Detection of elevated reactive oxygen species level in cultured rat hepatocytes treated with aflatoxin B1

The Ameliorative Role of Lico A on Aflatoxin B1-Triggered Hepatotoxicity Partially by Activating Nrf2 Signal Pathway

Aflatoxin B1 (AFB1) is one of the most harmful and toxic mycotoxins in foods and feeds, posing a serious health risk to both humans and animals, especially its hepatotoxicity. Nuclear factor-erythroid 2-related factor 2 (Nrf2), an important nuclear transcription factor, is generally recognized as a potential target for phytochemicals to ameliorate liver injury. The current study sought to elucidate the molecular processes by which licochalcone A (Lico A), a compound derived from Xinjiang licorice Glycyrrhiza inflate, protects against AFB1 toxicity. In vivo, male wild-type (WT) and Nrf2 knockout (Nrf2-/-) C57BL/6 mice were orally administered AFB1 at 1.5 mg/kg body weight (BW) with or without Lico A at 5 mg/kg. In vitro, AML12 cells were utilized to evaluate the protective effect and mechanism of Lico A against the AFB1-induced hepatotoxicity. Our findings demonstrated that AFB1 caused severe hepatotoxicity, while Lico A treatment successfully relieved the toxicity. Meanwhile, Lico A effectively improved liver injury, inflammatory mediators, oxidative insults, apoptosis, liver fibrosis, and pyroptosis, which contributed to the inhibition of toll receptor 4 (TLR4)-NF-κB/MAPK and NOD-like receptors protein 3 (NLRP3)/caspase-1/GSDMD signaling pathway activation. Furthermore, Lico A was able to enhance the Nrf2 antioxidant signaling pathway. Intriguingly, Lico A still had a protective effect on AFB1-caused liver injury in mice via the inhibition of inflammation and pyroptosis, while apoptosis and liver fibrosis were blocked in the absence of Nrf2. To sum up, the present study first elucidated that Lico A ameliorated AFB1-induced hepatotoxic effects and its main mechanism involved the inhibitory effects on oxidative stress, apoptosis, liver fibrosis, inflammation, and pyroptosis, which might be partially dependent on the regulation of Nrf2. The work may enrich the role and mechanism of Lico A's resistance to liver injury caused by various factors, and its application is promising.

Chitosan/alginate nanogel potentiate berberine uptake and enhance oxidative stress mediated apoptotic cell death in HepG2 cells

Biopolymer-based nanoscale drug delivery systems have become a promising approach to overcome the limitations associated with conventional chemotherapeutics used for cancer treatment. Herein, we reported to develop a hydrophilic nanogel (NG) composed of Chitosan (Chi) and sodium alginate (Alg) using the ion gelation method for delivering Berberine hydrochloride (BBR), an alkaloid obtained from Berberis aristata roots. The use of different nanocarriers for BBR delivery has been reported previously, but the bioavailability of these carriers was limited due to phagocytic uptake and poor systemic delivery. The developed NG showed enhanced stability and efficient entrapment of BBR ∼92 %, resulting in a significant increase in bioavailability. The pH-dependent release behavior demonstrated sustained and effective release of ∼86 %, ∼74 % and, ∼53 % BBR at pH 5.5, 6.6, and 7.4 respectively after 72h, indicating its potential as a drug carrier. Additionally, the cellular uptake of BBR was significantly higher ∼19 % in the BBR-NG (25 μM) than in bulk BBR (100 μM), leading to enhanced ROS generation, mitochondrial depolarisation, and inhibition of cell proliferation and colony formation in HepG2 cells. In summary, the results suggest that the Chi/Alg biopolymer-based nano-formulation could be an effective approach for delivering BBR and enhancing its cellular uptake, efficacy, and cytotoxicity.

Aflatoxin B1 induces infertility, fetal deformities, and potential therapies

Aflatoxin B1 (AFB1) is a subsidiary poisonous metabolite, archetypally spawned by Aspergillus flavus and A. parasiticus, which are often isolated in warm or tropical countries across the world. AFB1 is capable of disrupting the functioning of several reproductive endocrine glands by interrupting the enzymes and their substrates that are liable for the synthesis of various hormones in both males and females. In men, AFB1 is capable of hindering testicular development, testicular degeneration, and reduces reproductive capabilities. In women, a direct antagonistic interaction of AFB1 with steroid hormone receptors influencing gonadal hormone production of estrogen and progesterone was responsible for AFB1-associated infertility. AFB1 is potentially teratogenic and is responsible for the development of malformation in humans and animals. Soft-tissue anomalies such as internal hydrocephalus, microphthalmia, cardiac defects, augmented liver lobes, reproductive changes, immune modifications, behavioral changes and predisposition of animals and humans to neoplasm development are AFB1-associated anomalies. Substances such as esculin, selenium, gynandra extract, vitamins C and E, oltipraz, and CDDO-Im are potential therapies for AFB1. Thus, this review elucidates the pivotal pathogenic roles of AFB1 in infertility, fetal deformities, and potential therapies because AFB1 toxicity is a key problem globally.

Detection and Elimination of Senescent Cells with a Self-Assembled Senescence-Associated β-Galactosidase-Activatable Nanophotosensitizer

Senescent cells have become an important therapeutic target for many age-related dysfunctions and diseases. We report herein a novel nanophotosensitizing system that is responsive to the senescence-associated β-galactosidase (β-gal) for selective detection and elimination of these cells. It involves a dimeric zinc(II) phthalocyanine linked to a β-galactose unit via a self-immolative linker. This compound can self-assemble in aqueous media, forming stable nanoscale particles in which the phthalocyanine units are stacked and self-quenched for fluorescence emission and singlet oxygen production. Upon internalization into senescent HeLa cells, these nanoparticles interact with the overproduced senescence-associated β-gal inside the cells to trigger the disassembly process through enzymatic cleavage of the glycosidic bonds, followed by self-immolation to release the photoactive monomeric phthalocyanine units. These senescent cells can then be lit up with fluorescence and eliminated through the photodynamic action upon light irradiation with a half-maximal inhibitory concentration of 0.06 μM.

Yeast polysaccharide mitigated oxidative injury in broilers induced by mixed mycotoxins via regulating intestinal mucosal oxidative stress and hepatic metabolic enzymes

This study was aimed to investigate the effects of yeast polysaccharides (YPS) on growth performance, intestinal health, and aflatoxin metabolism in livers of broilers fed diets naturally contaminated with mixed mycotoxins (MYCO). A total of 480 one-day-old Arbor Acre male broilers were randomly allocated into a 2 × 3 factorial arrangement of treatments (8 replicates with 10 birds per replicate) for 6 wk to assess the effects of 3 levels of YPS (0, 1, or 2 g/kg) on the broilers fed diets contaminated with or without MYCO (95 μg/kg aflatoxin B1, 1.5 mg/kg deoxynivalenol, and 490 μg/kg zearalenone). Results showed that mycotoxins contaminated diets led to significant increments in serum malondialdehyde (MDA) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels, mRNA expressions of TLR4 and 4EBP1 associated with oxidative stress, mRNA expressions of CYP1A1, CYP1A2, CYP2A6, and CYP3A4 associated with hepatic phase Ⅰ metabolizing enzymes, mRNA expressions of p53 associated with hepatic mitochondrial apoptosis, and AFB1 residues in the liver (P < 0.05); meanwhile dietary MYCO decreased the jejunal villus height (VH), villus height/crypt depth (VH/CD), the activity of serum total antioxidant capacity (T-AOC), mRNA expressions of jejunal HIF-1α, HMOX, and XDH associated with oxidative stress, mRNA expressions of jejunal CLDN1, ZO1, and ZO2, and mRNA expression of GST associated with hepatic phase Ⅱ metabolizing enzymes of broilers (P < 0.05). Notably, the adverse effects induced by MYCO on broilers were mitigated by supplementation with YPS. Dietary YPS supplementation reduced the concentrations of serum MDA and 8-OHdG, jejunal CD, mRNA expression of jejunal TLR2, and 4EBP1, hepatic CYP1A2, and p53, and the AFB1 residues in the liver (P < 0.05), and elevated the serum T-AOC and SOD, jejunal VH, and VH/CD, and mRNA expression of jejunal XDH, hepatic GST of broilers (P < 0.05). There were significant interactions between MYCO and YPS levels on the growth performance (BW, ADFI, ADG, and F/G) at d 1 to 21, d 22 to 42, and d 1 to 42, serum GSH-Px activity, and mRNA expression of jejunal CLDN2 and hepatic ras of broilers (P < 0.05). In contrast with MYCO group, the addition of YPS increased BW, ADFI, and ADG, the serum GSH-Px activity (14.31%-46.92%), mRNA levels of jejunal CLDN2 (94.39%-103.02%), decreased F/G, and mRNA levels of hepatic ras (57.83%-63.62%) of broilers (P < 0.05). In conclusion, dietary supplements with YPS protected broilers from mixed mycotoxins toxicities meanwhile keeping normal performance of broilers, presumably via reducing intestinal oxidative stress, protecting intestinal structural integrity, and improving hepatic metabolic enzymes to minimize the AFB1 residue in the liver and enhance the performance of broilers.

Biomimetic Molybdenum Sulfide-Catalyzed Tumor Ferroptosis and Bioimaging

The chemical generation of singlet oxygen (¹ O₂ ) by the MoO₄ ^2- -catalyzed disproportionation of hydrogen peroxide (H₂ O₂ ) has been widely applied in numerous catalytic processes; however, such molybdate ions cannot be administered for redox-based cancer therapeutics. This work reports the albumin-mediated biomimetic synthesis of highly active molybdenum sulfide (denoted MoB) nanocatalysts that mediate the simultaneous generation of ¹ O₂ and superoxide anion (O₂ ^•- ) from H₂ O₂ , which is relatively abundant in malignant tumors. The MoB-catalyzed reactive oxygen species (ROS) are able to activate the ferroptosis pathway and cause lipid peroxidation for efficient cancer therapy. Furthermore, for the first time, the catalytic activity of MoB is visualized in situ. Moreover, a catalytic imaging modality based on MoB is developed for specific imaging of inflammation diseases without background interference. Therefore, this study presents a biomimetic strategy toward Mo-based nanocatalysts for ROS-facilitated tumor ferroptosis and catalytic imaging.

Fungal infections and the fungal microbiome in hepatobiliary disorders

Liver and biliary diseases affect more than a billion people worldwide, with high associated morbidity and mortality. The impact of the intestinal bacterial microbiome on liver diseases has been well established. However, the fungal microbiome, or mycobiome, has been overlooked for a long time. Recently, several studies have shed light on the role of the mycobiome in the development and progression of hepatobiliary diseases. In particular, the fungal genus Candida has been found to be involved in the pathogenesis of multiple hepatobiliary conditions. Herein, we compare colonisation and infection, describe mycobiome findings in the healthy state and across the various hepatobiliary conditions, and point toward communalities. We detail how quantitation of immune responses to fungal antigens can be employed to predict disease severity, e.g. using antibodies to Saccharomyces cerevisiae or specific anti-Candida albicans antibodies. We also show how fungal products (e.g. beta-glucans, candidalysin) activate the host's immune system to exacerbate liver and biliary diseases. Finally, we describe how the gut mycobiome can be modulated to ameliorate hepatobiliary conditions.

Aflatoxin-B1-Exposure-Induced Hepatic Injury Could Be Alleviated by Polydatin through Reducing Oxidative Stress, Inhibiting Inflammation and Improving Mitophagy

Aflatoxin B1 (AFB1) is a toxic food/feed pollutant, exerting extensive deleterious impacts on the liver. Oxidative stress and inflammation are considered to be vital contributors to AFB1 hepatotoxicity. Polydatin (PD), a naturally occurring polyphenol, has been demonstrated to protect and/or treat liver disorders caused by various factors through its antioxidant and anti-inflammatory properties. However, the role of PD in AFB1-induced liver injury is still elusive. Therefore, this study was designed to investigate the protective effect of PD on hepatic injury in mice subjected to AFB1. Male mice were randomly divided into three groups: control, AFB1 and AFB1-PD groups. The results showed that PD protected against AFB1-induced hepatic injury demonstrated by the reduced serum transaminase activity, the restored hepatic histology and ultrastructure, which could be attributed to the enhanced glutathione level, the reduced interleukin 1 beta and tumor necrosis factor alpha concentrations, the increased interleukin 10 expression at transcriptional level and the up-regulated mRNA expression related to mitophagy. In conclusion, PD could alleviate AFB1-induced hepatic injury by reducing oxidative stress, inhibiting inflammation and improving mitophagy.

Curcumin attenuates AFB1-induced duck liver injury by inhibiting oxidative stress and lysosomal damage

Aflatoxin B1 (AFB1), as the most toxic secondary metabolite produced by Aspergillus flavus, is a serious threat to human and animal health. Curcumin, a polyphenol from the plant turmeric, has demonstrated unique anti-damage properties in several studies. But, its ability to alleviate AFB1-induced liver damage in ducks and the underlying mechanisms are not completely elucidated. In this study, we investigated the intervention of curcumin on AFB1-induced hepatotoxicity in ducks. Research data showed that the combination of curcumin and AFB1 alleviated oxidative stress, reduced malondialdehyde (MDA) accumulation and relieved hepatotoxicity after 28 days of treatment, compared with AFB1. Also, curcumin upregulated the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and its downstream antioxidant enzymes (SOD, HO-1), which enhanced the antioxidant capacity of the liver. In addition, curcumin inhibited AFB1-induced lysosomal damage in the liver, with the character of reduced lysosomal membrane permeabilization, restored autophagic flux, and promoted lysosomal biogenesis, thereby enhancing the self-protective capacity of the liver. In conclusion, our results suggest that curcumin alleviates AFB1-induced duck hepatotoxicity by inhibiting oxidative stress and lysosomal damage.

Unravelling the instability of mutational signatures extraction via archetypal analysis

The high cosine similarity between some single-base substitution mutational signatures and their characteristic flat profiles could suggest the presence of overfitting and mathematical artefacts. The newest version (v3.3) of the signature database available in the Catalogue Of Somatic Mutations In Cancer (COSMIC) provides a collection of 79 mutational signatures, which has more than doubled with respect to previous version (30 profiles available in COSMIC signatures v2), making more critical the associations between signatures and specific mutagenic processes. This study both provides a systematic assessment of the de novo extraction task through simulation scenarios based on the latest version of the COSMIC signatures and highlights, through a novel approach using archetypal analysis, which COSMIC signatures are redundant and more likely to be considered as mathematical artefacts. 29 archetypes were able to reconstruct the profile of all the COSMIC signatures with cosine similarity > 0.8. Interestingly, these archetypes tend to group similar original signatures sharing either the same aetiology or similar biological processes. We believe that these findings will be useful to encourage the development of new de novo extraction methods avoiding the redundancy of information among the signatures while preserving the biological interpretation.

A comprehensive and mechanistic review on protective effects of kaempferol against natural and chemical toxins: Role of NF-κB inhibition and Nrf2 activation

Different toxins, including chemicals and natural, can be entered from various routes and influence human health. Herbal medicines and their active components can attenuate the toxicity of agents via multiple mechanisms. For example, kaempferol, as a flavonoid, can be found in fruits and vegetables, and has an essential role in improving disorders such as cardiovascular disorders, neurological diseases, cancer, pain, and inflammation situations. The beneficial effects of kaempferol may be related to the inhibition of oxidative stress, attenuation of inflammatory factors such as tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), cyclooxygenase-2 (COX-2) and nuclear factor ĸB (NF-ĸB) as well as the modulation of apoptosis and mitogen-activated protein kinase (MAPK) signaling pathways. This flavonoid boasts a wide spectrum of toxin targeting effects in tissue fibrosis, inflammation, and oxidative stress thus shows promising protective effects against natural and chemical toxin induced hepatotoxicity, nephrotoxicity, cardiotoxicity, neurotoxicity, lung, and intestinal in the in vitro and in vivo setting. The most remarkable aspect of kaempferol is that it does not focus its efforts on just one organ or one molecular pathway. Although its significance as a treatment option remains questionable and requires more clinical studies, it seems to be a low-risk therapeutic option. It is crucial to emphasize that kaempferol's poor bioavailability is a significant barrier to its use as a therapeutic option. Nanotechnology can be a promising way to overcome this challenge, reviving optimism in using kaempferol as a viable treatment agent against toxin-induced disorders.

Impact of Mycotoxin Contaminations on Aquatic Organisms: Toxic Effect of Aflatoxin B1 and Fumonisin B1 Mixture

(1) Background: Multiple contaminations of several mycotoxins have been detected in human and veterinary food and feed worldwide. To date, a number of studies on the combined effects of mycotoxins have been conducted on cell and animal models, but very limited studies have been done on aquatic organisms. (2) The purpose of the present study was to evaluate the combined toxic effects of Aflatoxin B1 (AFB1) and Fumonisin B1 (FB1) on zebrafish (Danio rerio) embryos. (3) Results: Our results showed that the combination of AFB1 and FB1 at nontoxic concentrations exerted a negative effect on the lethal endpoints analyzed, such as survival, hatching, and heart rate. In addition, the mixture of mycotoxins caused an increase in the levels of enzymes and proteins involved in the antioxidant process, such as superoxide dismutase (SOD) and catalase (CAT), both in terms of protein levels and gene expression, as well as an increase in the levels of the detoxification enzymes glutathione s-transferases (GST) and cytochromes P450 (CYP450). Furthermore, we showed that the mycotoxin mixture induced an increase in pro-apoptotic proteins such as bax and caspase 3, and at the same time reduced the gene expression of the anti-apoptotic bcl-2 protein. Finally, a significant decrease in thyroid function was observed in terms of triiodothyronine (T3), thyroxine (T4), and vitellogenin (VTG) levels. (4) Conclusion: We can say that the mixture of mycotoxins carries a greater risk factor than individual presences. There is a greater need for effective detoxification methods to control and reduce the toxicity of multiple mycotoxins and reduce the toxicity of multiple mycotoxins in feed and throughout the food chain.

PINK1/Parkin-mediated mitophagy is activated to protect against AFB1-induced immunosuppression in mice spleen

Aflatoxin B₁ (AFB₁) can cause mitochondrial malfunction and immunosuppression in spleen. Mitochondrial damage can lead to oxidative stress and aggravate immune cell dysfunction. Phosphatase and tensin homolog (PTEN)-induced putative kinase1 (PINK1)/ E3 ubiquitin ligase PARK2 (Parkin)-mediated mitophagy can scavenge damaged mitochondria and alleviate oxidative stress to maintain cellular homeostasis. However, the role of PINK1/Parkin-mediated mitophagy in AFB₁-induced immunosuppression in spleen is unclear. In this study, sixty male mice were sensibilized orally with AFB₁ at different concentrations [0, 0.5, 0.75, and 1 mg/kg body weight (BW)] for 28 days, and AFB₁ caused splenic structure injury and immunosuppression, also led to upregulation of PINK1/Parkin-mediated mitophagy in a dose-dependent manner. Subsequently, thirty male WT C57BL/6 N mice and thirty male Parkin knockout (Parkin^-/-) C57BL/6 N mice were sensibilized orally with AFB₁ at 0 or 1 mg/kg BW for 28 days, and Parkin^-/- inhibited mitophagy and further aggravated AFB₁-induced splenic structure injury, immunosuppression, mitochondrial damage and oxidative stress. Collectively, these results indicate that AFB₁ exposure activates PINK1/Parkin-mediated mitophagy, which protects against immunosuppression in spleen.

Antagonism of Cyanamide-3-O-glucoside and protocatechuic acid on Aflatoxin B1-induced toxicity in zebrafish larva (Danio rerio)

The zebrafish model was used to evaluate the antioxidant properties of cyanidin-3-O-glucoside (C₃G) and its metabolite protocatechuic acid (PCA) against aflatoxin B₁ (AFB₁)-induced hepatotoxicity and oxidative stress. In this study, zebrafish larvae were cultured for 3 days post fertilization (dpf) and then induced with AFB₁. After induced 4 h, 8 h, 12 h, and 24 h, 5 μg/mL C₃G/PCA was added and then co-cultured to 5 dpf, respectively. The experiments showed that C₃G/PCA suppressed AFB₁-induced zebrafish liver atrophy and delayed the absorption of the yolk sac. In addition, reactive oxygen species (ROS) and cell death were also significantly decreased by 5 μg/mL C₃G/PCA (P ˂ 0.05). C₃G/PCA significantly reduced hepatic biomarkers in the serum contents (P ˂ 0.05). Besides, glutathione (GSH) contents were significantly upregulated, and the activities of superoxide dismutase (SOD) and catalase (CAT) were significantly elevated in zebrafish (P ˂ 0.05). The addition of 5 μg/mL C₃G/PCA was capable of reducing the apoptotic levels of caspase-9 and caspase-3 after 100 ng/mL AFB₁ intoxication. In conclusion, these results suggested that C₃G and its metabolite PCA might antagonize the hepatotoxicity of AFB₁, reduce oxidative damage and inhibit cell death.

Metabolic Disruption by Naturally Occurring Mycotoxins in Circulation: A Focus on Vascular and Bone Homeostasis Dysfunction

Naturally occurring food/feed contaminants have become a significant global issue due to animal and human health implications. Despite risk assessments and legislation setpoints on the mycotoxins' levels, exposure to lower amounts occurs, and it might affect cell homeostasis. However, the inflammatory consequences of this possible everyday exposure to toxins on the vascular microenvironment and arterial dysfunction are unexplored in detail. Circulation is the most accessible path for food-borne toxins, and the consequent metabolic and immune shifts affect systemic health, both on vascular apparatus and bone homeostasis. Their oxidative nature makes mycotoxins a plausible underlying source of low-level toxicity in the bone marrow microenvironment and arterial dysfunction. Mycotoxins could also influence the function of cardiomyocytes with possible injury to the heart. Co-occurrence of mycotoxins can modulate the metabolic pathways favoring osteoblast dysfunction and bone health losses. This review provides a novel insight into understanding the complex events of coexposure to mixed (low levels) mycotoxicosis and subsequent metabolic/immune disruptions contributing to chronic alterations in circulation.

Mycotoxins binder supplementation alleviates aflatoxin B1 toxic effects on the immune response and intestinal barrier function in broilers

This experiment was conducted to evaluate whether a commercial mycotoxins-binder, XL, could effectively attenuate the negative effects of Aflatoxin B₁ (AFB₁) on growth performance, immunological function, and intestinal health in birds. Two hundred forty 1-day-old Arbor Acres broiler chickens were randomly divided into 4 treatments using a 2 × 2 factorial randomized design with 2 levels of dietary mycotoxins binder (0 or 2g /kg) and 2 AFB₁ supplemented levels (0 or 200 μg/kg) from 0 to 42 d. Results showed that AFB₁ exposure impaired growth performance by decreasing BWG in 1–21 d and 1–42 d, decreasing FI in 1–21 d, increasing FCR in 1–21 d and 1–42 d (P < 0.05). Broilers fed AFB₁- contaminated diet impaired the immune function, as evident by decreasing IgA contents, Newcastle disease antibody titers in serum, and sIgA contents of jejunal mucosa at 21 d (P < 0.05). On the other hand, AFB₁ challenge significantly increased the gene expression of proinflammatory factors in spleen at 21 d and liver at 42 d, and significantly decreased claudin-1 expression at 42 d and occludin expression at 21 d, and increased claudin-2 at 21 d in jejunum of broiler chickens (P < 0.05) compared to the basal diet group. Dietary XL supplementation significantly decreased the gene expression of IL-6 in spleen at 21 d and IL-1β in liver at 42 d, cytochrome P450 3A4 (CYP3A4) expression in liver at 21 d of broilers (P < 0.05) compared with the nonsupplemented birds, regardless of AFB₁ challenged or not. Inclusion of 2 g/kg XL increased serum ALB at 42 d, IgM and IgA at 42 d, Newcastle disease antibody titer level at 35 d (P < 0.05). Dietary XL addition enhanced intestinal barrier function by increasing the expression of claudin-1 at 21 d and Occludin at 42 d (P < 0.05) in jejunum. Conclusively, 2 g/kg mycotoxins-binder can relieve the toxic effect of AFB₁ on broilers.

One-pot peptide cyclisation and surface modification of photosensitiser-loaded red blood cells for targeted photodynamic therapy

We report herein a one-pot approach to cyclise a tumour-targeting peptide and conjugate it on the surface of red blood cells loaded with a boron dipyrromethene-based photosensitiser using a bifunctional linker consisting of a bis(bromomethyl)phenyl unit and an ortho-phthalaldehyde unit. This cell-based photosensitiser with surface modification with cyclic RGD peptide moieties can selectively bind against the α_vβ₃ integrin-overexpressed cancer cells, leading to enhanced photocytotoxicity. The results demonstrate that this facile strategy is effective for live-cell surface modification for a wide range of applications.

Aflatoxin B1 Toxicity in Zebrafish Larva (Danio rerio): Protective Role of Hericium erinaceus

Aflatoxin B1 (AFB1), a secondary metabolite produced by fungi of the genus Aspergillus, has been found among various foods as well as in fish feed. However, the effects of AFB1 on fish development and its associated toxic mechanism are still unclear. In the present study, we confirmed the morphological alterations in zebrafish embryos and larvae after exposure to different AFB1 doses as well as the oxidative stress pathway that is involved. Furthermore, we evaluated the potentially protective effect of Hericium erinaceus extract, one of the most characterized fungal extracts, with a focus on the nervous system. Treating the embryos 6 h post fertilization (hpf) with AFB1 at 50 and 100 ng/mL significantly increased oxidative stress and induced malformations in six-day post-fertilization (dpf) zebrafish larvae. The evaluation of lethal and developmental endpoints such as hatching, edema, malformations, abnormal heart rate, and survival rate were evaluated after 96 h of exposure. Hericium inhibited the morphological alterations of the larvae as well as the increase in oxidative stress and lipid peroxidation. In conclusion: our study suggests that a natural extract such as Hericium may play a partial role in promoting antioxidant defense systems and may contrast lipid peroxidation in fish development by counteracting the AFB1 toxicity mechanism.

Gene expression network related to DNA methylation and miRNA regulation during the process of aflatoxin B1-induced malignant transformation of L02 cells

Aflatoxin is a secondary metabolite secreted by Aspergillus flavus, parasitic Aspergillus, and other fungi through the polyketone pathway, and it can be detected in many foods. Aflatoxin has strong toxicity and carcinogenicity, and many studies have shown that aflatoxin is highly associated with liver cancer. In the present study, malignant transformation of L02 cells was induced by aflatoxin B1 (AFB1), and the gene expression, miRNA expression, and methylation level were detected by high-throughput sequencing. The gene and miRNA expression results showed that 2547 genes and 315 miRNAs were changed in the AFB1-treated group compared with the DMSO group. Among them, RSAD2 and SCIN were significantly upregulated, whereas TRAPPC3L and UBE2L6 were significantly downregulated. Has-miR-33b-3p was significantly upregulated, whereas Has-miR-3613-5p was significantly downregulated. The methylation results showed that 2832 CpG sites were methylated on the promoter or coding DNA sequence (CDS) of the gene, whereas the expression of DNMT3a and DNMT3b was significantly upregulated. Moreover, hypermethylation occurred in TRAPPC3L, CDH13, and SPINK13. The results of GO and KEGG pathway analyses showed that significantly changed genes and miRNAs were mainly involved in tumor formation, proliferation, invasion, and migration. The results of network map analysis showed that Hsa-miR-3613-5p, Hsa-miR-615-5p, Hsa-miR-615-3p, and Hsa-miR-3158-3p were the key miRNAs for malignant transformation of L02 cells induced by AFB1. In addition, the expression of ONECUT2, RAP1GAP2, and FSTL4 was regulated by DNA methylation and miRNAs. These results suggested that the gene expression network regulated by DNA methylation and miRNAs may play a vital role in AFB1-induced hepatocellular carcinoma.

Toxicogenicity and mechanistic pathways of aflatoxin B1 induced renal injury

The study investigated the toxicogenic effects, molecular mechanisms and proteomic assessment of aflatoxin B₁ (AFB₁ ) on human renal cells. Hek293 cells were exposed to AFB₁ (0-100 μM) for 24 h. The effect on cell viability was assessed using the methylthiazol tetrazolium (MTT) assay, which also produced the half maximal inhibitory concentration (IC₅₀ ) used in subsequent assays. Free radical production was evaluated by quantifying malondialdehyde (MDA) and nitrate concentration, while DNA fragmentation was determined using the single cell gel electrophoresis (SCGE) assay and DNA gel electrophoresis. Damage to cell membranes was ascertained using the lactate dehydrogenase (LDH) assay. The concentration of ATP, reduced glutathione (GSH), necrosis, annexin V and caspase activity was measured by luminometry. Western blotting and quantitative PCR was used to assess the expression of proteins and genes associated with apoptosis and oxidative stress. The MTT assay revealed a reduction in cell viability of Hek293 cells as the AFB₁ concentration was increased, with a half maximum inhibitory concentration (IC₅₀ ) of 32.60 μM. The decreased viability corresponded to decreased ATP concentration. The upregulation of Hsp70 indicated that oxidative stress was induced in the AFB₁ -treated cells. While this implies an increased production of free radicals, the accompanying upregulation of the antioxidant system indicates the activation of defense mechanisms to prevent cellular damage. Thus, membrane damage associated with increased radical formation was prevented as indicated by the reduced LDH release and necrosis. In addition, cytotoxic effects were evident as AFB₁ activated the intrinsic pathway of apoptosis with corresponding increased DNA fragmentation, p53 and Bax upregulation and increased caspase activity, but externalization of phosphatidylserine (PS), a major hallmark of apoptosis, did not occur in AFB₁ treated renal cells. The results suggest that AFB₁ induced oxidative stress leading to cell death by the intrinsic pathway of apoptosis in renal cells.

Luteolin Alleviates AflatoxinB1-Induced Apoptosis and Oxidative Stress in the Liver of Mice through Activation of Nrf2 Signaling Pathway

Aflatoxin B₁ (AFB₁), a threatening mycotoxin, usually provokes oxidative stress and causes hepatotoxicity in animals and humans. Luteolin (LUTN), well-known as an active phytochemical agent, acts as a strong antioxidant. This research was designed to investigate whether LUTN exerts protective effects against AFB₁-induced hepatotoxicity and explore the possible molecular mechanism in mice. A total of forty-eight mice were randomly allocated following four treatment groups (n = 12): Group 1, physiological saline (CON). Group 2, treated with 0.75 mg/kg BW aflatoxin B₁ (AFB₁). Group 3, treated with 50 mg/kg BW luteolin (LUTN), and Group 4, treated with 0.75 mg/kg BW aflatoxin B₁ + 50 mg/kg BW luteolin (AFB₁ + LUTN). Our findings revealed that LUTN treatment significantly alleviated growth retardation and rescued liver injury by relieving the pathological and serum biochemical alterations (ALT, AST, ALP, and GGT) under AFB₁ exposure. LUTN ameliorated AFB₁-induced oxidative stress by scavenging ROS and MDA accumulation and boosting the capacity of the antioxidant enzyme (CAT, T-SOD, GSH-Px and T-AOC). Moreover, LUTN treatment considerably attenuates the AFB₁-induced apoptosis in mouse liver, as demonstrated by declined apoptotic cells percentage, decreased Bax, Cyt-c, caspase-3 and caspase-9 transcription and protein with increased Bcl-2 expression. Notably, administration of LUTN up-regulated the Nrf2 and its associated downstream molecules (HO-1, NQO1, GCLC, SOD1) at mRNA and protein levels under AFB₁ exposure. Our results indicated that LUTN effectively alleviated AFB₁-induced liver injury, and the underlying mechanisms were associated with the activation of the Nrf2 signaling pathway. Taken together, LUTN may serve as a potential mitigator against AFB₁-induced liver injury and could be helpful for the development of novel treatment to combat liver diseases in humans and/or animals.

An octabrominated Sn(iv) tetraisopropylporphyrin as a photosensitizer dye for singlet oxygen biomedical applications

Two novel Sn(iv) tetraisopropylphenylporphyrins have been synthesized to explore the effect of octabromination at the β-pyrrole positions on their photophysical properties and photodynamic activity. The lower energy Q band of an octabrominated complex lies at 675 nm well within the therapeutic window. The octabrominated dye has a relatively high singlet oxygen quantum yield of 0.78 in DMF and exhibits favorable photodynamic activity against MCF-7 cells with an IC50 value of 10.7 μM and a 5.74 log reduction value (5 μM) towards S. aureus under illumination at 660 nm for 60 min with a Thorlabs M660L3 LED (280 mW cm-2).

Aflatoxin in Dairy Cows: Toxicity, Occurrence in Feedstuffs and Milk and Dietary Mitigation Strategies

Aflatoxins are poisonous carcinogens produced by fungi, mainly Aspergillus flavus and Aspergillus parasiticus. Aflatoxins can contaminate a variety of livestock feeds and cause enormous economic losses, estimated at between US$52.1 and US$1.68 billion annually for the U.S. corn industry alone. In addition, aflatoxin can be transferred from the diet to the milk of cows as aflatoxin M1 (AFM1), posing a significant human health hazard. In dairy cows, sheep and goats, chronic exposure to dietary aflatoxin can reduce milk production, impair reproduction and liver function, compromise immune function, and increase susceptibility to diseases; hence, strategies to lower aflatoxin contamination of feeds and to prevent or reduce the transfer of the toxin to milk are required for safeguarding animal and human health and improving the safety of dairy products and profitability of the dairy industry. This article provides an overview of the toxicity of aflatoxin to ruminant livestock, its occurrence in livestock feeds, and the effectiveness of different strategies for preventing and mitigating aflatoxin contamination of feeds.

AFB1-induced mice liver injury involves mitochondrial dysfunction mediated by mitochondrial biogenesis inhibition

Aflatoxin B1 (AFB1) pollutes foodstuffs and feeds, causing a food safety problem and seriously endangering human and animal health. Liver is the principal organ for AFB1 accumulation and biotransformation, during which AFB1 can cause acute and chronic liver damage, however, the specific mechanism is not completely clear. Mitochondria are the primary organelle of cellular bio-oxidation, providing 95% energy for liver to execute its multiple functions. Therefore, we speculated that mitochondrial dysfunction is involved in AFB1-induced liver injury. To verify the hypothesis, a total of eighty healthy male mice were randomly divided into four groups on average, and exposed with 0, 0.375, 0.75 and 1.5 mg/kg body weight AFB1 by intragastric administration for 30 d. The results displayed that AFB1 triggered liver injury accompanied by oxidative stress. AFB1 exposure also damaged mitochondria structure, decreased mitochondrial membrane potential (MMP), as well as increased cytoplasmic cytochrome c (Cyt-c) protein expression, Bax, p53, Caspase-3/9 protein and/or mRNA expression levels and terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine-5'-triphosphate (dUTP) nick end labeling (TUNEL) staining positive cells in mice liver. Meanwhile, AFB1 exposure elevated pyruvate content, inhibited tricarboxylic acid (TCA) cycle rate-limiting enzymes and electron transport chain (ETC) complexes I-V activities, disturbed ETC complexes I-V subunits mRNA expression levels and reduced adenosine triphosphate (ATP) level in mice liver. These results indicated that AFB1 destroyed mitochondrial structure, activated mitochondrion-dependent apoptosis and induced mitochondrial dysfunction. In addition, AFB1 disrupted mitochondrial biogenesis, presented as the abnormalities of protein and/or gene expression levels of voltage dependent anion channel protein 1 (VDAC1), peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α), nuclear respiratory factor 1 (Nrf1) and mitochondrial transcription factor A (Tfam). This may contribute to hepatic and mitochondrial lesions induced by AFB1. These results provide a new perspective for elucidating the mechanisms of AFB1 hepatotoxicity.

Resveratrol, curcumin and gallic acid attenuate glyoxal-induced damage to rat renal cells

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RES, CUR and GA protected renal cells from GO–induced cells death.

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RES, CUR and GA reduced formation of ROS.

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RES, CUR and GA diminished lipid peroxidation products.

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RES, CUR and GA repressed GO-induced mitochondrial membrane potential collapse.

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RES, CUR and GA decreased lysosomal membrane leakage in GO-treated cells.

Glyoxal (GO), a by-product of glucose auto-oxidation, is involved in the glycation of proteins/ lipids and formation of advanced glycation (AGE) and lipoxidation (ALE) end products. AGE/ALE were shown to contribute to diabetic complications development/progression such as nephropathy. Diabetic nephropathy progression has an oxidative nature. Given the antioxidant effects of polyphenols, potential protective effects of resveratrol, curcumin and gallic acid, in rat renal cells treated with GO, were evaluated in the present work. According to our results, incubation of GO with the cells reduced their viability and led to membrane lysis, reactive oxygen species (ROS) formation, lipid peroxidation, mitochondrial membrane potential collapse, and lysosomal membrane leakage. These findings were prevented by pre-treatment with resveratrol, curcumin and gallic acid. Mitochondrial and lysosomal toxic interactions appear to worsen oxidative stress/cytotoxicity produced by GO. Resveratrol, curcumin and gallic acid inhibited ROS formation and attenuated GO-induced renal cell death.

Ameliorative effect of selenium nanoparticles on the structure and function of testis and in vitro embryo development in Aflatoxin B1-exposed male mice

The purpose of the research was to investigate the therapeutic ability of selenium nanoparticles (Se-NPs) on the aflatoxin B1 (AFB1) toxicity induced in the male reproductive system. For this experiment, the mature male mice were put into four groups. Control (0.5 ml PBS, 60 days; IP, n = 7), Se-NPs (0.5 µg kg^-1  day^-1 for 60 days; IP), AFB1 (4.5 mg kg^-1  day^-1 for 60 days; IP) and AFB1 + Se-NPs (4.5 mg kg^-1  day^-1  + 0.5 µg kg^-1  day^-1 for 60 days; IP). After treatment, the histological structure of testis, serum testosterone level and sperm parameters, including concentration, motility, viability, morphology and DNA fragmentation, were examined. The results demonstrated that the AFB1 destroyed the testicular tissue structure and decreased the sperm concentration, motility, viability and normal morphology significantly. AFB1 also could significantly increase sperm DNA fragmentation and reduce in vitro fertilisation and embryo development compared to the control group (p < .001). Our data show that Se-NPs could inhibit AFB1-induced damage to the testis and improve sperm parameters as well as in vitro fertilisation and embryo production in AFB1 exposed male mice. This study revealed that the administration of Se-NPs could attenuate the testicular injury of AFB1 and improve the male reproductive system function in AFB1 exposed mice.

Comparative Toxigenicity and Associated Mutagenicity of Aspergillus fumigatus and Aspergillus flavus Group Isolates Collected from the Agricultural Environment

The mutagenic patterns of A. flavus, A. parasiticus and A. fumigatus extracts were evaluated. These strains of toxigenic Aspergillus were collected from the agricultural environment. The Ames test was performed on Salmonella typhimurium strains TA98, TA100 and TA102, without and with S9mix (exogenous metabolic activation system). These data were compared with the mutagenicity of the corresponding pure mycotoxins tested alone or in reconstituted mixtures with equivalent concentrations, in order to investigate the potential interactions between these molecules and/or other natural metabolites. At least 3 mechanisms are involved in the mutagenic response of these aflatoxins: firstly, the formation of AFB1-8,9-epoxide upon addition of S9mix, secondly the likely formation of oxidative damage as indicated by significant responses in TA102, and thirdly, a direct mutagenicity observed for higher doses of some extracts or associated mycotoxins, which does not therefore involve exogenously activated intermediates. Besides the identified mycotoxins (AFB1, AFB2 and AFM1), additional "natural" compounds contribute to the global mutagenicity of the extracts. On the other hand, AFB2 and AFM1 modulate negatively the mutagenicity of AFB1 when mixed in binary or tertiary mixtures. Thus, the evaluation of the mutagenicity of "natural" mixtures is an integrated parameter that better reflects the potential impact of exposure to toxigenic Aspergilli.

Proteomics reveals the alleviation of zinc towards aflatoxin B1-induced cytotoxicity in human hepatocyes (HepG2 cells)

Aflatoxin B1 (AFB1) is a known carcinogen found in contaminated food and designated by the World Health Organization as a class I carcinogenic substance. AFB1 presents with carcinogenicity, teratogenicity, and mutagenicity, and the liver is the human organ most susceptible to AFB1. Zinc (Zn), which is one of the essential nutrient elements that could protect the cells from biological toxins, heavy metals, hydrogen peroxide, metal chelators and radiation, is assessed in this study for its potential to alleviate AFB1-induced cytotoxicity. Samples were divided into three groups, namely CK, AFB1, and AFB1+Zn. Protein expressions were analyzed by two-way electrophoresis combined with flight mass spectrometry, with 41 differentially expressed proteins identified in the results, mainly related to oxidative stress, cell apoptosis, DNA damage, and energy metabolism. Zn was found to regulate the expression of peroxidases (peroxiredoxin-1, peroxiredoxin-5, peroxiredoxin-6) to relieve AFB1-induced oxidative stress. Moreover, Zn could decrease the expression of pro-apoptotic genes (cleaved-caspase-3, caspase-9, and Bax) and increase the expression of anti-apoptotic genes (Bcl-2 and Bcl-xl) to alleviate the cell apoptosis induced by AFB1. In addition, AFB1 reduced intracellular ATP levels, whereas Zn supplementation boosted ATP levels and maintained homeostasis and a steady state of cellular energy metabolism by modulating AMPK-ACC phosphorylation levels, while many zinc finger proteins changed after AFB1 treatment. These results, therefore, indicate that Zn could alleviate AFB1-induced cytotoxicity by changing the expressions of zinc finger proteins in liver hepatocellular carcinoma (HepG2 cells).

Melatonin and vitamin E alleviate homocysteine-induced oxidative injury and apoptosis in endothelial cells

A relationship exists between hyperhomocysteinemia and cardiovascular diseases, although the underlying mechanisms are still incompletely defined. One possibility involves a homocysteine (Hcy)-induced increased oxidative stress. Melatonin (Mel) and vitamin E (vitE) are important anti-oxidants. The main purpose of this study was (1) to compare the effect of treatments with Mel, vitE or both, on Hcy-induced apoptosis in human umbilical vein endothelial cells (HUVECs), and (2) to investigate the underlying mechanisms. Cell proliferation assay was carried out by Water Soluble Tetrazolium-1 (WST-1) assay kit. Apoptotic index was calculated by TUNEL Assay. Anti-oxidant parameters were studied by measurement of reactive oxygen species (ROS) and lipid peroxidation (LPO) levels. mRNA and protein expression levels of apoptotic and anti-apoptotic genes and proteins were studied by quantitative real time polymerase chain reaction (qRT-PCR) and Western blotting experiments respectively. The results showed that treatments with Mel, vitE or Mel + vitE suppressed Hcy-induced cell death, with a higher efficiency for the Mel and Mel + vitE treatments. Our results suggests that the mechanisms by which these anti-oxidants protected endothelial cells include the decrease in ROS and LPO levels, an increase in cell migration, the downregulation of pro-apoptotic proteins Cas 3, Cas 9, Cyt C and Bax and the upregulation of anti-apoptotic protein Bcl 2. Collectively, these results revealed the protective role of vitE and Mel against Hcy-induced cell apoptosis, which may add insight into therapeutic approaches to Hcy-induced damages.

Oxidative stress and genotoxicity of co-exposure to chlorpyrifos and aflatoxin B1 in HepG2 cells

Chlorpyrifos (CPF) and aflatoxin B₁ (AFB₁) are each known to adversely affect hepatic tissue individually, but their combined hepatic effects have never been previously investigated. HepG2 cell viability, oxidative status, and genetic impairment were examined after exposing HepG2 cells to: (1) CPF alone, (2) AFB₁ alone, and (3) CPF and AFB₁ combined (20:1). CPF exposure decreased cell viability, reduced glutathione (GSH) content, and superoxide dismutase (SOD) activity but increased both glutathione peroxidase (GPx) and paraoxonase 1 activity. AFB₁ exposure decreased cell viability and GSH content but increased reactive oxygen species (ROS) production. CPF and AFB₁ combined exposure decreased GSH content (p < 0.05) further over individual CPF and AFB₁ exposures. Induction of micronucleus formation was detected in AFB₁-treated cells but undetected in both CPF and combination-treated cells. In conclusion, cytotoxic effects caused by combined exposure were antagonistic, as shown by a combination index value of 1.67. Although no change in ROS production was observed in CPF groups, the overall results confirmed the occurrence of oxidative stress through the alterations of GSH content, GPx, and SOD activity. Only intracellular GSH was evidently changed upon exposure to CPF and AFB₁ combined. Thus, this study suggested cellular GSH as a potential indicator for detecting the combined effects of CPF and AFB₁ in HepG2 cells, the detection of which could be adapted to estimate the potential toxicity of additional multiple toxicant exposures.

Investigation of the effect of magnetite iron oxide particles size on cytotoxicity in A549 cell line

INTRODUCTION

Magnetite as iron oxide is widely used in various industries, in the pharmaceutical industry in particular where it is used for its magnetic properties. The environmental and occupational exposure to airborne nanoparticles and microparticles of iron oxide compounds have been reported. Since authors have reported contradictory results, the objective of this study was to investigate the effect of particles' size in their toxicities.

METHODS

The human cell line A₅₄₉ was exposed with magnetite iron oxide in two size categories of micro (≥5 µm) and nano (<100 nm), with four concentrations of 10, 50, 100, and 250 µg/ml at two time periods of 24 and 72 h. The cell viability, reactive oxygen species (ROS), changes in mitochondrial membrane potential, and incidence of apoptosis were studied.

RESULTS

Nano and micro magnetite particles demonstrated diverse toxicity effects on the A₅₄₉ cell line at the 24- and 72-h exposure periods; however, the effects produced were time- and concentration-dependent. Nano magnetite particles produced greater cellular toxicities in forms of decreased viabilities at concentration exposures greater than 50 µg/ml (p < 0.05), along with increased ROS (p < 0.05), decreased cellular membrane potential (p < 0.05), and reduced rate of apoptosis (p < 0.05).

DISCUSSION

The results of this study demonstrated that magnetite iron in nano-range sizes had a greater absorbability for the A₅₄₉ cell line compared to micro sizes, and at the same time, nanoparticles were more toxic than microparticles, demonstrating higher production of ROS and decreased viabilities. Considering the greater toxicity of nanoparticles of magnetite iron in this study, thorough precautionary control measures must be taken before they can be used in various industries.

Combined effects of aflatoxin B1 and deoxynivalenol on the expression of glutathione redox system regulatory genes in common carp

The purpose of the present study was to evaluate the short-term effects of aflatoxin B₁ (AFB₁ ) and deoxynivalenol (DON) exposure on the expression of the genes encoding the glutathione redox system glutathione peroxidase 4a (gpx4a), glutathione peroxidase 4b (gpx4b), glutathione synthetase (gss) and glutathione reductase (gsr) and the oxidative stress response-related transcription factors Kelch-like ECH-associated protein 1 (keap1) and nuclear factor-erythroid 2 p45-related factor 2 (nrf2) in liver, kidney and spleen of common carp. During the 24-hr long experiment, three different doses (5 µg AFB₁ and 110 µg DON; 7.5 µg AFB₁ and 165 µg DON or 10 µg AFB₁ and 220 µg DON/kg bw) were used. The results indicated that the co-exposure of AFB₁ and DON initiated free radical formation in liver, kidney and spleen, which was suggested by the increase in Nrf2 dependent genes, namely gpx4a, gpx4b, gss and gsr. Expression of keap1 gene showed upregulation after 8 hr of mycotoxin exposure, and also upregulation of nrf2 gene was found in kidney after 8 hr of exposure, while in the liver, only slight differences were observed. The changes in the expression of the analysed genes suggest that level of reactive oxygen species reached a critical level where other signalling pathway was activated as described by the hierarchical model of oxidative stress.

Modulatory Effect of the Intracellular Content of Lactobacillus casei CRL 431 Against the Aflatoxin B1-Induced Oxidative Stress in Rats

It has been recognized that lactic acid bacteria exhibit antioxidant properties, which have been mainly endorsed to the intact viable bacteria. However, recent studies have shown that intracellular content (IC) may also be good sources of antioxidative metabolites, which may potentially contribute to oxidative homeostasis in vivo. Hence, the modulatory effect of the intracellular content of Lactobacillus casei CRL 431 (IC431) on aflatoxin B₁ (AFB₁)-induced oxidative stress in rats was evaluated on the basis of its influence on hepatic lipid peroxidation (LPO), antioxidant status-antioxidant capacity (TAC), catalase (CAT), and glutathione peroxidase (GPx) activities; and on the oxidative stress index (OSi). Results demonstrated that CAT and GPx activities, and TAC, determined in plasma samples, were significantly (P < 0.05) higher in rats treated with AFB₁ plus IC431 (3.98 μM/min/mg protein, 1.88 μM/min/mg protein, and 238.7 μM Trolox equivalent, respectively) than AFB₁-treated rats (3.47 μM/min/mg protein, 1.46 μM/min/mg protein, and 179.7 μM Trolox equivalent, respectively). Furthermore, plasma and liver tissue samples from rats treated with AFB₁ plus IC431 showed significantly (P < 0.05) lower LPO values (52 and 51%, respectively) and OSi (59 and 51%, respectively) than AFB₁-treated rats. Hence, our results proved that the intracellular content of Lact. casei CRL 431 contains metabolites that are capable to modulate the antioxidant defense systems in living organism, which may help to ameliorate the damage associated to AFB₁-induced oxidative stress.

Sensitive CometChip assay for screening potentially carcinogenic DNA adducts by trapping DNA repair intermediates

Genotoxicity testing is critical for predicting adverse effects of pharmaceutical, industrial, and environmental chemicals. The alkaline comet assay is an established method for detecting DNA strand breaks, however, the assay does not detect potentially carcinogenic bulky adducts that can arise when metabolic enzymes convert pro-carcinogens into a highly DNA reactive products. To overcome this, we use DNA synthesis inhibitors (hydroxyurea and 1-β-d-arabinofuranosyl cytosine) to trap single strand breaks that are formed during nucleotide excision repair, which primarily removes bulky lesions. In this way, comet-undetectable bulky lesions are converted into comet-detectable single strand breaks. Moreover, we use HepaRG™ cells to recapitulate in vivo metabolic capacity, and leverage the CometChip platform (a higher throughput more sensitive comet assay) to create the 'HepaCometChip', enabling the detection of bulky genotoxic lesions that are missed by current genotoxicity screens. The HepaCometChip thus provides a broadly effective approach for detection of bulky DNA adducts.

Synthesis and anti-cancer activity studies of dammarane-type triterpenoid derivatives

Two series of novel derivatives of AD-2, an active ginsenoside derived from ginseng were designed and synthesized. Five human cancer cell lines (MGC-803, SGC-7901, A549, MCF-7, PC-3 cells) and one normal ovarian cell IOSE144 were employed to evaluate the anti-proliferative activity. Most of derivatives possessed obvious enhanced activity compared with AD-2. Among them, compound 4c displayed the most excellent activity in all tested cancer cell lines, especially A549 cells with an IC50 value of 1.07 ± 0.05 μM. The underlying mechanism study suggested that 4c induced S-phase arrest and apoptosis in A549 cells. Increasing the level of ROS and inducing collapse of MMP in cells treated with 4c were also proved. Moreover, Western blot analysis showed that the expression level of p53 and p21 were obviously increased. 4c could remarkably up-regulate the expression of cyt c in cytosol, the ratio of Bax to Bcl-2 and activate caspase-3/9/PARP. Besides, the expression level of MDM2 was remarkably decreased. The results indicated that 4c caused apoptosis through the mitochondrial pathway, which ROS generation was probably involved in, and had the potent to serve as anti-proliferative agent.

Lack of Dose- and Time-Dependent Effects of Aflatoxin B1 on Gene Expression and Enzymes Associated with Lipid Peroxidation and the Glutathione Redox System in Chicken

Effects of aflatoxin B1 (AFB1) on lipid peroxidation and glutathione system were investigated in chicken liver. In a three-week feeding trial, different doses (<1.0 μg/kg (control diet), 17.0 µg (diet A1), 92.0 µg (diet A2), and 182.0 µg (diet A3) AFB1 kg/feed) were used. Markers of lipid peroxidation, conjugated dienes and trienes showed higher values in A3, while amounts of thiobarbituric acid reactive substances were increased in the A1 group at day 21. Glutathione content was lower at day 14 in Group A2. Glutathione peroxidase 4 activity was increased at days 7 and 21 in the A3 group but reduced in the A2 and A3 groups at day 14. The GPX4 gene was downregulated at day 7 in the A2 group, but overregulated at days 14 and 21, and at day 14 in the A3 group. GSS was downregulated at day 14 in the A1 group but overregulated at day 21 in A1 and A2 groups. GSR was downregulated at days 7 and 21 in all treatment groups, but on day 14, induction was observed in the A3 group. The results indicated that AFB1 did not induce dose- or time-dependent effects on the glutathione redox system and its encoding genes at the dose range used, which means that oxidative stress is not the primary effect of AFB1 toxicity.

Hemoadsorption Improves Survival of Rats Exposed to an Acutely Lethal Dose of Aflatoxin B1

Mycotoxins, such as aflatoxin B1 (AFB1), pose a serious threat as biological weapons due to their high toxicity, environmental stability, easy accessibility and lack of effective therapeutics. This study investigated if blood purification therapy with CytoSorb (CS) porous polymer beads could improve survival after a lethal aflatoxin dose (LD90). The effective treatment window and potential therapeutic mechanisms were also investigated. Sprague Dawley rats received a lethal dose of AFB1 (0.5-1.0 mg/kg) intravenously and hemoperfusion with a CS or Control device was initiated immediately, or after 30, 90, or 240-minute delays and conducted for 4 hours. The CS device removes AFB1 from circulation and significantly improves survival when initiated within 90 minutes of toxin administration. Treated subjects exhibited improved liver morphology and health scores. Changes in the levels of cytokines, leukocytes and platelets indicate a moderately-severe inflammatory response to acute toxin exposure. Quantitative proteomic analysis showed significant changes in the level of a broad spectrum of plasma proteins including serine protease/endopeptidase inhibitors, coagulation factors, complement proteins, carbonic anhydrases, and redox enzymes that ostensibly contribute to the therapeutic effect. Together, these results suggest that hemoadsorption with CS could be a viable countermeasure against acute mycotoxin exposure.

Chronic and Acute Toxicities of Aflatoxins: Mechanisms of Action

There are presently more than 18 known aflatoxins most of which have been insufficiently studied for their incidence, health-risk, and mechanisms of toxicity to allow effective intervention and control means that would significantly and sustainably reduce their incidence and adverse effects on health and economy. Among these, aflatoxin B1 (AFB1) has been by far the most studied; yet, many aspects of the range and mechanisms of the diseases it causes remain to be elucidated. Its mutagenicity, tumorigenicity, and carcinogenicity-which are the best known-still suffer from limitations regarding the relative contribution of the oxidative stress and the reactive epoxide derivative (Aflatoxin-exo 8,9-epoxide) in the induction of the diseases, as well as its metabolic and synthesis pathways. Additionally, despite the well-established additive effects for carcinogenicity between AFB1 and other risk factors, e.g., hepatitis viruses B and C, and the hepatotoxic algal microcystins, the mechanisms of this synergy remain unclear. This study reviews the most recent advances in the field of the mechanisms of toxicity of aflatoxins and the adverse health effects that they cause in humans and animals.

Lycopene alleviates AFB1-induced immunosuppression by inhibiting oxidative stress and apoptosis in the spleen of mice

Lycopene (LYC) has been reported to exhibit antioxidant and immunoprotective activities, and our previous studies confirmed that LYC can alleviate multiple tissue damage induced by aflatoxin B1 (AFB1). However, it is unclear whether LYC could relieve the AFB1-induced immunosuppression. Thus, forty-eight male mice were randomly allocated and treated with LYC (5 mg kg-1) and/or AFB1 (0.75 mg kg-1) by intragastric administration for 30 days. We found that LYC alleviated AFB1-induced immunosuppression by relieving splenic structure injury and increasing the spleen weight, spleen coefficient, T lymphocyte subsets, the contents of IL-2, IFN-γ and TNF-α in serum, as well as the mRNA expression of IL-2, IFN-γ and TNF-α in spleen. Furthermore, LYC inhibited oxidative stress induced by AFB1via decreasing the levels of reactive oxygen species (ROS), hydrogen peroxide (H2O2) and malondialdehyde (MDA), while enhancing the total antioxidant capacity (T-AOC) and antioxidant enzyme activities. In addition, LYC also restrained splenic apoptosis through blocking mitochondria-mediated apoptosis in AFB1 intoxicated mice, presenting as the increase of mitochondrial membrane potential, and the decrease of cytoplasmic Cyt-c protein expression, cleaved Caspase-3 protein expression, Caspase-3/9 activities and mRNA expressions, as well as balancing the mitochondrial protein and mRNA expressions of Bax and Bcl-2. These results indicate that LYC can alleviate AFB1-induced immunosuppression by inhibiting oxidative stress and mitochondria-mediated apoptosis of mice spleen.

Glutathione- and light-controlled generation of singlet oxygen for triggering drug release in mesoporous silica nanoparticles

An activatable phthalocyanine-based photosensitiser and a singlet-oxygen-triggered doxorubicin releasing system have been incorporated into mesoporous silica nanoparticles, which can release the encapsulated doxorubicin in a controllable manner.

Non-aggregated lipophilic water-soluble tin porphyrins as photosensitizers for photodynamic therapy and photodynamic antimicrobial chemotherapy

Readily-synthesized water-soluble Sn(iv) tetrapyridylporphyrin dyes have been prepared which exhibit enhanced properties for use as photosensitizer dyes in biomedical applications.

Cytotoxic effects of thioxanthone derivatives as photoinitiators on isolated rat hepatocytes

Thioxanthone and its analogues, 2- or 4-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-diethylthioxanthone (DETX) and xanthone, are used as photoinitiators of ultraviolet (UV) light-initiated curable inks. As these photoinitiators were found in numerous food/beverage products packaged in cartons printed with UV-cured inks, the cytotoxic effects and mechanisms of these compounds were studied in freshly isolated rat hepatocytes. The toxicity of DETX was greater than that of other compounds. DETX elicited not only concentration (0-2.0 mm)- and time (0-3 hours)-dependent cell death accompanied by the depletion of cellular adenosine triphosphate (ATP), and reduced glutathione (GSH) and protein thiol levels, but also the accumulation of GSH disulfide and malondialdehyde. Pretreatment of hepatocytes with either fructose at a concentration of 10 mm or N-acetyl-l-cysteine (NAC) at a concentration of 5.0 mm ameliorated DETX (1 mm)-induced cytotoxicity. Further, the exposure of hepatocytes to DETX resulted in the induction of reactive oxygen species (ROS) and loss of mitochondrial membrane potential, both of which were partially prevented by the addition of NAC. These results indicate that: (1) DETX-induced cytotoxicity is linked to mitochondrial failure and depletion of cellular GSH; (2) insufficient cellular ATP levels derived from mitochondrial dysfunction were, at least in part, ameliorated by the addition of fructose; and (3) GSH loss and/or ROS formation was prevented by NAC. Taken collectively, these results suggest that the onset of toxic effects caused by DETX may be partially attributable to cellular energy stress as well as oxidative stress.

Aflatoxin compromises development of the preimplantation bovine embryo through mechanisms independent of reactive oxygen production

Aflatoxin is a potent carcinogen often found in animal feedstuffs. Although it reportedly impairs development of the preimplantation pig embryo, it is not known whether it adversely affects development of the preimplantation bovine embryo. We conducted 3 experiments to investigate this possibility and determine whether deleterious effects of aflatoxin were caused by increased production of reactive oxygen species (ROS). Experiments were conducted with embryos produced in vitro and cultured after fertilization with various concentrations of aflatoxin. For experiment 1, embryos were treated with 0 (control), 40, 400, or 4,000 µg/L of aflatoxin B₁ (AFB₁). Treatment at all concentrations of AFB₁ tended to reduce cleavage rate, with the 2 highest concentrations having significant effects. As compared with the control, 40 µg/L AFB₁ reduced the percentage of oocytes becoming blastocysts and the percentage of cleaved embryos becoming blastocysts (19.7 vs. 8.1% and 30.3 vs. 14.3%, respectively). Complete inhibition of blastocyst formation occurred at concentrations of 400 and 4,000 µg/L of AFB₁. Experiments 2 and 3 involved a 2 × 2 factorial design with effects of AFB₁ (0 and 40 µg/L), the antioxidant Trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid, a water-soluble analog of vitamin E; 0 and 5 µM), and their interaction on production of ROS in putative zygotes (experiment 2) and development to the blastocyst stage (experiment 3). Production of ROS was increased by AFB₁, and this effect was reversed by Trolox. However, Trolox did not prevent the reduction in development to the blastocyst stage caused by AFB₁. Thus, the anti-developmental effects of AFB₁ are not caused solely by increased ROS production. Rather, other underlying mechanisms exist for the adverse effects of aflatoxin on embryonic development. Overall, results indicate the potential for feeding aflatoxin-contaminated feed to cause embryonic loss in cattle.