Nanotoxicological study of polyol-made cobalt-zinc ferrite nanoparticles in rabbit

The increasing use of engineered nanomaterials in commercial manufacturing and consumer products presents an important toxicological concern. Superparamagnetic zinc-cobalt ferrite nanoparticles (SFN) emerge as a promising tool for early cancer diagnostics and targeted therapy. However, toxicity and biological activities of SFN should be evaluated in vitro and in vivo in animal before any clinical application. In this study we aim to synthesize and characterize such objects using polyol process in order to assess its nanotoxicological profile in vitro as well as in vivo. The produced particles consist of a cobalt-zinc ferrite phase corresponding to the Zn_0.8Co_0.2Fe₂O₄ composition. They are isotropic in shape single crystals of 8 nm in size. The thermal variation of their dc-magnetization confirms their superparamagnetic behavior. In vitro, acute exposure (4 h) to them (100 μg mL⁻¹) induced an important decrease of healthy Human Umbilical Vein Endothelial Cells (HUVECs) viability. In vivo investigation in New-Zealand rabbits revealed that they lead to tissue toxicities; in lungs, liver and kidneys. Our investigations report, for the first time as far as we know, that SFN exhibit harmful properties in human cells and mammals.     

Development and characterization of an orodispersible film containing drug nanoparticles

In this study, a novel orodispersible film (ODF) containing drug nanoparticles was developed with the goal of transforming drug nanosuspensions into a solid dosage form and enhancing oral bioavailability of drugs with poor water solubility. Nanosuspensions were prepared by high pressure homogenization and then transformed into ODF containing drug nanoparticles by mixing with hydroxypropyl methylcellulose solution containing microcrystalline cellulose, low substituted hydroxypropylcellulose and PEG-400 followed by film casting and drying. Herpetrione, a novel and potent antiviral agent with poor water solubility that extracted from Herpetospermum caudigerum, was chosen as a model drug and studied systematically. The uniformity of dosage units of the preparation was acceptable according to the criteria of Japanese Pharmacopoeia 15. The ODF was disintegrated in water within 30 s with reconstituted nanosuspensions particle size of 280 ± 11 nm, which was similar to that of drug nanosuspensions, indicating a good redispersibility of the fast dissolving film. Result of X-ray diffraction showed that HPE in the ODF was in the amorphous state. In the in vitro dissolution test, the ODF containing HPE nanoparticles showed an increased dissolution velocity markedly. In the pharmacokinetics study in rats, compared to HPE coarse suspensions, the ODF containing HPE nanoparticles exhibited significant increase in AUC_0–24h, C_max and decrease in T_max, MRT. The result revealed that the ODF containing drug nanoparticles may provide a potential opportunity in transforming drug nanosuspensions into a solid dosage form as well as enhancing the dissolution rate and oral bioavailability of poorly water-soluble drugs.     

Impact of iron oxide nanoparticles on brain,heart, lung,liver and kidneys mitochondrial respiratory chain complexes activities and coupling

The present study evaluates the effects of iron oxide nanoparticles (ION) on mitochondrial respiratory chain complexes activities in five organs characterized by different oxidative capacities and strongly involved in body detoxification. Isolated mitochondria were extracted from brain, heart, lung, liver and kidneys in twelve Wistar rats (8 weeks) using differential centrifugations. Maximal oxidative capacities (Vmax), mitochondrial respiratory chain complexes activity using succinate (Vsucc, complexes II, III, and IV activities) or N, N, N′, N′-tetramethyl-p-phenylenediaminedihydrochloride (tmpd)/ascorbate (Vtmpd, complex IV activity) and, mitochondrial coupling (Vmax/Vo) were determined in controls and after exposure to 100, 200, 300 and 500 μg/ml Fe₃O₄. Data showed that baseline maximal oxidative capacities were 26.3 ± 4.7, 48.9 ± 4.6, 11.3 ± 1.3, 27.0 ± 2.5 and 13.4 ± 1.7 μmol O₂/min/g protein in brain, heart, lung, liver, and kidneys mitochondria, respectively. Complexes II, III, and IV activities also significantly differed between the five organs. Interestingly, as compared to baseline values and in all tissues examined, exposure to ION did not alter mitochondrial respiratory chain complexes activities whatever the nanoparticles (NPs) concentration used. Thus, ION did not show any toxicity on mitochondrial coupling and respiratory chain complexes I, II, III, and IV activities in these five major organs.     

Dichloro-dihydro-fluorescein diacetate (DCFH-DA) assay: A quantitative method for oxidative stress assessment of nanoparticle-treated cells

No consensus exists on how to address possible toxicity of nanomaterials as they interfere with most in vitro screening tests based on colorimetric and fluorimetric probes such as the dichloro-dihydro-fluorescein diacetate (DCFH-DA) assay for detection of oxidative species.In the present research, nanomaterial interaction with DCFH-DA was studied in relation to its nature and/or assay conditions (cell-based and time exposure) by incubating Rhodamine (Rhd)-labeled 25 nm and 50 nm silica (SiO₂), naked and oleic acid coated magnetite, (Fe₃O₄) and maghemite (Fe₂O₃) iron oxide, titanium dioxide (TiO₂) and poly(ethylene oxide)-poly(lactide/glycolide) acid (PLGA-PEO) nanoparticles (NPs) with metabolically active rat hepatocytes for 4 and 24-h periods. Data indicated that nanoparticle uptake correlated with quenching of dye fluorescence emission. In spite of their masking effect, the oxidative potential of NPs could be detected at a limited threshold concentration when exposed for periods of time longer than those frequently used for this test. However, changes in the experimental conditions did not systematically result in free radical formation for all nanomaterials tested.Overall data indicate that despite the quenching effect of nanoparticles on DCFH-DA assay, it can be considered as a useful tool for quantitative measurement of NPs-induced oxidative stress by minor modifications of standardized protocols.     

TiO2 nanoparticles and bulk material stimulate human peripheral blood mononuclear cells

Nanomaterials are increasingly produced and used throughout recent years. Consequently the probability of exposure to nanoparticles has risen. Because of their small 1–100 nm size, the physicochemical properties of nanomaterials may differ from standard bulk materials and may pose a threat to human health. Only little is known about the effects of nanoparticles on the human immune system. In this study, we investigated the effects of TiO₂ nanoparticles and bulk material in the in vitro model of human peripheral blood mononuclear cells (PBMC) and cytokine-induced neopterin formation and tryptophan breakdown was monitored. Both biochemical processes are closely related to the course of diseases like infections, atherogenesis and neurodegeneration. OCTi60 (25 nm diameter) TiO₂ nanoparticles and bulk material increased neopterin production in unstimulated PBMC and stimulated cells significantly, the effects were stronger for OCTi60 compared to bulk material, while P25 TiO₂ (25 nm diameter) nanoparticles had only little influence. No effect of TiO₂ nanoparticles on tryptophan breakdown was detected in unstimulated cells, whereas in stimulated cells, IDO activity and IFN-γ production were suppressed but only at the highest concentrations tested. Because neopterin was stimulated and tryptophan breakdown was suppressed in parallel, data suggests that the total effect of particles would be strongly pro-inflammatory.     

Measurement and Decomposition Kinetics of Residual Hydrogen Peroxide in the Presence of Commonly used Excipients and Preservatives

Quantitation of residual hydrogen peroxide (H₂O₂) and evaluation of the impact on product stability is necessary as unwanted H₂O₂ can potentially be introduced during the manufacturing of pharmaceuticals, biologics, and vaccines. A sensitive and convenient microplate-based method with fluorescence detection for H₂O₂ quantitation was recently reported (Towne et al., 2004, Anal Biochem 334: 290–296). This method was found to be highly robust and reproducible, with a level of detection of 0.015 ppm and a level of quantitation of 0.025 ppm (in water). The relatively small sample requirements and amenability for automation make this assay an attractive tool for detecting residual H₂O₂ levels. Without additional manipulation, the assay can be conducted on heterogeneous solutions with significant degree of turbidity, such as the presence of suspensions or aluminum-containing adjuvants. The quantitation of H₂O₂ and its decomposition kinetics was also studied in presence of two common vaccine preservatives (thimerosal and phenol) and eight commonly used excipients (polyols). Over time, there is a distinct, temperature dependent decrease in H₂O₂ recovered in thimerosal and phenol containing samples versus non-preservative containing controls. Based on the half-life of spiked H₂O₂, the decay rates in eight polyols tested were found to be: ribose > sucrose > (glycerol, glucose, lactose, mannitol, sorbitol, and xylose). © 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 98:3987–3996, 2009     

Oxidative stress contributes to silica nanoparticle-induced cytotoxicity in human embryonic kidney cells

In order to elucidate the nanoparticle-induced cytotoxicity and its mechanism, the effects of 20 and 50 nm silica nanoparticles on cultured human embryonic kidney (HEK293) cells were investigated. Cell viability, mitochondrial function, cell morphology, reactive oxygen species (ROS), glutathione (GSH), thiobarbituric acid reactive substance (TBARS), cell cycle and apoptosis were assessed under control and silica exposed conditions. Exposure to 20 or 50 nm SiO₂ nanoparticles at dosage levels between 20 and 100 μg/ml decreased cell viability in a dose-dependent manner. Median lethal dose (LD₅₀) of 24 h exposure was 80.2 ± 6.4 and 140.3 ± 8.6 μg/ml for 20 and 50 nm SiO₂ nanoparticles, respectively. Morphological examination revealed cell shrinkage and nuclear condensation after SiO₂ nanoparticle exposure. Increase in intracellular ROS level and reduction in GSH content were also observed in SiO₂ nanoparticle-exposed HEK293 cells. Increase in the amount of TBARS suggested an elevated level of lipid peroxidation. Flow cytometric analysis showed that SiO₂ nanoparticles can cause G2/M phase arrest and apoptotic sub-G1 population increase in a dose-dependent manner. In summary, exposure to SiO₂ nanoparticles resulted in a dose-dependent cytotoxicity in cultured HEK293 cells that was associated with increased oxidative stress.     

In vitro mutagenicity assessment of aluminium oxide nanomaterials using the Salmonella/microsome assay

The aim of the current study was to evaluate the potential mutagenicity of aluminium oxide nanomaterials (NMs) (Al₂O₃-30 nm and Al₂O₃-40 nm). Characterization of the NMs was done before the initiation of the study. The mutagenicity of the NMs was studied by the Ames test with Salmonella typhimurium TA100, TA1535, TA98, TA97a and TA102 strains, in the presence and absence of the S9 mixture. Based on a preliminary cytotoxicity study conducted on the strains, different concentrations of Al₂O₃-30 nm, Al₂O₃-40 nm and Al₂O₃-bulk were selected. At all the concentrations tested, Al₂O₃-30 nm and Al₂O₃-40 nm did not significantly increase the number of revertant colonies compared to the Al₂O₃-bulk and control with or without S9 mixture. Our findings suggest that Al₂O₃ NMs were devoid of any size and concentration dependent mutagenicity compared to the Al₂O₃-bulk and control.     

Experimental investigation and oral bioavailability enhancement of nano-sized curcumin by using supercritical anti-solvent process

The biomedical applications of curcumin (CUR) are limited due to its poor oral bioavailability. In this work, CUR nanoparticles were successfully prepared by combining the supercritical anti-solvent (SAS) process with Tween 80 as a solubilizing agent and permeation enhancer. Different processing parameters that can govern the mean particle size and size distribution of nanoparticles were well investigated by manipulating the types of solvents, mixing vessel pressure, mixing vessel temperature, CO₂ flow rate, solution flow rate and solution concentration. Solid state characterization was done by Fourier Transform infrared spectroscopy, differential scanning calorimetry, dynamic light scattering, scanning electron microscopy, and powder X-ray diffraction study. Solubility and dissolution profile of SAS-processed CUR were found to be significantly increased in comparison with native CUR. Further, a validated ultra-performance liquid chromatographic method with quadrupole-time of flight-mass spectrometry was developed to investigate the pharmacokinetic parameters after a single oral dose (100 mg/kg) administration of CUR (before/after SAS-processed) in male Wistar rats. From the plasma concentration vs. time profile graph, oral bioavailability of SAS-processed CUR was found to be increased approximately 11.6-fold (p < 0.001) as compared to native CUR.     

Susceptibility of avian influenza viruses of the N6 subtype to the neuraminidase inhibitor oseltamivir

Avian influenza viruses are a source of genetic material that can be transmitted to humans through direct introduction or reassortment. Although there is a wealth of information concerning global monitoring for antiviral resistance among human viruses of the N1 and N2 neuraminidase (NA) subtypes, information concerning avian viruses of these and other NA subtypes is limited. We undertook a surveillance study to investigate the antiviral susceptibility of avian influenza N6 NA viruses, the predominant subtype among wild waterfowl. We evaluated 73 viruses from North American ducks and shorebirds for susceptibility to the NA inhibitor oseltamivir in a fluorescence-based NA enzyme inhibition assay. Most (90%) had mean IC₅₀ values ranging from <0.01 to 5.0 nM; 10% were from 5.1 to 50.0 nM; and none were >50.0 nM. Susceptibility to oseltamivir remained stable among all isolates collected over approximately three decades (P ? 0.74). Two isolates with I222V NA substitution had moderately reduced susceptibility to oseltamivir in vitro (IC₅₀, 30.0 and 40.0 nM). One field sample was a mixed population containing an avian paramyxovirus (APMV) and H4N6 influenza virus, as revealed by electron microscopy and hemagglutination inhibition assays with a panel of anti-APMV antisera. This highlights the importance of awareness and careful examination of non-influenza pathogens in field samples from avian sources. This study showed that oseltamivir-resistant N6 NA avian influenza viruses are rare, and must be tested both phenotypically and genotypically to confirm resistance.     

An integrated microfluidic device utilizing vancomycin conjugated magnetic beads and nanogold-labeled specific nucleotide probes for rapid pathogen diagnosis

A PCR-free assay for rapid pathogen diagnosis was implemented on an integrated microfluidic system in this study. Vancomycin-conjugated magnetic beads were used to capture multiple strains of bacteria and nucleotide probes labeled gold nanoparticles were used to specify and detect a specific strain by hybridization-induced color change. The assay was entirely automated within an integrated microfluidic device that was composed of suction-type micropumps, microvalves, microchannels, and microchambers that fabricated by microfluidic technology. Multiple strains of bacteria could be captured simultaneously by vancomycin-conjugated magnetic beads, with capturing efficiency exceeding 80%. Subsequently, sensitive and strain-specific detection against target bacteria could be achieved by using nanogold labeled specific nucleotide probes. The limit of detection of 10² CFU bacteria was achieved. Importantly, nucleic acid amplification was not involved in the diagnostic procedures; the entire analytic process required only 25 min. The developed platform may provide a promising tool for rapid diagnosis of bacterial infections.From the Clinical EditorIn this novel study, a PCR-free pathogen detection method is demonstrated. After vancomycin-conjugated magnetic beads captured bacteria, nucleotide probes-labeled gold nanoparticles were employed to specify and detect specific strains via hybridization-induced color change. Multiple strains of bacteria could be captured simultaneously with an efficiency exceeding 80%, enabling the detection of as low as 10² CFU of bacteria.     

Cerium oxide nanoparticles: influence of the high-Z component revealed on radioresistant 9L cell survival under X-ray irradiation

This article pioneers a study into the influence of the high-Z component of nanoparticles on the efficacy of radioprotection some nanoparticles offer to exposed cells irradiated with X-rays. We reveal a significant decrease in the radioprotection efficacy for cells exposed to CeO₂ nanoparticles and irradiated with 10 MV and 150 kVp X-rays. In addition, analysis of the 150 kVp survival curve data indicates a change in radiation quality, becoming more lethal for irradiated cells exposed to CeO₂ nanoparticles. We attribute the change in efficacy to an increase in high linear energy transfer Auger electron production at 150 kVp which counterbalances the CeO₂ nanoparticle radioprotection capability and locally changes the radiation quality. This study highlights an interesting phenomenon that must be considered if radiation protection drugs for use in radiotherapy are developed based on CeO₂ nanoparticles.From the Clinical EditorCeO₂ nanoparticles are thought to offer radioprotection; however, this study reveals significant decrease in the radioprotection efficacy for cells exposed to CeO₂ nanoparticles and irradiated with 10 MV and 150 kVp X-rays. This phenomenon must be considered when developing radiation protection drugs based on CeO₂ nanoparticles.     

Spray freeze drying for dry powder inhalation of nanoparticles

Formulating nanoparticles for delivery to the deep lung is complex and many techniques fail in terms of nanoparticle stability. Spray freeze drying (SFD) is suggested here for the production of inhalable nanocomposite microcarriers (NCM). Different nanostructures were prepared and characterized including polymeric and lipid nanoparticles. Nanoparticle suspensions were co-sprayed with a suitable cryoprotectant into a cooled, stainless steel spray tower, followed by freeze drying to form a dry powder while equivalent compositions were spray dried (SD) as controls. SFD-NCM possess larger specific surface areas (67–77 m²/g) and lower densities (0.02 g/cm³) than their corresponding SD-NCM. With the exception of NCM of lipid based nanocarriers, SFD produced NCM with a mass median aerodynamic diameter (MMAD) of 3.0 ± 0.5 μm and fine particle fraction (FPF ⩽ 5.2 μm) of 45 ± 1.6% with aerodynamic performances similar to SD-NCM. However, SFD was superior to SD in terms of maintaining the particle size of all the investigated polymeric and lipid nanocarriers following reconstitution (S_f/S_i ratio for SFD ≈ 1 versus >1.5 for SD). The SFD into cooled air proved to be an efficient technique to prepare NCM for pulmonary delivery while maintaining the stability of the nanoparticles.     

Development of a binary lipid nanoparticles formulation of itraconazole for parenteral administration and controlled release

The principal aim of this study was to develop an intravenous formulation of itraconazole (ITZ) using lipid nanoparticles based on binary mixture of liquid and solid lipids. Lipid nanoparticles were developed to provide the controlled release of ITZ as well as to improve the solubility of ITZ. Lipid nanoparticles were prepared with tristearin as a solid lipid, triolein as a liquid lipid, and a surfactant mixture of eggPC, Tween 80 and DSPE-PEG₂₀₀₀. ITZ was incorporated at the concentration of 20 mg/g. Lipid nanoparticles were manufactured by high-pressure homogenization method. The particle size and polydispersity index (PI) of lipid nanoparticles were below 280 nm and 0.2, respectively. Zeta potentials and incorporation efficiencies of lipid nanoparticles were around ?30 mV and above 80%, respectively. Lipid nanoparticles containing 1% of liquid lipid showed the smallest particles size and the highest incorporation efficiency. Results from SEM, DSC and PXRD revealed that ITZ in lipid nanoparticles exists in an amorphous state. Release rates were increased as the amount of liquid lipid in lipid core increased, demonstrating that the release of ITZ from lipid nanoparticles could be controlled by modulation of the amount of liquid lipid in lipid core. Pharmacokinetic studies were performed after intravenous administration of lipid nanoparticles in rats at the dose of 5 mg/kg. The plasma concentration of ITZ was prolonged after intravenous administration of lipid nanoparticles. It is concluded that binary lipid nanoparticles could control the release and pharmacokinetic parameters of ITZ.     

Toxicity assessment of anatase and rutile titanium dioxide nanoparticles: The role of degradation in different pH conditions and light exposure

Titanium dioxide nanoparticles (TiO₂NPs), in the two crystalline forms, rutile and anatase, have been widely used in many industrial fields, especially in cosmetics. Therefore, a lot of details about their safety issues have been discussed by the scientific community. Many studies have led to a general agreement about TiO₂NPs toxicity, in particular for anatase form, but no mechanism details have been proved yet. In this study, data confirm the different toxic potential of rutile and anatase TiO₂NPs in two cell lines up to 5 nM nanoparticles concentration. Moreover, we evaluated the role of titanium ions released by TiO₂NPs in different conditions, at pH = 4.5 (the typical lysosomal compartment pH) and at pH = 5.5 (the skin physiological pH) in conditions of darkness and light, to mimic the dermal exposure of cosmetics. Anatase nanoparticles were proner to degradation both in the acidic conditions and at skin pH. Our study demonstrates that pH and sunlight are dominant factors to induce oxidative stress, TiO₂NPs degradation and toxicity effects.     

Morphological changes of the red blood cells treated with metal oxide nanoparticles

The toxic effect of Al₂O₃, SiО₂ and ZrО₂ nanoparticles on red blood cells of Wistar rats was studied in vitro using the atomic force microscopy and the fluorescence analysis. Transformation of discocytes into echinocytes and spherocytes caused by the metal oxide nanoparticles was revealed. It was shown that only extremely high concentration of the nanoparticles (2 mg/ml) allows correct estimating of their effect on the cell morphology. Besides, it was found out that the microviscosity changes of red blood cell membranes treated with nanoparticles began long before morphological modifications of the cells. On the contrary, the negatively charged ZrO₂ and SiO₂ nanoparticles did not affect ghost microviscosity up to concentrations of 1 μg/ml and 0.1 mg/ml, correspondingly. In its turn, the positively charged Al₂O₃ nanoparticles induced structural changes in the lipid bilayer of the red blood cells already at a concentration of 0.05 μg/ml. A decrease in microviscosity of the erythrocyte ghosts treated with Al₂O₃ and SiO₂ nanoparticles was shown. It was detected that the interaction of ZrO₂ nanoparticles with the cells led to an increase in the membrane microviscosity and cracking of swollen erythrocytes.     

Cytotoxic interactions of bare and coated NaGdF4:Yb3 +:Er3 + nanoparticles with macrophage and fibroblast cells

The lanthanide nano-compounds are well suited to serve as fluorescent and magnetic contrast agents and luminescent labels. Although they are considered as promising materials for bio-imaging and bio-sensors in vivo or in vitro, the amount of data is still insufficient for deep understanding the toxicity of these nanomaterials. This knowledge is of great importance in the light of growing use of the biofunctionalized nanoparticles, which raises some questions about safety of these materials. Despite lanthanide-doped NaGdF₄ nanocrystals are considered as non-toxic, here we present the data showing the fatal effect of newly synthetized NaGdF₄:Yb^3 +:Er^3 + on chosen types of cells. Our studies were performed on two cell lines NIH3T3 fibroblasts, and RAW264.7 macrophages. Cytotoxic properties of NaGdF₄:Yb^3 +:Er^3 + nanoparticles and their biological effects were studied by assessing cell culture viability (MTS), proliferation and apoptosis. Bare NaGdF₄:Yb^3 +:Er^3 + nanocrystals were cytotoxic and induced apoptosis of both NIH3T3 and RAW264.7 cells. Their cytotoxicity was reduced by PEGylation, at the expense of minimizing direct interactions between the compound and the cell. On the other hand, coating with silica reduced cell death induced by Yb^3 +:Er^3 + codoped NaGdF₄ nanocrystals (but proliferation was still inhibited). The NH₂-modified silica coated nanoparticles were clearly less cytotoxic than pristine nanoparticles, which suggests that both, silica and PEG coatings are reasonable approaches to decrease cytotoxicity of the nanocrystal labels. The silica and PEG shell, should also enable and simplify further bio-functionalization of these luminescent labels.The authors acknowledge the financial support from: Institute of Immunology and Experimental Therapy, Polish Academy of Sciences (IITD PAN) grant no. 3/15, Polish Ministry of Science and Higher Education, Grant N N507 499538 and from the Wroclaw Research Centre EIT + within the project “The Application of Nanotechnology in Advanced Materials” — NanoMat (POIG.01.01.02-02-002/08) financed by the European Regional Development Fund (Operational Program Innovative Economy, 1.1.2).     

Anti-angiogenic effect of bare titanium dioxide nanoparticles on pathologic neovascularization without unbearable toxicity

Local application requires fewer nanoparticles than systemic delivery to achieve effective concentration. In this study, we investigated the potential toxicity and efficacy of bare titanium dioxide (TiO₂) nanoparticles by local administration into the eye. Mono-disperse, 20 nm-size TiO₂ nanoparticles did not affect the viability of retinal constituent cells within certain range of concentrations (~ 1.30 μg/mL). Furthermore, local delivery of TiO₂ nanoparticles did not induce any significant toxicity at the level of gene expression and histologic integrity in the retina of C57BL/6 mice. Interestingly, at the low concentration (130 ng/mL) without definite toxicity, these nanoparticles suppressed in vitro angiogenesis processes and in vivo retinal neovascularization in oxygen-induced retinopathy mice when they are administered intravitreally. Taken together, our results demonstrate that even TiO₂ nanoparticles can be safely utilized for the treatment of retinal diseases at the adequate concentration levels, especially through local administration.From the Clinical EditorIn this paper the local application of titanium dioxide is described as a local treatment for retinal diseases associated with neovascularization. While these nanoparticles have known systemic toxicity, this work demonstrates that when applied locally in a mouse model, they can be used without observable toxicity even in their native forms.     

Induction of oxidative stress and inflammatory cytokines by manganese chloride in cultured T98G cells,human brain glioblastoma cell line

Manganese, an essential trace nutrient in human beings, has been widely used in the steel industry to improve hardness, stiffness, and strength. With the increased applications of manganese compounds, discharge into the environment has rapidly increased and may exert adverse effects on human health. In this study, manganese toxicity was investigated using cultured T98G cells, which are derived from human glioblasts with the ability to differentiate into several different types of neuroglia. Cytotoxicity was shown in manganese-treated groups (100, 200, 400, and 800 μM of MnCl₂), and cell viability was decreased to 58.8% of the control group at 2 days after treatment with 800 μM of MnCl₂. When cells were treated with manganese for 24 h, ROS dose-dependently increased while antioxidant intracellular GSH decreased. With the generation of ROS, the increased activity of caspase-3 was shown, and was followed by chromatin condensation and breakage, which is an indication of the cellular apoptotic process. ROS also triggered pro-inflammatory responses in cultured T98G cells, which were demonstrated by the increased gene expression and protein levels of IL-6 and IL-8.