Effect of Zinc Oxide nanoparticles on cellular oxidative stress and antioxidant defense mechanisms in mouse liver

Zinc oxide nanoparticles (ZnO₂), a common ingredient of cosmetics has a huge variety of applications. Previous studies reported oxidative stress mediated toxicity of ZnO₂ nanoparticles on various mammalian cell lines. Although zinc (Zn) is an essential mineral at higher concentrations this metal is toxic. The present study focused on size determination by monitoring changes in activities of antioxidant defense mechanism in response to oxidative stress induced by ZnO₂ nanoparticles using mouse liver tissue homogenates. The study also investigated effects of oxidative stress induced DNA damage by determining formation of 8-OHdG in mouse liver homogenate. A cytotoxicity assay was also carried out in L929 cells to determine cell viability. The results of the study indicated that 50μg/ml of ZnO₂ nanoparticles induced 50% cell death. Alterations in antioxidant parameters and 8-OHdG were also noted. Data showed that there was a concentration-dependent fall in cell viability, decrease antioxidant enzyme levels and increase formation of DNA adduct (8-OHdG) when mouse liver tissue homogenate were exposed to ZnO₂ nanoparticles.     

邻苯二甲酸酯类增塑剂的体外细胞毒性评价

邻苯二甲酸酯(Phthalate esters, PAEs)是环境介质中的一类典型的有机污染物。已有研究表明,PAEs具有明显的内分泌干扰毒性,并会对动物和人体的生殖发育与神经系统造成损伤。体外细胞评价模型因具有高通量、测试周期短、成本低和毒性效应易于探明等技术优点,被广泛应用到PAEs毒理学效应的研究中。本文从内分泌干扰毒性、胚胎发育毒性、神经毒性、免疫毒性、遗传毒性以及致癌作用等方面,对PAEs的一些体外细胞毒性评价模型进行了分类和总结,并对其相应的研究进展进行了综述。本文旨在为体外细胞毒性评价模型的有效利用提供借鉴,并对PAEs毒性作用机制的深入研究提供思路和依据。     

人工纳米材料对斑马鱼生态毒理效应研究进展

随着纳米技术的快速发展,人工纳米材料在光电、生物医药、化妆品等诸多领域得到了广泛应用。人工纳米材料在生产、使用和废弃处理等过程中,不可避免地通过水体、土壤、大气等进入环境,其对环境产生的生态效应逐渐引起国内外的广泛关注。斑马鱼(Danio rerio)作为一种重要的脊椎模式生物,在环境毒理学研究中应用广泛,可以作为检测人工纳米材料生态毒理效应的一种重要工具。本文介绍了人工纳米材料对水生态环境的影响及斑马鱼在生态毒理学研究中的优势,总结了其对斑马鱼的毒性效应,主要包括急性毒性和对个体发育的影响、对组织细胞及基因表达的影响,分析了人工纳米材料对斑马鱼的毒性机制,以期为人工纳米材料毒理学研究提供基础信息。     

人工纳米材料对贝类生态毒理效应的研究进展

纳米技术已成为21世纪发展最迅猛的技术领域之一。纳米材料因其具备新异的物理、化学特性而广泛应用于各种领域,包括农业,电子工业,生物医学,制造业,医药品和化妆品等,因此纳米颗粒不可避免会释放到水环境中。贝类由于其具有分布广,处于食物链中的关键位置,滤食食性,对重金属及污染物有较强的生物累积能力,且很多贝类具有养殖和商业价值,因而纳米颗粒对贝类的生态毒性效应备受关注。本文通过对已有相关研究成果进行归纳分析,重点阐述了3方面的内容:1)人工纳米材料在水环境中的行为;2)贝类作为水生污染监测指示生物的重要意义;3)人工纳米材料对贝类的毒性效应,主要包括贝类对纳米颗粒摄取、积累和转移,并从组织细胞水平,分子和基因水平,胚胎发育和个体生长水平等阐述了纳米材料对贝类的毒性效应。     

In vitro cytotoxicity of multi-wall carbon nanotubes on human cell lines

The aim of this study was to evaluate the in vitro toxicity of two multi-wall carbon nanotubes on four different cell lines: human alveolar epithelial (A549) cells, hepatocytes (Hep 3B cells), human embryonic kidney cells, and intestinal (P407 cells) cells. The adverse effects of carbon nanoparticles were analyzed after 24 h incubation with different cell lines using the trypan blue dye exclusion method. Incubation of carbon nanotubes with different cells produced a concentration-dependent inhibition of growth of the cells. The TC₅₀ or IC₅₀ values (toxic concentration 50, i.e., concentration of particles inducing 50% cell mortality) of two nanoparticles were (1) found to be in the range 23.5–30.5 µg mL^?1, and (2) less than that of quartz (known toxic agent, 28.8–66.9 µg mL^?1), indicating the greater cytotoxic effect of carbon nanoparticles than quartz particles.     

Determination of F2-isoprostanes in cultured human lung epithelial cells after exposure to metal oxide and silica nanoparticles by high-performance liquid chromatography/tandem mass spectrometry

The environmental impact of nanotechnology has caused a great concern. Many in vitro studies showed that many types of nanoparticles were cytotoxic. However, whether these nanoparticles caused cell membrane damage was not well studied. F₂-isoprostanes are specific products of arachidonic acid peroxidation by nonenzymatic reactive oxygen species and are considered as reliable biomarkers of oxidative stress and lipid peroxidation. In this article, we investigated the cytotoxicity of different nanoparticles and the degree of cellular membrane damage by using F₂-isoprostanes as biomarkers after exposure to nanoparticles. The human lung epithelial cell line A549 was exposed to four silica and metal oxide nanoparticles: SiO₂ (15 nm), CeO₂ (20 nm), Fe₂O₃ (30 nm), and ZnO (70 nm). The levels of F₂-isoprostanes were determined by using high-performance liquid chromatography/mass spectrometry. The F₂-isoprostanes’ peak was identified by retention time and molecular ion m/z at 353. Oasis HLB cartridge was used to extract F₂-isoprostanes from cell medium. The results showed that SiO₂, CeO₂, and ZnO nanoparticles increased F₂-isoprostanes levels significantly in A549 cells. Fe₂O₃ nanoparticle also increased F₂-isoprostanes level, but was not significant. This implied that SiO₂, CeO₂, ZnO, and Fe₂O₃ nanoparticles can cause cell membrane damage due to the lipid peroxidation. To the best of our knowledge, this is the first report on the investigation of effects of cellular exposure to metal oxide and silica nanoparticles on the cellular F₂-isoprostanes levels.     

Entomotoxic effect of silicon dioxide nanoparticles on Plutella xylostella (L.) (Lepidoptera: Plutellidae) under laboratory conditions

The use of higher dosage and repeated applications of conventional pesticides have led to the rapid development of insect resistance to pesticide and adverse effects on human health and environment. Accordingly, researchers are prompted to identify an alternative entomotoxic agent for crop protection. Nanocides are being considered as alternatives to conventional insecticides because they are expected to lessen the application rate and reduce the chances of resistance development in pests. In this study, we evaluated the entomotoxic effects of nanosilica on larvae of Plutella xylostella, in a laboratory by using dust spray, larva dipping, leaf dipping, and solution spray methods. Dust treatment showed a more highly significant effect than the other three treatments. The mortality percentage increased up to 58% and 85% at 24 and 72 h after treatment, respectively, when nanosilica was applied at a rate of 1 mg cm^?2. In all four bioassays, mortality rate increased with both increased time after nanosilica exposure and increased concentration. Light microscopy and scanning electron microscopy images showed that larval death was due to desiccation, body wall abrasion, and spiracle blockage. These results suggested that nanosilica can be an alternative to conventional pesticides if dust formulation would be properly used.     

Biodegradation and phytotoxicity assessment of phenanthrene by biosurfactant-producing Bacillus pumilus 1529 bacteria

ABSTRACT

Phenanthrene is a toxic and mutagenic pollutant that can cause severe environmental and human health issues. The bioremediation of these polyaromatic hydrocarbons (PAHs) is possible with a biosurfactant by enhancing hydrophobicity. In this study, the production of a biosurfactant by Bacillus pumilus 1529 and its effects on the phenanthrene biodegradation pathway were examined. Biosurfactant production was determined using hemolytic activity, emulsification index, and surface tension. For phenanthrene metabolite detection, samples at 0, 7, 14, and 21 incubation days were analysed by gas chromatography-mass (GC-mass) spectrometry. The results showed that Bacillus pumilus 1529 can reduce surface tension to 22.83?±?1.1?mN?m^?1. Furthermore, the GC-mass spectrometry analysis showed that 1-hydroxy-2-naphthoic acid, benzaldehyde, o-phthalic acid, and phenylacetic acid were notable phenanthrene metabolites produced during phenanthrene biodegradation. Biodegraded phenanthrene and its metabolites have a less toxic effect on the germination of safflower seeds than non-biodegraded phenanthrene. The IC50 of phenanthrene on seed germination after biodegradation was increased to approximately 113?mg?L^?1. In general, biodegradation aided by biosurfactant producing bacteria contributed to turning the toxic phenanthrene into less harmful metabolites with lower phytotoxicity effects, indicating that its application in the bioremediation of PAHs is promising.     

海洋酸化与重金属、有机污染物和人工纳米颗粒的联合毒性效应研究进展

由于大量人类活动的影响,大气CO_2浓度持续增加,其中约1/3被海洋吸收,导致表层海水pH值降低和碳酸盐平衡体系波动,即"海洋酸化"现象。污染物的海洋环境效应一直是全球环境科学领域研究的热点。在实际环境中,海洋酸化往往与污染物共同存在并作用于海洋生态系统,且海洋酸化极有可能改变污染物的海洋环境行为从而影响其毒性效应。但现有研究大多针对海洋酸化或者污染物单独作用下的毒性效应展开,对海洋酸化与污染物的联合毒性效应的研究不足、亟待加强。为此,综述了近年来海洋酸化与典型污染物(重金属、有机污染物)及新型污染物(人工纳米颗粒)的相关文献,重点阐述了海洋酸化对污染物环境行为的影响和海洋酸化与污染物对海洋生物的联合毒性效应,指出当前的研究不足,并对未来的研究方向进行了展望。     

4种典型纳米材料对小鼠胚胎成纤维细胞毒性的初步研究

为探讨不同种类纳米材料对原代培养小鼠胚胎成纤维细胞(Mouse embryo fibroblasts,MEF)的毒性效应及作用机制,选择4种典型的纳米材料(纳米碳、单壁碳纳米管、纳米氧化锌、纳米二氧化硅)制备颗粒悬液,设立5个剂量组(5、10、20、50、100μg·mL-1)对BALB/c小鼠MEF细胞进行24、48、72h染毒培养,利用细胞形态学观察和噻唑蓝实验(MTT比色法)检测上述4种纳米材料对MEF细胞活性的影响,同时,测定染毒24h后细胞培养液上清中乳酸脱氢酶(LDH)活性以探讨纳米颗粒对细胞膜完整性的影响.结果显示:1)4种纳米材料均能明显影响MEF细胞的生长形态.染毒24h后,MEF细胞发生不同程度的回缩变形,细胞间隙增大,排列稀疏,胞内颗粒物增多,细胞透明度下降.2)纳米碳、纳米氧化锌、纳米二氧化硅对MEF细胞增殖的抑制作用和对细胞膜完整性的损伤作用均随染毒剂量的升高而增强,具有明显的剂量-效应关系,其半数致死浓度(24h-IC50)分别为21.85、21.94、461.10μg·mL-1;碳纳米管组的剂量-效应之间不呈对数线性关系,未能得出其24h-IC50.3)在不同染毒剂量水平上,4种纳米材料的毒性对比差异显著:低剂量水平上纳米碳与碳纳米管的毒性强于纳米氧化锌和纳米二氧化硅,随着剂量的升高纳米氧化锌的细胞毒性升高最为显著.结果提示,纳米材料能够对MEF细胞造成毒性损伤,破坏细胞膜的完整性可能只是作用途径之一;纳米材料的毒性可能受粒径、形状、化学组成等许多因素的影响.     

Nanoparticles influence on expression of cell cycle related genes in Drosophila: a microarray-based toxicogenomics study

Relatively little is known regarding the interaction of nanoscale objects with dynamic complex biological systems. Microarray-based toxicogenomics studies may serve as a suitable technique to explore the genome wide effects of nanoparticles on any organism through a single experiment. The influence of nanoporous aluminosilicate nanoparticles (NP), citrate-capped gold NP, lipophilic silica NP, BSA-capped silver NP, and lipophilic zinc oxide NP were studied on 75 cell cycle-related genes of adult Drosophila melanogaster. Microarray experiments were conducted after the flies were fed with NP-mixed media for 15 days. Data showed that silver, zinc oxide, and alumino silicate NP predominantly perturbed cell cycle genes, whereas gold and silica NP exerted the least influence on these genes.     

磺胺与金属氧化物纳米颗粒对发光菌的急性联合毒性及其机制初探

磺胺与金属氧化物纳米颗粒同作为抗菌剂对环境与人体健康皆有危害。为探究其对细菌的毒性作用,测定了4种磺胺,包括磺胺氯哒嗪(SCP)、磺胺吡啶(SPY)、磺胺甲基异恶唑(SMZ)、磺胺嘧啶(SD),与3种金属氧化物纳米颗粒,纳米ZnO(n-ZnO)、纳米CuO(n-CuO)、纳米Cr_2O_3(n-Cr_2O_3)对发光菌(Vibriofischeri)的单一毒性及二元急性联合毒性。结果表明,SCP对V.fischeri的单一毒性明显大于其他3种磺胺;n-ZnO的单一毒性远大于n-CuO和n-Cr_2O_3;磺胺与金属氧化物纳米颗粒的二元急性联合毒性效应表现为拮抗、相加和协同,协同居多,说明金属氧化物纳米颗粒增加了磺胺的生物毒性,两者在环境中的共存带来了更大的环境生态风险。     

纳米银的体内毒性及毒作用机制研究进展

很多研究表明纳米银对机体的消化系统、呼吸系统、生殖系统等多个系统均会产生毒作用，且其毒作用受到多种因素的影响。目前关于纳米银的毒作用机制尚未明确，研究发现纳米银的毒作用机制可能与银离子释放，活性氧自由基产生，氧化应激的发生，炎症反应等有关，最新研究指出纳米银的毒性作用还可能与内质网应激和自噬有关，本文将就纳米银的体内毒性及毒作用机制进行综述。     

纳米银的体内毒性及毒作用机制研究进展

很多研究表明纳米银对机体的消化系统、呼吸系统、生殖系统等多个系统均会产生毒作用,且其毒作用受到多种因素的影响。目前关于纳米银的毒作用机制尚未明确,研究发现纳米银的毒作用机制可能与银离子释放、活性氧自由基产生、氧化应激的发生、炎症反应等有关,最新研究指出纳米银的毒性作用还可能与内质网应激和自噬有关,本文将就纳米银的体内毒性及毒作用机制进行了综述。     

ZnO纳米粒子通过线粒体通路抑制小鼠光感受器细胞Na~+/K~+-ATP酶表达和活性的作用研究

氧化锌(ZnO)纳米粒子已被发现具有生物毒性,氧化应激被认为是最重要的因素之一。前期实验证实,ZnO纳米粒子能显著减少锰超氧化物歧化酶(Mn SOD)蛋白的表达,降低Mn SOD活性。本文通过检测乳酸脱氢酶(LDH)释放、线粒体活性氧(ROS)水平和膜电位(Δφm)、延迟整流钾电流变化和Na~+/K~+-ATP酶的表达及活性等变化,检测ZnO纳米粒子对小鼠光感受器细胞的细胞毒作用。结果表明,ZnO纳米粒子可显著增强小鼠光感受器细胞中LDH的释放、增加线粒体内ROS水平并下调Δφm、阻断延迟整流钾电流,同时降低Na~+/K~+-ATP酶的表达及活性,从而对小鼠视网膜光感受器细胞产生细胞毒作用,提示ZnO纳米粒子可通过线粒体通路引起氧化应激,从而抑制小鼠光感受器细胞Na~+/K~+-ATP酶表达和活性,产生细胞毒性,导致细胞死亡。本文的研究结果有助于理解ZnO纳米粒子引起细胞毒性的作用机理。     

Interactive effects of pH,temperature and light during ammonia toxicity events in Elodea canadensis

Increased nutrient loading threatens many freshwater ecosystems. Elevated temperatures may increase the sensitivity to eutrophication in these ecosystems. Higher concentrations of possibly toxic reduced nitrogen (NH _x ) in the water layer may be expected as production and anaerobic breakdown rates will increase. Apart from temperature, NH _x and its effect on aquatic macrophytes will also depend on pH and light. We examined the interactive effects of NH _x , temperature, pH and light on Elodea canadensis in a full factorial laboratory experiment. Results demonstrate that high NH _x and high temperature together with low pH and low light causes the strongest toxic effects regarding relative growth rate and leaf tissue mortality. The adverse effects of high temperature and low light are most likely caused by increased metabolic activity and reduced photosynthesis, respectively. Severe toxicity at low pH compared to high pH can be ascribed to the ability of E. canadensis to induce a specialised bicarbonate-concentrating pathway at high pH, resulting in much higher carbon availability, needed for detoxification of NH _x . We conclude that NH _x toxicity will become more pronounced under higher temperatures, but that effects on aquatic macrophytes will strongly depend on pH of the water layer and specific metabolic adaptations of different species.     

Occupational exposure to airborne aromatic amines in rubber manufacturing: Determination by gas chromatography‐mass spectrometry

Aromatic amines (AAs) are used in a variety of chemical industries and consequently they are the object of great attention in occupational hygiene owing to the carcinogenic effects that many of them have shown. This work outlines a procedure for the determination of occupational exposure to airborne AAs in the rubber industry and the application of this method in a tyre manufacturing plant using p‐phenylenediamines as antiozonants. Samples were collected on a glass fibre filter followed by a silica gel tube and analyzed by GC‐MS/SIM using a capillary column coated with methyl silicone. p‐Phenylendiamines and other AAs probably formed as thermodegradation products were found in concentrations of up to 10 μg/m³ during rubber vulcanization.     

Carbon nanotubes and Cu–Zn nanoparticles synthesis using hyperaccumulator plants

This article reports a novel way to synthesize carbon nanotubes and Cu/ZnO nanoparticles using metal hyperaccumulator plants. Metal hyperaccumulator plants are traditionally used for phytoremediation to clean soil polluted by toxic metals. However, the transfer of toxic metals in plant shoots and leaves is an environmental issue because animals and other living organisms feeding on plants will transfer the metals to the ecosystem. Therefore, we suggest that hyperaccumulator plants could be used to synthesize nanoparticles. Here, Brassica juncea L., a Cu-hyperaccumulator plant, was collected around a copper mine and used as a raw chemical to produce carbon nanotubes and Cu/ZnO nanoparticles. The chlorophyll in shoots of B. juncea plants was ethanol extracted to yield chlorophyllin. Cu and Zn were extracted by HNO₃ to form Cu/Zn(NO₃)₂. The chlorophyllin reacted with Cu/Zn(NO₃)₂ to form Cu/Zn chlorophyllin. Cu/ZnO nanoparticles were synthesized by direct precipitation of Cu/Zn chlorophyllin with NaOH and ethanol. The vascular bundles in B. juncea plants, which have been purified and carbonized by HNO₃, were rapidly heated to about 400°C and then they were cooled to room temperature to obtain carbon nanotubes. Results indicate that the outer diameter of carbon nanotubes was around 80 nm. Cu/ZnO nanoparticles have a Cu_0.05Zn_0.95O composition, and had a diameter of about 97 nm. Our study not only inspires the search for a new strategy on the synthesis of nanostructure from renewable natural products, but also breaks through the traditional and limited ideas about the reuse of metals by hyperaccumulator plants.     

Fate of domoic acid ingested by the copepod <Emphasis Type="Italic">Acartia clausi</Emphasis>

Two important issues in the studies of harmful algae include ecological role of the toxic compounds and their fate through the food web. The aims of this study were to determine whether the production of domoic acid is a strategy evolved to avoid predation and the role of copepods in the fate of this toxic compound through the food web. The copepod Acartia clausi was fed with single and mixed cultures of the toxic diatom Pseudo-nitzschia multiseries and the non-toxic diatom Pseudo-nitzschia delicatissima. Ingestion rate as a function of diatom abundance was the same for the toxic and non-toxic Pseudo-nitzschia species, indicating no selective feeding behaviour against P. multiseries. The toxins ingested by the copepods did not affect mortality, feeding behaviour, egg production and egg hatching of the copepods. Copepods assimilated the 4.8% of the total domoic acid ingested. Although the amount of toxins daily detoxificated by the copepods was 63.6%, the copepods accumulated domoic acid in their tissues. We conclude that domoic acid is not toxic for copepods and, probably for this reason, this toxin does not act as feeding deterrent for copepods. However, even though the production of domoic acid has apparently not evolved to deter predation, copepods may play an important role on the fate of this toxic compound through the marine food web.     

Nanosilica exerts cytotoxicity and apoptotic response via oxidative stress in mouse embryonic fibroblasts

Nanoscale silica is an important industrial material and extensively used in medicines. The objective of this study was to determine potential cytotoxicity and genotoxic effects attributed to nanosilica exposure in mouse embryonic fibroblasts (L929) cells. Nanosilica produced mild cytotoxicity in L929 cells. Results showed that nanosilica increased thiobarbituric acid reactive substance levels and enhanced superoxide dismutase activity but decreased levels of glutathione. This was accompanied by a concomitant generation of reactive oxygen species, loss of mitochondrial membrane potential, and activation of caspase-3 activity. In addition, in the single-cell gel test, nanosilica (50–300 μg/ml) at two treatment times 24 and 48 hr produced concentration- and time-dependent increase of DNA damage. Therefore, the obtained results indicate that nanosilica may induce genotoxic effects in cultured L929 cells associated with induction of oxidative stress.