Multispecies and multibiomarker assessment of fish health from Iguaçu River reservoir, Southern Brazil.

This study investigated the impact of micropollutants on fish health from Segredo hydroelectric reservoir (HRS) along the Iguaçu River, Southern Brazil, contaminated by urban, industrial, and agricultural activities. This is the first comprehensive study assessment in the river after the severe drought in the 2020s in three fish species from different trophic levels Astyanax spp. (water column depth/omnivorous), Hypostomus commersoni (demersal/herbivorous), and Pimelodus maculatus (demersal/omnivorous). Animals, water, and sediment samples were collected from three distinct sites within the reservoir: Floresta (upstream), Iratim (middle), and Station (downstream). The chemical analysis revealed elevated concentrations of metals (Al, Cu, Fe) and the metalloid As in water, or Cu, Zn, and As in sediment, surpassing Brazilian regulatory limits, while the organic pollutants as DDT, PAHs, PCBs, and PBDEs were found under the Brazilian regulatory limits. The metal bioaccumulation was higher in gills with no significant differences among sites. The species Astyanax spp. and H. commersoni displayed variations in hepatosomatic index (HSI) and P. maculatus in the condition factor index (K) between sites, while adverse effects due to micropollutants bioaccumulation were observed by biochemical, genotoxic, and histopathological biomarkers. The principal component analysis and integrated biomarker response highlighted the upstream site Floresta as particularly inhospitable for biota, with distinctions based on trophic level. Consequently, this multifaceted approach, encompassing both fish biomarkers and chemical analyses, furnishes valuable insights into the potential toxic repercussions of micropollutant exposure. These findings offer crucial data for guiding management and conservation endeavors in the Iguaçu River.

Low concentration of 2,4,6-tribromophenol (TBP) represents a risk to South American silver catfish Ramdia quelen (Quoy and Gaimard, 1824) population.

The 2,4,6-tribromophenol (TBP) is an environmental persistent pollutant widely used as flame retardant, antimicrobial and insecticide agent in wood preservation and plastic production. Currently, TBP is found in environmental compartments such as soil, freshwater, groundwater, sewage sludge and domestic dust, but the effects to biota and the risk of exposure to aquatic vertebrates are still scarce. In the present study, Rhamdia quelen fish embryos (8 h post-fertilization - hpf) were exposed to 0.3 and 3.0 µg L-1 of TBP until 96 hpf. Biochemical biomarkers, hatching, survival and larvae/embryo malformations were evaluated after exposure. Additionally, a mathematical model was proposed to evaluate the effects along further generations. The results showed that TBP decreased the survival level but did not cause significant difference in the hatching rates. After 72 and 96 hpf, individuals from the highest tested concentration group showed more severe malformations than individuals from control and the lower concentrations groups. The deformities were concentrated on the embryos facial region where the sensorial structures related to fish behavior are present. The biochemical biomarkers revealed both oxidative stress and neurotoxicity signs after exposure to the contaminant, while the application of the mathematical model showed a decrease of population in both tested TBP concentrations. In conclusion, the current results demonstrated that TBP is toxic to R. quelen embryos and represents a risk to population after early life stage exposure.

Malignancy and tumorigenicity of melanoma B16 cells are not affected by silver and gold nanoparticles.

Gold (AuNP) and silver (AgNP) nanoparticles have been incorporated into many therapeutic and diagnostic applications. However, previous studies revealed toxic properties as well as the hormesis phenomenon of many nanoparticles in different biological models. To evaluate the effects of low concentrations of AuNP and AgNP on murine melanoma cells B16F1 and B16F10 and relate them with phenotype changes, cells were exposed for 24 and 48 h. No cytotoxicity was observed for B16 cells through neutral red, MTT, trypan blue, and crystal violet assays at concentrations from 0.01 to 10 ng mL-1. Likewise, the nanoparticles did not interfere with drug-efflux activity, cell migration, cell cycle, and colony formation. Slight toxicity was observed for B16F10 exposed to 100 ng mL-1, with a decreased number of viable and attached cells, indicating differential sensitivity of B16F1 and B16F10 cells to the nanoparticles. Furthermore, colony size dispersion decreased for both B16 cell sub-lines. Therefore, there is no evidence that the tested concentrations of AuNP and AgNP can render B16 cells more aggressive and malignant, which is important since both nanoparticles are already largely used in nanotechnological products. Considering studies that have showed the hormesis effect of nanoparticles at low concentrations, which could protect cancer cells against chemotherapy, further investigation is advised.

Comparative bioaccumulation and effects of purified and cellular extract of cylindrospermopsin to freshwater fish Hoplias malabaricus.

Many tropical freshwater ecosystems are impacted by cyanobacteria blooms increasing the risk of cyanotoxins exposure to aquatic organisms while human populations may be exposed by eating fish, drinking water, or dermal swimming. However, few toxicological data are available on the influence of cyanobacteria blooms in particular, cylindrospermopsin (CYN) on Brazilian neotropical fish. A number of studies demonstrated the ability of CYN to bioaccumulate in freshwater organisms and consequently enter the human food chain. The aim of the current study was to examine the effects of CYN following single intraperitoneal injection (50 µg/kg) of purified CYN (CYNp) or aqueous extract of CYN-producing cyanobacteria extract (CYNex) after 7 or 14 days. Biomarkers such as histopathology (liver), oxidative stress (liver and brain), and acetylcholinesterase (AChE) activity (muscle and brain) were utilized in order to assess the influence of CYN on Hoplias malabaricus. In terms of AChE activity, administration of CYNex and CYNp both muscle and brains were used as target tissues. In brain an increase of glutathione S-transferase (GST) activity and lipid peroxidation (LPO) levels was noted suggesting an imbalance in redox cycling. The majority of biomarkers did not present significant alterations in liver, but an elevation in superoxide dismutase (SOD) and glucose 6 phosphate dehydrogenase (G6PDH) activities was found. Different profiles of GST activity were observed in both studied groups (CYNex and CYNp) while LPO (CYNex and CYNp) and protein carbonylation (PCO) (CYNp) levels increased after exposure to CYN. The incidence of necrosis, melanomacrophages centers, and free melanomacrophages were detected as evidence of cell death and immune responses. Nonprotein thiols (NPT) levels were not markedly affected in both exposed groups. Data demonstrated that in vivo exposure to CYN produced biochemical and morphological disturbances in liver and brain of H. malabaricus.

Diffuse sources of contamination in freshwater fish: Detecting effects through active biomonitoring and multi-biomarker approaches.

Aquatic organisms are usually exposed to a mixture of xenobiotics that may exert a large effect even in low concentrations, and when information is obtained exclusively from chemical analyses the prediction of the deleterious effects is potentially hindered. Therefore, the application of complementary monitoring methods is a priority. Here, in addition to chemical analyses, an active biomonitoring study using multiple biomarker responses in Nile tilapia Oreochromis niloticus was conducted to assess the effects of a contamination gradient along four reservoirs in Iguaçu River. Chemical analysis in the muscle showed high levels of metals in fish from the reservoir closest to an industrialized and environmentally degraded area, however fish exposed to all studied reservoirs showed hepatic alterations (necrosis and inflammatory processes). Also, significant variations of biochemical biomarkers were observed with no clear indication of contamination gradient, since an indicative of higher impact was found in an intermediary reservoir, including high concentrations of biliary polycyclic aromatic hydrocarbons (PAHs). However, nuclear morphological alterations (NMA) were less frequent at the same reservoir. Thus, the multi-biomarker approach allied to active biomonitoring is a practical and important tool to assess deleterious effects of contamination in freshwater, providing data for monitoring and conservation protocols.

Responses of human hepatoma HepG2 cells to silver nanoparticles and polycyclic aromatic hydrocarbons.

The nanotechnology has revolutionized the global market with silver nanoparticles (AgNP) occupying a prominent position due to their remarkable anti-bacterial properties. However, there is no data about the adverse and toxic effects of associations of AgNP and ubiquitous compounds, such as polycyclic aromatic hydrocarbons (PAH). In the current study, we investigated the responses of HepG2 cells to realistic concentrations of AgNP (0.09, 0.9, and 9 ng ml-1) and mixture of PAH (30 and 300 ng ml-1), separately and in association. Cell viability and cytotoxicity (neutral red retention and MTT production assays) and proliferation (crystal violet [CV] assay), xenobiotic efflux transporter activity (rhodamine B accumulation assay), ROS levels (dichlorodihydrofluorescein diacetate assay), and lipid peroxidation (pyrenylphosphine-1-diphenyl assay) were analyzed. There was no decreases of cell viability after exposure to AgNP, PAH and most of AgNP + PAH associations, but increases of cell viability/number (CV assay) occurred. Efflux transporter activity was not affected, with exception of one AgNP + PAH associations, ROS levels increased, but lipid peroxidation decreased. Some toxicological interactions occurred, particularly for the highest concentrations of AgNP and PAH, but there is no evidence that these interactions increased the toxicity of AgNP and PAH.

Toxicological interactions of silver nanoparticles and organochlorine pesticides in mouse peritoneal macrophages.

Nanotechnology occupies a prominent space in economy and science due to the beneficial properties of nanomaterials. However, nanoparticles may pose risks to living organisms due to their adsorption and pro-oxidative properties. The aim of the current study was to investigate the effects of polymer-coated silver nanoparticles (AgNPs) and organochlorine pesticides (OCPs), as well as their combined effects on mouse peritoneal macrophages. Macrophages were isolated and exposed to three concentrations of AgNPs (groups: N1 = 30, N2 = 300 and N3 = 3000 ng.ml(-1)), two concentrations of OCPs (groups: P1 = 30 and P2 = 300 ng.ml(-1)) and the six possible combinations of these two contaminants for 24 h. AgNPs had irregular shape, Feret diameter of 8.7 ± 7.5 nm and zeta potential of -28.7 ± 3.9 mV in water and -10.7 ± 1.04 mV in culture medium. OCP mixtures and the lower concentrations of AgNPs had no detectable effects on cell parameters, but the highest AgNPs concentration showed high toxicity (trypan blue and MTT assays) resulting in morphological changes, increase of nitric oxide levels and phagocytic index. Foremost, the association of N3 and P2 led to distinct effects from those observed under single exposure.

Cylindrospermopsin effects on protein profile of HepG2 cells.

Human hepatoma cells (HepG2) were exposed to purified cylindrospermopsin (CYN), a potent toxicant for eukaryotic cells produced by several cyanobacteria. Exposure to 10 µg l-1 of CYN for 24 h resulted in alteration of expression of 48 proteins, from which 26 were identified through mass spectrometry. Exposure to 100 µg l-1 of CYN for 24 h affected nuclear area and actin filaments intensity, which can be associated with cell proliferation and toxicity. The proteins are implicated in different biological processes: protein folding, xenobiotic efflux, antioxidant defense, energy metabolism and cell anabolism, cell signaling, tumorigenic potential, and cytoskeleton structure. Protein profile indicates that CYN exposure may lead to alteration of glucose metabolism that can be associated with the supply of useful energy to cells respond to chemical stress and proliferate. Increase of G protein-coupled receptors (GPCRs), heterogeneous nuclear ribonucleoproteins (hnRNP), and reactive oxygen species (ROS) levels observed in HepG2 cells can associate with cell proliferation and resistance. Increase of MRP3 and glutathione peroxidase can protect cells against some chemicals and ROS. CYN exposure also led to alteration of the expression of cytoskeleton proteins, which may be associated with cell proliferation and toxicity.

Glyphosate and aminomethylphosphonic acid metabolite (AMPA) modulate the phenotype of murine melanoma B16-F1 cells.

Pesticides are contaminants run-offs from agricultural areas with a global concern due to their toxicity for non-target organisms. The Brazilian Health Surveillance Agency reported about 63% of the food contain pesticide residues. Glyphosate is a herbicide used worldwide but its toxicity is not a consensus among specialists around the world. AMPA (aminomethylphosphonic acid) is a glyphosate metabolite that can be more toxic than the parental molecule. Melanoma murine B16-F1 cells were exposed to glyphosate and AMPA to investigate the cell profile and possible induction to a more malignant phenotype. Glyphosate modulated the multi-drug resistance mechanisms by ABCB5 gene expression, decreasing cell attachment, increasing cell migration and inducing extracellular vesicles production, and the cells exposed to AMPA revealed potential damages to DNA. The present study observed that AMPA exhibits high cytotoxicity, which suggests a potential impact on non-tumor cells, which are, in general, more susceptible to chemical exposure. Conversely, glyphosate favored a more metastatic and chemoresistant behavior in cancer cells, highlighting the importance of additional research in this area.

BDE-209 exposure in murine melanoma (B16-F1) cells modulates tumor malignancy and progression in vivo.

Melanoma is a type of skin cancer considered aggressive due to its high metastatic ability and rapid progression to other tissues and organs. BDE-209 (2,2',3,3',4,4',5,5',6,6'-decabromodiphenyl ether) is an additive used as a flame retardant and classified as a persistent organic pollutant that has a high bioaccumulation capacity due to its lipophilic nature. This substance has already been detected in rivers, air, soil, plants and even in different human biological samples, such as plasma, umbilical cord blood and breast milk, revealing a great concern to human populations. Thus, in the current study we investigated whether prior exposure of murine melanoma B16-F1 cells to BDE-209 modulates in vivo progression and malignancy of melanoma. B16-F1 cells were cultured and exposed in vitro to BDE-209 (0.01, 0.1 e 1 nM) for 15 days and then inoculated, via caudal vein, in C57BL/6 mice for experimental metastasis analysis after 20 days. Inoculation of BDE-209-exposed cells resulted in 82% increase of metastasis colonized area in the lungs of mice, downregulation of tumor suppressors genes, such as Timp3 and Reck, decrease of lipid peroxidation and increase of systemic and local inflammatory response. These findings are related to melanoma progression. Additionally, the histopathological analysis revealed greater number of focal points of metastases in the lungs and invasiveness of metastases to the mice brain (89%). The results showed that exposure to BDE-209 may alter the phenotype of B16-F1 cells, worsening their metastatic profile. Current data showed that BDE-209 may interfere with the prognosis of melanoma by modulating cells with less invasiveness capacity to a more aggressive profile.

Pollutant bioaccumulation in sentinel fish chronically exposed in Iguaçu river reservoirs (Southern Brazil) and human health risk of fish consumption.

Bioaccumulation studies in fish mark the initial phase of assessing the risk of chemical exposure to biota and human populations. The Iguaçu River boasting a diverse endemic ichthyofauna, is grappling with the repercussions of human activities. This study delved into the bioaccumulation of micropollutants, the early-warning effects on Rhamdia quelen and Oreochomis niloticus in the Segredo Reservoir (HRS) and the potential risk of human exposure. Two groups of caged fish in three sites of the reservoir were exposed during the autumn-winter and spring-summer, while a third group (O. niloticus) underwent a twelve-month exposure, and inorganic and organic chemicals analysis in water, sediment, and biota. Additionally, metallothionein expression and genotoxicity were employed as biomarkers. PAHs, PCBs, Al, Cu, Fe, and As in water and DDTs, Cu, Zn, and As in sediment surpassed the thresholds set by Brazilian regulations, where DDT exhibited bioaccumulation in muscle, alongside metals in liver, kidney, gills, and muscle tissues. R. quelen showed metallothionein expression whereas DNA damage and NMA frequencies were elevated in target organs and in brain and erythrocytes of O. niloticus during summer. In this species the DNA damage in liver was remarkable after twelve months. Target Hazard Quotients and Cancer Risk values shedding light on the vulnerability of both children and adults. The reservoir's conditions led to heightened sensitivity to micropollutants for R. quelen species. The data presented herein provides decision-makers with pertinent insights to facilitate effective management and conservation initiatives within the Iguaçu Basin.

Complex metabolic interactions between benzo(a)pyrene and tributyltin in presence of dichlorodiphenyltrichloroethane in South American catfish Rhamdia quelen.

In an attempt to explore complex metabolic interactions between toxicants present in polluted freshwater, hepatic metabolism of benzo(a)pyrene (BaP) and tributyltin (TBT) in fish was investigated when these compounds were administrated alone, mixed together and along with dichlorodiphenyltrichloroethane (DDT). Ten Rhamdia quelen per group were treated with a single intra-peritoneal (IP) dose (5-day experiment) or three successive doses (15-day experiment) either containing BaP (0.3; 3 or 30mgkg(-1)) or TBT (0.03; 0.3 or 3mgkg(-1)) or a combination of BaP+TBT, BaP+DDT, TBT+DDT and BaP+TBT+DDT under their respective lower doses, with DDT dose kept at 0.03mgkg(-1). Tetrahydroxy-benzo(a)pyrene (BaP-tetrol-I), and dibutyltin (DBT) and monobutyltin (MBT) were analyzed to assess BaP and TBT hepatic metabolism, respectively. A significant difference in BaP-tetrol-I concentration was observed in liver and bile between the lowest and the highest doses of BaP in both 5 and 15-day experiments. In the 15-day experiment, the presence of TBT with BaP reduced the amount of BaP-tetrol-I in bile compared to the BaP alone. The time of exposure and the number of doses affected BaP-tetrol-I concentration in the bile of fish exposed to BaP 0.3mgkg(-1) and BaP+DDT. TBT and its metabolites concentrations showed a dose-dependent increase in the liver in both experiments and in the bile in the 5-day experiment. TBT at its lowest dose was completely metabolized into DBT and MBT in the liver in the 15-day experiment. No TBT metabolites were detected in the bile of fish exposed to the mixtures in the 5-day experiment, except for a small MBT amount found in BaP+TBT+DDT. This study strengthens the hypothesis of a metabolic interaction between BaP and TBT in fish and suggests DDT as an important third player when present in the mixture.

Immunotoxicity of relevant mixtures of pesticides and metabolites on THP-1 cells.

Pesticides are used to combat agricultural pests but also trigger side effects on non-target organisms. Particularly, immune system dysregulation is a major concern due to the organism's increased vulnerability to diseases, including cancer development. Macrophages play essential roles in innate and adaptive immunity and can undergo classical (M1) or alternative (M2) activation. The M1 pro-inflammatory phenotype has an antitumor role, while M2 favors tumor promotion. Although previous studies have linked pesticide exposure to immune compromise, macrophage polarization is still poorly studied. Here, we investigated the effects of 72 h-long exposure to the mixture of four pesticides widely used in Brazil (glyphosate, 2,4-D, mancozeb, and atrazine), and their main metabolites (aminomethylphosphonic acid, 2,4-diclorophenol, ethylenethiourea, and desethylatrazine) on human leukemia monocytic THP-1 cell line at concentrations based on the Acceptable Daily Intake (ADI) value established in the country. The data revealed immunotoxicity related to impaired cell metabolism in all exposed groups, decreased cell attachment (Pes: 10-1; Met: 10-1; Mix: all concentrations), and disturbance in nitric oxide (NO) levels (Met: 10-1, 101; Mix: all concentrations). The polarization of macrophages towards a more pro-tumor M2-like phenotype was also supported by decreased secretion of the pro-inflammatory cytokine TNF-α (Pes 100, 101) and increased IL-8 (Pes 101). These outcomes alert about the risk of pesticide exposure in the Brazilian population.

Monitoring water quality in reservoirs for human supply through multi-biomarker evaluation in tropical fish.

Paraíba do Sul River is located at a very densely inhabited region of Brazil crossing the three most industrialized states of the country (São Paulo, Minas Gerais and Rio de Janeiro states). As a result, industrial and farming residues as well as urban sewage are frequently disposed without appropriate treatment. The current study aimed at investigating the water quality in three reservoirs along the Paraíba do Sul River (Ilha dos Pombos, Santa Cecília and Santa Branca), through physiological, morphological, biochemical, and genetic biomarkers. The bioindicator chosen was the catfish Pimelodus maculatus, sampled during the dry (June 2008) and rainy (February 2009) seasons. Also, some water physicochemical parameters were analyzed from the sampling sites, but displayed no alterations according to the Brazilian Agency for Water Quality Legislation. Branchial carbonic anhydrase activity was inhibited in the dry season, while renal carbonic anhydrase activity was inhibited in the rainy season in the Santa Branca reservoir, indicating disturbance of osmoregulatory and acid-base regulation processes. Histopathological alterations were observed in the gills (neoplasic and tissue hyperplasia processes) and liver (necrosis), indicating serious damage to the functional integrity of these organs. A high incidence of melanomacrophage centers was observed in the liver, suggesting an intense immune response in all reservoirs. Acetylcholinesterase and catalase activity showed also differences corroborating some morphological results. Likewise, the induction of the micronucleus and DNA damage indicate genotoxicity, but mainly in the Santa Branca reservoir. Thus, the health status of P. maculatus warrants caution in the use of the water from the 3 reservoirs for direct human consumption, particularly after the accidental spill of endosulfan in November 2008, three months before the rainy season sampling.

Potential risks of natural mercury levels to wild predator fish in an Amazon reservoir.

Mercury (Hg) is a toxic metal that bioaccumulates in aquatic organisms and along food chain. Many studies have reported the problem of mercury exposure in aquatic systems from Amazon basin, but very few have focused on the potential risks to wild fish. The present study reports the bioaccumulation of mercury and alterations in target organs of the predator fish Hoplias malabaricus (traíra) from Samuel reservoir, Amazon basin, Northern Brazil. About 18% of fish had mercury levels in muscle exceeding the safe limit for ingestion through food, established by WHO (0.5 µg Hg g(-1)). Fish were separated in two groups according to mercury bioaccumulation in liver (<0.2 µg Hg g(-1)-group I and >0.2 µg Hg g(-1)-group II) for biomarker comparisons. Catalase activity and number of macrophage centers were statistically higher in group II, confirming the potential of Hg to interfere with redox balance and to recruit defense cells to the liver. Conversely, erythrocyte nuclear alterations were less frequent in group II, indicating a more rigorous selection of erythrocytes or hormesis pattern of response. Glutathione S-transferase activity, lipid peroxidation, and histopathological analyses were not statistically different in the liver and gills of both groups. Comparison of lipid peroxidation levels of these fish with others captured in Southern Brazil during another study and the high incidence of morphological alterations in the liver and gills suggest that the bioaccumulation of mercury during continuous exposure is posing potential risks to the species.

Polybrominated diphenyl ethers BDE-47 and BDE-99 modulate murine melanoma cell phenotype in vitro.

Cancer is one of the leading causes of mortality worldwide. Even with the advances of pharmaceutical industry and treatments, the mortality rate for various types of cancer remains high. In particular, phenotypic alterations of tumor cells concerning drug efflux, migratory and invasive capabilities may represent a hurdle for cancer treatment and contribute to poor prognosis. In the present study, we investigated the effects of polybrominated diphenyl ethers (PBDEs) used as flame retardants on phenotypic features of melanoma cells that are important for cancer. Murine melanoma B16-F1 (less metastatic) and B16-F10 (more metastatic) cells were exposed to 0.01-1.0 nM of BDE-47 (2,2',4,4'-tetrabromodiphenyl ether), BDE-99 (2,2',4,4',5-pentabromodiphenyl ether), and the mixture of both (at 0.01 nM) for 24 h (acute exposure) and 15 days (chronic exposure). The polybrominated diphenyl ethers (PBDEs) did not affect cell viability but led to increased drug efflux transporter activity, cell migration, and colony formation, as well as overexpression of Abcc2 (ATP-binding cassette subfamily C member 2), Mmp-2 (matrix metalloproteinase-2), Mmp-9 (matrix metalloproteinase-9), and Tp53 (tumor protein p53) genes and downregulation of Timp-3 (tissue inhibitor of metalloproteinase 3) gene in B16-F10 cells. These effects are consistent with increased aggressiveness and malignancy of tumors due to exposure to the flame retardants and raise some concerns on the effects such chemicals may have on melanoma treatment and cancer prognosis.

BDE-209 and TCDD enhance metastatic characteristics of melanoma cells after chronic exposure.

TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) and BDE-209 (decabromodiphenyl ether) are persistent organic pollutants (POPs) produced by industrial activities and associated with several diseases. TCDD is a known human carcinogen, but few studies investigated about the effects of exposure to both compounds, i.e., whether BDE-209 and TCDD can render tumor cells more aggressive and metastatic. In the current study we investigated if the exposure of B16-F1 and B16-F10 melanoma murine cells to environmental relevant concentrations of TCDD and BDE-209 at 24 h and 15-day exposure modulates the expression of genes related to metastasis, making the cells more aggressive. Both pollutants did not affect cell viability but lead to increase of cell proliferation, including the upregulation of vimentin, MMP2, MMP9, MMP14 and PGK1 gene expression and downregulation of E-cadherin, TIMP2, TIMP3 and RECK, strongly suggesting changes in cell phenotypes defined as epithelial to mesenchymal transition (EMT) in BDE-209 and TCDD-exposed cells. Foremost, increased expression of metalloproteinases and decreased expression of their inhibitors made B16-F1 cells similar the more aggressive B16-F10 cell line. Also, the higher secretion of extracellular vesicles by cells after acute exposure to BDE-209 could be related with the phenotype changes. These results are a strong indication of the potential of BDE-209 and TCDD to modulate cell phenotype, leading to a more aggressive profile.

Toxicological effects of silver nanoparticles and cadmium chloride in macrophage cell line (RAW 264.7): An in vitro approach.

BACKGROUND: Silver nanoparticles (AgNP) are largely used in nanotechnological products, but the real risks for human and environment are still poorly understood if we consider the effects of mixtures of AgNP and environmental contaminants, such as non-essential metals. METHODS: The aim of the present study was to investigate the cytotoxicity and toxicological interaction of AgNP (1-4 nm, 0.36 and 3.6 µg mL-1) and cadmium (Cd, 1 and 10 µM) mixtures. The murine macrophage cell line RAW 264.7 was used as a model. RESULTS: Effects were observed after a few hours (4 h) on reactive oxygen species (ROS) and became more pronounced after 24 h-exposure. Cell death occurred by apoptosis, and loss of cell viability (24 h-exposure) was preceded by increases of ROS levels and DNA repair foci, but not of NO levels. Co-exposure potentiated some effects (decrease of cell viability and increase of ROS and NO levels), indicating toxicological interaction. CONCLUSION: These effects are important findings that must be better investigated, since the interaction of Cd with AgNP from nanoproducts may impair the function of macrophages and represent a health risk for humans.

2,4,6-Tribromophenol is toxic to Oreochromis niloticus (Linnaeus, 1758) after trophic and subchronic exposure.

The presence of 2,4,6-Tribromophenol (TBP) in the environment increased the risk of exposure to aquatic organisms affecting the animal development or metabolism. The current study investigated the low, subchronic and trophic effect of TBP in both, male and female adult of Oreochromis niloticus. The fish were exposed to 0.5 or 50 ng g-1 of TBP every ten days for 70 days. Then, hepatosomatic (HSI) and gonadosomatic (GSI) indexes, erythrocyte parameters (hemoglobin content, nuclear morphology and morphometrical abnormalities), biochemical endpoints (glutathione S-Transferase and catalase activities, non-protein thiols, lipid peroxidation and protein carbonylation levels in the liver; and acetylcholinesterase activity in the brain and muscle), histopathological analysis (liver) and vitellogenin levels (plasma) were considered. TBP affected the HSI in male and female fish, but not the GSI. Principal Component Analysis revealed that erythrocytes from males are more sensitive to TBP exposure. Likewise, TBP induced the expression of vitellogenin, CAT activity and liver lesion in male fish comparatively with control group, but GST and NPT were influenced only by sex. Finally, the results showed that the antioxidant mechanism and cholinesterase activity effects were more pronounced in male than in female. The current data shows evidences of estrogenic endocrine disruption and toxicity in O. niloticus exposed to TBP, revealing the risk of exposure to biota.

Effects of trophic 2,2', 4,4'-tetrabromodiphenyl ether (BDE-47) exposure in Oreochromis niloticus: A multiple biomarkers analysis.

Polybrominated diphenyl esters are emerging environmental contaminants with few toxicological data, being a concern for the scientific community. This study evaluated the effects of BDE-47 on the health of Oreochromis niloticus fish. The animals were exposed to three doses of BDE-47 (0, 0.253, 2.53, 25.3 ng g-1) every 10 days, for 80 days. The BDE-47 affected the hepatosomatic and gonadosomatic index in female and the condition factor by intermediate dose in both sexes. The levels of estradiol decreased and the T4 are increased, but the vitellogenin production was not modulated in male individuals. Changes in AChE, GST, LPO and histopathology were observed while the integrated biomarker response index suggests that the lowest dose of BDE-47 compromised the activity of antioxidant enzymes. The oral exposure to BDE-47 in environmental concentrations is toxic to O. niloticus and the use of multiple biomarkers is an attribution in ecotoxicology studies and biomonitoring programs.