Zinc oxide nanoparticles impacts: cytotoxicity,genotoxicity, developmental toxicity,and neurotoxicity

Zinc oxide (ZnO) is the most commonly used nanoparticles among different nanoparticles. Its applications ranged from personal care products, sensors, antibacterial creams, and biomedical applications. The broad range of applications raises concern in regards to their potential toxicity. Therefore, it is required to understand their toxicity mechanism and pattern on various levels. The primary aim of this review is to summarize the cytotoxicity, genotoxicity, neurotoxicity, and developmental toxicity of ZnO nanoparticles in various kinds of cells in vitro and in vivo. Literatures available on ZnO nanoparticles toxicity suggest that dissolution, organism dependent cellular uptake, generation of reactive oxygen species (ROS), and induced inflammatory responses seem to be common factors which govern the toxicity of ZnO nanoparticles.     

Cytotoxicity of ethanol in primary cultures of rat midbrain neurons

Primary cultures of midbrain neurons were obtained from 15-day-old rat fetuses. Neuron cultures were exposed to ethanol (27 mM, 43 mM and 120 mM) for 24 h and evaluated by light microscopy, a viability measure, and protein content. Ethanol concentrations of 43 and 120 mM appeared to affect the cultures both in terms of cell viability and protein. This effect was independent of any osmotic effect, when sucrose was run as a control. We conclude that primary cultures of midbrain neurons are sensitive to relatively low concentrations of ethanol, compared to cell culture preparations used by other investigators.     

Fluorescent estimation on cytotoxicity of methylmercury in dissociated rat cerebellar neurons: its comparison with ionomycin

To study the cellular basis of the neurotoxicity of methylmercury, the effects of methylmercury on dissociated rat cerebellar neurons were examined using a flow cytometer, a confocal laser microscope and three fluorescent dyes, fluo-3 for monitoring the changes in intracellular Ca²⁺ concentration ([Ca²⁺]_i) and for detecting live neurons, ethidium for assessing the neurons that are dead or have compromised membranes, and 5-chloromethylfluorescein (CMF) for estimating the cellular content of nonprotein thiols. Methylmercury at concentrations of 1 μM or greater increased the [Ca²⁺]_i of almost all neurons. Prolonged exposure to methylmercury (3 and 10 μM) produced a further increase in [Ca²⁺]_i, in association with compromising membranes in some neurons. Thereafter, methylmercury induced blebs on membranes of some neurons with increased [Ca²⁺]_i. Methylmercury at concentrations of 0.3 μM or greater dose-dependently decreased the cellular content of nonprotein thiols. Results suggest that methylmercury may induce the loss of membrane integrity through destabilized Ca²⁺ homeostasis and oxidative stress in mammalian brain neurons.     

Neurotoxicity of metal‐containing nanoparticles and implications in glial cells

With the development of nanotechnology, metal‐containing nanoparticles are used widely in the diagnosis, monitoring and treatment of central nervous system (CNS) diseases. The neurotoxicity of these nanoparticles has drawn attention. Glial cells (particularly microglial cells and astrocytes) have important functions in the CNS. Neural disorders are related to functional/histologic damage to glial cells. Dysfunctions of microglial cells or astrocytes injure the brain, and cause the neurodegeneration seen in Alzheimer's disease and Parkinson's disease. We have summarized the route of access of metal‐containing nanoparticles to the CNS, as well as their neurotoxicity and potential molecular mechanisms involved in glial cells. Metal‐containing nanoparticles cross or bypass the blood‐brain barrier, access the CNS and cause neurotoxicity. The potential mechanisms are related to inflammation, oxidative stress, DNA and/or mitochondrial damage and cell death, all of which are mediated by microglial cell activation, inflammatory factor release, generation of reactive oxygen species, apoptosis and/or autophagy in glial cells. Moreover, these processes increase the burden of the CNS and even accelerate the occurrence or development of neurodegenerative diseases. Some important signaling pathways involved in the mechanism of neurotoxicity in glial cells caused by nanoparticles are also discussed.     

Impact of silver nanoparticles on human cells: Effect of particle size

Abstract

This work investigated the cytotoxicities of three silver nanoparticles (SNPs) SNP-5, SNP-20 and SNP-50 with different sizes (～ 5 nm, ～ 20 nm and ～ 50 nm) using four human cell models (A549, SGC-7901, HepG2 and MCF-7). Endpoints included cell morphology, cell viability, cellular membrane integrity, oxidative stress and cell cycle progression. Observable deleterious effects on the cell morphologies and membrane integrity were induced by SNP-5 and SNP-20. SNPs elevated the ROS levels in cells and arrested the cells at S phase. Apoptosis occurred for 4–9% of the exposed cells. All these cellular responses as well as EC50 values were found to be size-dependent for the tested SNPs. Ultrastructural observations confirmed the presence of SNPs inside cells. Elemental analysis of silver in cells by ICP-MS showed that smaller nanoparticles enter cells more easily than larger ones, which may be the cause of higher toxic effects. The findings may assist in the design of SNP applications and provide insights into their toxicity.     

紫杉醇聚氰基丙烯酸正丁酯纳米粒对人卵巢癌细胞的毒性

目的:评价制备紫杉醇聚氰基丙烯酸正丁酯纳米粒(PTX-PBCA-NPs)的原料的生物安全性以及PTX-PBCA-NPs的细胞毒性。方法:采用四噻唑蓝法(MTT法)和检测乳酸脱氢酶(LDH)活性的方法考察空白PBCA-NPs及其聚合的原料、PTX-PBCA-NPs对L-02人正常肝细胞、卵巢癌敏感株(A2780)和卵巢癌耐紫杉醇肿瘤细胞株(A2780/T)的细胞毒性。结果:制备的空白PBCA-NPs只有在大于608 ng·mL-1时,对于L-02细胞具有明显的毒性(P<0.05);在质量浓度304～608 ng·mL-1,空白PBCA-NPs对A2780和A2780/T细胞有明显毒性(P<0.05)。与同一浓度PTX溶液比较,PTX-PBCA-NPs对A2780和A2780/T细胞的毒性作用明显(P<0.05)。结论:空白PBCA-NPs有一定的生物安全性,PTX-PBCA-NPs在对卵巢癌肿瘤细胞有一定的杀伤能力。     

Health hazards of nanoparticles: understanding the toxicity mechanism of nanosized ZnO in cosmetic products

In recent years, nanoparticles are being used extensively in personal healthcare products such as cosmetics, sunscreens, soaps, and shampoos. Particularly, metal oxide nanoparticles are gaining competence as key industrial constituents, progressing toward a remarkable rise in their applications. Zinc oxide and titanium oxide nanoparticles are the most commonly employed metal oxide nanoparticles in sunscreens, ointments, foot care, and over the counter topical products. Dermal exposure to these metal oxides predominantly occurs through explicit use of cosmetic products and airway exposure to nanoparticle dusts is primarily mediated via occupational exposure. There is a compelling need to understand the toxicity effects of nanoparticles which can easily enter the cells and induce oxidative stress. Consequently, these products have become a direct source of pollution in the environment and thereby greatly impact our ecosystem. A complete understanding of the toxicity mechanism of nano-ZnO is intended to resolve whether and to what extent such nanoparticles may pose a threat to the environment and to human beings. In this review article, we have discussed the characteristics of metal oxide nanoparticles and its applications in the cosmetic industry. We have also highlighted about their toxicity effects and their impact on human health.     

Evaluation of the toxicity of food additive silica nanoparticles on gastrointestinal cells

Silica nanoparticles (NPs) have been widely used in food products as an additive; however, their toxicity and safety to the human body and the environment still remain unclear. As a food additive, silica NPs firstly enter the human gastrointestinal tract along with food, thus their gastrointestinal toxicity deserves thorough study. Herein, we evaluated the toxicity of food additive silica NPs to cells originating from the gastrointestinal tract. Four silica NP samples were introduced to human gastric epithelial cell GES‐1 and colorectal adenocarcinoma cell Caco‐2 to investigate the effect of silica sample, exposure dose and exposure period on the morphology, viability and membrane integrity of cells. The cell uptake, cellular reactive oxygen species (ROS) level, cell cycle and apoptosis were determined to reveal the toxicity mechanism. The results indicate that all four silica NPs are safe for both GES‐1 and Caco‐2 cells after 24‐h exposure at a concentration lower than 100 µg ml^–1. At a higher concentration and longer exposure period, silica NPs do not induce the apoptosis/necrosis of cells, but arrest cell cycle and inhibit the cell growth. Notably, silica NPs do not pass through the Caco‐2 cell monolayer after 4‐h contact, indicating the low potential of silica NPs to cross the gastrointestinal tract in vivo. Our findings indicate that silica NPs could be used as a safe food additive, but more investigations, such as long‐term in vivo exposure, are necessary in future studies. Copyright © 2013 John Wiley & Sons, Ltd.     

Species-specific toxicity of copper nanoparticles among mammalian and piscine cell lines

The four copper nanoparticles (CuNPs) with the size of 25, 50, 78 and 100 nm and one type of micron-sized particles (MPs) (～500 nm) were exposed to two mammalian (H4IIE and HepG2) and two piscine (PLHC-1 and RTH-149) cell lines to test the species-specific toxicities of CuNPs. The results showed that the morphologies, ion release and size of the particles all played an important role when investigating the toxicity. Furthermore, the authors found that the particle forms of CuNPs in suspensions highly contribute to the toxicity in all exposed cell lines whereas copper ions (Cu²⁺) only caused significant responses in mammalian cell lines, indicating the species-specific toxicity of CuNPs. This study revealed that the morphologies, ion release rate of NPs as well as the species-specific vulnerabilities of cells should all be considered when explaining and extrapolating toxicity test results among particles and among species.     

Cellular uptake and toxicity effects of silver nanoparticles in mammalian kidney cells

The rapid progress and early commercial acceptance of silver‐based nanomaterials is owed to their biocidal activity. Besides embracing the antimicrobial potential of silver nanoparticles (AgNPs), it is imperative to give special attention to the potential adverse health effects of nanoparticles owing to prolonged exposure. Here, we report a detailed study on the in vitro interactions of citrate‐coated AgNPs with porcine kidney (Pk15) cells. As uncertainty remains whether biological/cellular responses to AgNPs are solely as a result of the release of silver ions or whether the AgNPs themselves have toxic effects, we investigated the effects of Ag⁺ on Pk15 cells for comparison. Next, we investigated the cellular uptake of both AgNPs and Ag⁺ in Pk15 cells at various concentrations applied. The detected Ag contents in cells exposed to 50 mg l^?1 AgNPs and 50 mg l^?1 Ag⁺ were 209 and 25 µg of Ag per 10⁶ cells, respectively. Transmission electron microscopy (TEM) images indicated that the Pk15 cells internalized AgNPs by endocytosis. Both forms of silver, nano and ionic, decreased the number of viable Pk15 cells after 24 h in a dose‐dependent manner. In spite of a significant uptake into the cells, AgNPs had only insignificant toxicity at concentrations lower than 25 mg l^?1, whereas Ag⁺ exhibited a significant decrease in cell viability at one‐fifth of this concentration. The Comet assay suggested that a rather high concentration of AgNP (above 25 mg l^?1) is able to induce genotoxicity in Pk15 cells. Further studies must seek deeper understanding of AgNP behavior in biological media and their interactions with cellular membranes. Copyright © 2014 John Wiley & Sons, Ltd.     

Effect of curcumin nanoparticles on the cisplatin-induced neurotoxicity in rat

The present study is conducted to evaluate the neuroprotective effect of curcumin nanoparticles (CUR NP) against the neurotoxicity induced by cisplatin (CP) in rat. Rats were divided into control group that received saline solution, CP-treated rats that received a single i.p. injection of CP (12?mg/kg body wt), and CP-treated rats that received a single i.p injection of CP (12?mg/kg body wt) followed by a daily oral administration of CUR NP (50?mg/kg body wt) for 14 days. At the end of the experiment, the motor activity of rats was evaluated by open field test. The neurochemical and histopathological changes were investigated in the cerebral cortex. A significant decrease in motor activity was observed in CP-treated rats. This was associated with a significant increase in the cortical levels of lipid peroxidation, nitric oxide, tumor necrosis factor-α, caspase-3, and acetylcholinesterase activity. However, CP induced a significant decrease in reduced glutathione levels and Na⁺, K⁺-ATPase activity. In rats treated with CP and CUR NP, no significant changes were recorded in the parameters of the open field test as compared to control. In addition, treatment with CUR NP prevented all the neurochemical changes induced by CP except the increased value of nitric oxide. CUR NP also reduced the histopathological changes induced by CP. It is clear from the present data that CUR NP could ameliorate the neurotoxic effect induced by cisplatin.     

Comparison of in vitro toxicity of silver ions and silver nanoparticles on human hepatoma cells

Scientific information on the potential harmful effects of silver nanoparticles (AgNPs) on human health severely lags behind their exponentially growing applications in consumer products. In assessing the toxic risk of AgNP usage, liver, as a detoxifying organ, is particularly important. The aim of this study was to explore the toxicity mechanisms of nano and ionic forms of silver on human hepatoblastoma (HepG2) cells. The results showed that silver ions and citrate‐coated AgNPs reduced cell viability in a dose‐dependent manner. The IC50 values of silver ions and citrate‐coated AgNPs were 0.5 and 50 mg L^?1, respectively. The LDH leakage and inhibition of albumin synthesis, along with decreased ALT activity, indicated that treatment with either AgNP or Ag ions resulted in membrane damage and reduced the cell function of human liver cells. Evaluation of oxidative stress markers demonstrating depletion of GSH, increased ROS production, and increased SOD activity, indicated that oxidative stress might contribute to the toxicity effects of nano and ionic forms of silver. The observed toxic effect of AgNP on HepG2 cells was substantially weaker than that caused by ionic silver, while the uptake of nano and ionic forms of silver by HepG2 cells was nearly the same. © 2014 Wiley Periodicals, Inc. Environ Toxicol 31: 679–692, 2016.     

雷洛昔芬可减弱β-淀粉样蛋白对原代海马神经元的毒性作用

目的研究雌激素受体调节剂雷洛昔芬对原代海马神经元的保护作用。方法将原代培养的海马神经元分为五组:对照(A)组;β-淀粉样蛋白(Aβ)(B)组;Aβ+17β雌二醇(C)组;Aβ+苯甲酸雌二醇(D)组;Aβ+雷洛昔芬(E)组。用MTT方法观测各组海马神经元活力;通过AnnexinV-FITC双染流式细胞术检测各组海马神经元的凋亡。结果 B组海马神经元活力(72.5±10.7)%,显著低于A组的100%(P<0.01);B组凋亡率(31.5±1.9)%,明显高于与A组的(9.0±0.6)%(P<0.01)。C、D、E组海马神经元活力均高于与B组(P<0.05或P<0.01),而凋亡率均降低(P<0.05),但C、D、E三组之间差异无统计学意义。结论雷洛昔芬可减弱Aβ对原代海马神经元的毒性作用;雷洛昔芬对原代海马神经元的保护作用与雌激素相似。     

Silver nanoparticles induce neurotoxicity in a human embryonic stem cell-derived neuron and astrocyte network

Silver nanoparticles (AgNPs) are among the most extensively used nanoparticles and are found in a variety of products. This ubiquity leads to inevitable exposure to these particles in everyday life. However, the effects of AgNPs on neuron and astrocyte networks are still largely unknown. In this study, we used neurons and astrocytes derived from human embryonic stem cells as a cellular model to study the neurotoxicity that is induced by citrate-coated AgNPs (AgSCs). Immunostaining with the astrocyte and neuron markers, glial fibrillary acidic protein and microtubule-associated protein-2 (MAP2), respectively, showed that exposure to AgSCs at the concentration of 0.1?µg/mL increased the astrocyte/neuron ratio. In contrast, a higher concentration of AgSCs (5.0?µg/ml) significantly changed the morphology of astrocytes. These results suggest that astrocytes are sensitive to AgSC exposure and that low concentrations of AgSCs promote astrogenesis. Furthermore, our results showed that AgSCs reduced neurite outgrowth, decreased the expression of postsynaptic density protein 95 and synaptophysin, and induced neurodegeneration in a concentration-dependent manner. Our findings additionally suggest that the expression and phosphorylation status of MAP2 isoforms, as modulated by the activation of the Akt/glycogen synthase kinase-3/caspase-3 signaling pathway, may play an important role in AgSC-mediated neurotoxicity. We also found that AgNO₃ exposure only slightly reduced neurite outgrowth and had little effect on MAP2 expression, suggesting that AgSCs and AgNO₃ have different neuronal toxicity mechanisms. In addition, most of these effects were reduced when the cell culture was co-treated with AgSCs and the antioxidant ascorbic acid, which implies that oxidative stress is the major cause of AgSC-mediated astrocytic/neuronal toxicity and that antioxidants may have a neuroprotective effect.     

Complete transformation of ZnO and CuO nanoparticles in culture medium and lymphocyte cells during toxicity testing

Here, we present evidence on complete transformation of ZnO and CuO nanoparticles, which are among the most heavily studied metal oxide particles, during 24?h in vitro toxicological testing with human T-lymphocytes. Synchrotron radiation-based X-ray absorption near edge structure (XANES) spectroscopy results revealed that Zn speciation profiles of 30?nm and 80?nm ZnO nanoparticles, and ZnSO₄- exposed cells were almost identical with the prevailing species being Zn-cysteine. This suggests that ZnO nanoparticles are rapidly transformed during a standard in vitro toxicological assay, and are sequestered intracellularly, analogously to soluble Zn. Complete transformation of ZnO in the test conditions was further supported by almost identical Zn spectra in medium to which ZnO nanoparticles or ZnSO₄ was added. Likewise, Cu XANES spectra for CuO and CuSO₄-exposed cells and cell culture media were similar. These results together with our observation on similar toxicological profiles of ZnO and soluble Zn, and CuO and soluble Cu, underline the importance of dissolution and subsequent transformation of ZnO and CuO nanoparticles during toxicological testing and provide evidence that the nano-specific effect of ZnO and CuO nanoparticles is negligible in this system. We strongly suggest to account for this aspect when interpreting the toxicological results of ZnO and CuO nanoparticles.     

NGF对烧伤大鼠血清引起纹状体神经元细胞毒性的影响

目的　观察NGF对烧伤大鼠血清引起神经毒性的影响 ,初步探讨NGF对烧伤后神经元损伤的保护作用及其机制。方法　测定烧伤大鼠纹状体组织NO和LDH含量 ;给予原代培养纹状体神经元不同浓度NGF 2 4h后 ,加入不同浓度烧伤大鼠血清 ,测定细胞存活率及培养液中NO含量。结果　大鼠烧伤后 ,纹状体组织NO和LDH含量明显升高 ,烧伤大鼠血清可引起培养的纹状体神经元存活率下降 ,培养液中NO含量升高。NGF能降低纹状体组织中NO和LDH的含量 ,提高培养的纹状体神经元的存活率 ,减少培养液中NO含量 ,其作用呈剂量依赖性 ,NGF对神经元存活率的影响与NO含量呈显著负相关。结论　NGF对烧伤大鼠血清引起的纹状体神经元损伤有保护作用 ,其作用机制可能是通过抑制NO的神经毒性。     

Titanium dioxide nanoparticles induced intracellular calcium homeostasis modification in primary human keratinocytes. Towards an in vitro explanation of titanium dioxide nanoparticles toxicity

Abstract

Deciphering the molecular basis of toxicology mechanism induced by nanoparticles (NPs) remains an essential challenge. Ion Beam Analysis (IBA) was applied in combination with Transmission Electron Microscopy and Confocal Microscopy to analyze human keratinocytes exposed to TiO₂-NPs. Investigating chemical elemental distributions using IBA gives rise to a fine quantification of the TiO₂-NPs uptake within a cell and to the determination of the intracellular chemical modifications after TiO₂-NPs internalization. In addition, fluorescent dye-modified TiO₂-NPs have been synthesized to allow their detection, precise quantification and tracking in vitro. The internalization of these TiO₂-NPs altered the calcium homeostasis and induced a decrease in cell proliferation associated with an early keratinocyte differentiation, without any indication of cell death. Additionally, the relation between the surface chemistry of the TiO₂-NPs and their in vitro toxicity is clearly established and emphasizes the importance of the calcium homeostasis alteration in response to the presence of TiO₂-NPs.     

Formulation,characterization, and cellular toxicity assessment of tamoxifen-loaded silk fibroin nanoparticles in breast cancer

Silk fibroin (SF) is a natural polymeric biomaterial that is widely adopted for the preparation of drug delivery systems. Herein, we aimed to fabricate and characterize SF nanoparticles loaded with the selective estrogen receptor modulator; tamoxifen citrate (TC-SF-NPs) and to assess their in vitro efficacy against breast cancer cell lines (MCF-7 and MDA-MB-231). TC-loaded SF-NPs were characterized for particle size, morphology, entrapment efficiency, and release profile. In addition, we examined the in vitro cytotoxicity of TC-SF-NPs against human breast cancer cell lines and evaluated the anticancer potential of TC-SF-NPs through apoptosis assay and cell cycle analysis. Drug-loaded SF-NPs showed an average particle size of 186.1 ± 5.9 nm and entrapment efficiency of 79.08%. Scanning electron microscopy (SEM) showed the nanoparticles had a spherical morphology with smooth surface. Tamoxifen release from SF-NPs exhibited a biphasic release profile with an initial burst release within the first 6 h and sustained release for 48 h. TC-SF-NPs exerted a dose-dependent cytotoxic effect against breast cancer cell lines. In addition, flow cytometry analysis revealed that cells accumulate in G₀/G₁ phase, with a concomitant reduction of S- and G₂-M-phase cells upon treatment with TC-SF-NPs. Consequently, the potent anticancer activities of TC-SF-NPs against breast cancer cells were mainly attributed to the induction of apoptosis and cell cycle arrest. Our results indicate that SF nanoparticles may represent an attractive nontoxic nanocarrier for the delivery of anticancer drugs.