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1.
J Environ Sci (China) ; 85: 94-106, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31471036

RESUMO

Titanium dioxide nanoparticles (TiO2 NPs) are subjected to various transformation processes (chemical, physical and biological processes) in the environment, potentially affecting their bioavailability and toxic properties. However, the size variation of TiO2 NPs during aging process and subsequent effects in mammalian cells are largely unknown. The aim of this study was to illustrate the adverse effects of TiO2 NPs in different sizes (5, 15 and <100 nm) during aging process on human-hamster hybrid (AL) cells. There was an aging-time dependent enhancement of average hydrodynamic size in TiO2 NPs stock suspensions. The cytotoxicity of fresh TiO2 NPs increased in a size-dependent manner; in contrast, their genotoxicity decreased with the increasing sizes of NPs. No significant toxicity difference was observed in cells exposed to either fresh or 60 day-aged TiO2 NPs. Both Fresh and aged TiO2 NPs efficiently induced mitochondrial dysfunction and activated Caspase-3/7 in a size-dependent manner. Using mitochondrial-DNA deficient (ρ0) AL cells, we further discovered that mitochondrial dysfunction made significant contribution to the size-dependent toxicity induced by TiO2 NPs during the aging process. Taken together, our data indicated that TiO2 NPs could significantly induced the cytotoxicity and genotoxicity in an aging time-independent and size-dependent manner, which were triggered by mitochondrial dysfunction. Our study suggested the necessity to include size as an additional parameter for the cautious monitoring of TiO2 NPs disposal before entering the environment.


Assuntos
Nanopartículas/toxicidade , Titânio/toxicidade , Animais , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Cricetinae , Dano ao DNA , Humanos , Testes de Toxicidade
2.
J Agric Food Chem ; 67(33): 9382-9389, 2019 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-31361959

RESUMO

Early stage exposure of foodborne substances, such as brightening agent titanium dioxide nanoparticles (TiO2 NPs), can cause long-term effects in adulthood. We aimed to explore the potential adverse effect of long-term dietary intake of TiO2 NPs. After feeding for 2-3 months from weaning, TiO2 NPs-exposed mice showed lower body weight and induced intestinal inflammation. However, this phenomenon was not observed in gut microbiota-removed mice. TiO2 NPs exposure rarely affected the diversity of microbial communities, but significantly decreased the abundance of several probiotic taxa including Bifidobacterium and Lactobacillus. Additionally, TiO2 NPs aggravated DSS-induced chronic colitis and immune response in vivo, and reduced the population of CD4+T cells, regulatory T cells, and macrophages in mesenteric lymph nodes. Therefore, dietary TiO2 NPs could interfere with the balance of immune system and dynamic of gut microbiome, which may result in low-grade intestinal inflammation and aggravated immunological response to external stimulus, thus introducing potential health risk.


Assuntos
Intestinos/efeitos dos fármacos , Intestinos/imunologia , Nanopartículas/metabolismo , Nanopartículas/toxicidade , Titânio/metabolismo , Titânio/toxicidade , Animais , Bactérias/classificação , Bactérias/efeitos dos fármacos , Bactérias/genética , Bactérias/isolamento & purificação , Peso Corporal/efeitos dos fármacos , Linfócitos T CD4-Positivos/efeitos dos fármacos , Linfócitos T CD4-Positivos/imunologia , Feminino , Microbioma Gastrointestinal/efeitos dos fármacos , Intestinos/microbiologia , Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Linfócitos T Reguladores/efeitos dos fármacos , Linfócitos T Reguladores/imunologia , Fatores de Tempo
3.
Aquat Toxicol ; 214: 105257, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31336221

RESUMO

The interactions between nanoparticles (NPs) and metals in aquatic environments may modify the bioavailability and toxicity of metals to organisms. In this study, we investigated the effects of titanium dioxide NPs (n-TiO2) on the bioconcentration, depuration, and neurotoxic effects of lead (Pb) in zebrafish larvae. Transmission electron microscopy coupled with energy-dispersive X-ray spectroscopy showed that Pb2+ was adsorbed by n-TiO2 to form NP-Pb complexes in suspension, and these complexes were observed in larval tissues. The bioconcentration of Pb in larvae along with the depuration rates of Pb were higher in the presence of n-TiO2 compared to when n-TiO2 was absent. Exposure to Pb alone induced the expression of the biomarker metallothionein, downregulated neurodevelopment-related genes, and reduced swimming activity of larvae. However, the addition of n-TiO2 to the exposure solution alleviated these effects. The results suggest that n-TiO2 can act as a carrier of Pb to increase its bioconcentration; however, the formation of NP-Pb complexes likely reduces the amount of free Pb2+, thereby reducing toxicity to larvae.


Assuntos
Chumbo/toxicidade , Nanopartículas/toxicidade , Titânio/toxicidade , Peixe-Zebra/metabolismo , Adsorção , Animais , Comportamento Animal/efeitos dos fármacos , Disponibilidade Biológica , Larva/efeitos dos fármacos , Larva/genética , Larva/ultraestrutura , Locomoção/efeitos dos fármacos , Metalotioneína/metabolismo , Nanopartículas/ultraestrutura , Suspensões , Transcrição Genética/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Peixe-Zebra/genética
4.
Environ Pollut ; 252(Pt B): 1764-1771, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31295695

RESUMO

Phagocytosis suppression induced by nanoparticles (NPs) exposure is increasingly reported in marine species. However, the mechanisms underlying this impact remain poorly understood. In order to improve our present understanding of the immunotoxicity of NPs, acute (96 h) TiO2 NP exposure and rescue trials via exogenous supply of Ca2+ were performed in the blood clam, Tegillarca granosa. The results show that the phagocytosis rate, cell viability, and intracellular Ca2+ concentration of haemocytes were significantly suppressed, whereas the intracellular ROS concentration of haemocytes significantly increased upon nTiO2 exposure. Exposure to nTiO2 also led to the significant downregulation of Caspase-3, Caspase-6, apoptosis regulator Bcl-2, Bcl-2-associated X, calmodulin kinase II, and calmodulin kinase kinase II. Furthermore, the toxic impacts of nTiO2 were partially mitigated by the addition of exogenous Ca2+, as indicated by the recovery tendency in almost all the measured parameters. The present study indicates that Ca2+ signaling could be one of the key pathways through which nTiO2 attacks phagocytosis.


Assuntos
Apoptose/efeitos dos fármacos , Arcidae/efeitos dos fármacos , Cálcio/farmacologia , Hemócitos/efeitos dos fármacos , Nanopartículas/toxicidade , Fagocitose/efeitos dos fármacos , Titânio/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Apoptose/genética , Arcidae/fisiologia , Cálcio/metabolismo , Sinalização do Cálcio/efeitos dos fármacos , Sinalização do Cálcio/genética , Sobrevivência Celular/efeitos dos fármacos , Regulação para Baixo , Hemócitos/patologia
5.
Aquat Toxicol ; 213: 105195, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31203167

RESUMO

Titanium dioxide nanoparticles (n-TiO2) are among the man-made nanomaterials that are predicted to be found at high concentrations in the aquatic environment. There, they likely co-exist with other chemical pollutants. Thus, n-TiO2 and other chemical pollutants can be taken up together or accumulate independently from each other in prey organisms of fish. This can lead to dietary exposure of fish to n-TiO2-chemical pollutant mixtures. In this study, we examine if simultaneous dietary exposure to n-TiO2 and 3,3',4,4'-Tetrachlorobiphenyl (PCB77) -used as a model compound for persistent organic pollutants with dioxin-like properties- can influence the uptake and toxicological response elicited by the respective other substance. Juvenile brown trout (Salmo trutta) were fed custom-made food pellets containing n-TiO2, PCB77 or n-TiO2+PCB77 mixtures for 15 days. Ti and PCB77 concentrations in the liver were measured by ICP-MS and GC-MS, respectively. Besides, n-TiO2 uptake was assessed using TEM. Combination effects on endpoints specific for PCB77 (i.e., cytochrome P450 1A (CYP1A) induction) and endpoints shared by both PCB77 and n-TiO2 (i.e., oxidative stress-related parameters) were measured in intestine and liver using RT-qPCR and enzyme activity assays. The results show that genes encoding for proteins/enzymes essential for tight junction function (zo-1) and ROS elimination (sod-1) were significantly upregulated in the intestine of fish exposed to n-TiO2 and PCB77 mixtures, but not in the single-substance treatments. Besides, n-TiO2 had a potentiating effect on PCB77-induced CYP1A and glutathione reductase (GR) expression/enzyme activity in the liver. This study shows that simultaneous dietary exposure to nanomaterials and traditional environmental pollutants might result in effects that are larger than observed for the substances alone, but that understanding the mechanistic basis of such effects remains challenging.


Assuntos
Dieta , Exposição Ambiental , Nanopartículas/toxicidade , Bifenilos Policlorados/toxicidade , Titânio/toxicidade , Truta/fisiologia , Animais , Biomarcadores/metabolismo , Citocromo P-450 CYP1A1/genética , Citocromo P-450 CYP1A1/metabolismo , Comportamento Alimentar , Regulação da Expressão Gênica/efeitos dos fármacos , Intestinos/efeitos dos fármacos , Fígado/efeitos dos fármacos , Fígado/metabolismo , Fígado/ultraestrutura , Metalotioneína/metabolismo , Nanopartículas/ultraestrutura , Estresse Oxidativo/efeitos dos fármacos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Poluentes Químicos da Água/toxicidade
6.
Chemosphere ; 233: 579-589, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31195263

RESUMO

Complex interactions have been established between nanoparticles (NPs) and heavy metals in real environments. Herein we used zebrafish embryos to investigate the influence of titanium dioxide NPs (n-TiO2) on the uptake, bioconcentration, and depuration, and toxicity of Pb. The formation of n-TiO2-Pb complexes was confirmed in an exposure suspension. An increase in Pb bioconcentration was observed in zebrafish embryos upon co-exposure to n-TiO2 and Pb; moreover, n-TiO2-Pb complexes could be found in the embryos, indicating the bioavailability of NPs. However, there was no difference in the depuration rates of Pb in the presence of n-TiO2. Metallothionein (MT) content was significantly increased upon exposure to Pb alone, and the content significantly increased even further upon co-exposure. A downregulation in the expression levels of the neurodevelopment-related genes gfap, syn2α, and elavl3 was observed in the embryos, and we also noted a reduction in the swimming speed of and the total distance traveled by the larvae. To summarize, our results indicate that n-TiO2 can act as an effective carrier of Pb to enhance its uptake, bioavailability, and toxicity in zebrafish embryos.


Assuntos
Embrião não Mamífero/fisiologia , Chumbo/toxicidade , Nanopartículas Metálicas/toxicidade , Titânio/toxicidade , Poluentes Químicos da Água/toxicidade , Peixe-Zebra/embriologia , Animais , Disponibilidade Biológica , Embrião não Mamífero/efeitos dos fármacos , Embrião não Mamífero/metabolismo , Larva/metabolismo , Metalotioneína/metabolismo , Nanopartículas/toxicidade , Peixe-Zebra/metabolismo
7.
Chemosphere ; 233: 363-372, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31176899

RESUMO

Titanium dioxide nanoparticles (TiO2 NPs) find applications in our day-to-day life because of unique physicochemical properties. Their release into the aquatic environment poses a possible risk to the organisms. However, the continuing exposure of NPs might reduce their bioavailability to marine organisms owing to aggregation and sedimentation in the aqueous systems thus significantly reducing their toxic impact. In this regard, the present study investigates the effect of continuous exposure of TiO2 NPs to marine microalgae Chlorella sp. under UV-A irradiation through "tanks in series" mode of experiments. In a three-cycle experiment, concentration of TiO2 NPs in the first cycle was fixed at 62.6 µM, and the interacted nanoparticles was subsequently exposed to fresh batches of algae in the next two cycles. After the interaction, the NPs underwent severe aggregation (mean hydrodynamic diameter 3000 ±â€¯18.2 nm after cycle I) leading to gravitational settling in the medium and thus decreased bioavailability. The aggregation can be attributed to interactions between the particles themselves (homo-aggregation) further aggravated by the presence of the algal cells (hetero-aggregation). Cellular viability after cycle I was found to be only 24.2 ±â€¯2.5%, and it was enhanced to 96.5 ±â€¯2.8% after the cycle III in the course of continuous exposure. The results were validated with estimation of oxidative stress markers such as intracellular ROS (total ROS, superoxide and hydroxyl radicals) and LPO after each cycle of exposure. The continuing decrease in the EPS across the cycles further confirmed the diminishing toxicity of the NPs.


Assuntos
Organismos Aquáticos/efeitos dos fármacos , Chlorella/efeitos dos fármacos , Microalgas/efeitos dos fármacos , Nanopartículas/toxicidade , Titânio/toxicidade , Poluentes Químicos da Água/toxicidade , Organismos Aquáticos/metabolismo , Disponibilidade Biológica , Chlorella/metabolismo , Exposição Ambiental , Microalgas/metabolismo , Modelos Teóricos , Nanopartículas/química , Estresse Oxidativo/efeitos dos fármacos , Tamanho da Partícula , Titânio/química , Titânio/metabolismo , Raios Ultravioleta , Poluentes Químicos da Água/química , Poluentes Químicos da Água/metabolismo
8.
Sci Total Environ ; 685: 19-27, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31170592

RESUMO

Few data are available about the effect of dimethylated forms (DMA) on aquatic organisms. As rarely a contaminant occurs alone, studies evaluating the combined effect of different contaminants in aquatic organisms are needed. In fact, the presence of nanomaterials, such as titanium dioxide nanoparticles (nTiO2), in the aquatic environment is now a reality due to its intensive production and use. So, this study evaluated the toxicological effects of DMA in an acute exposure condition and considered the potential influence of nTiO2 on the effects induced by DMA in the polychaete, Laeonereis culveri. The animals were exposed over 48 h to DMA (50 and 500 µg/l) alone or in combination with nTiO2 (1 mg/l). Biochemical parameters such as concentration of reactive oxygen species (ROS), glutathione-S-transferase (GST) activity, levels of reduced glutathione levels (GSH) and macromolecular (lipid and DNA) damage were evaluated, as well the DNA repair system. In addition, the accumulation of total As and the chemical speciation of the metalloid in the organisms was determined. The results showed that: (1) only the group exposed to 500 µg of DMA/l accumulated As and when co-exposed to nTiO2, this accumulation was not observed. (2) The levels of ROS increased in the group exposed to 50 µg/l of DMA alone and the effect was reversed when this group was co-exposed to nTiO2 (3) None of the treatments showed altered GST activity or GSH levels. (4) All groups that received nTiO2 (alone or in combination with DMA) showed lipid peroxidation. (5) The exposure to DMA (both concentrations) alone or in combination with nTiO2 induced DNA damage in L. culveri. These results showed that DMA exhibits a genotoxic effect and that co-exposure to nTiO2 had an influence on its toxicity. So the occurrence of both contaminants simultaneously can represent a threat to aquatic biota.


Assuntos
Ácido Cacodílico/toxicidade , Nanopartículas Metálicas/toxicidade , Poliquetos/fisiologia , Titânio/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Glutationa/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Estresse Oxidativo
9.
Sci Total Environ ; 686: 246-253, 2019 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-31181512

RESUMO

Nanoparticles (NPs) often serve as carriers of background toxins and enhance their toxicity on aquatic organisms such as Ceriodaphnia dubia (C. dubia). However, foods, especially algae, are also present in natural water and impacts this type of toxicity. This study investigated the effect of algae on the combined toxicity of nano-TiO2 and lead (Pb). A mixture of yeast-trout chow-cereal leaves (YTC) was also used as another model food. Results indicated that, both algae and YTC significantly reduce the combined toxicity of nano-TiO2 and Pb. Further investigation indicated that the ingestion of algae had minimal impacts on Pb uptake by, Pb depuration from, and Pb distribution within the C. dubia. Therefore, the toxicity reduction from algae ingestion should come from mechanisms other than the change in Pb mass and speciation in C. dubia, which will need future investigation. Nevertheless, the effect of food on the mitigation of combined toxicity of NPs and heavy metals must be considered when assessing the toxicity of nanoparticles in the natural environment because food always exists in natural waterbodies where aquatic organisms grow.


Assuntos
Clorófitas/fisiologia , Cladóceros/fisiologia , Chumbo/toxicidade , Titânio/toxicidade , Animais , Nanopartículas/toxicidade , Testes de Toxicidade , Poluentes Químicos da Água/toxicidade
10.
Ecotoxicol Environ Saf ; 181: 292-300, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31201961

RESUMO

The widespread use of titanium dioxide nanoparticles (NPs) and their inevitable release into aquatic environments have caused great concerns about their ecotoxicity. However, the chronic toxicity to TiO2 NPs of aquatic organisms has not been fully understood. In particular, research is lacking on the influence of the crystalline forms of TiO2 NPs on their mechanisms of toxicity. This study investigated the chronic toxicity (i.e., 21-day toxicity tests) of 5 types of TiO2 NPs with various percentages of crystalline forms on Daphnia magna. Results revealed that the crystalline form composed of 80% anatase and 20% rutile (i.e., the M1 form) had the highest energy band gap (i.e., Eg, the energy interval between the valence band edge and the conduction band edge) and caused maximal D. magna mortality compared with other crystalline forms. The crystalline form comprising 100% rutile (i.e., the R-S form) had the lowest Eg and exhibited a minimal effect on the physiological parameters of D. magna. Moreover, in a suitable environment without TiO2 NPs, D. magna progenies could recover to a normal physiological level (e.g., the mortalities of D. magna progenies were lower than those of parental D. magna that were exposed to TiO2 NPs at a concentration of 0.5 mg/L). Correlation analysis revealed that the body length, time of first brood, and number of neonates in the first brood of D. magna were negatively correlated with titanium accumulation in vivo. Furthermore, the indices of Ti accumulation and the product of Eg and Ti accumulation (i.e., Eg × Ti accumulation) were positively correlated (p < 0.05) with D. magna mortality, thus indicating that crystalline forms with a high Eg may cause severe toxicity to aquatic organisms at the same TiO2 bioaccumulation level.


Assuntos
Nanopartículas Metálicas/toxicidade , Titânio/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Correlação de Dados , Daphnia/efeitos dos fármacos , Daphnia/fisiologia , Humanos , Nanopartículas Metálicas/química , Titânio/química , Testes de Toxicidade Crônica , Poluentes Químicos da Água/química
11.
Environ Sci Pollut Res Int ; 26(21): 21394-21403, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31124068

RESUMO

The use of P25 TiO2 NPs in consumer products, their release, and environmental accumulation will have harmful effects on the coastal ecosystems. The sensitivity to TiO2 NPs may vary depending on the structural property and physiological mechanism of algal species. Therefore, the present study investigates the differences in sensitivity of two marine algae, Dunaliella salina and Chlorella sp., towards P25 TiO2 NPs. Among the two species, Chlorella sp. was more sensitive to TiO2 NPs than Dunaliella salina. The different working concentrations of TiO2 NPs, 0.1, 1, and 10 mg L-1, were selected based on the EC50 value. The EC50 value of TiO2 NPs for Dunaliella salina was found to be 1.8 and 13.3 mg L-1 under UV-A and dark conditions, respectively. The EC50 value of TiO2 NPs for Chlorella sp. was found to be 1.6 and 5.0 mg L-1 under UV-A and dark conditions, respectively. The decrease in cell viability was significantly higher for Chlorella sp. compared to Dunaliella salina at all concentrations except 0.1 mg L-1. The cellular viability data was in correlation with the oxidative stress markers such as total ROS and LPO. A concentration-dependent increase in ROS and lipid peroxidation was noted under UV-A exposure, which was higher in Chlorella sp. compared to Dunaliella salina. The decrease in the SOD activity with NP concentration was more in Dunaliella salina than Chlorella sp. under both conditions, whereas Chlorella sp. showed increased CAT activity with increasing concentration. The uptake of TiO2 NPs was more in Chlorella sp. than Dunaliella salina.


Assuntos
Microalgas/fisiologia , Nanopartículas/toxicidade , Titânio/toxicidade , Poluentes Químicos da Água/toxicidade , Chlorella , Ecossistema , Peroxidação de Lipídeos , Estresse Oxidativo
12.
Aquat Toxicol ; 212: 28-36, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31048143

RESUMO

Titanium dioxide nanoparticles (TiO2 NPs) are widely used in various products and inevitably released with different sizes and forms into aquatic environment. The purpose of this study was to assess the differential immune toxicity of TiO2 NPs with size difference on mussel hemocytes using flow cytometry (FCM) assays. Hemocyte parameters, including total hemocyte count (THC), hemocyte mortality (HM), phagocytosis activity (PA), lysosomal content (LC), esterase activity (EA), mitochondrial number (MN), mitochondrial membrane potential (MMP) and reactive oxygen species content (ROS) were evaluated in the mussels Mytilus coruscus exposed to two types of TiO2 NPs (25nm & 100nm: 0.1, 1, 10 mg/L, respectively). In general, size- and concentration-dependent toxicity was pronounced with 25nm-NP and highest concentration (10mg/L) being the most toxic. Alhough a slight recovery from the TiO2 exposure was observed, significant carry-over effects were still detected. These results highlight the importance of differential size effects of metal oxide NPs on toxicity mechanisms in aquatic animals.


Assuntos
Hemócitos/efeitos dos fármacos , Mytilus/efeitos dos fármacos , Nanopartículas/toxicidade , Tamanho da Partícula , Titânio/toxicidade , Análise de Variância , Animais , Contagem de Células , Esterases/metabolismo , Hemócitos/citologia , Lisossomos/efeitos dos fármacos , Nanopartículas/ultraestrutura , Análise de Componente Principal , Poluentes Químicos da Água/toxicidade
13.
Aquat Toxicol ; 212: 47-53, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31071656

RESUMO

The increasing production of engineered inorganic nanoparticles (EINPs) elevates their release into aquatic ecosystems raising concerns about associated environmental risks. Numerous investigations indicate sediments as the final sink, facilitating the exposure of benthic species to EINPs. Although reports of sub-lethal EINP effects on benthic species are increasing, the importance of exposure pathways (either waterborne or dietary) is poorly understood. This study investigates the influence of two EINPs, namely titanium dioxide (nTiO2) and silver (nAg), on the benthic model organism Gammarus fossarum specifically addressing the relative relevance of these pathways. For each type of EINP an individual 30-day long bioassay was conducted, applying a two-factorial test design. The factors include the presence or absence of the EINPs (nTiO2: ∼80 nm, 4 mg/L or nAg: ∼30 nm, 0.125 mg/L; n = 30) in the water phase (waterborne), combined with a preceding 6-day long aging of their diet (black alder leaves) also in presence or absence of the EINPs (dietary). Response variables were mortality, food consumption, feces production and energy assimilation. Additionally, the physiological fitness was examined using lipid content and dry weight of the organisms as measures. Results revealed a significantly reduced energy assimilation (up to ∼30%) in G. fossarum induced by waterborne exposure towards nTiO2. In contrast, the dietary exposure towards nAg significantly increased the organisms' energy assimilation (up to ∼50%). Hence, exposure pathway dependent effects of EINPs cannot be generalized and remain particle specific resting upon their intrinsic properties affecting their potential to interact with the surrounding environment. As a result of the different properties of the EINPs used in this study, we clearly demonstrated variations in type and direction of observed effects in G. fossarum. The results of the present study are thus supporting current approaches for nano-specific grouping that might enable an enhanced accuracy in predicting EINP effects facilitating their environmental risk assessment.


Assuntos
Anfípodes/efeitos dos fármacos , Exposição Ambiental , Nanopartículas Metálicas/toxicidade , Prata/toxicidade , Titânio/toxicidade , Animais , Biomassa , Metabolismo Energético/efeitos dos fármacos , Fezes , Comportamento Alimentar/efeitos dos fármacos , Lipídeos/análise , Tamanho da Partícula , Folhas de Planta/metabolismo , Poluentes Químicos da Água/toxicidade
14.
Chemosphere ; 230: 567-577, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31125885

RESUMO

Effluent from wastewater treatment plants contains a wide variety of engineered nanoparticles (ENPs) released from different sources. Although single type ENPs have been studied extensively with respect to their environmental impact, ENPs in mixed forms have not been investigated much at environmentally relevant concentrations. This study was designed to test the effect of mixed ENPs at three combinations and concentrations on an aquatic bacterial community. After mixing artificial treated wastewater with river water and exposing the microbial community to ENPs for three days, the ENPs were characterized by SP-ICP-MS. Results from this study showed that: 1) the size distribution of Ti and Zn at the beginning and end of the experiment did not vary much among all tested conditions. For Ag, the most frequent size increased more than 2-fold when the highest Ag ENPs were added; 2) particle concentrations of ENPs generally correlated positively with added concentrations; 3) dissolved Zn and Ag increased significantly as a result of spike; and 4) the bacterial community structure was shifted significantly as a consequence of ENPs' addition. With the dominant population being suppressed, the community exposed to ENPs became more diverse and even. Surprisingly, further increase of the doses of the three ENPs did not bring significant change to the microbial community. These results revealed that ENPs could bring significant impacts to prokaryotes even at low concentrations. But these impacts do not necessarily correlate positively with doses.


Assuntos
Nanopartículas Metálicas/toxicidade , Microbiota/efeitos dos fármacos , Rios/microbiologia , Prata/toxicidade , Titânio/toxicidade , Poluentes Químicos da Água/toxicidade , Óxido de Zinco/toxicidade , Relação Dose-Resposta a Droga , Modelos Teóricos , Águas Residuárias/química
15.
Environ Sci Pollut Res Int ; 26(21): 21556-21564, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31127514

RESUMO

The evaluation of the toxicological effects of titanium dioxide nanoparticles (TiO2NPs) is increasingly important due to their growing occupational and industrial use. Curcumin is a yellow curry spice with a long history of use in herbal medicine and has numerous protective potentials such as antioxidant, antimicrobial, anti-inflammatory, and anti-apoptotic effects. Accordingly, we tested the hypothesis that curcumin could ameliorate TiO2NP-induced cardiotoxic and genotoxic effects in adult male albino rats. For this purpose, 48 adult male albino rats were randomized into five groups; all treatment was by oral gavage once daily for 90 days: group I (8 rats), untreated control; group II (16 rats), subdivided into vehicle control IIa (8 rats) received saline and vehicle control IIb (8 rats) received corn oil; group III (8 rats) orally gavaged with curcumin dissolved in 0.5 ml corn oil at a dose of 200 mg/kg b.w./day; group IV treated with TiO2NPs at a dose of 1200 mg/kg b.w./day (1/10 LD50) suspended in 1 ml of 0.9% saline; group V treated with curcumin + TiO2NPs (the same previously mentioned doses). Curcumin was orally gavaged for 7 days before TiO2NPs treatment was initiated, and then they received TiO2NPs along with curcumin at the same doses for 90 days. TiO2NPs administration resulted in several myocardial cytomorphic changes as structurally disorganized, degenerated, and apoptotic cardiomyocytes and the newly implemented 3-nitrotyrosine immune expression rendered strong evidence that these effects derived from the cardio myocellular oxidative burden. Furthermore, comet assay results confirmed TiO2NP-related DNA damage. Remarkably, all these changes are partially mitigated in rats treated with both curcumin and TiO2NPs. Our results suggest that concurrent curcumin treatment has a beneficial role in ameliorating TiO2NP-induced cardiotoxicity and this may be mediated by its antioxidative property.


Assuntos
Antioxidantes/farmacologia , Curcumina/farmacologia , Nanopartículas/toxicidade , Titânio/toxicidade , Animais , Apoptose/efeitos dos fármacos , Cardiotoxicidade , Dano ao DNA/efeitos dos fármacos , Coração/efeitos dos fármacos , Masculino , Camundongos , Oxirredução , Oxirredutases , Coelhos , Distribuição Aleatória , Ratos , Titânio/química
16.
Environ Pollut ; 251: 407-414, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31103000

RESUMO

The widespread application of commercial TiO2 NPs inevitably leads to their release into environmental waters through various ways. TiO2 NPs released into water might be absorbed by and react with periphytic biofilms, which are a kind of aquatic environmental media of important ecological significance, and influence the physiological activity and ecological function of periphytic biofilms. This study investigated the effects of exposure to 1 mg/L and 5 mg/L of TiO2 NPs on periphytic biofilms cultured indoors. After a 10-day exposure to TiO2 NPs, the growth (measured by chlorophyll-a content) of microalgal community was inhibited greatly (more than 60%); however, the primary production (indicated by quantum yield) of periphytic biofilms maintained changeless. As for bacteria, TiO2 NP-exposure increased the bacterial diversity and altered the composition structure. Significant changes were observed in the bacterial communities at the class level, mainly including Alphaproteobacteria, Gammaproteobacteria, Cytophagia, Flavobacteriia, Sphingobacteriia, Synechococcophycideae and Oscillatoriophycideae. The enhancement of metabolic activities (the production of extracellular polymeric substances, especially proteins content increased by 48.51%) of periphytic biofilms was a resistance mechanism to toxicity of NPs. As for extracellular enzyme activities of periphytic biofilms, alkaline phosphatase activity was inhibited (22.43%) after exposed to 5 mg/L of TiO2 NPs, which posed a threat to phosphorus metabolism of periphytic biofilms. Overall, this study demonstrated that 1 mg/L and 5 mg/L of TiO2 NPs negatively influenced physiological activities and ecological functions of periphytic biofilms, highlighting that the ecological risks of TiO2 NPs should be paid attention to.


Assuntos
Biofilmes/efeitos dos fármacos , Exposição Ambiental/efeitos adversos , Perifíton/efeitos dos fármacos , Titânio/toxicidade , Poluentes Químicos da Água/toxicidade , Bactérias/classificação , Bactérias/efeitos dos fármacos , Bactérias/metabolismo , Microalgas/efeitos dos fármacos , Microalgas/crescimento & desenvolvimento , Microalgas/metabolismo , Nanopartículas/química , Nanopartículas/metabolismo , Titânio/química , Titânio/metabolismo , Poluentes Químicos da Água/química , Poluentes Químicos da Água/metabolismo
17.
World J Microbiol Biotechnol ; 35(6): 81, 2019 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-31134389

RESUMO

TiO2 nanoparticles (TiO2NPs) is one of the most widely used nanomaterials. Arbuscular mycorrhizal fungi (AMF) are an important and widely distributed group of soil microorganisms, which promote the absorption of nutrients by host plants and increase their tolerance to contaminants. However, the effects and mechanisms of AMF on plant TiO2NPs tolerance in wetland habitats are not clear. In this experiment, under the conditions of three soil moisture contents (drought 50%, normal 70% and flooding 100%) and four TiO2NPs concentrations (0, 100, 200 and 500 mg kg-1), the effects of Funneliformis mosseae on the growth, antioxidant enzyme activities, osmotic substances and the absorption and accumulation of Ti in the Phragmites australis (reed) seedlings were studied. The results showed that the inoculation of F. mosseae under three moisture content conditions significantly increased the plant nutrition and root activities of reeds. Compared with the non-inoculated control, inoculation with F. mosseae increased the activities of antioxidant enzymes, the contents of chlorophyll, proline, soluble protein, and free amino acids, and significantly reduced the contents of malondialdehyde (MDA) and reactive oxygen species (ROS) of leaves. The accumulating ability of inoculated reeds to Ti was significantly higher than that of non-inoculated controls (P < 0.05), and inoculation of F. mosseae changed the distribution of Ti in reeds, increased the accumulation of Ti in roots. It's confirmed that inoculation of F. mosseae under three water conditions could improve the plant growth and nutrition, the activities of antioxidant enzymes, and enhance the reeds tolerance to TiO2NPs in this study.


Assuntos
Glomeromycota/fisiologia , Nanopartículas/toxicidade , Poaceae/efeitos dos fármacos , Poaceae/microbiologia , Plântula/crescimento & desenvolvimento , Estresse Fisiológico , Titânio/toxicidade , Água/metabolismo , Aminoácidos/metabolismo , Antioxidantes/metabolismo , Clorofila/metabolismo , Secas , Tolerância a Medicamentos , Malondialdeído/metabolismo , Osmose , Desenvolvimento Vegetal , Folhas de Planta/metabolismo , Proteínas de Plantas/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Raízes de Plantas/microbiologia , Poaceae/crescimento & desenvolvimento , Prolina/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Plântula/efeitos dos fármacos , Plântula/microbiologia , Microbiologia do Solo , Áreas Alagadas
18.
J Toxicol Sci ; 44(5): 335-345, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31068539

RESUMO

Titanium dioxide nanoparticles (TiO2-NPs) are used to improve the aesthetic of toothpaste. While TiO2-NPs have been used safely in toothpaste products for a long time, there haven't been studies to determine whether absorption of TiO2-NPs by the mucous membranes in the mouth induces pathogenic conditions. Here, we assessed whether TiO2-NPs induce cyclooxygenase-2 (COX-2) and investigated the molecular mechanisms underlying the pro-inflammatory effect of TiO2-NPs on human periodontal ligament (PDL) cells. Treatment of PDL cells with TiO2-NPs led to induction of both COX-2 mRNA and protein expression. TiO2-NPs stimulated the nuclear translocation of nuclear factor-kappaB (NF-κB) as well as its DNA binding by inducing phosphorylation and subsequent degradation of the inhibitory protein IκBα in PDL cells. TiO2-NPs treatment resulted in rapid activation of extracellular signal-regulated kinase (ERK)1/2 and Akt, which could be upstream of NF-κB. Treatment of PDL cells with both the MEK1/2 inhibitor U0126 and the PI3K inhibitor LY294002 strongly attenuated TiO2-NPs-induced activation of NF-κB, and also the expression of COX-2. PDL cells treated with TiO2-NPs exhibited increased accumulation of intracellular reactive oxygen species (ROS). Pretreatment of cells with ROS scavenger N-acetyl cysteine (NAC) abrogated the stimulatory effect of TiO2-NPs on p65, p50, and COX-2 expression. In conclusion, ROS, concomitantly overproduced by TiO2-NPs, induce COX-2 expression through activation of NF-κB signaling, which may contribute to the inflammatory effect of PDL cells.


Assuntos
Ciclo-Oxigenase 2/metabolismo , Nanopartículas/toxicidade , Ligamento Periodontal/citologia , Espécies Reativas de Oxigênio/metabolismo , Titânio/toxicidade , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Humanos , Proteínas Quinases Ativadas por Mitógeno/metabolismo , NF-kappa B/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais/efeitos dos fármacos
19.
Int J Nanomedicine ; 14: 1919-1936, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30936694

RESUMO

Purpose: This study evaluated the effects of titanium dioxide nanoparticles (TiO2 NPs) on liver and intestine of normal rats. Methods: Male rats were divided into four groups as follows: 1) control rats, 2) control rats that orally received 10 mg/kg TiO2 NPs, 3) control rats that orally received 50 mg/kg TiO2 NPs, and 4) control rats that orally received 100 mg/kg TiO2 NPs. After 30 days, the NLRP3 inflammasome pathway (NLRP3, caspase-1, and IL-1ß), antioxidant pathway (superoxide dismutase [SOD], glutathione peroxidase [GPx], and catalase [CAT]), inflammatory pathway (inducible nitric oxide synthase [iNOS] and tumor necrosis factor-α [TNF-α]), and the apoptosis pathway (p53, Bax, Bcl-2, and caspase-3) were determined in the intestine and liver of the rats. H&E and Masson's trichrome (MT) staining as well as TUNEL assay were used to examine the liver and the intestine. Biochemical factors, cytotoxicity, ROS generation, and apoptosis rate were also determined in HepG2 and Caco-2 cells. Results: TiO2 NPs in a dose-dependent manner increased cytotoxicity, oxidative stress, and apoptosis rate in Caco-2 and HepG2 cells. The administration of TiO2 NPs significantly reduced antioxidant enzyme activity and gene expressions (SOD, CAT, and GPx) as well as glutathione (GSH) levels and total antioxidant capacity (TAC) in a dose-dependent manner. TiO2 NPs also induced the apoptosis pathway and inflammatory pathway gene expressions and caspase-3 activity in the intestine and liver. TUNEL assay was in agreement with gene expressions. TiO2 NPs also led to morphological changes in the liver and intestine. Conclusion: TiO2 NPs could have cytotoxic effects on the intestine and liver structure and function by inducing oxidative stress, inflammation, and apoptosis.


Assuntos
Apoptose , Inflamassomos/metabolismo , Intestinos/patologia , Fígado/patologia , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Nanopartículas/toxicidade , Estresse Oxidativo , Titânio/toxicidade , Animais , Antioxidantes/metabolismo , Apoptose/efeitos dos fármacos , Células CACO-2 , Catalase/metabolismo , Glutationa/metabolismo , Glutationa Peroxidase/metabolismo , Células Hep G2 , Humanos , Inflamação/patologia , Masculino , Estresse Oxidativo/efeitos dos fármacos , Ratos Wistar , Superóxido Dismutase/metabolismo
20.
Chemosphere ; 224: 680-688, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30849629

RESUMO

Advancement in nanotechnology has increased production of nanoparticles which initiates concerns for freshwater ecosystems. Nanosized TiO2 is one of the most used materials and its ecotoxicity has been extensively studied. Here, a freshwater microcosm experiment was performed to investigate the effects of nanosized (10, 60, and 100 nm) and bulk TiO2 at 1 g L-1 on the alteration in community structure of fungal decomposers and the consequences on litter decomposition of Typha angustifolia leaves. After 209 days of exposure, the decomposition rate was significantly higher in 100 nm TiO2 treatment compared to the control, which was caused by its promotion on fungal biomass and metabolic activity. Therefore, the study provides the multifaceted evidences for different effects of TiO2 with varied sizes on T. angustifolia leaf decomposition and highlights the importance of understanding the potential effects of varying sizes and long-term exposure in nanoparticle risk assessments.


Assuntos
Água Doce/química , Nanopartículas/química , Folhas de Planta/efeitos dos fármacos , Titânio/toxicidade , Biomassa , Ecossistema , Fungos/efeitos dos fármacos , Folhas de Planta/metabolismo , Typhaceae/efeitos dos fármacos
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