpain activation in RAW264.7 mouse monocytes

Cadmium (Cd) has toxic and suppressive effects on the immune system, but the underlying mechanisms remain poorly understood. Here, we show that autophagy plays a critical role in regulation of Cd-induced immunosuppression in RAW264.7 cells. Cd decreased cell viability in a dose-dependent manner; cleaved caspase-8, caspase-3, and poly (ADP-ribose) polymerase (PARP)-1; increased DNA laddering; induced CCAAT-enhancer-binding protein homologous protein (CHOP); and reduced tumor necrosis factor (TNF)-α expression; indicating that caspase-dependent and endoplasmic reticulum (ER)-mediated apoptosis are involved in Cd-induced immunotoxicity. Furthermore, Cd induced autophagy, as demonstrated by microtubule-associated protein 1 light chain 3B (LC3B) plasmid DNA transfection and its conversion from LC3-I to the LC3-II form by autophagy inhibitors, via AMP-activated protein kinase (AMPK)-mammalian target of rapamycin (mTOR) signaling. Pharmacological and genetic inhibition of autophagy suppressed Cd-induced apoptosis, as evidenced by inhibition of caspase-8, caspase-3, and PARP-1 cleavage, indicating that autophagy promotes apoptosis. The pan-caspase inhibitor zVAD inhibited Cd-induced apoptosis, but increased autophagy and decreased cell viability, indicating that autophagy can compensate for reduced apoptotic cell death. Calpain inhibitors blocked Cd-induced apoptosis and autophagy, indicating that calpain plays a critical role in Cd cytotoxicity. Treatment with Ca²⁺ chelators completely recovered Cd-induced cell viability and inhibited Cd-induced apoptosis and autophagy. Treatment with N-acetyl-l-cysteine (NAC) suppressed Cd-induced antioxidant enzyme levels, apoptosis, and autophagy. Collectively, Cd-induced oxidative stress triggers ER stress, leading to Ca^2+-dependent calpain activation and subsequent activation of autophagy and apoptosis, resulting in immune suppression.

Cadmium-induced ER stress and inflammation are mediated through C/EBP-DDIT3 signaling in human bronchial epithelial cells

Cadmium (Cd), a major component of cigarette smoke, disrupts the normal functions of airway cells and can lead to the development of various pulmonary diseases such as chronic obstructive pulmonary disease (COPD). However, the molecular mechanisms involved in Cd-induced pulmonary diseases are poorly understood. Here, we identified a cluster of genes that are altered in response to Cd exposure in human bronchial epithelial cells (BEAS-2B) and demonstrated that Cd-induced ER stress and inflammation are mediated via CCAAT-enhancer-binding proteins (C/EBP)-DNA-damaged-inducible transcript 3 (DDIT3) signaling in BEAS-2B cells. Cd treatment led to marked upregulation and downregulation of genes associated with the cell cycle, apoptosis, oxidative stress and inflammation as well as various signal transduction pathways. Gene set enrichment analysis revealed that Cd treatment stimulated the C/EBP signaling pathway and induced transcriptional activation of its downstream target genes, including DDIT3. Suppression of DDIT3 expression using specific small interfering RNA effectively alleviated Cd-induced ER stress and inflammatory responses in both BEAS-2B and normal primary normal human bronchial epithelial cells. Taken together, these data suggest that C/EBP signaling may have a pivotal role in the early induction of ER stress and inflammatory responses by Cd exposure and could be a molecular target for Cd-induced pulmonary disease.

The Effect of Selenium on the Cd-Induced Apoptosis via NO-Mediated Mitochondrial Apoptosis Pathway in Chicken Liver

Cd-induced apoptosis and the protective effects of Se against Cd-induced injury have been reported in previous studies. However, little is known regarding the effects of Cd-induced apoptosis in hepatic cells and the antagonistic effects of Se on Cd in poultry. In the present study, 128 healthy 31-week-old laying hens were randomly divided into four groups, which were fed basic diets, with the addition of Se (Na₂SeO₃, 2 mg/kg), Cd (CdCl₂, 150 mg/kg), or Se + Cd (150 mg/kg of CdCl₂ and 2 mg/kg of Na₂SeO₃) for 90 days. Ultrastructural changes, nitric oxide (NO) concentrations, inducible nitric oxide synthase (iNOS) activities, results of the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay of apoptosis, and the expression of iNOS and apoptosis-related genes in livers were determined. It was observed that Cd treatment significantly increased the concentrations of NO and iNOS activity in chicken livers. The production of excessive NO initiated the mitochondrial apoptotic pathway. Exposure to Cd increased the mRNA and the protein expression levels of iNOS, caspase-3, Bax, p53, and Cyt-c. Furthermore, the ratio of Bax/Bcl-2 increased, while the expression of Bcl-2 decreased. Treatment with Se significantly alleviated Cd-induced apoptosis in chicken livers, as evidenced by a reduction in the production of NO, iNOS activity, the number of apoptotic cells, and mRNA and protein expression levels of iNOS, caspase-3, Bax, and Cyt-c. It indicated that Cd induced NO-mediated apoptosis through the mitochondrial apoptotic pathway and Se exerted antagonizing effects. The present study provides new insights as to how Se affects Cd-induced toxicity in the chicken liver.

Complex effect of zinc oxide nanoparticles on cadmium chloride-induced hepatotoxicity in mice: protective role of metallothionein

The wide range of applications of ZnO nanoparticles (nano ZnO) in commercial products and the ubiquitous cadmium (Cd) contamination in the natural environment increase the chance of co-existence of nano ZnO with Cd in the surroundings. To investigate the effects of nano ZnO on CdCl₂-induced hepatotoxicity in mice, the histopathologic changes, metallothionein expression, oxidative stress responses and serum biochemical parameters were determined after oral administration of bulk or nano ZnO and/or CdCl₂ for seven consecutive days. Bulk or nano ZnO had low toxicity in mice. In contrast, CdCl₂ led to significant hepatic oxidative damage, as indicated by hepatic histopathological abnormalities and dysfunction. Bulk and nano ZnO had nearly identical influences on the hepatotoxicity of CdCl₂ in mice. Although co-administration of bulk or nano ZnO with CdCl₂ had a positive cooperative effect on the hepatic uptake of Cd and Zn, both bulk and nano ZnO significantly attenuated CdCl₂-caused hepatic damage via the reduction of oxidative stress. The increase in metallothionein synthesis and the reduction of Cd-induced perturbation of Zn²⁺ homeostasis after co-administration of bulk or nano ZnO with CdCl₂ play two important roles in the protective effect of bulk or nano ZnO on CdCl₂-caused hepatic oxidative damage.

Effects of metals cadmium and chromium alone and in combination on the liver and kidney tissue of male Spraque-Dawley rats: An ultrastructural and electron-energy-loss spectroscopy investigation

Heavy metal pollution has increased in the last decades. Water sources are contaminated and human exposure is often long term exposure to variable amounts of different metals. In this study, male Sprague-Dawley rats were exposed via oral gavage for 28 days to cadmium (Cd) and chromium (Cr), alone and in combination at concentrations 1000 times the human World Health Organization's acceptable water limits. Rat equivalent dosages were used. Blood markers of liver and kidney function were measured, changes to cellular morphology was determined with transmission electron microscopy and the intracellular metal localisation was determined with the electron energy-loss spectroscopy and energy filtered transmission electron microscopy analysis. Both Cd and Cr caused changes to the nuclear and mitochondrial membranes and irregular chromatin condensation of hepatocytes. Cr exposure caused dilation of the rough endoplasmic reticulum (rER). The combination caused nuclear and mitochondrial membrane damage as well as irregular chromatin condensation. In the kidney tissue, Cd caused irregular chromatin condensation in the cells of the proximal convoluted tubule (PCT). Cr caused changes to the outer nuclear and mitochondrial membrane and chromatin structure. The combination group caused membrane damage, irregular chromatin condensation and rER changes in the PCT. All the metal groups showed damage to the endothelial cells and pedicles, but not to the mesangial cells. Cd and Cr bio-accumulation was observed in the nucleus, mitochondria and rER of the liver and kidney and therefore are responsible for the cellular observed damage that can cause functional changes to the tissues and organs.

Effects of environmental pollutants on gut microbiota

Environmental pollutants have become an increasingly common health hazard in the last several decades. Recently, a number of studies have demonstrated the profound relationship between gut microbiota and our health. Gut microbiota are very sensitive to drugs, diet, and even environmental pollutants. In this review, we discuss the possible effects of environmental pollutants including antibiotics, heavy metals, persistent organic pollutants, pesticides, nanomaterials, and food additives on gut microbiota and their subsequent effects on health. We emphasize that gut microbiota are also essential for the toxicity evaluation of environmental pollution. In the future, more studies should focus on the relationship between environmental pollution, gut microbiota, and human health.

Cis-bifenthrin causes immunotoxicity in murine macrophages

Synthetic pyrethroids (SPs) are commonly used insecticides that have been detected in mammals, including humans, indicating a potential threat to human health. Bifenthrin (BF), as well as other pyrethroids, has been shown to possess neurotoxic, reproductive, hepatotoxic and nephrotoxic potential in mammals. However, studies regarding the immunotoxicity of BF and its mechanism are limited. In this study, we aim to exam the immunotoxicity of cis-BF on the murine macrophage cell line, RAW 264.7. MTT assay results demonstrated that cis-BF exposure induced apoptosis in RAW 264.7 cells in a concentration-dependent manner. We found that the expression of p53 and caspase-3 was up-regulated, while the expression of Bcl-2 was down-regulated during cis-BF-induced apoptosis. In addition, we also found that cis-BF exposure caused oxidative stress in RAW 264.7 cells in a dose-dependent manner. Interestingly, cis-BF exposure was found to inhibit the increase in transcription levels of IL-1β, IL-6 and TNF-α responding to LPS stimulation. We also found that the induced increase in IFN-β mRNA levels upon Sendai virus infection was blocked with cis-BF exposure. Finally, we found that cis-BF exposure increased ROS levels and dysregulated mRNA levels of oxidative stress-related genes in RAW 264.7 cells. The present study elucidates the immunotoxicity effect of cis-BF on macrophages and its possible underlying mechanism. The results from this study support the necessity to evaluate immune dysfunction in the risk assessment of cis-BF exposure.