Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.705
Filtrar
1.
Aquat Toxicol ; 227: 105582, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32823071

RESUMO

While it is likely that ENPs may occur together with other contaminants in nature, the combined effects of exposure to both ENPs and environmental contaminants are not studied sufficiently. In this study, we investigated the acute and sublethal toxicity of PVP coated silver nanoparticles (AgNP) and ionic silver (Ag+; administered as AgNO3) to the marine copepod Calanus finmarchicus. We further studied effects of single exposures to AgNPs (nominal concentrations: low 15 µg L-1 NPL, high 150 µg L-1 NPH) or Ag+ (60 µg L-1), and effects of co-exposure to AgNPs, Ag+ and the water-soluble fraction (WSF; 100 µg L-1) of a crude oil (AgNP + WSF; Ag++WSF). The gene expression and the activity of antioxidant defense enzymes SOD, CAT and GST, as well as the gene expression of HSP90 and CYP330A1 were determined as sublethal endpoints. Results show that Ag+ was more acutely toxic compared to AgNPs, with 96 h LC50 concentrations of 403 µg L-1 for AgNPs, and 147 µg L-1 for Ag+. Organismal uptake of Ag following exposure was similar for AgNP and Ag+, and was not significantly different when co-exposed to WSF. Exposure to AgNPs alone caused increases in gene expressions of GST and SOD, whereas WSF exposure caused an induction in SOD. Responses in enzyme activities were generally low, with significant effects observed only on SOD activity in NPL and WSF exposures and on GST activity in NPL and NPH exposures. Combined AgNP and WSF exposures caused slightly altered responses in expression of SOD, GST and CYP330A1 genes compared to the single exposures of either AgNPs or WSF. However, there was no clear pattern of cumulative effects caused by co-exposures of AgNPs and WSF. The present study indicates that the exposure to AgNPs, Ag+, and to a lesser degree WSF cause an oxidative stress response in C. finmarchicus, which was slightly, but mostly not significantly altered in combined exposures. This indicated that the combined effects between Ag and WSF are relatively limited, at least with regard to oxidative stress.


Assuntos
Copépodes/efeitos dos fármacos , Nanopartículas Metálicas/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Petróleo/toxicidade , Prata/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Antioxidantes/metabolismo , Copépodes/genética , Copépodes/metabolismo , Interações Medicamentosas , Expressão Gênica/efeitos dos fármacos , Íons , Nanopartículas Metálicas/química , Estresse Oxidativo/genética , Água do Mar/química , Prata/química , Solubilidade , Testes de Toxicidade Aguda , Testes de Toxicidade Subaguda , Poluentes Químicos da Água/química
2.
Ecotoxicol Environ Saf ; 204: 111070, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32763567

RESUMO

Silver nanoparticles (AgNPs) are widely used as antimicrobial agents and resulted in their accumulation in environment. The purpose of this study was to investigate the detailed molecular mechanisms underlying AgNP-induced lung cellular senescence which has been proposed as a pathogenic driver of chronic lung disease. Herein, we demonstrate that exposure to AgNPs elevates multiple senescence biomarkers in lung cells, with cell cycle arrest in the G2/M phase, and potently activates genes of the senescence-associated secretory phenotype (SASP) in human fetal lung fibroblast cell line MRC5. Fluorescence-based assay also reveals that apoptosis induced by AgNPs is associated with senescence. Furthermore, we show that AgNPs cause premature senescence through an increase in transcription factor nuclear factor kappa B (NF-κB), cyclooxygenase-2 (COX2) expression and over-production of prostaglandin E2 (PGE2) in lung cells. Inhibition of COX2 reduces AgNPs-induced senescence to a normal level. Moreover, AgNPs also induce upregulation of COX2 and accelerate lung cellular senescence in vivo and cause mild fibrosis in the lung tissue of mice. Taken together, our studies support a critical role of AgNPs in the induction of lung cellular senescence via the upregulation of the COX2/PGE2 intracrine pathway, and suggest the adverse effects to the human respiratory system.


Assuntos
Senescência Celular/efeitos dos fármacos , Ciclo-Oxigenase 2/metabolismo , Dinoprostona/metabolismo , Pulmão/efeitos dos fármacos , Nanopartículas Metálicas/toxicidade , Prata/toxicidade , Animais , Apoptose/efeitos dos fármacos , Linhagem Celular , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Fibroblastos/patologia , Humanos , Pulmão/metabolismo , Pulmão/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , NF-kappa B/metabolismo , Prata/metabolismo
3.
Toxicol Lett ; 332: 118-129, 2020 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-32659471

RESUMO

Silver-based antimicrobials are widely used topically to treat infections associated with multi-drug resistant (MDR) pathogens. Expanding this topical use to aerosols to treat lung infections requires understanding and preventing silver toxicity in the respiratory tract. A key mechanism resulting in silver-induced toxicity is the production of reactive oxygen species (ROS). In this study, we have verified ROS generation in silver-treated bronchial epithelial cells prompting evaluation of three antioxidants, N-acetyl cysteine (NAC), ascorbic acid, and melatonin, to identify potential prophylactic agents. Among them, NAC was the only candidate that abrogated the ROS generation in response to silver acetate exposure resulting in the rescue of these cells from silver-associated toxicity. Further, this protective effect directly translated to preservation of metabolic activity, as demonstrated by the normal levels of citric acid cycle metabolites in NAC-pretreated silver acetate-exposed cells. Because the citric acid cycle remained functional, silver-exposed cells pre-incubated with NAC demonstrated significantly higher levels of adenosine triphosphate levels compared with NAC-free controls. Moreover, we found that this prodigious capacity of NAC to rescue silver acetate-exposed cells was due not only to its antioxidant activity, but also to its ability to directly bind silver. Despite binding to silver, NAC did not alter the antimicrobial activity of silver acetate.


Assuntos
Acetilcisteína/farmacologia , Antibacterianos/farmacologia , Depuradores de Radicais Livres/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Prata/farmacologia , Prata/toxicidade , Acetatos/farmacologia , Trifosfato de Adenosina/metabolismo , Ácido Ascórbico/farmacologia , Linhagem Celular , Cromatografia Gasosa-Espectrometria de Massas , Glutationa/metabolismo , Humanos , Melatonina/farmacologia , Testes de Sensibilidade Microbiana , Compostos de Prata/farmacologia , Superóxidos/metabolismo
4.
Environ Sci Pollut Res Int ; 27(31): 38871-38880, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32638302

RESUMO

The present study was designed to investigate the nephrotoxicity of silver nanoparticles (AgNPs; 80 mg/kg; > 100 nm) and to evaluate the protective effect exercised by Beta vulgaris (beetroot) juice (RBR; 200 mg/kg) on male rats' kidney. Serum-specific parameters (urea, creatinine, electrolytes and histopathology of kidney tissue) were examined to assess the AgNPs nephrotoxicity effect. Moreover, this study analysed oxidative stress (lipid peroxidation, glutathione, superoxide dismutase and catalase) and anti-apoptotic markers (Bcl-2). AgNPs intoxication increased kidney function marker levels and lipid peroxidation and decreased the glutathione, superoxide dismutase and catalase activities in kidney tissue. Additionally, Bcl-2 expression was downregulated following AgNPs intoxication. Moreover, AgNPs induced a significant increase in renal DNA damage displayed as an elevation in tail length, tail DNA percentage and tail moment. Interestingly, RBR post-treatment restored the biochemical and histological alterations induced by AgNPs exposure, reflecting its nephroprotective effect. Collectively, the present data suggest that RBR could be used as a potential therapeutic intervention to prevent AgNPs-induced nephrotoxicity.


Assuntos
Beta vulgaris , Nanopartículas Metálicas/toxicidade , Animais , Antioxidantes , Rim , Peroxidação de Lipídeos , Masculino , Estresse Oxidativo , Ratos , Prata/toxicidade , Superóxido Dismutase
5.
Int J Nanomedicine ; 15: 3471-3482, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32547008

RESUMO

Introduction: Nanoparticles are at the forefront of rapidly developing nanotechnology and have gained much attention for their application as an effective drug delivery system and as a mediated therapeutic agent for cancer. However, the cytotoxicity of nanoparticles is still relatively unknown and, therefore, additional study is required in order to elucidate the potential toxicity of these nanoparticles on cells. Materials and Methods: Thus, the following work aimed to investigate the capability of Beta vulgaris (beetroot) water extract (BWE; 200 mg/kg) to protect hepatic tissue following silver nanoparticles (AgNPs; 80 mg/kg; >100 nm) intoxication in male rats. Results: AgNPs-intoxication elevated the liver function markers - including serum transaminases and alkaline phosphatase activities - and decreased serum levels of albumin and total proteins, in addition to disturbing the oxidation homeostasis. This is evidenced by the increased lipid peroxidation, the depleted glutathione, and the suppressed activity of superoxide dismutase and catalase. In addition, an apoptotic reaction was observed following AgNPs treatment, as indicated by the up-regulation of p53 and down-regulating Bcl-2 expressions, examined by the immunohistochemistry method. Furthermore, AgNPs exhibited a marked elevation in liver DNA damage that was indicated by an increase in tail length, tail DNA% and tail movement. However, BWE eliminated the biochemical and histological alterations, reflecting its hepatoprotection effect in response to AgNPs. Discussion: Collectively, the present data suggest that BWE could be used following AgNPs as a potential therapeutic intervention to minimize AgNPs-induced liver toxicity.


Assuntos
Beta vulgaris/química , Sucos de Frutas e Vegetais , Fígado/patologia , Nanopartículas Metálicas/toxicidade , Prata/toxicidade , Animais , Dano ao DNA , Fragmentação do DNA/efeitos dos fármacos , Peroxidação de Lipídeos/efeitos dos fármacos , Fígado/efeitos dos fármacos , Testes de Função Hepática , Masculino , Nanopartículas Metálicas/ultraestrutura , Estresse Oxidativo/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Ratos Sprague-Dawley , Superóxido Dismutase/metabolismo , Proteína Supressora de Tumor p53/metabolismo
6.
Aquat Toxicol ; 225: 105543, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32585540

RESUMO

Species sensitivity distributions (SSDs) are used in chemical safety assessments to derive predicted-no-effect-concentrations (PNECs) for substances with a sufficient amount of relevant and reliable ecotoxicity data available. For engineered nanomaterials (ENMs), ecotoxicity data are often compromised by poor reproducibility and the lack of nano-specific characterization needed describe an ENM under test exposure conditions. This may influence the outcome of SSD modelling and hence the regulatory decision-making. This study investigates how the outcome of SSD modelling is influenced by: 1) Selecting input data based on the nano-specific "nanoCRED" reliability criteria, 2) Direct SSD modelling avoiding extrapolation of data by including long-term/chronic NOECs only, and 3) Weighting data according to their nano-specific quality, the number of data available for each species, and the trophic level abundance in the ecosystem. Endpoints from freshwater ecotoxicity studies were collected for the representative nanomaterials NM-300 K (silver) and NM-105 (titanium dioxide), evaluated for regulatory reliability and scored according to the level of nano-specific characterization conducted. The compiled datasets are unique in exclusively dealing with representative ENMs showing minimal batch-to-batch variation. The majority of studies were evaluated as regulatory reliable, while the degree of nano-specific characterization varied greatly. The datasets for NM-300 K and NM-105 were used as input to the nano-weighted n-SSWD model, the probabilistic PSSD+, and the conventional SSD Generator by the US EPA. The conventional SSD generally yielded the most conservative, but least precise HC5 values, with 95 % confidence intervals up to 100-fold wider than the other models. The inclusion of regulatory reliable data only, had little effect on the HC5 generated by the conventional SSD and the PSSD+, whereas the n-SSWD estimated different HC5 values based on data segregated according to reliability, especially for NM-105. The n-SSWD weighting of data significantly affected the estimated HC5 values, however in different ways for the sub-datasets of NM-300 K and NM-105. For NM-300 K, the inclusion of NOECs only in the weighted n-SSWD yielded the most conservative HC5 of all datasets and models (a HC5 based on NOECs only could not be estimated for NM-105, due to limited number of data). Overall, the estimated HC5 values of all models are within a relatively limited concentration range of 25-100 ng Ag/L for NM-300 K and 1-15 µgTiO2/L for NM-105.


Assuntos
Nanoestruturas/toxicidade , Testes de Toxicidade/métodos , Poluentes Químicos da Água/toxicidade , Ecossistema , Água Doce/química , Reprodutibilidade dos Testes , Medição de Risco , Prata/toxicidade , Titânio/toxicidade
7.
Aquat Toxicol ; 225: 105549, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32599437

RESUMO

Efficient antibacterial and antifungal properties of silver nanoparticles (AgNPs) sparked its commercial application in several industrial and household products. Drastic increase of AgNPs production raised concerns over aquatic organisms' exposure. The toxic dose, mechanism of toxicity, physiological damages, gene expression alteration, hematological and blood parameter distortion by AgNP needs to be investigated to explore inevitable risk in aquatic animals. In this study, rainbow trout (Oncorhynchus mykiss) (122.4 ± 1.4 g, 23.8 ± 0.7 cm) were exposed to colloidal AgNPs (28.3 ± 12.6 um) to determine the lethal concentration (LC50)(8.9 mg/l). Sub-lethal concentrations (10 %LC50, 25 %LC50, plus LC50 value) impact on hematologic, histological and molecular responses were evaluated. Results showed sever damage to blood cells morphology, and hematologic parameters change including RBC, WBC, Hct and Hb in all AgNP-treated groups. Histological damage in gill and liver of exposed fish were observed. Significant up-regulating of HSP70 and P53 genes were detected in response to AgNPs, whereas, it was found that in comparison to HSP70 gene, P53 induction occurred in lower AgNPs concentrations and lower exposure time. These results indicate adversely effects of AgNPs exposure to aquatic environments.


Assuntos
Nanopartículas Metálicas/toxicidade , Oncorhynchus mykiss/fisiologia , Prata/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Brânquias/química , Oncorhynchus mykiss/metabolismo
8.
Nanotoxicology ; 14(7): 893-907, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32529924

RESUMO

This study aimed to evaluate the effects of an intratesticular injection of silver nanoparticles (AgNPs) on reproductive parameters and health of rats, and to evaluate the AgNPs biodistribution in order to develop a nanotechnological contraceptive agent for male animals. Treated animals received 220 µL of AgNPs solution (0.46 µg-Ag/ml) in each testicle and were euthanized: seven, 14, 28, and 56 days after injection. A significant decrease (p < 0.05) in the percentage of motile sperm in D7 (8.8%) was observed, comparing to the control (73.3%), D14 (86.0%), D28 (68.2%), and D56 (90.0%) groups. D7 group also presented a decrease (p < 0.05) in the percentage of normal spermatozoa. Additionally, D7 group showed an increase (p < 0.05) in abnormal midpiece and sperm head morphology compared to the Control group. Seminiferous tubules presented all germline cell types and spermatozoa for all groups. However, D7 group did not present spermatozoa in the epididymis, whereas some spermatozoa and cellular debris were visible in D14 and D28 groups. All animals presented hematological parameters, creatinine, and alanine aminotransferase values within the normal limits for Wistar rats. The percentage of silver found in the liver was always higher than in the other organs analyzed. A pioneering mathematical model is proposed, from which the half-life time of silver in the liver (17 days), spleen (23 days), lungs (30 days), and kidneys (35 days) was extracted. In conclusion, some acute and severe toxic effects were observed in sperm cells following intratesticular injection of AgNPs, although these effects were reversible. No adverse effects to general animal health were observed.


Assuntos
Nanopartículas Metálicas/toxicidade , Reprodução/efeitos dos fármacos , Prata/toxicidade , Espermatozoides/efeitos dos fármacos , Testículo/efeitos dos fármacos , Alanina Transaminase/metabolismo , Animais , Epididimo/efeitos dos fármacos , Epididimo/metabolismo , Rim/efeitos dos fármacos , Rim/metabolismo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , Nanopartículas Metálicas/administração & dosagem , Ratos , Ratos Wistar , Prata/administração & dosagem , Prata/farmacocinética , Espermatozoides/metabolismo , Baço/efeitos dos fármacos , Baço/metabolismo , Testículo/metabolismo , Distribuição Tecidual
9.
Nanotoxicology ; 14(7): 908-928, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32574512

RESUMO

Silver nanoparticles (AgNP) are used in multiple applications but primarily in the manufacturing of antimicrobial products. Previous studies have identified AgNP toxicity in airway epithelial cells, but no in vitro studies to date have used organotypic cultures as a high-content in vitro model of the conducting airway to characterize the effects of interactions between host genetic and acquired factors, or gene × phenotype interactions (G × P), on AgNP toxicity. In the present study, we derived organotypic cultures from primary murine tracheal epithelial cells (MTEC) to characterize nominal and dosimetric dose-response relationships for AgNPs with a gold core on barrier dysfunction, glutathione (GSH) depletion, reactive oxygen species (ROS) production, lipid peroxidation, and cytotoxicity across two genotypes (A/J and C57BL/6J mice), two phenotypes ('Normal' and 'Type 2 [T2]-Skewed'), and two exposures (an acute exposure of 24 h and a subacute exposure of 4 h, every other day, over 5 days [5 × 4 h]). We characterized the 'T2-Skewed' phenotype as an in vitro model of chronic respiratory diseases, which was marked by increased sensitivity to AgNP-induced barrier dysfunction, GSH depletion, ROS production, lipid peroxidation, and cytotoxicity, suggesting that asthmatics are a sensitive population to AgNP exposures in occupational settings. This also suggests that exposure limits, which should be based upon the most sensitive population, should be derived using in vitro and in vivo models of chronic respiratory diseases. This study highlights the importance of considering dosimetry as well as G × P effects when screening and prioritizing potential respiratory toxicants. Such in vitro studies can be used to inform regulatory policy aimed at special protections for all populations.


Assuntos
Antibacterianos/toxicidade , Células Epiteliais/efeitos dos fármacos , Nanopartículas Metálicas/toxicidade , Prata/toxicidade , Traqueia/efeitos dos fármacos , Animais , Antibacterianos/química , Técnicas de Cultura de Células , Relação Dose-Resposta a Droga , Células Epiteliais/metabolismo , Células Epiteliais/patologia , Genótipo , Glutationa/metabolismo , Ouro/química , Ouro/toxicidade , Peroxidação de Lipídeos/efeitos dos fármacos , Nanopartículas Metálicas/química , Camundongos , Camundongos Endogâmicos C57BL , Fenótipo , Espécies Reativas de Oxigênio/metabolismo , Prata/química , Propriedades de Superfície , Traqueia/metabolismo , Traqueia/patologia
10.
Chemosphere ; 258: 127346, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32544815

RESUMO

Although biosynthesized nanoparticles are regarded as green products, research on their toxicity to aquatic food chains is scarce. Herein, biosynthesized silver nanoparticles (Alcea rosea-silver nanoparticles, AR-AgNPs) were produced by the reaction of Ag ions with leaf extract of herbal plant Alcea rosea. Then, the toxic effects of AR-AgNPs and their precursors such as Ag+ ions and coating agent (A. rosea leaf extract) on organisms of different trophic levels of a freshwater food chain were investigated. To the three studied aquatic organisms including phytoplankton (Chlorella vulgaris), zooplankton (Daphnia magna) and fish (Danio rerio), the coating agents of AR-AgNPs showed no toxic effects, and Ag+ ions were more toxic in comparison to AR-AgNPs. Further investigations revealed that the release of Ag+ ions from AR-AgNPs to the test media were not considerable due to the high stability of AR-AgNPs, thus the toxicity stemmed mainly from the particles of AR-AgNPs in all the three trophic levels. Based on values of 72-h EC50 for C. vulgaris, 48-h LC50 for D. magna and 96-h LC50 for D. rerio, the most sensitive organism to AR-AgNPs exposure was D. magna (the second trophic level).


Assuntos
Organismos Aquáticos/efeitos dos fármacos , Nanopartículas Metálicas/toxicidade , Prata/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Chlorella vulgaris/efeitos dos fármacos , Daphnia/efeitos dos fármacos , Água Doce , Dose Letal Mediana , Malvaceae/metabolismo , Peixe-Zebra
11.
Bull Environ Contam Toxicol ; 105(2): 244-249, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32556691

RESUMO

The aim of the study was to assess the effects of silver nanoparticles (AgNPs1 = 2.7 d·nm, AgNPs2 = 6.5 d·nm) and silver nitrate (AgNO3) on Enchytraeus crypticus and Folsomia candida using toxicity tests (OECD Guideline 220, 232). A 28-day chronic toxicity study was performed to evaluate the reproduction and mortality rate. E. crypticus reproduction was more sensitive to AgNO3 with a 28dEC50 of 86.40 (62.52-119.4) mg·kg-1 dry weight (d.w.) compared to AgNPs1 (28dEC50 = 119.3 (60.4-235.6) mg·kg-1 d.w). Similarly, the reproduction of F. candida was inhibited the most by AgNO3 with a 28dEC50 of 126.2 (104.2-152.9) mg·kg-1 d.w. followed by AgNPs1 (28dEC50 = 158.7 (64.05-393.2) mg·kg-1 d.w.) and AgNPs2 (28dEC50 = 206.4 (181.9-234.1) mg·kg-1 d.w.). No mortalities were observed for tested soil invertebrates exposed to AgNPs at concentrations up to 166 mg·kg-1 d.w. of AgNPs1 and 300 mg·kg-1 d.w. of AgNPs2, respectively. It was found that silver ions are more toxic in comparison with AgNPs.


Assuntos
Artrópodes/efeitos dos fármacos , Nanopartículas Metálicas/toxicidade , Oligoquetos/efeitos dos fármacos , Nitrato de Prata/toxicidade , Prata/toxicidade , Poluentes do Solo/toxicidade , Animais , Íons , Nanopartículas Metálicas/química , Reprodução/efeitos dos fármacos , Prata/química , Solo/química , Solo/normas , Poluentes do Solo/química , Testes de Toxicidade Crônica
12.
Nanotoxicology ; 14(6): 740-756, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32401081

RESUMO

Despite numerous studies on the environmental health and safety (EHS) of silver nanoparticles (AgNPs), most studies looked into their gross toxicities with rather limited understanding on their labyrinthine implicit effects on the target sites, such as the endocrine system. Burgeoning evidence documents the disrupting effects of AgNPs on endocrine functions; however, little research has been invested to recognize the potential impacts on the mammary gland, a susceptible estrogen-responsive organ. Under this setting, we here aimed to scrutinize AgNP-induced effects on the development of pubertal mammary glands at various concentrations that bear significant EHS relevance. We unearthed that AgNPs could accumulate in mouse mammary glands and result in a decrease in the percentage of ducts and terminal ducts in the adult mice after chronic exposure. Strikingly, smaller sized AgNPs showed greater capability to alter the pubertal mammary development than larger sized particles. Intriguingly, mechanistic investigation revealed that the reduction of epithelial proliferation in response to AgNPs was ascribed to reduced ERα expression, which, at least partially, accounted for diseased epithelial morphology in mammary glands. Meanwhile, the decline in fibrous collagen deposition around the epithelium was found to contribute to the compromised development of mammary glands under the exposure of AgNPs. Moreover, as an extension of the mechanism, AgNPs diminished serum levels of estradiol in exposed animals. Together, these results uncovered a novel toxicity feature of AgNPs: compromised development of mouse pubertal mammary glands through the endocrine-disrupting actions. This study would open a new avenue to unveil the EHS impacts of AgNPs.


Assuntos
Disruptores Endócrinos/toxicidade , Estrogênios/metabolismo , Glândulas Mamárias Animais/efeitos dos fármacos , Nanopartículas Metálicas/toxicidade , Prata/toxicidade , Animais , Relação Dose-Resposta a Droga , Disruptores Endócrinos/farmacocinética , Epitélio/efeitos dos fármacos , Epitélio/crescimento & desenvolvimento , Epitélio/metabolismo , Receptor alfa de Estrogênio/metabolismo , Estrogênios/farmacologia , Feminino , Glândulas Mamárias Animais/crescimento & desenvolvimento , Glândulas Mamárias Animais/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Tamanho da Partícula , Transdução de Sinais , Prata/farmacocinética , Propriedades de Superfície , Distribuição Tecidual
13.
Ecotoxicol Environ Saf ; 196: 110487, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32229327

RESUMO

Despite numerous investigations into AgNP-induced toxicity, little has been taken into consideration the potential health impacts of aged AgNPs in comparison to fresh AgNPs. In the current study, we scrutinized the potential effects of aged AgNPs in animals. We first found that AgNPs underwent morphological transformations after natural ageing in aqueous solution upon exposure to air and sunlight for 9 days, as characterized by significant aggregation with increase of particle size approximately by 2 fold. Meanwhile, dissolved Ag ions from aged AgNPs increased by 33% compared to fresh AgNPs. Strikingly, the acute exposure results showed that aged AgNPs induced lower toxicity in mice relative to fresh AgNPs. Aged AgNPs caused milder local inflammation in the peritoneal cavity of mice, as evidenced by 63% reduction of tumor necrosis factor α (TNF-α) than that induced by fresh AgNPs. The deposition mass of aged AgNPs in the liver, spleen, lung and kidney was diminished by 69%, 39%, 83% and 40%, respectively, compared to the distribution profiles in response to fresh AgNPs. Whereby, milder splenic hyperemia was observed, and no significant hepatoxicity was found. Additionally, aged AgNPs provoked milder increase of periphery leukocytes and malondialdehyde (MDA) in mice in comparison to fresh AgNPs. Taken together, this study unraveled that the ageing process elicited remarkable alterations to physicochemical properties and toxic effects as well. This study would provide new insights into the potential health impacts of AgNPs under transformation-determined exposure scenarios.


Assuntos
Nanopartículas Metálicas/química , Nanopartículas Metálicas/toxicidade , Prata/química , Prata/toxicidade , Animais , Mamíferos , Nanopartículas Metálicas/efeitos da radiação , Camundongos , Tamanho da Partícula , Prata/metabolismo , Prata/efeitos da radiação , Luz Solar , Distribuição Tecidual , Testes de Toxicidade Aguda , Poluentes Químicos da Água/química , Poluentes Químicos da Água/metabolismo , Poluentes Químicos da Água/efeitos da radiação , Poluentes Químicos da Água/toxicidade
14.
Chemosphere ; 253: 126705, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32302904

RESUMO

Polystyrene microplastics (PSMPs) with different sizes, surface charges and aging statuses simulated field PSMPs and were applied to understand their cytotoxicity to Escherichia coli. The PSMPs hardly affected the viability, membrane integrity, ROS generation and ATPase activity of E. coli, and the cytotoxicity of field PSMPs is marginal and assumed to be overestimated. Low concentrations (1.0 mg L-1) of PSMPs dynamically affect the cytotoxicity of Ag+ to E. coli through various toxic mechanisms. PSMPs likely mitigated the cytotoxicity of Ag+ during the initial 24 h of co-exposure by protecting the cell membrane, inhibiting ROS generation and/or recovering ATPase activity (p < 0.05 or p < 0.01). During prolonged co-exposure for 48 h, nonfunctionalized polystyrene (PS-NF) still mitigated the cytotoxicity of Ag+ by protecting the integrity of the cell membrane, and aged PS-NF slightly affected cytotoxicity. PS-NH2 and PS-COOH intensified the cytotoxicity of Ag+ because PS markedly promoted ROS generation and inhibited ATPase activity. Thus, field PSMPs were assumed to exhibit marginal cytotoxicity to E. coli and can combine with surrounding Ag+ to modify the E. coli population levels and even the structure of aquatic ecosystems. Accordingly, the environmental and health risks of field PSMPs require further intensive investigation, and the combined toxicity effects of field PSMPs with Ag+ should be considered carefully due to their dynamic toxic effects and mechanisms.


Assuntos
Microplásticos/toxicidade , Poliestirenos/toxicidade , Prata/toxicidade , Ecossistema , Escherichia coli/efeitos dos fármacos , Íons , Microplásticos/química , Poliestirenos/química , Prata/química
15.
Ecotoxicol Environ Saf ; 197: 110570, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32311611

RESUMO

In recent times, however, due to the emergence of bacterial strains with resistance to conventional antibiotics, silver has again gained attention as an alternative for developing new efficient bactericides, including the use of silver nanoparticles (AgNPs). However, the improper disposal of these items after use may cause toxicological effects on organisms in the environment. To evaluate the potential environmental hazard of nanosilver-coated dressings, the nematode Caenorhabditis elegans was chosen as a test organism. The assays were conducted in 24-well plates that contain four different sizes of coated dressing to obtain different concentrations. L1 and L4 C. elegans larval stages were exposed to these nanosilver concentrations. Dressing cutouts were arranged between two layers of agar for 3 days and Escherichia coli (OP 50 strain) was added as food source for the worms. After the exposure period, growth, reproduction, fertility, silver concentration in the medium and the concentration of reactive oxygen species (ROS) in the worms were evaluated. Scanning and transmission electron microscopy analyses were performed on the coated dressings, as well as analyses of zeta potential, ionic release and antibacterial power in two bacterial strains (Pseudomonas aeruginosa and Staphylococcus aureus). It was verified the antibacterial power of the coated dressing, in both bacteria strains tested. Characterization of the coated dressing indicated heterogeneous nanoparticles, as well as distinct zeta potentials for the medium in water and saline medium (0.9% NaCl). L1 larval worms exposed to nanosilver-coated dressing showed a high ROS concentration and reductions in growth, fertility and reproduction. Worms exposed to the coated dressing during the L4 stage showed almost no response. Overall, the obtained results indicate the potential environmental hazard of nanosilver-coated dressings.


Assuntos
Bandagens , Caenorhabditis elegans/efeitos dos fármacos , Poluentes Ambientais/toxicidade , Nanopartículas Metálicas/toxicidade , Prata/toxicidade , Animais , Antibacterianos/química , Antibacterianos/toxicidade , Bactérias/efeitos dos fármacos , Caenorhabditis elegans/fisiologia , Poluentes Ambientais/química , Larva/efeitos dos fármacos , Larva/fisiologia , Nanopartículas Metálicas/química , Espécies Reativas de Oxigênio/metabolismo , Prata/química
16.
Environ Toxicol ; 35(9): 952-960, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32293792

RESUMO

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


Assuntos
Brassicaceae/química , Nanopartículas Metálicas/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Extratos Vegetais/farmacologia , Prata/toxicidade , Testículo/efeitos dos fármacos , Animais , Antioxidantes/metabolismo , Glutationa/metabolismo , Hormônio Luteinizante/sangue , Masculino , Ratos , Ratos Wistar , Sementes/química , Superóxido Dismutase/metabolismo , Testículo/enzimologia , Testículo/metabolismo , Testosterona/sangue
17.
Nanotoxicology ; 14(6): 725-739, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32324436

RESUMO

Metal-based nanoparticles exhibiting antimicrobial activity are of emerging concern to human and environmental health. In addition to their direct adverse effects to plants and animals, indirect effects resulting from disruption of beneficial host-microbiota interactions may contribute to the toxicity of these particles. To explore this hypothesis, we compared the acute toxicity of silver and zinc oxide nanoparticles (nAg and nZnO) to zebrafish larvae that were either germ-free or colonized by microbiota. Over two days of exposure, germ-free zebrafish larvae were more sensitive to nAg than microbially colonized larvae, whereas silver ion toxicity did not differ between germ-free and colonized larvae. Using response addition modeling, we confirmed that the protective effect of colonizing microbiota against nAg toxicity was particle-specific. Nearly all mortality among germ-free larvae occurred within the first day of exposure. In contrast, mortality among colonized larvae increased gradually over both exposure days. Concurrent with this gradual increase in mortality was a marked reduction in the numbers of live host-associated microbes, suggesting that bactericidal effects of nAg on protective microbes resulted in increased mortality among colonized larvae over time. No difference in sensitivity between germ-free and colonized larvae was observed for nZnO, which dissolved rapidly in the exposure medium. At sublethal concentrations, these particles moreover did not exert detectable bactericidal effects on larvae-associated microbes. Altogether, our study shows the importance of taking host-microbe interactions into account in assessing toxic effects of nanoparticles to microbially colonized hosts, and provides a method to screen for microbiota interference with nanomaterial toxicity.


Assuntos
Interações Hospedeiro-Parasita/efeitos dos fármacos , Larva/efeitos dos fármacos , Nanopartículas Metálicas/toxicidade , Microbiota/efeitos dos fármacos , Prata/toxicidade , Peixe-Zebra/microbiologia , Animais , Humanos , Larva/microbiologia , Óxido de Zinco/toxicidade
18.
Ecotoxicol Environ Saf ; 194: 110353, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32146193

RESUMO

The present study aimed to evaluate the effects of different waterborne sublethal concentrations of Ag-NPs LC50 (96h) on common carp Cyprinus carpio using a multi-biomarker approach. Fish (9.22 ± 0.12 g) were stocked in fiberglass tanks and exposed to concentrations of 0 (control), 12.5%, 25% and 50% of Ag-NPs LC50 (96h) or Ag-NO3 LC50 (96h), as the source of Ag+ ion, for a period of 21 days. At the end of study, tissue Ag contents were significantly (P < 0.05) higher and different in fish exposed to concentrations of 25% and 50% compared to the control. The numbers of RBCs, hematocrit, and MCHC values at these concentrations differed significantly in respect to the control. No significant effects were observed for hemoglobin, MCH, and MCV values. The number of WBCs was significantly higher at concentrations of 12.5% and 25% compared to the control. Meanwhile, the percentage of neutrophils significantly elevated at concentrations of 25% and 50%. Serum total protein at concentration of 50% detected significantly lower than that of 12.5% or the control. The serum albumin and globulin levels significantly declined in Ag-NPs-exposed groups versus the control. The serum ACH50 and total immunoglobulins showed significantly lower values in the treatments of 25% and 50% compared to the control. The serum glucose, cortisol, ALT, and ALP values significantly escalated upon Ag-NPs exposure. The serum SOD and CAT showed enhanced activity in the treatment of 12.5% vice versa significantly diminished at concentrations of 25% and 50% compared to the control. The exposure to the concentrations of 25% and 50% significantly dwindled the lysozyme activity and total immunoglobulin levels in skin mucus. In conclusion, sublethal concentrations of Ag-NPs LC50 (96h) impaired fish health status at higher concentrations and 12.5% of Ag-NPs LC50 (96h) was presumably safe for common carp aquaculture.


Assuntos
Carpas/fisiologia , Nanopartículas Metálicas/toxicidade , Prata/toxicidade , Animais , Antioxidantes/metabolismo , Aquicultura , Bioacumulação , Carpas/metabolismo , Eritrócitos/metabolismo , Hematócrito , Hematologia , Hemoglobinas/metabolismo , Dose Letal Mediana
19.
Artigo em Inglês | MEDLINE | ID: mdl-32167009

RESUMO

Silver nanoparticles (AgNPs) have been widely used for a multitude of applications without full comprehensive knowledge regarding their safety. In particular, lack of data on hazard characterization may lead to uncertainties regarding potential human health risk. To provide the foundation for human health risk assessment of AgNPs, this study evaluates existing hazard characterization data, including reported pharmacokinetics, symptoms, and their corresponding dose-response relationships. Human equivalent relationships are also provided by extrapolation from animal dose-response relationships. From the data analyzed, it appears that AgNPs may persist for long periods (from days to years) in the human body. It was found that AgNP toxicity on traditional major targets of exogenous substances were generally underestimated. Some omissions of toxicity on sensitive systems in the AgNP toxicity assessment require attention, such as reprotoxicity and neurotoxicity. The necessity of the establishment of toxicity tests specifically for nanomaterials is highlighted. The scientific basis of a toxicity testing strategy is advised by this study, which paves the way for the monitoring and regulation of the ENP utilization in various industries.


Assuntos
Exposição Ambiental/efeitos adversos , Substâncias Perigosas/toxicidade , Nanopartículas Metálicas/toxicidade , Prata/toxicidade , Administração Cutânea , Administração Oral , Animais , Exposição Ambiental/análise , Substâncias Perigosas/administração & dosagem , Substâncias Perigosas/química , Substâncias Perigosas/farmacocinética , Humanos , Exposição por Inalação , Injeções Intravenosas , Injeções Subcutâneas , Nanopartículas Metálicas/administração & dosagem , Nanopartículas Metálicas/química , Especificidade de Órgãos , Prata/administração & dosagem , Prata/química , Prata/farmacocinética , Distribuição Tecidual , Testes de Toxicidade
20.
Nanotoxicology ; 14(5): 654-666, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32141361

RESUMO

Quantifying the relative bioavailability of particles versus ions is a key step toward understanding the mechanisms of bioaccumulation and toxicity of silver nanoparticles (AgNPs). Here we investigated AgNP uptake kinetics by wheat Triticum aestivum L. at different ages (i.e. 15- and 30-day after germination) in hydroponics. The concentration-dependent accumulation of AgNPs under the experimental conditions, in which AgNP dissolution in bulk suspension and at the biological interface was ruled out, confirmed the direct uptake of particles. This was further validated by the detection of Ag-containing particles within plants by single particle inductively coupled plasma mass spectrometry. Plants differentiated particles and dissolved ions, with uptake rate constants of particles and dissolved ions 4.3 ± 0.6 to 5.2 ± 0.6 and 288.6 ± 13.4 to 450.6 ± 63.4 L kg-1 h-1, respectively. Plant age appeared to have a negligible influence on uptake rate constant ratio of particles to ions. As a result, the relative contribution of particulate uptake to overall AgNP accumulation varied as a function of AgNP dissolution in nature. Particulate uptake was dominant when the dissolution was less than 1.2%. These findings help clearing up the inconsistency of uptake mechanisms of AgNPs in literature and could be used to predict their environmental impact and significance.


Assuntos
Nanopartículas Metálicas/toxicidade , Prata/toxicidade , Triticum/metabolismo , Disponibilidade Biológica , Íons , Cinética , Nanopartículas Metálicas/química , Prata/química , Prata/metabolismo , Solubilidade , Análise Espectral , Suspensões
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA