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1.
Chem Biol Interact ; 330: 109219, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32846153

RESUMO

The lack of tissue selectivity of anticancer drugs generates intense collateral and adverse effects of cancer patients, making the incorporation of vitamins or micronutrients into the diet of individuals to reduce side or adverse effects of antineoplastics. The study aimed to evaluate the effects of retinol palmitate (RP) on the toxicogenic damages induced by cyclophosphamide (CPA), doxorubicin (DOX) and its association with the AC protocol (CPA + DOX), in Sarcoma 180 (S-180) tumor cell line, using the micronuclei test with a block of cytokinesis (CBMN); and in non-tumor cells derived from Mus musculus using the comet assay. The results suggest that CPA, DOX and AC protocol induced significant toxicogenic damages (P < 0.05) on the S-180 cells by induction of micronuclei, cytoplasmic bridges, nuclear buds, apoptosis, and cell necrosis, proving their antitumor effects, and significant damage (P < 0.001) to the genetic material of peripheral blood cells of healthy mice, proving the genotoxic potential of these drugs. However, RP modulated the toxicogenic effects of antineoplastic tested both in the CBMN test (P < 0.05), at the concentrations of 1, 10 and 100 IU/mL; as in the comet assay (P < 0.001) at the concentration of 100 IU/kg for the index and frequency of genotoxic damage. The accumulated results suggest that RP reduced the action of antineoplastics in non-tumor cells as well as the cytotoxic, mutagenic, and cell death in neoplastic cells.


Assuntos
Antineoplásicos/toxicidade , Diterpenos/farmacologia , Vitamina A/análogos & derivados , Animais , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/toxicidade , Apoptose/efeitos dos fármacos , Linhagem Celular , Linhagem Celular Tumoral , Ensaio Cometa , Ciclofosfamida/efeitos adversos , Ciclofosfamida/toxicidade , Dano ao DNA/efeitos dos fármacos , Relação Dose-Resposta a Droga , Doxorrubicina/efeitos adversos , Doxorrubicina/toxicidade , Interações Medicamentosas , Humanos , Camundongos , Testes para Micronúcleos , Mutagênese/efeitos dos fármacos , Vitamina A/farmacologia
2.
Toxicol Lett ; 332: 56-64, 2020 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-32621954

RESUMO

The comet assay has been extensively used in biomonitoring studies. To avoid intra-experimental variability, the incorporation of assay controls in each work session for data normalization has been suggested by some authors but has never been thoroughly analyzed. The aim of this study was to address the impact of data normalization in the results of a biomonitoring study using different normalization models. Human peripheral blood mononuclear cells (PBMC) from 140 healthy individuals were analyzed using the alkaline and FPG-modified version of the comet assay across seven different work sessions. In addition to negative standards, methyl methanesulfonate (MMS) and Ro 19-8022 plus light treated PBMC, were also included in the assay as positive standards. To verify the impact of data normalization, some demographic, lifestyle and environmental exposure-related variables were selected. Significant associations with independent study variables were observed using normalized comet endpoints, as opposed to raw data. After normalization, levels of DNA strand breaks were significantly higher among males and older individuals (>71 years), while net FPG-sensitive sites were positively related to smoking habits and environmental exposures (i.e. air pollution and bottled water consumption). This study highlights how the normalization strategies can influence the statistical results of a human biomonitoring study and lead to different data interpretations.


Assuntos
Monitoramento Biológico/estatística & dados numéricos , Ensaio Cometa/estatística & dados numéricos , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Interpretação Estatística de Dados , Demografia , Determinação de Ponto Final , Exposição Ambiental , Feminino , Humanos , Estilo de Vida , Luz , Masculino , Metanossulfonato de Metila/toxicidade , Pessoa de Meia-Idade , Modelos Estatísticos , Monócitos/metabolismo , Projetos de Pesquisa , Fatores Sexuais
3.
Toxicol Lett ; 332: 202-212, 2020 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-32659469

RESUMO

A variety of methods have been developed for accurate and systematic evaluation of chemical genotoxicity. Ceric ammonium nitrate (CAN) and 1,3-propane sultone (1,3-PS) have been extensively applied in industrial fields. Although 1,3-PS, but not CAN, has been reported as a potent carcinogen, systematic assessment of the genotoxic properties of these chemicals has not been conducted. The purpose of this study was to establish a decision tree for evaluating genotoxicity based on the good laboratory practices (GLP) system using 1,3-PS and CAN as test chemicals. In vitro studies were performed including the bacterial reverse mutation assay, chromosomal aberration assay, and micronucleus assay. We conducted in vivo studies using a combined micronucleus and alkaline comet (MN-CMT) assay and the Pig-a gene mutation assay, which is a promising method for detecting gene mutations in vivo. CAN showed negative responses in all in vitro genotoxicity assays and the in vivo combined MN-CMT assay. Meanwhile, 1,3-PS had positive results in all in vitro and in vivo genotoxicity assays. In this study, we confirmed the genotoxicity of 1,3-PS and CAN using both in vitro and in vivo assays. We propose a decision tree for evaluating chemical-induced genotoxicity.


Assuntos
Cério/toxicidade , Árvores de Decisões , Mutagênicos/toxicidade , Tiofenos/toxicidade , Animais , Bactérias/efeitos dos fármacos , Linhagem Celular/efeitos dos fármacos , Aberrações Cromossômicas/efeitos dos fármacos , Ensaio Cometa , Cricetinae , Cricetulus , Dano ao DNA , Relação Dose-Resposta a Droga , Feminino , Humanos , Masculino , Testes para Micronúcleos , Testes de Mutagenicidade , Ratos Sprague-Dawley
4.
Bull Environ Contam Toxicol ; 105(2): 224-229, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32710385

RESUMO

This study deals with bleak (Alburnus alburnus) sensitivity in detecting of the wastewater related pressure in large lowland rivers. The major objective was to investigate if the response measured in bleak should be linked to a certain stretch of the river and characterised as "stretch specific", or it should be linked to the sampling site and characterised as "site specific". The response was evaluated via condition index, metal pollution index, DNA damage and cell viability using integrated biomarker response approach. The study was conducted at 3 sub-sites characterized by different pollution levels in a relatively short stretch (2 km) of the Sava River (Serbia). Results indicated that the response of the biomarkers in bleak can be interpreted as "site specific". Among the studied biomarkers, DNA damage assessed by comet assay and micronucleus test has shown high sensitivity in differentiation of the sites.


Assuntos
Cyprinidae/crescimento & desenvolvimento , Dano ao DNA , Rios/química , Águas Residuárias/química , Poluentes Químicos da Água/análise , Animais , Ensaio Cometa , Cyprinidae/genética , Monitoramento Ambiental/métodos , Testes para Micronúcleos , Sérvia
5.
Life Sci ; 257: 118108, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32682920

RESUMO

AIM: Preparation of pegylated gold nanorods (PEG-AuNRs) that are capable of converting near infrared (NIR) light into heat. Evaluation of cancer therapeutic efficacy and long-term toxicity of the proposed photothermal therapy in comparison with other conventional modalities. MATERIALS AND METHODS: Prepared PEG-AuNRs were characterized by measuring their absorption spectra, zeta potential, and transmission electron microscope (TEM). Cancer therapeutic efficacy was assessed by monitoring tumor growth, measuring DNA damage and superoxide dismutase (SOD) and malondialdehyde (MDA) levels in addition to examining tumor histopathology. Further analysis concerning the toxicity of all the proposed treatment modalities was also assessed by evaluating the cytotoxicity and genotoxicity in liver and kidney tissues. KEY FINDINGS: The results demonstrated that both photothermal therapy (PEG-AuNRs + NIR laser) and chemotherapy (cisplatin) have higher efficacy in diminishing Ehrlich tumor growth with significance DNA damage over the other treatment modalities. Concerning the biosafety issue, mice treated photothermally exhibited lower MDA level and higher SOD activity in liver and kidney tissues compared with other treated groups. DNA damage represented by tail moment and olive moment of kidney tissues exhibited lower values for photothermal treated group and higher values for cisplatin treated group. SIGNIFICANCE: Photothermal therapy (PEG-AuNRs + NIR laser) potentiates higher efficacy in treating Ehrlich tumor with minimum toxicity in comparison with other conventional treatment modalities.


Assuntos
Carcinoma de Ehrlich/terapia , Ouro/administração & dosagem , Nanotubos/toxicidade , Fototerapia/métodos , Animais , Carcinoma de Ehrlich/patologia , Ensaio Cometa , Dano ao DNA/efeitos dos fármacos , Feminino , Ouro/uso terapêutico , Ouro/toxicidade , Malondialdeído/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Microscopia Eletrônica de Transmissão , Nanotubos/ultraestrutura , Transplante de Neoplasias , Estresse Oxidativo , Superóxido Dismutase/metabolismo
7.
Mutat Res ; 854-855: 503209, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32660823

RESUMO

We have measured the toxicity and genotoxicity of 2-methylfuran, which is formed in foods during thermal processing. The agent was administered by oral gavage to male Sprague-Dawley rats, daily for 28 days, before performing general toxicology analysis and the following genotoxicity tests: comet assay (peripheral blood, liver); Pig-a gene mutation assay (peripheral blood); micronucleus test (peripheral blood, bone marrow). Liver was the primary target organ; histological changes (oval cell hyperplasia) were observed but without significant changes in serum enzyme markers. For hepatotoxicity, the no-observed-adverse-effect level was 5 mg/kg bw/d. Histopathological changes were also seen in the bone marrow. Genotoxicity assays were uniformly negative.


Assuntos
Furanos/toxicidade , Animais , Ensaio Cometa , Dano ao DNA/efeitos dos fármacos , Fígado/efeitos dos fármacos , Masculino , Testes para Micronúcleos/métodos , Testes de Mutagenicidade/métodos , Mutagênicos/toxicidade , Ratos , Ratos Sprague-Dawley
8.
Mutat Res ; 854-855: 503200, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32660824

RESUMO

Germ cell tumour (GCT) patients who fail to respond to chemotherapy or who relapse have a poor prognosis. Timely and accurately stratifying such patients could optimise their therapy. We identified endogenous DNA damage levels as a prognostic marker for progression-free (PFS) and overall (OS) survival in chemotherapy-naïve GCT patients. In the present study, we have extended our previous results and reviewed the prognostic power of DNA damage level in GCTs. Endogenous DNA damage levels were measured with the comet assay. Receiver operator characteristic analysis was applied to determine the optimal cut-off value and to evaluate its prognostic accuracy. PFS and OS were estimated by the Kaplan-Meier method and compared using the log-rank test. Hazard ratio (HR) estimates were calculated by Cox regression analysis. A cut-off value of 6.34 provided the highest sensitivity and specificity, with area under curve values of 0.813 and 0.814 for disease progression and mortality, respectively. A % DNA in tail > 6.34 was significantly associated with shorter PFS (HR = 9.54, 95 % confidence interval [CI]: 3.43-26.55, p < 0.001) and OS (HR = 14.62, 95 % CI: 3.14-67.95, p = 0.001) by univariate analysis. The prognostic value of DNA damage measurement was confirmed by multivariate models (HR = 6.45, 95 % CI: 2.22-18.75, p = 0.001 for PFS and HR = 9.40, 95 % CI: 1.70-52.09, p = 0.010 for OS), when HR was adjusted for relevant clinical categories. The added prognostic value of DNA damage in combination with International Germ Cell Cancer Collaborative Group (IGCCCG) risk groups has been revealed. Endogenous DNA damage is an independent prognosticator for PFS and OS in GCT patients and its clinical use, particularly in combination with IGCCCG risk groups, may help in stratifying these patients.


Assuntos
Células Sanguíneas/patologia , Dano ao DNA/genética , Neoplasias Embrionárias de Células Germinativas/genética , Neoplasias Embrionárias de Células Germinativas/patologia , Adulto , Células Cultivadas , Ensaio Cometa/métodos , Progressão da Doença , Intervalo Livre de Doença , Feminino , Humanos , Estimativa de Kaplan-Meier , Leucócitos Mononucleares/patologia , Masculino , Pessoa de Meia-Idade , Prognóstico , Intervalo Livre de Progressão , Modelos de Riscos Proporcionais , Fatores de Risco
9.
Environ Sci Pollut Res Int ; 27(32): 40443-40455, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32666461

RESUMO

The immune system is exposed to extremely low doses of neutrons under different circumstances, such as through exposure to cosmic rays, nuclear accidents, and neutron therapy. Peripheral blood mononuclear cells (PBMCs) are the primary immune cells that exhibit selective immune responses. Changes in the functions of the protein components of PBMC can be induced by structural modifications of these proteins themselves. Herein, we have investigated the effect of low-dose fast neutrons on PBMC proteins at 0, 2, 4, and 8 days post-whole body irradiation. 64 Wistar rats were used in this study of which, 32 were exposed to fast neutrons at a total dose of 10 mGy (241Am-Be, 0.2 mGy/h), and the other 32 were used as controls. Blood samples were drawn, and PBMCs were isolated from whole blood. Fourier transform infrared (FTIR) spectroscopy and fluorescence spectroscopy were used to estimate the changes in the proteins of PBMCs. An alkaline comet assay was performed to assess DNA damage. Hierarchical cluster analysis (HCA) and principal components analysis (PCA) were utilized to discriminate between irradiated and non-irradiated samples. FTIR and fluorescence spectra of the tested samples revealed alterations in the amides and tryptophan, and therefore protein structure at time intervals of 2 and 4 days post-irradiation. No changes were recorded in samples tested at time intervals of 0 and 8 days post-irradiation. The FTIR band intensities of the PBMC proteins of the irradiated samples decreased slightly and were statistically significant. Curve fitting of the amide I band in the FTIR spectra showed changes in the secondary structure of the proteins. At 2 days post-irradiation, fluorescence spectra of the tested samples revealed decreases in the band tryptophan. The comet assay revealed low levels of DNA damage. In conclusion, low-dose fast neutrons can affect the proteins of PBMC.


Assuntos
Nêutrons Rápidos , Leucócitos Mononucleares , Animais , Ensaio Cometa , Nêutrons , Ratos , Ratos Wistar
10.
Environ Toxicol ; 35(11): 1202-1211, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32621570

RESUMO

Polybrominated diphenyl ethers (PBDEs) are ubiquitous and prolific contaminant in both the abiotic and biotic environment because of the wide industrial applications of these chemicals. In the present study, the effects of 2,2',4,4'-tetrabrominateddiphenyl ether (BDE-47) and 2,2',4,4',5,5'-hexabromodiphenyl ether (BDE-153) exposure on the induction of hepatic oxidative stress, DNA damage, and the expression of apoptosis-related genes in adult zebrafish were investigated. The activities of antioxidant enzymes, such as catalase and superoxide dimutase, significantly increased when adult zebrafish was exposed to various concentrations of BDE-47 and BDE-153 for 7 and 15 days. BDE-47 and BDE-153 elicited significant alterations in zebrafish 7-Ethoxyresorufin-O-deethylase activity at 3, 7, or 15 days of exposure. In addition, the significant increase in comet assay parameters of zebrafish hepatocytes in a concentration-dependent manner indicated BDE-47 and BDE-153 induced DNA damage, probably due to observed oxidative stress. Furthermore, a monotonically upregulation of p53 and Caspase3, which are apoptotic-regulated genes, and decreased expression ratio of the anti-apoptotic B-cell lymphoma/leukaemia-2 and Bcl2-associated X protein genes for all BDE-47 and BDE-153 treatments at 7 and 15 days indicated apoptosis induction in zebrafish liver. Our findings help elucidate the mechanisms of BDE-47- and BDE-153-induced toxicity in zebrafish hepatocytes.


Assuntos
Éteres Difenil Halogenados/toxicidade , Bifenil Polibromatos/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Antioxidantes/metabolismo , Apoptose/efeitos dos fármacos , Caspase 3 , Ensaio Cometa , Citocromo P-450 CYP1A1/metabolismo , Dano ao DNA , Éteres Difenil Halogenados/metabolismo , Hepatócitos/metabolismo , Fígado/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Peixe-Zebra/metabolismo
11.
Toxicon ; 185: 114-119, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32659238

RESUMO

Scorpion envenomation represents an important health problem in many parts of the world, due to the high number and severity of accidents. Recent studies demonstrated that some species can produce venoms with genetic damage potential. Here, we evaluated whether Tityus stigmurus venom causes genetic damage in blood and testicular cells of Swiss mice. We also analyzed the effect of the venom on the number of spermatogenic lineage cells. Five groups of mice received 0.387 mg/kg of the venom, intraperitoneally; one group received saline solution (control group). Blood and testicular cells were collected for comet assay and histological analysis at different times after treatment (1, 2, 6, 12, and 48 h). Blood was also collected 48 h after treatment for the micronucleus test in erythrocytes. Histological analysis was performed by counting cells of the spermatogenic lineages; the nuclear area of elongated spermatocytes was also evaluated. Treatment with the venom induced DNA damage that endured from 1 h to 48 h, as confirmed by the comet assay. The micronucleus test demonstrated that the venom induced mutations in erythrocytes. The number of spermatogonia and rounded spermatids decreased in some groups; the number of elongated spermatids increased, and their nuclear size decreased 1 h after treatment. Genetic damage can be caused directly by the venom, but we suggested that reactive oxygen species that result from inflammatory process caused by the envenomation may have an important role in the DNA damage. Genetic damage and apoptosis may explain the changes in the number of spermatogenic cells. Furthermore, the decrease in nuclear area may result from chromatin loss. Genetic damage in testicular cells, associated with alterations in the number and morphology of spermatogenic cells, can result in reproduction disorders in animals, or humans, stung by T. stigmurus.


Assuntos
Venenos de Escorpião/toxicidade , Escorpiões , Animais , Ensaio Cometa , Dano ao DNA , Humanos , Masculino , Camundongos , Testículo
12.
Mar Pollut Bull ; 156: 111232, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32510378

RESUMO

In this study, to better our understanding of the current state of conservation of Cardisoma guanhumi and its habitats, we evaluated the potential spatio-temporal genomic damage of this species across five estuaries in Brazil. The experiment was performed over two consecutive years, and the sampling was performed in the winter and summer seasons. Two genetic tests - micronucleus test and comet assay - were used to quantify the DNA damage. Unlike in the summers and in the winter of 2013, in the winter of 2012 a significant increase was noted in the frequency of micronucleated cells and genomic damage index. The occurrence of genomic damage coincided with the arrival of the harsh winter of 2012 as the water sourced from the coastal rivers significantly affected the estuarine species under study. Our results confirmed that this species was resilient to the atypical climatic conditions, which facilitated the generation of excessive waste.


Assuntos
Braquiúros , Estuários , Animais , Brasil , Ensaio Cometa , Monitoramento Ambiental , Rios , Estações do Ano
13.
Environ Sci Pollut Res Int ; 27(26): 33215-33225, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32529609

RESUMO

Malachite green (MG) is a triphenylmethane dye that is widely used in aquaculture as a fungicide, bactericide, ectoparasiticide, and antiprotozoal. There is great debate regarding the potential for this compound to trigger adverse effects. Here, we review the previous findings and then evaluate the lethal and sublethal effects of MG in the species Hemichromis bimaculatus (jewelfish). The lethal concentration for 50% of the fish in 96 h was 1 mg/L. We observed a dose-dependent increase in the percentage of fish mortality as well as physical and behavioral changes. We further found that the highest tested sublethal dose significantly increased the DNA damage index identified using the comet assay (74.97 ± 13.8 at a significant level of P < 0.05 for the 0.75 mg/L concentration), but did not significantly alter the results of the micronucleus test. Although our results suggest that MG confers risks on exposed fish, the findings were significant only at the highest exposure concentration (0.75 mg/L). At lower concentrations (0.25 mg/L and 0.5 mg/L), no adverse effect was observed. The maximum MG concentration recommended for use in ornamental fish farming is 0.2 mg/L. Therefore, our results suggest that, specifically for the parameters analyzed in this work, MG does not have any adverse effect when users strictly adhere to the recommended concentration criteria for ornamental fish.


Assuntos
Brânquias , Poluentes Químicos da Água , Animais , Ensaio Cometa , Dano ao DNA , Testes para Micronúcleos , Corantes de Rosanilina
14.
Environ Sci Pollut Res Int ; 27(27): 33903-33915, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32535828

RESUMO

In this study, few different evaluation concepts were used for the assessment of genotoxic potential at the stretch of the Danube River identified as a significant hotspot of pollution originated through the untreated wastewaters. Three sites were chosen: one site upstream of the wastewater outlet in Novi Sad (Serbia), one at the outlet of wastewaters, and one site few kilometer downstream. Ex situ approach comprised prokaryotic SOS/umuC test on Salmonella typhimurium TA1535/pSK1005 and comet assay on human hepatoma cell line (HepG2). In situ approach was based on the active monitoring (cage approach) using freshwater mussels Sinanodonta woodiana and fish Cyprinus carpio. The comet and micronucleus assays were selected for evaluation of DNA damage in mussel haemocytes and fish blood cells. Within the ex situ part of the study, our results indicated that the eukaryotic model system is more sensitive compared to the prokaryotic one. In situ bioassays are recommended for obtaining a better insight into ecosystem status and in the case of our study the complete insight of genotoxic pressure. However, the choice of animals as bioindicators also has a significant impact on the quality of the obtained information. Differential response between fish and mussels was observed at the highly polluted site suggesting possible involvement of additional protective mechanism such as valve closure in mussels.


Assuntos
Carpas , Poluentes Químicos da Água , Animais , Bioensaio , Monitoramento Biológico , Ensaio Cometa , Dano ao DNA , Ecossistema , Monitoramento Ambiental , Humanos , Testes para Micronúcleos , Sérvia
15.
Aquat Toxicol ; 225: 105546, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32574930

RESUMO

In natural environments, organisms are often exposed to several environmental pollutants at any one time, and the potential effects of such co-exposures on human and environmental health are of considerable concern. It is thought that multi-walled carbon nanotubes (MWCNTs) may interact with other pollutants in aquatic systems and induce considerably different effects compared with exposure to a single contaminant. The objective of this study was to evaluate the potential acute combined effects of mixtures of MWCNTs and 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) on embryonic development stages, oxidative stress, apoptosis and DNA damage in developing zebrafish (Danio rerio). The embryos were treated with BDE-47 (5, 10, and 50 µg/L) and MWCNTs (50 mg/L), either combined or individually, for 96 h. Following exposure, BDE-47 induced significant acute toxicity, while the MWCNTs exhibited slight toxicity. When compared with BDE-47-only exposure, the inhibited growth induced by BDE-47 was weakened in the presence of MWCNTs. Similarly, the levels of oxidative stress biomarkers (reactive oxygen species, superoxide dismutase, catalase activities and malondialdehyde), apoptosis (apoptosis rate, caspase-3 and caspase-9 activities) and DNA damage (comet assay and comet olive tails) decreased in the presence of MWCNTs compared to those exposed to BDE-47 alone. These results demonstrate that MWCNTs can weaken the developmental inhibition, oxidative stress, apoptosis and DNA damage induced by BDE-47 in the early stages of zebrafish development.


Assuntos
Éteres Difenil Halogenados/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Apoptose/efeitos dos fármacos , Caspase 3 , Ensaio Cometa , Dano ao DNA , Humanos , Malondialdeído , Nanotubos de Carbono/toxicidade , Oxirredução , Estresse Oxidativo/efeitos dos fármacos , Espécies Reativas de Oxigênio , Superóxido Dismutase/metabolismo , Peixe-Zebra/embriologia
16.
Ecotoxicol Environ Saf ; 202: 110892, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32593098

RESUMO

Carbon nanotubes presence in the environment increases every year because of exponential industrial production around the world. In aquatic environments, carbon nanotubes can interact with other pollutants based on their adsorbent surface chemistry properties. Heavy metal ions represent one of the biggest concerns in water resources nowadays due to anthropogenic activities, in which cadmium (Cd) is one of the most harmful metal for aquatic organisms. This study investigated the influence of two co-exposure protocols differing by the order of interaction of oxidized multiwalled carbon nanotubes (ox-MWCNT) with Cd in zebrafish liver cell line (ZFL). The ox-MWCNT was characterized, Cd content in culture medium and uptake by cells were quantified using ICP-MS and, the reactive oxygen species (ROS), the biotransformation enzymes activity of phase I and II as well as the antioxidants defenses and oxidative damage were analyzed. The effects on the cell cycle were investigated by flow cytometry and DNA damage by comet assay. The exposure to ox-MWCNT alone decreased the activity of catalase, glutathione peroxidase, and glutathione S-transferase and altered the cell cycle with a reduction of cells in the G2/M phase. Cd exposure alone decreased the activity of catalase and glutathione S-transferase, increased ROS, metallothionein, and lipid peroxidation content and causes genotoxicity in the cells. Despite different incubation protocol, the co-exposure ox-MWCNT-Cd increased the Cd content in ZFL cells after 24 h exposure, increased ROS production and DNA damage without differences between them. Our results showed the modulation of ox-MWCNT on Cd effects and contributed to future co-exposure toxicity investigations and nanosafety regulations involving carbon nanomaterials and aquatic pollutants.


Assuntos
Cádmio/toxicidade , Nanotubos de Carbono/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Antioxidantes/metabolismo , Catalase/metabolismo , Ciclo Celular , Linhagem Celular , Ensaio Cometa , Dano ao DNA , Glutationa Peroxidase/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Metais Pesados/farmacologia , Oxirredução , Estresse Oxidativo/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Testes de Toxicidade , Peixe-Zebra/metabolismo
17.
Toxicol Lett ; 331: 124-129, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32534006

RESUMO

DNA damage quantified as the comet tail length was assessed using in vitro and in vivo comet assay on one- and two-cell mouse embryos obtained by natural mating. The use of a protocol with three layers of agarose reduces the embryo loss and makes it possible to study a small number of embryos. A significantly lower level of basal, but not induced DNA damage was found in embryos with cleaved zona pellucida compared to embryos with intact zona pellucida. There were no significant differences in the length of the comet's tail between embryos lysed in different lysis solutions, both in cases of basal and induced DNA damage. A significant increase in the comet tail length was detected in one-cell embryos of mice treated with methyl methanesulfonate and etoposide compared to the control. The data show that DNA damage induced in maternal germ cells persists, which can be detected in embryos using the comet assay.


Assuntos
Dano ao DNA , Embrião de Mamíferos/efeitos dos fármacos , Desenvolvimento Embrionário/efeitos dos fármacos , Mutagênicos/toxicidade , Zona Pelúcida/efeitos dos fármacos , Animais , Ensaio Cometa , Embrião de Mamíferos/patologia , Desenvolvimento Embrionário/genética , Feminino , Masculino , Exposição Materna , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos CBA , Gravidez , Zona Pelúcida/patologia
18.
Toxicology ; 441: 152507, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32512035

RESUMO

Vorinostat was approved as the first histone deacetylase inhibitor for the management of cutaneous T cell lymphoma. However, it's in vivo genetic and epigenetic effects on non-cancerous cells remain poorly understood. As genetic and epigenetic changes play a critical role in the pathogenesis of carcinogenesis, we investigated whether vorinostat induces genetic and epigenetic alterations in mouse bone marrow cells. Bone marrow cells were isolated 24 h following the last oral administration of vorinostat at the doses of 25, 50, or 100 mg/kg/day for five days (approximately equal to the recommended human doses). The cells were then used to assess clastogenicity and aneugenicity by the micronucleus test complemented by fluorescence in situ hybridization assay; DNA strand breaks, oxidative DNA strand breaks, and DNA methylation by the modified comet assay; apoptosis by annexin V/PI staining analysis and the occurrence of the hypodiploid DNA content; and DNA damage/repair gene expression by polymerase chain reaction (PCR) Array. The expression of the mRNA transcripts were also confirmed by real-time PCR and western blot analysis. Vorinostat caused structural chromosomal damage, numerical chromosomal abnormalities, DNA strand breaks, oxidative DNA strand breaks, DNA hypomethylation, and programed cell death in a dose-dependent manner. Furthermore, the expression of numerous genes implicated in DNA damage/repair were altered after vorinostat treatment. Accordingly, the genetic/epigenetic mechanism(s) of action of vorinostat may play a role in its carcinogenicity and support the continued study and development of new compounds with lower toxicity.


Assuntos
Antineoplásicos/toxicidade , Células da Medula Óssea/efeitos dos fármacos , Vorinostat/toxicidade , Animais , Antineoplásicos/administração & dosagem , Apoptose/efeitos dos fármacos , Aberrações Cromossômicas/induzido quimicamente , Ensaio Cometa , Metilação de DNA/efeitos dos fármacos , Reparo do DNA/efeitos dos fármacos , Relação Dose-Resposta a Droga , Regulação para Baixo , Masculino , Camundongos , Estresse Oxidativo/efeitos dos fármacos , Vorinostat/administração & dosagem
19.
Mutat Res ; 853: 503194, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32522349

RESUMO

Obesity is associated with elevated cancer risk, which may be represented by elevated genomic damage. Oxidative stress plays a key role in obesity related detrimental health consequences including DNA oxidation damage. The elevated cancer risk in obesity may be a consequence. Weight loss has been shown to reduce genomic damage, but the role of oxidative stress in that has not been clarified. The aim of this study is therefore to investigate the influence of bariatric surgery induced weight loss on DNA oxidation damage in morbidly obese subjects. For this aim, we used cryopreserved peripheral blood mononuclear cells in the FPG comet assay. Advanced protein oxidation products and 3-nitrotyrosine were measured as oxidative and nitrative protein stress markers. Furthermore, expression of oxidative stress related proteins HSP70 and Nrf2 as well as mitochondrial enzyme citrate synthase and NADPH oxidase subunit p22 phox were analysed. Our findings revealed significantly reduced DNA strand breaks, but DNA base oxidation was not reduced. We observed significant reduction in plasma AOPPs and 3-nitrotyrosine, which indicated an improvement in oxidative/nitrative stress. However, expression of HSP70 and Nrf2 were not altered after weight loss. In addition, expression of citrate synthase and p22 phox were also unaltered. Overall, bariatric surgery induced significant reduction in excess body weight and improved the patients' health status, including reduced DNA strand breaks and slightly improved antioxidant status in some of the investigated endpoints, while cellular ROS formation and DNA oxidation damage stayed unaltered. This complex situation may be due to combined beneficial effects of weight loss and burdening of the body with fat breakdown products. In the future, collecting samples two years after surgery, when patients have been in a weight plateau for some time, might be a promising approach.


Assuntos
Dano ao DNA/fisiologia , Estresse Oxidativo/fisiologia , Perda de Peso/fisiologia , Adulto , Antioxidantes/metabolismo , Cirurgia Bariátrica/métodos , Ensaio Cometa/métodos , Feminino , Humanos , Leucócitos Mononucleares/metabolismo , Masculino , Obesidade/metabolismo , Obesidade/cirurgia , Oxirredução , Espécies Reativas de Oxigênio/metabolismo
20.
Nat Commun ; 11(1): 2147, 2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-32358495

RESUMO

Upon genotoxic stress, PCNA ubiquitination allows for replication of damaged DNA by recruiting lesion-bypass DNA polymerases. However, PCNA is also ubiquitinated during normal S-phase progression. By employing 293T and RPE1 cells deficient in PCNA ubiquitination, generated through CRISPR/Cas9 gene editing, here, we show that this modification promotes cellular proliferation and suppression of genomic instability under normal growth conditions. Loss of PCNA-ubiquitination results in DNA2-dependent but MRE11-independent nucleolytic degradation of nascent DNA at stalled replication forks. This degradation is linked to defective gap-filling in the wake of the replication fork and incomplete Okazaki fragment maturation, which interferes with efficient PCNA unloading by ATAD5 and subsequent nucleosome deposition by CAF-1. Moreover, concomitant loss of PCNA-ubiquitination and the BRCA pathway results in increased nascent DNA degradation and PARP inhibitor sensitivity. In conclusion, we show that by ensuring efficient Okazaki fragment maturation, PCNA-ubiquitination protects fork integrity and promotes the resistance of BRCA-deficient cells to PARP-inhibitors.


Assuntos
Antígeno Nuclear de Célula em Proliferação/metabolismo , Linhagem Celular Tumoral , Montagem e Desmontagem da Cromatina/genética , Montagem e Desmontagem da Cromatina/fisiologia , Ensaio Cometa , DNA/genética , Dano ao DNA/genética , Dano ao DNA/fisiologia , Reparo do DNA/genética , Reparo do DNA/fisiologia , Replicação do DNA/genética , Replicação do DNA/fisiologia , Imunofluorescência , Instabilidade Genômica/genética , Instabilidade Genômica/fisiologia , Células HEK293 , Células HeLa , Humanos , Antígeno Nuclear de Célula em Proliferação/genética , Ligação Proteica , Ubiquitinação/genética , Ubiquitinação/fisiologia
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