Zearalenone induced toxicity in SHSY-5Y cells: The role of oxidative stress evidenced by N-acetyl cysteine

Zearalenone (ZEN) is a mycotoxin from Fusarium species commonly found in many food commodities and are known to cause reproductive disorders, genotoxic and immunosuppressive effects. Although many studies have demonstrated the cytotoxic effects of ZEN, the mechanisms by which ZEN mediates its cytotoxic effects appear to differ according to cell type and route of exposure. Meantime, the available information on the neurotoxic effects of ZEN is very much limited. In the present study we evaluated the role of oxidative stress in ZEN mediated neurotoxicity in SH-SY5Y cells and investigated the possible underlying mechanism. ZEN induced ROS formation and elevated levels of MDA, loss of mitochondrial membrane potential (MMP) and increase in DNA damage in a dose dependent manner as assessed by COMET assay and agarose gel electrophoresis. However, there was no DNA damage by plasmid breakage assay at 6, 12 and 24 h time points. DAPI staining showed apoptotic nuclei at 12 and 24 h. Further, ZEN treated SH-SY5Y cells showed a marked suppressive effect on the neuronal gene expression. Use of an antioxidant N-acetylcysteine (NAC) reversed the toxin-induced generation of ROS and also attenuated loss of MMP. Collectively, these results suggest that ROS is the main upstream signal leading to increased ZEN mediated neurotoxicity in SH-SY5Y cells.     

Protective effect of sulphoraphane against oxidative stress mediated toxicity induced by CuO nanoparticles in mouse embryonic fibroblasts BALB 3T3

Despite the great interest in nanoparticles (NPs) safety, no comprehensive test paradigm has been developed. Oxidative stress has been implicated as an explanation behind the toxicity of NPs. It is reported that sulphoraphane (SFN) present in cruciferous vegetables like cauliflower and broccoli has potential to protect cells from oxidative damage and inflammation. However, protective role of SFN in nanotoxicity is not explored. We investigated the protective effect of SFN against the toxic response of copper oxide (CuO) NPs in mouse embryonic fibroblasts (BALB 3T3). Results showed that CuO NPs induced dose-dependent (5-15 μg/ml) cytotoxicity in BALB 3T3 cells demonstrated by MTT and lactate dehydrogenase (LDH) assays. CuO NPs were also found to induce oxidative stress in dose-dependent manner indicated by induction of reactive oxygen species (ROS) and lipid peroxidation (LPO) and depletion of glutathione and glutathione reductase. Co-treatment of BALB 3T3 cells with SFN (6 μM) significantly attenuated the cytotoxicity, ROS generation and oxidative stress caused by CuO NPs. Moreover, we found that co-treatment of another antioxidant N-acetyl-cysteine (NAC) (2 mM) also significantly attenuated glutathione depletion caused by CuO NPs but protection from the loss of cell viability due to CuO NPs exposure was not significant. We believe this is the first report showing that SFN significantly protected the BALB 3T3 cells from CuO NPs toxicity, which is mediated through generation of oxidants and depletion of antioxidants. Consequently, protective mechanism of SFN against CuO NPs toxicity was different from NAC that should be further investigated.     

Paracetamol: overdose-induced oxidative stress toxicity,metabolism, and protective effects of various compounds in vivo and in vitro

Paracetamol (APAP) is one of the most widely used and popular over-the-counter analgesic and antipyretic drugs in the world when used at therapeutic doses. APAP overdose can cause severe liver injury, liver necrosis and kidney damage in human beings and animals. Many studies indicate that oxidative stress is involved in the various toxicities associated with APAP, and various antioxidants were evaluated to investigate their protective roles against APAP-induced liver and kidney toxicities. To date, almost no review has addressed the APAP toxicity in relation to oxidative stress. This review updates the research conducted over the past decades into the production of reactive oxygen species (ROS), reactive nitrogen species (RNS), and oxidative stress as a result of APAP treatments, and ultimately their correlation with the toxicity and metabolism of APAP. The metabolism of APAP involves various CYP450 enzymes, through which oxidative stress might occur, and such metabolic factors are reviewed within. The therapeutics of a variety of compounds against APAP-induced organ damage based on their anti-oxidative effects is also discussed, in order to further understand the role of oxidative stress in APAP-induced toxicity. This review will throw new light on the critical roles of oxidative stress in APAP-induced toxicity, as well as on the contradictions and blind spots that still exist in the understanding of APAP toxicity, the cellular effects in terms of organ injury and cell signaling pathways, and finally strategies to help remedy such against oxidative damage.     

MPP<Superscript>+</Superscript>-induced toxicity in the presence of dopamine is mediated by COX-2 through oxidative stress

Accumulating evidence suggests that endogenous dopamine may act as a neurotoxin and thereby participate in the pathophysiology of Parkinson’s disease (PD). Cyclooxygenase-2 (COX-2) has been implicated in the pathogenesis of PD due to its ability to generate reactive oxygen species (ROS). Inhibition of COX-2 leads to neuroprotection by preventing the formation of dopamine-quinone. In this study, we examined whether dopamine mediates 1-methyl-4-phenylpyridinium (MPP⁺)-induced toxicity in primary ventral mesencephalic (VM) neurons, an in vitro model of PD, and if so, whether the protective effects of COX-2 inhibitors on dopamine mediated MPP⁺-induced VM neurotoxicity and VM dopaminergic cell apoptosis result from the reduction of ROS. Reserpine, a dopamine-depleting agent, significantly reduced VM neurotoxicity induced by MPP⁺, whereas dopamine had an additive effect on MPP⁺-induced VM neurotoxicity and VM dopaminergic cell apoptosis. However, inhibition of COX-2 by a selective COX-2 inhibitor (DFU) or ibuprofen significantly attenuated MPP⁺-induced VM cell toxicity and VM dopaminergic cell apoptosis, which was accompanied by a decrease in ROS production in VM dopaminergic neurons. These results suggest that dopamine itself mediates MPP⁺-induced VM neurotoxicity and VM dopaminergic cell apoptosis in the presence of COX-2.     

The inhibition of human T cell proliferation by the caspase inhibitor z-VAD-FMK is mediated through oxidative stress

The caspase inhibitor benzyloxycarbony (Cbz)-l-Val-Ala-Asp (OMe)-fluoromethylketone (z-VAD-FMK) has recently been shown to inhibit T cell proliferation without blocking caspase-8 and caspase-3 activation in primary T cells. We showed in this study that z-VAD-FMK treatment leads to a decrease in intracellular glutathione (GSH) with a concomitant increase in reactive oxygen species (ROS) levels in activated T cells. The inhibition of anti-CD3-mediated T cell proliferation induced by z-VAD-FMK was abolished by the presence of low molecular weight thiols such as GSH, N-acetylcysteine (NAC) and l-cysteine, whereas d-cysteine which cannot be metabolised to GSH has no effect. These results suggest that the depletion of intracellular GSH is the underlying cause of z-VAD-FMK-mediated inhibition of T cell activation and proliferation. The presence of exogenous GSH also attenuated the inhibition of anti-CD3-induced CD25 and CD69 expression mediated by z-VAD-FMK. However, none of the low molecular weight thiols were able to restore the caspase-inhibitory properties of z-VAD-FMK in activated T cells where caspase-8 and caspase-3 remain activated and processed into their respective subunits in the presence of the caspase inhibitor. This suggests that the inhibition of T cell proliferation can be uncoupled from the caspase-inhibitory properties of z-VAD-FMK. Taken together, the immunosuppressive effects in primary T cells mediated by z-VAD-FMK are due to oxidative stress via the depletion of GSH.     

TXNIP介导的氧化应激在疾病中的作用机制

硫氧还蛋白相互作用蛋白(TXNIP)通过与硫氧还蛋白(Trx)的结合而抑制Trx的抗氧化作用,促进了活性氧簇(ROS)的产生与积聚,诱发内质网应激与线粒体应激,最终可诱导炎症或细胞凋亡。TXNIP所介导的氧化应激在糖尿病及其并发症(糖尿病肾病、糖尿病视网膜病变等)、动脉粥样硬化、缺血/再灌注损伤、癌症(肝细胞癌、膀胱癌、乳腺癌、白血病)等疾病的发生、发展过程中起着重要的调控作用。该文就TXNIP介导的氧化应激在相关疾病中的作用机制及研究进展进行综述。     

NADPH氧化酶在氟诱导小胶质细胞氧化应激中的作用

目的：观察NADPH氧化酶在氟引起的小胶质细胞氧化应激中的作用,为进一步研究氟致中枢神经系统损伤机制提供实验依据.方法：用1,5,10,25,50,100 mg/L的氟化钠处理BV-2小胶质细胞6,12,24h后,检测细胞活力、细胞内活性氧（ROS）含量,以及NADPH氧化酶抑制剂API处理后的小胶质细胞ROS水平变化情况.结果：BV-2小胶质细胞细胞氟化钠染毒后,细胞活力显著降低,差异有统计学意义（P＜0.05）.染毒组细胞内ROS含量显著高于对照组,差异有统计学意义（P＜0.05）.与单独染氟组相比,NADPH氧化酶抑制剂API能够显著降低氟化钠诱导的BV-2细胞内活性氧（ROS）含量.结论：氟能引起小胶质细胞氧化应激,NADPH氧化酶在氟诱导的ROS产生中起一定作用。     

Translational responses of Mytilus galloprovincialis to environmental pollution: integrating the responses to oxidative stress and other biomarker responses into a general stress index

Heavy metals are commonly associated with the generation of reactive oxygen species (ROS), which may cause oxidative damage to several cellular macromolecules and organelles. In an attempt to correlate biomarker responses to oxidative stress, caged mussels (Mytilus galloprovincialis) were exposed for 30 days in a relatively clean site and two areas (Stations 1 and 2) unevenly polluted by heavy metals in Gulf of Patras (Greece). Three periods of caging were: one in winter, the second in spring, and the third in autumn. Heavy metal content was determined in digestive glands of the exposed mussels as a measure of metal pollution, metallothionein content as an adaptive and detoxifying index, lysosomal membrane stability as a biomarker of general stress, superoxide radical production and lipid peroxidation as indicators of oxidative stress, and micronucleus frequency in gill cells as an index of chromosomal damage. Considering that protein-synthesizing machinery is one of the candidate targets for ROS, the in vivo activity of ribosomes in digestive glands was also tested. Compared with the reference samples, mussels transplanted to Station 1 showed increased levels of heavy metals and metallothionein in digestive glands, lower lysosomal membrane stability, higher values in oxidative stress indices, reduced activity of ribosomes, and increased chromosomal damage in gill cells. In addition, run-off ribosomes isolated from mussels transplanted to Station 1 were less efficient at initiating protein synthesis in a cell-free system than those from mussels in the reference site. Mussels transplanted to Station 2 exhibited similar but less pronounced responses. Statistical analysis revealed a strong positive correlation of ribosomal activity with lysosomal membrane stability, as well as a significant negative correlation with the oxidative stress indices, metallothionein content, micronucleus frequency, and the digestive gland content in Cr, Cu and Mn. Integration of all the measured biomarker responses into one general "stress index" demonstrated a clear distinction between the sampling sites, allowing classification along a pollution gradient (reference site相似文献   

The role of oxidative stress in zearalenone-mediated toxicity in Hep G2 cells: oxidative DNA damage, gluthatione depletion and stress proteins induction

Zearalenone (ZEN) is a fusarial mycotoxin with several adverse effects in laboratory and domestic animals including mainly estrogenicity. While most ZEN toxic effects have been quite well investigated, little is known regarding its mechanism of toxicity. Our previous investigations have shown the involvement of cytotoxicity, inhibition of macromolecules synthesis as well as genotoxicity. However, there are no available data regarding the involvement of the oxidative stress pathway in ZEN toxicity. In this context, the aim of this study was to find out whether ZEN induces oxidative cell damage. Using human hepatocytes Hep G2 cells, ZEN-induced stress response is monitored at several levels in these cells. ZEN mediated induction of oxidative DNA damage (comet assay using the repair enzymes), modulation of gluthatione (GSH), cytotoxicity (growth inhibition) and the oxidative stress responsive gene Hsp 70 and Hsp 90 were investigated with respect to concentration and time dependency. Hep G2 cells respond to ZEN exposure by loss of cell viability, induction of oxidative DNA damage, GSH depletion and Hsp 70 and Hsp 90 induction already at concentrations, which are not yet cytotoxic. The perturbation of the oxidative status was further confirmed by the significant reduction of the induced oxidative DNA damage as well as stress protein induction when cells were pre-treated with Vitamin E prior to exposure to ZEN. Our study clearly demonstrates that oxidative damage is likely to be evoked as one of the main pathway of ZEN toxicity. This oxidative damage may therefore be an initiating event and contribute, at least in part, to the mechanism of ZEN different genotoxic and cytotoxic effects.     

NOX4‐ and Nrf2‐mediated oxidative stress induced by silver nanoparticles in vascular endothelial cells

It has been widely reported that silver nanoparticles (AgNPs) induce oxidative stress in various cell lines. However, the mechanism for this effect and its consequences for cellular signaling are poorly understood. In this study, human umbilical vein endothelial cells (HUVECs) were used to assess the toxicity and investigate the associated molecular mechanisms caused by exposure to AgNPs. We demonstrated that AgNP exposure significantly and dose‐dependently decreased the cell viability, induced reactive oxygen species (ROS) generation and led to early apoptosis in HUVECs. Our findings showed that AgNPs induced excess ROS production that affected the signaling pathways by a mechanism that depended on activation of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity through upregulation of NADPH oxidase 4 (NOX4) protein expressions. Moreover, AgNPs could disrupt the inactivation of the nuclear factor erythroid 2‐related factor 2 (Nrf2)‐mediated antioxidant response, which is considered another important element for oxidative stress caused by AgNPs in HUVECs. The redox imbalance between NOX4 and Nrf2 was an important cause for the ROS overproduction that led to cell injury in HUVECs. The results provided insight into the mechanisms of oxidative stress induced by AgNPs in vascular endothelial cells.     

Assessment of thyroid endocrine system impairment and oxidative stress mediated by cobalt ferrite (CoFe2O4) nanoparticles in zebrafish larvae

Fascinating super paramagnetic uniqueness of iron oxide particles at nano‐scale level make them extremely useful in the state of the art therapies, equipments, and techniques. Cobalt ferrite (CoFe₂O₄) magnetic nanoparticles (MNPs) are extensively used in nano‐based medicine and electronics, results in extensive discharge and accumulation into the environment. However, very limited information is available for their endocrine disrupting potential in aquatic organisms. In this study, the thyroid endocrine disrupting ability of CoFe₂O₄ NPs in Zebrafish larvae for 168‐h post fertilization (hpf) was evaluated. The results showed the elevated amounts of T4 and T3 hormones by malformation of hypothalamus pituitary axis in zebrafish larvae. These elevated levels of whole body THs leads to delayed hatching, head and eye malformation, arrested development, and alterations in metabolism. The influence of THs disruption on ROS production and change in activities of catalase (CAT), mu‐glutathione s‐transferase (mu‐GST), and acid phosphatase (AP) were also studied. The production of significantly higher amounts of in vivo generation of ROS leads to membrane damage and oxidative stress. Presences of NPs and NPs agglomerates/aggregates were also the contributing factors in mechanical damaging the membranes and physiological structure of thyroid axis. The increased activities of CAT, mu‐GST, and AP confirmed the increased oxidative stress, possible DNA, and metabolic alterations, respectively. The excessive production of in vivo ROS leads to severe apoptosis in head, eye, and heart region confirming that malformation leads to malfunctioning of hypothalamus pituitary axis. ROS‐induced oxidative DNA damage by formation of 8‐OHdG DNA adducts elaborates the genotoxicity potential of CoFe₂O₄ NPs. This study will help us to better understand the risk and assessment of endocrine disrupting potential of nanoparticles. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 2068–2080, 2016.     

The role of oxidative stress in diazinon-induced tissues toxicity in Wistar and Norway rats

Diazinon (DZN) is an organophosphate pesticide widely used in agricultural to control insects and in veterinary medicine to control ectoparasites. This study investigated the induction of oxidative stress in the brain, heart, and spleen of Wistar and Norway rats treated with acute doses of DZN. Female Wistar and Norway rats were treated with 25, 50, 100, and 200?mg/kg of DZN by intraperitoneal injection. The animals were sacrificed 24?h after treatment, and tissues were isolated and analyzed. The result of this study shows that DZN at higher doses increased the level of malondialdehyde, superoxide dismutase and glutathione S-transferase activities and decreased glutathione (GSH) level, lactate dehydrogenase, and cholinesterase activities in the brain, heart, and spleen of both rat strains. At these concentrations, DZN toxicity also lead to a significant decrease in catalase (CAT) activity in all tissues of Wistar rat and brain of Norway rat, while it increased heart CAT activity in Norway rat. However, the alteration of these parameters was observed at lower doses of DZN in Wistar rat. These results suggest that DZN at higher doses induces the production of free radicals and oxidative stress in rat tissues and strains by alteration of antioxidant enzyme activity, depletion of GSH, and increasing lipid peroxidation. Induction of oxidative stress in DZN-treated rats is in the order of brain > heart > spleen. Wistar rats appear to be more sensitive to the effects of DZN on oxidative stress induction compared to Norway rat.     

Therapeutic effects of rocket seeds (Eruca sativa L.) against testicular toxicity and oxidative stress caused by silver nanoparticles injection in rats

Silver nanoparticles (AgNPs), one of the most well‐known nanomaterials, are regularly utilized in everyday consumer products. The present study aimed to investigate the testicular toxicity and oxidative stress by AgNPs and the therapeutic role of the rocket seeds (Eruca sativa) in treatments. Forty male Wistar rats were divided into four equivalent groups (group 1, control; group 2, rocket seeds extract [RS]; group 3, AgNPs; group 4, AgNPs+RS). Our results showed that AgNPs induced a significant decrease in serum total testosterone, FSH (follicle‐animating hormone), prolactin and LH (luteinizing hormone), testicular glutathione (GSH), superoxide dismutase (SOD), and glutathione S‐transferase (GST). In contrast, a significant increase in testicular DNA, injury, testicular thiobarbituric acid, proliferating cell nuclear antigen, and tumor necrosis factor‐α (TNFα) expressions after treatments with AgNPs when contrasted with the control group. Treatments of AgNPs with rocket seeds extract (AgNPs+RS) improved testicular functions and structure. Rocket seeds extract might offer benefits against the toxic nature of AgNPs.     

Cisplatin-induced nephrotoxicity is associated with oxidative stress, redox state unbalance, impairment of energetic metabolism and apoptosis in rat kidney mitochondria

The clinical use of cisplatin (cis-diamminedichloroplatinum II) is highly limited by its nephrotoxicity. The precise mechanisms involved in cisplatin-induced mitochondrial dysfunction in kidney have not been completely clarified. Therefore, we investigated in vivo the effects of cisplatin on mitochondrial bioenergetics, redox state, and oxidative stress as well as the occurrence of cell death by apoptosis in cisplatin-treated rat kidney. Adult male Wistar rats weighing 200–220 g were divided into two groups. The control group (n = 8) was treated only with an intraperitoneal (i.p.) injection of saline solution (1 ml per 100 g body weight), and the cisplatin group (n = 8) was given a single injection of cisplatin (10 mg/kg body weight, i.p.). Animals were sacrificed 72 h after the treatment. The cisplatin group presented acute renal failure characterized by increased plasmatic creatinine and urea levels. Mitochondrial dysfunction was evidenced by the decline in membrane electrochemical potential and the substantial decrease in mitochondrial calcium uptake. The mitochondrial antioxidant defense system was depleted, as shown by decreased GSH and NADPH levels, GSH/GSSG ratio, and increased GSSG level. Moreover, cisplatin induced oxidative damage to mitochondrial lipids, including cardiolipin, and oxidation of mitocondrial proteins, as demonstrated by the significant decrease of sulfhydryl protein concentrations and increased levels of carbonylated proteins. Additionally, aconitase activity, which is essential for mitochondrial function, was also found to be lower in the cisplatin group. Renal cell death via apoptosis was evidenced by the increased caspase-3 activity. Results show the central role of mitochondria and the intensification of apoptosis in cisplatin-induced acute renal failure, highlighting a number of steps that might be targeted to minimize cisplatin-induced nephrotoxicity.     

The use of liver spheroids as an in vitro model for studying induction of the stress response as a marker of chemical toxicity.

Stress protein induction has been advocated as a sensitive indicator of compound-induced toxicity. In monolayer cultures of primary hepatocytes, however, the two stress proteins, Hsp25 and Hsp72/3 are up-regulated, probably due to the effect of the isolation procedure and adaptation of the cells to the culture conditions. The aim of the current studies was to determine whether liver spheroids would provide an improved experimental model for the study of heat shock protein induction in vitro. Primary rat hepatocytes were cultured as liver spheroids and the expression of Hsp25 and Hsp72/3 measured along with the levels of ATP, GSH and albumin secretion. Hsp72/3 was initially increased in spheroid culture but returned to in vivo levels after 3 days of culture. Hsp25 was maintained at in vivo levels until day 6 of culture, after which levels increased slightly. The effects of the two hepatotoxins, hydrazine and cadmium chloride (CdCl(2)), were therefore measured on day 6 of spheroid culture. CdCl(2) had no effect on Hsp25 but increased Hsp72/3 at concentrations that affected other biochemical parameters. Hydrazine caused a rapid reduction in ATP levels and albumin secretion, but did not affect Hsp72/3. Hsp25 was slightly induced by hydrazine at later sampling times at concentrations, however, that affected other biochemical parameters. It can be concluded that liver spheroids provide a model for studying stress protein expression. However, the increase in stress proteins appears to be a relatively insensitive parameter compared to other more conventionally used toxicity endpoints and the response appears to vary with individual toxins under study.     

Decrease in Fungizone toxicity induced by the use of Lipofundin as a dilutent: an in vitro study

The aim of this work was to develop an in vitro experimental protocol for the evaluation of toxicity and efficacy of an amphotericin B (AmB) micelle system, Fungizone, which was previously diluted with a lipid based emulsion for parenteral use, named Lipofundin LCT/MCT-20%. Two cell models were used for the experiments: Red Blood Cells (RBC) from human donnors and Candida tropicalis (Ct). These models were used to perform the toxicity and activity of the Fungizone/ Lipofundin admixture (AmB-LP) and the Fungizone (AmB-M) alone. While potassium (K+) and hemoglobin leakage from RBC were the parameters used to evaluate the acute and chronic toxicity, respectively, the efficacy of AmB-LP and AmB-M were assessed by K+ leakage or cell survival rate (CSR) from Ct. The results show that the toxicity of AmB-LP to RBC was concentration dependent concerning the K+ leakage; while at high concentrations, 5 and 50 mg x mL(-1), the leakage was 50.91 +/- 2.09% and 95.71 +/- 0.64%, respectively, at a concentration of 0.5 mg x mL(-1) this value was 17.16 +/- 1.57% and the value tended to zero for the lowest concentration studied, 0.05 mg x mL(-1). Surprisingly, AmB-LP induced very low hemoglobin leakage for all concentrations studied. At the highest concentration, 50 mg x mL(-1), this value was around 3%. When the cell model was Ct, the results changed completely. Not only high concentrations of AmB-LP, but also lower ones were able to induce a K+ permeability of around 100%. The CSR parameter showed an inverse correlation with the concentration; high values, between 50 and 5 mg x mL(-1), resulted in a CSR of around 8%. On the other hand, for lower concentration values, 0.05 and 0.5 mg x mL(-1), this one was around 80%. The same profile of activity against Ct was found for AmB-M. Only a small variation was found for the K+ leakage at 0.05 mg x mL(-1) that presented a value of 96.99 +/- 2.53%. However, AmB-M seemed to be much more toxic than AmB-LP. Its induction of hemoglobin leakage started at 0.5 mg x mL(-1) and reached the 100% at 5 mg x mL(-1). K+ leakage results were worse. The intermediate concentrations of study, 0.5 and 5 mg x mL(-1), presented a significant increase compared to AmB-LP. All together these results reveal that the activity of AmB is not only concentration dependent, but also depends on the drug carrier in which this compound was inserted. The AmB-LP preparation showed the same efficacy as AmB-M, but with a low toxicity. Therefore, AmB-LP presented a higher therapeutic index that permits the administration of high concentration of AmB without revealing side effects. However, the simple mixture of two complex pharmaceutical entities, as micelles and emulsions, should be analyzed carefully to assure that physicochemical stability is not reduced and thereby cause a different biodistribution in vivo.