RESUMO
Arsenic is considered a worldwide pollutant that can be present in drinking water. Arsenic exposure is associated with various diseases, including cancer. Antioxidants as selenite and α-tocopherol-succinate have been shown to modulate arsenic toxic effects. Since changes in STAT3 and PSMD10 gene expression have been associated with carcinogenesis, the aim of this study was to evaluate the effect of arsenic exposure and co-treatments with selenite or α-tocopherol-succinate on the expression of these genes, in the livers of chronically exposed Syrian golden hamsters. Animals were divided into six groups: (i) control, (ii) chronically treated with 100 ppm arsenic, (iii) treated with 6 ppm α-tocopherol-succinate (α-TOS), (iv) treated with 8.5 ppm selenite, (v) treated with arsenic + α-TOS, and (vi) treated with arsenic + selenite. Urine samples and livers were collected after 20 weeks of continuous exposure. The urine samples were analyzed for arsenic species by atomic absorption spectrophotometry, and real-time RT-qPCR analysis was performed for gene expression evaluation. A reduction in STAT3 expression was observed in the selenite-treated group. No differences in PSMD10 expression were found among groups. Histopathological analysis revealed hepatic lymphocytosis in selenite-treated animals. As a conclusion, long-term exposure to arsenic does not significantly alter the expression of STAT3 and PSMD10 oncogenes in the livers of hamsters; however, selenite down-regulates STAT3 expression and provokes lymphocytosis.
Assuntos
Antioxidantes/farmacologia , Arsênio/efeitos adversos , Fígado/efeitos dos fármacos , Linfocitose/induzido quimicamente , Fator de Transcrição STAT3/genética , Ácido Selenioso/farmacologia , Administração Oral , Animais , Antioxidantes/administração & dosagem , Arsênio/administração & dosagem , Arsênio/urina , Regulação para Baixo/efeitos dos fármacos , Estimativa de Kaplan-Meier , Fígado/patologia , Masculino , Mesocricetus , Complexo de Endopeptidases do Proteassoma/genética , Complexo de Endopeptidases do Proteassoma/metabolismo , Fator de Transcrição STAT3/metabolismo , Ácido Selenioso/administração & dosagem , Aumento de Peso/efeitos dos fármacos , alfa-Tocoferol/farmacologia , alfa-Tocoferol/uso terapêuticoRESUMO
The ability of environmental pollutants to alter the epigenome with resultant development of behavioral alterations has received more attention in recent years. These alterations can be transmitted and affect later generations that have not been directly in contact with the contaminant. Arsenic (As) is a neurotoxicant and potent epigenetic disruptor that is widespread in the environment; however, the precise potential of As to produce transgenerational effects is unknown. Our study focused on the possible transgenerational effects on behavior by ancestral exposure to doses relevant to the environment of As, and the epigenetic mechanisms that could be involved. Embryos of F0 (ancestral generation) were directly exposed to 50 or 500 ppb of As for 150 days. F0 adults were raised to produce the F1 generation (intergeneration) and subsequently the F2 generation (transgeneration). We evaluated motor and cognitive behavior, neurodevelopment-related genes, and epigenetic markers on the F0 and F2 generation. As proposed in our hypothesis, ancestral arsenic exposure altered motor activity through the development and increased anxiety-like behaviors which were transmitted to the F2 generation. Additionally, we found a reduction in brain-derived neurotrophic factor expression between the F0 and F2 generation, and an increase in methylation on histone H3K4me3 in the nervous system.
Assuntos
Arsênio/toxicidade , Comportamento Animal/efeitos dos fármacos , Epigênese Genética/efeitos dos fármacos , Animais , Arsênio/administração & dosagem , Western Blotting , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Cognição/efeitos dos fármacos , Metilação de DNA/efeitos dos fármacos , Feminino , Código das Histonas/efeitos dos fármacos , Histonas/metabolismo , Masculino , Atividade Motora/efeitos dos fármacos , Atividade Motora/genética , Peixe-Zebra , Proteínas de Peixe-Zebra/metabolismoRESUMO
The Chacopampean plain is one of the most arsenic affected areas in Argentina, especially in groundwater, used both for animal drinking and forage irrigation. The main objective of this study was to determine the effect of arsenic (As) present in irrigation water on the germination parameters of red clover (Trifolium pratense L.), white clover (Trifolium repens L.), and alfalfa (Medicago sativa L.) seeds exposed to different concentrations of As(V). The germination and viability parameters of seeds from the three species were not affected by elevated concentrations of As. However, As significantly reduced the radicle and hypocotyl lengths of the three forage specimens. The inhibition level of the plants increased with the increase in the concentration of As. Regarding to hypocotyl length/radicle length ratio, the results evidenced that both the hypocotyl and radicle of clover species are affected in the same degree, while alfalfa radicles seemed more affected than hypocotyls at higher concentrations of As. Our results showed that irrigation with solutions containing As affect seedling growth parameters differently in the three species, and the effect of As is mostly evidenced when in high concentrations.(AU)
A planície de Chacopampeana é uma das áreas mais afetadas pelo arsênico na Argentina, principalmente em águas subterrâneas, usada tanto para água potável animal quanto para irrigação forrageira. O principal objetivo deste estudo é determinar o efeito do arsênio (As) presente na água de irrigação sobre os parâmetros de germinação de sementes forrageiras: trevo vermelho (Trifolium pratense L.), trevo branco (Trifolium repens L.) e alfafa (Medicago sativa L.) expostos a diferentes concentrações de As (V). Verificou-se que os parâmetros de germinação e viabilidade das sementes das três espécies não foram afetados pelas concentrações elevadas de As. No entanto, reduziu significativamente o comprimento da radícula e o comprimento do hipocótilo das três mudas de forragem, e seu nível de inibição é maior com o aumento da concentração de As. Quanto à relação comprimento de hipocótilo/comprimento da radícula, os resultados evidenciaram que nas espécies de trevo tanto o hipocótilo quanto a radícula são afetados no mesmo grau, enquanto as radículas de alfafa pareceram mais afetadas do que os hipocótilos em concentrações maiores de As. Nossos resultados mostraram que a irrigação com soluções contém Afetar os parâmetros de crescimento de plântulas de maneira diferente nas três espécies, e foi demonstrado que o efeito do As é principalmente evidenciado em altas concentrações.(AU)
Assuntos
Arseniatos/administração & dosagem , Arsênio/administração & dosagem , Germinação/efeitos dos fármacos , Fabaceae/efeitos dos fármacos , Sementes/efeitos dos fármacos , Trifolium , Medicago sativaRESUMO
The Chacopampean plain is one of the most arsenic affected areas in Argentina, especially in groundwater, used both for animal drinking and forage irrigation. The main objective of this study was to determine the effect of arsenic (As) present in irrigation water on the germination parameters of red clover (Trifolium pratense L.), white clover (Trifolium repens L.), and alfalfa (Medicago sativa L.) seeds exposed to different concentrations of As(V). The germination and viability parameters of seeds from the three species were not affected by elevated concentrations of As. However, As significantly reduced the radicle and hypocotyl lengths of the three forage specimens. The inhibition level of the plants increased with the increase in the concentration of As. Regarding to hypocotyl length/radicle length ratio, the results evidenced that both the hypocotyl and radicle of clover species are affected in the same degree, while alfalfa radicles seemed more affected than hypocotyls at higher concentrations of As. Our results showed that irrigation with solutions containing As affect seedling growth parameters differently in the three species, and the effect of As is mostly evidenced when in high concentrations.
A planície de Chacopampeana é uma das áreas mais afetadas pelo arsênico na Argentina, principalmente em águas subterrâneas, usada tanto para água potável animal quanto para irrigação forrageira. O principal objetivo deste estudo é determinar o efeito do arsênio (As) presente na água de irrigação sobre os parâmetros de germinação de sementes forrageiras: trevo vermelho (Trifolium pratense L.), trevo branco (Trifolium repens L.) e alfafa (Medicago sativa L.) expostos a diferentes concentrações de As (V). Verificou-se que os parâmetros de germinação e viabilidade das sementes das três espécies não foram afetados pelas concentrações elevadas de As. No entanto, reduziu significativamente o comprimento da radícula e o comprimento do hipocótilo das três mudas de forragem, e seu nível de inibição é maior com o aumento da concentração de As. Quanto à relação comprimento de hipocótilo/comprimento da radícula, os resultados evidenciaram que nas espécies de trevo tanto o hipocótilo quanto a radícula são afetados no mesmo grau, enquanto as radículas de alfafa pareceram mais afetadas do que os hipocótilos em concentrações maiores de As. Nossos resultados mostraram que a irrigação com soluções contém Afetar os parâmetros de crescimento de plântulas de maneira diferente nas três espécies, e foi demonstrado que o efeito do As é principalmente evidenciado em altas concentrações.
Assuntos
Arseniatos/administração & dosagem , Arsênio/administração & dosagem , Fabaceae/efeitos dos fármacos , Germinação/efeitos dos fármacos , Sementes/efeitos dos fármacos , Medicago sativa , TrifoliumRESUMO
Environmental arsenic exposure is associated with increased risk of non-cancerous chronic diseases and a variety of cancers in humans. The aims of this study were to carry out for the first time a health risk assessment for two common arsenic exposure routes (drinking water and soil ingestion) in children living in the most important agricultural areas in the Yaqui and Mayo valleys in Sonora, Mexico. Drinking water sampling was conducted in the wells of 57 towns. A cross-sectional study was done in 306 children from 13 villages in the valleys. First morning void urine samples were analyzed for inorganic arsenic (InAs) and monomethyl and dimethyl arsenic (MMA and DMA) by HPLC/ICP-MS. The results showed a wide range of arsenic levels in drinking water between 2.7 and 98.7 µg As/L. Arsenic levels in agricultural and backyard soils were in the range of < 10-27 mg As/kg. The hazard index (HI) = ∑hazard quotient (HQ) for drinking water, agricultural soil, and backyard soil showed values > 1 in 100% of the study towns, and the carcinogenic risk (CR) was greater than 1E-04 in 85%. The average of arsenic excreted in urine was 31.7 µg As/L, and DMA had the highest proportion in urine, with averages of 77.8%, followed by InAs and MMA with 11.4 and 10.9%, respectively, percentages similar to those reported in the literature. Additionally, positive correlations between urinary arsenic levels and HI values were found (r = 0.59, P = 0.000). These results indicated that this population is at high risk of developing chronic diseases including cancer.
Assuntos
Arsênio/urina , Água Potável/química , Exposição Ambiental , Solo/química , Arsênio/administração & dosagem , Criança , Água Potável/administração & dosagem , Exposição Ambiental/efeitos adversos , Exposição Ambiental/análise , Feminino , Humanos , Masculino , México , Medição de RiscoRESUMO
This study investigated acute arsenic toxicity and bioconcentration capacity in Litopenaeus vannamei because it has been frequently exposed to lower salinities than its isosmotic point (25â¯gâ¯L-1). Juveniles (9.9⯱â¯0.4â¯g) were exposed to low (5-10â¯gâ¯L-1) and isosmotic salinity (25â¯gâ¯L-1) levels; As values were 30.8, 20.2, 16.8 and 13.9â¯mgâ¯L-1 at 5â¯gâ¯L-1; 30.4, 19.1, 16.8 and 14.8â¯mgâ¯L-1 at 10â¯gâ¯L-1; 31.5, 19.0, 15.0 and 11.9â¯mgâ¯L-1 at 25â¯gâ¯L-1 at 24, 48, 72 and 96â¯h LC50, respectively. No significant differences were found among As LC50 values calculated for different salinity levels and same exposure times, concluding that low salinity did not affect shrimp sensitivity to As. Likewise, no significant differences were observed in As bioconcentration in shrimp exposed to the same waterborne As and distinct salinity, supporting the results of acute toxicity. Bioconcentration factors of As maintained a relatively stable tendency where all values (0.8⯱â¯0.2 to 1.7⯱â¯0.4) were statistically comparable to 1, indicating that As was accumulated in a similar proportion to waterborne As concentration at three salinity levels. This study proposed 135.3⯱â¯12.1⯵gâ¯L-1 for salinities from 5 to 25â¯gâ¯L-1 as provisional safe As concentration. According to these results, the hypothesis that sustains an effect of low salinity on As acute toxicity and its bioconcentration capacity cannot be acceptable. Therefore, the information provided allows knowing the threshold levels of As in water to avoid ecological and economic losses.
Assuntos
Arsênio/toxicidade , Penaeidae/efeitos dos fármacos , Penaeidae/crescimento & desenvolvimento , Salinidade , Cloreto de Sódio/farmacologia , Envelhecimento , Animais , Arsênio/administração & dosagem , Relação Dose-Resposta a Droga , Feminino , MasculinoRESUMO
BACKGROUND: Exposure to inorganic arsenic increases the risk of cancer and non-malignant diseases. Inefficient arsenic metabolism is a marker for susceptibility to arsenic toxicity. Arsenic may alter gene expression, possibly by altering DNA methylation. OBJECTIVES: To elucidate the associations between arsenic exposure, gene expression, and DNA methylation in peripheral blood, and the modifying effects of arsenic metabolism. METHODS: The study participants, women from the Andes, Argentina, were exposed to arsenic via drinking water. Arsenic exposure was assessed as the sum of arsenic metabolites in urine (U-As), using high performance liquid-chromatography hydride-generation inductively-coupled-plasma-mass-spectrometry, and arsenic metabolism efficiency was assessed by the urinary fractions (%) of the individual metabolites. Genome-wide gene expression (N=80 women) and DNA methylation (N=93; 80 overlapping with gene expression) in peripheral blood were measured using Illumina DirectHyb HumanHT-12 v4.0 and Infinium Human-Methylation 450K BeadChip, respectively. RESULTS: U-As concentrations, ranging 10-1251µg/L, was associated with decreased gene expression: 64% of the top 1000 differentially expressed genes were down-regulated with increasing U-As. U-As was also associated with hypermethylation: 87% of the top 1000CpGs were hypermethylated with increasing U-As. The expression of six genes and six individual CpG sites were significantly associated with increased U-As concentration. Pathway analyses revealed enrichment of genes related to cell death and cancer. The pathways differed somewhat depending on arsenic metabolism efficiency. We found no overlap between arsenic-related gene expression and DNA methylation for individual genes. CONCLUSIONS: Increased arsenic exposure was associated with lower gene expression and hypermethylation in peripheral blood, but with no evident overlap.
Assuntos
Intoxicação por Arsênico/sangue , Intoxicação por Arsênico/genética , Metilação de DNA/fisiologia , Água Potável/efeitos adversos , Adolescente , Adulto , Argentina/epidemiologia , Arsênio/administração & dosagem , Arsênio/toxicidade , Intoxicação por Arsênico/epidemiologia , Criança , Metilação de DNA/efeitos dos fármacos , Feminino , Expressão Gênica/efeitos dos fármacos , Expressão Gênica/fisiologia , Humanos , Pessoa de Meia-Idade , Adulto JovemRESUMO
Artisanal and small-scale gold mining (ASGM) offers low-skilled workers an opportunity to elevate themselves out of poverty. However, this industry operates with little to no pollution controls and the cost to the environment and human health can be large. The objectives of this study were to measure levels of arsenic (As), manganese (Mn), cobalt (Co), lead (Pb), and mercury (Hg) in the environment and characterize health risks to miners and residents in an area with active ASGM operations. An exposure assessment was conducted at two different mining sites and a nearby village in the Bolivian Anders. The resulting measurements were then used to quantify cancerous and noncancerous health risks to children and adults working at and living near ASGM areas. Soil concentrations of As were well above background levels and showed great variations between the village and mining area. Mercury vapor levels at the two mining sites were approximately 30 times larger than the EPA reference concentration. The risk of developing non-cancerous health effects were primarily due to exposure to As and Hg. The probability of individuals developing cancer was considerably increased with adult miners having a probability of 1.3 out of 100. Cancer potential was driven by exposure to As, with de minimus cancer risk from all other elements. Based on the environmental characterization of elements in soils and Hg vapors, the risk of developing cancerous and non-cancerous health outcomes were above a level of concern based on EPA risk assessment guidance. Personal protective equipment was not worn by workers and Hg amalgam is commonly heated in workers' homes. Better education of the risks of ASGM is needed as well as simple controls to reduce exposure.
Assuntos
Exposição Ambiental/análise , Mineração/métodos , Exposição Ocupacional/análise , Administração por Inalação , Adolescente , Adulto , Poluentes Atmosféricos/análise , Poluentes Ocupacionais do Ar/análise , Arsênio/administração & dosagem , Arsênio/análise , Arsênio/toxicidade , Bolívia , Carcinógenos/análise , Carcinógenos/toxicidade , Criança , Humanos , Mercúrio/administração & dosagem , Mercúrio/análise , Mercúrio/toxicidade , Metais/administração & dosagem , Metais/análise , Metais/toxicidade , Medição de Risco , Pele/efeitos dos fármacos , Poluentes do Solo/análiseRESUMO
The Argentinean autochthonous toad Rhinella arenarum was selected to study the chronic toxicity of arsenic (As) and the biochemical responses elicited by exposure to As in water during embryonic and larval development. Significant decreases in the total reactive antioxidant potential and in catalase activity were observed in individuals exposed chronically to sublethal concentrations of As, which is indicative of an oxidative stress situation. However, an antioxidant response was elicited during chronic exposure to As, as evidenced by the increase in endogenous reduced glutathione content and glutathione-related enzymatic activities such as glutathione S-transferase (GST) and glutathione reductase. This protective response might prevent a deeper decline in the antioxidant system and further oxidative damage. Alternatively, it might be linked to As conjugation with reduced glutathione for its excretion. Considering the sustained increase in GST activity and the decrease in the total antioxidant reactive potential observed, the authors propose them as good candidates to be used as biomarkers during As exposure. Interestingly, glutathione reductase activity was inhibited at a very low concentration of As considered safe for aquatic life. Environ Toxicol Chem 2017;36:1614-1621. © 2016 SETAC.
Assuntos
Antioxidantes/metabolismo , Arsênio/toxicidade , Bufo arenarum/embriologia , Estresse Oxidativo/efeitos dos fármacos , Animais , Arsênio/administração & dosagem , Biomarcadores/sangue , Bufo arenarum/crescimento & desenvolvimento , Catalase/metabolismo , Esquema de Medicação , Poluentes Ambientais/toxicidade , Glutationa/metabolismo , Glutationa Redutase/metabolismo , Glutationa Transferase/metabolismo , Larva/efeitos dos fármacos , Estresse Oxidativo/fisiologiaRESUMO
Objective: To evaluate the response of rat subcutaneous tissue in implanted polyethylene tubes that were filled with GMTA Angelus and Portland cements containing different arsenic concentrations. Material and Methods: Atomic absorption spectrophotometry was utilized to obtain the values of the arsenic concentration in the materials. Thirty-six rats were divided into 3 groups of 12 animals for each experimental period. Each animal received two implants of polyethylene tubes filled with different test cements and the lateral of the tubes was used as a control group. After 15, 30 and 60 days of implantation, the animals were killed and the specimens were prepared for descriptive and morphometric analysis considering: inflammatory cells, collagen fibers, fibroblasts, blood vessels and other components. The results were analyzed utilizing the Kuskal-Wallis test and the Dunn's Multiple test for comparison (p<0.05). Results: The materials showed, according to atomic absorption spectrophotometry, the following doses of arsenic: GMTA Angelus: 5.01 mg/kg, WPC Irajazinho: 0.69 mg/kg, GPC Minetti: 18.46 mg/kg and GPC Votoran: 10.76 mg/kg. In a 60-day periods, all specimens displayed a neoformation of connective tissue with a structure of fibrocellular aspect (capsule). Control groups and MTA Angelus produced the lower amount of inflammatory reaction and GPC Minetti, the highest reaction. Conclusions: There was no direct relationship between the concentration of arsenic present in the composition of the materials and the intensity of the inflammatory reactions. Higher values, as 18.46 mg/kg of arsenic in the cement, produce characteristics of severe inflammation reaction at the 60-day period. The best results were found in MTA angelus. .
Assuntos
Animais , Masculino , Arsênio/toxicidade , Bismuto/toxicidade , Compostos de Cálcio/toxicidade , Cimentos Dentários/toxicidade , Óxidos/toxicidade , Silicatos/toxicidade , Tela Subcutânea/efeitos dos fármacos , Arsênio/administração & dosagem , Bismuto/química , Vasos Sanguíneos/efeitos dos fármacos , Colágeno/efeitos dos fármacos , Cimentos Dentários/química , Fibroblastos/efeitos dos fármacos , Teste de Materiais , Óxidos/química , Polietileno/química , Ratos Wistar , Valores de Referência , Espectrofotometria Atômica , Fatores de TempoRESUMO
OBJECTIVE: To evaluate the response of rat subcutaneous tissue in implanted polyethylene tubes that were filled with GMTA Angelus and Portland cements containing different arsenic concentrations. MATERIAL AND METHODS: Atomic absorption spectrophotometry was utilized to obtain the values of the arsenic concentration in the materials. Thirty-six rats were divided into 3 groups of 12 animals for each experimental period. Each animal received two implants of polyethylene tubes filled with different test cements and the lateral of the tubes was used as a control group. After 15, 30 and 60 days of implantation, the animals were killed and the specimens were prepared for descriptive and morphometric analysis considering: inflammatory cells, collagen fibers, fibroblasts, blood vessels and other components. The results were analyzed utilizing the Kuskal-Wallis test and the Dunn's Multiple test for comparison (p<0.05). RESULTS: The materials showed, according to atomic absorption spectrophotometry, the following doses of arsenic: GMTA Angelus: 5.01 mg/kg, WPC Irajazinho: 0.69 mg/kg, GPC Minetti: 18.46 mg/kg and GPC Votoran: 10.76 mg/kg. In a 60-day periods, all specimens displayed a neoformation of connective tissue with a structure of fibrocellular aspect (capsule). Control groups and MTA Angelus produced the lower amount of inflammatory reaction and GPC Minetti, the highest reaction. CONCLUSIONS: There was no direct relationship between the concentration of arsenic present in the composition of the materials and the intensity of the inflammatory reactions. Higher values, as 18.46 mg/kg of arsenic in the cement, produce characteristics of severe inflammation reaction at the 60-day period. The best results were found in MTA angelus.
Assuntos
Arsênio/toxicidade , Bismuto/toxicidade , Compostos de Cálcio/toxicidade , Cimentos Dentários/toxicidade , Óxidos/toxicidade , Silicatos/toxicidade , Tela Subcutânea/efeitos dos fármacos , Animais , Arsênio/administração & dosagem , Bismuto/química , Vasos Sanguíneos/efeitos dos fármacos , Colágeno/efeitos dos fármacos , Cimentos Dentários/química , Fibroblastos/efeitos dos fármacos , Masculino , Teste de Materiais , Óxidos/química , Polietileno/química , Ratos Wistar , Valores de Referência , Espectrofotometria Atômica , Fatores de TempoRESUMO
Arsenic concentrations greater than 100 µg/L in drinking water are a known cause of cancer, but the risks associated with lower concentrations are less well understood. The unusual geology and good information on past exposure found in northern Chile are key advantages for investigating the potential long-term effects of arsenic. We performed a case-control study of lung cancer from 2007 to 2010 in areas of northern Chile that had a wide range of arsenic concentrations in drinking water. Previously, we reported evidence of elevated cancer risks at arsenic concentrations greater than 100 µg/L. In the present study, we restricted analyses to the 92 cases and 288 population-based controls who were exposed to concentrations less than 100 µg/L. After adjustment for age, sex, and smoking behavior, these exposures from 40 or more years ago resulted in odds ratios for lung cancer of 1.00, 1.43 (90% confidence interval: 0.82, 2.52), and 2.01 (90% confidence interval: 1.14, 3.52) for increasing tertiles of arsenic exposure, respectively (P for trend = 0.02). Mean arsenic water concentrations in these tertiles were 6.5, 23.0, and 58.6 µg/L. For subjects younger than 65 years of age, the corresponding odds ratios were 1.00, 1.62 (90% confidence interval: 0.67, 3.90), and 3.41 (90% confidence interval: 1.51, 7.70). Adjustments for occupation, fruit and vegetable intake, and socioeconomic status had little impact on the results. These findings provide new evidence that arsenic water concentrations less than 100 µg/L are associated with higher risks of lung cancer.
Assuntos
Arsênio/efeitos adversos , Neoplasias Pulmonares/induzido quimicamente , Poluentes Químicos da Água/efeitos adversos , Idoso , Arsênio/administração & dosagem , Estudos de Casos e Controles , Chile/epidemiologia , Água Potável/química , Feminino , Humanos , Neoplasias Pulmonares/epidemiologia , Masculino , Pessoa de Meia-Idade , Poluentes Químicos da Água/administração & dosagemRESUMO
The arsenic (As) and fluoride (Fâ») concentration in groundwater and potential adverse human health risk was investigated in the Central-West Region of the Chaco Province, northern Argentina. The mean concentration of As in shallow groundwater was 95 µg/L, where 76% of samples exceeded the World Health Organization (WHO) guideline value of 10 µg/L, while in deep groundwater it was 90 µg/L, where 63% samples exceeded 10 µg/L. For As health risk assessment, the average daily dose, hazard quotient (HQ), and cancer risk were calculated. The values of HQ were found to be >1 in 77% of samples. This level of contamination is considered to constitute a high chronic risk compared with U.S. Environmental Protection Agency (EPA) guidelines. Further, a significant portion of the population has lifetime carcinogenic risk >10â»4 and may suffer from cancer. A positive correlation was observed between As and Fâ» in groundwater. The Código Alimentario Argentino (CAA) suggested a limit of Fâ» in drinking water as low as 0.8 mg/L under tropical environmental conditions; however, in shallow (39%) and deep groundwater (32%), samples exceeded these values. Exposure to Fâ» was calculated and compared with the adequate intake of minimal safe level exposure dose of 0.05 mg/kg/d and it was noted that 42% of population may be at high risk of fluorosis. Chronic exposure to high As and Fâ» levels in this population represents a concern due to possible adverse health effects attributed to these elements.
Assuntos
Arsênio/toxicidade , Exposição Ambiental , Fluoretos/toxicidade , Água Subterrânea/química , Poluentes Químicos da Água/toxicidade , Adulto , Argentina/epidemiologia , Arsênio/administração & dosagem , Arsênio/análise , Carcinógenos Ambientais/administração & dosagem , Carcinógenos Ambientais/análise , Carcinógenos Ambientais/toxicidade , Criança , Fluoretos/administração & dosagem , Fluoretos/análise , Fluorose Dentária/epidemiologia , Guias como Assunto , Humanos , Lactente , Neoplasias/induzido quimicamente , Neoplasias/epidemiologia , Medição de Risco , Saúde da População Rural , Saúde Suburbana , Estados Unidos , United States Environmental Protection Agency , Poluentes Químicos da Água/administração & dosagem , Poluentes Químicos da Água/análise , Poluição Química da Água/efeitos adversos , Poluição Química da Água/legislação & jurisprudência , Qualidade da Água/normas , Organização Mundial da SaúdeRESUMO
En las áreas costeras del norte de Chile es común encontrar en el agua para consumo humano niveles medios o altos de arsénico. La exposición al arsénico puede ir asociada a efectos agudos o crónicos. El objetivo de esta investigación fue determinar el daño histológico que provoca el trióxido de arsénico a nivel de los compartimentos del timo de ratas Sprague-Dawley. Se utilizaron 24 ratas de ambos sexos de 55 días de vida. Las ratas fueron pesadas y divididas en 3 grupos (4 hembras y 4 machos). A los grupos tratados se les aplicó 5 mg y 10 mg de As2O3 respectivamente, en dosis única diaria vía intraperitoneal por 15 días. Al grupo control se le aplicó agua destilada sin arsénico. Después del tratamiento los animales fueron sacrificados y retirado el timo de ellos, los cuales fueron lavados, pesados y seccionados en dos, luego se fijaron en formol tamponado al 10 por ciento. Mediante técnica histológica convencional se obtuvieron 4 muestras seriadas de cada timo, de 5 um de espesor y separadas por 100 um entre si, luego fueron teñidas con H-E. Se analizaron 30 campos (120 campos por órgano). Los resultados muestran que el As2O3 provoca la pérdida de celularidad en ambos compartimentos del timo, tanto en la corteza como en la médula, viéndose más afectado el compartimento medular (junto a la unión corticomedular). Se observó una reducción significativa del tamaño de la zona medular en ambos grupos tratados (5 y 10 mg de As2O3 respectivamente), siendo probablemente la disminución de este tejido el responsable de la atrofia del timo. Además se observó un aumento del tamaño de la corteza en las ratas hembras tratadas con 10 mg de As2O3. La unión corticomedular de las ratas tratadas se observó difusa o difícil de distinguir.
In coastal areas of northern Chile medium or high levels of arsenic are commonly found in drinking water. Arsenic exposure may be associated with acute or chronic effects. The objective of this investigation was to determine the histological damage caused by arsenic trioxide level of the compartments of the thymus of Sprague-Dawley rats. We used 24 rats of both sexes of 55 days of life. The rats were weighed and divided into 3 groups (4 females and 4 males). In the treated groups were administered 5 mg and 10 mg of As2O3 respectively, in a single daily dose for 15 days intraperitoneally. The control group was administered distilled water without arsenic. After treatment the animals were sacrificed and the thymus removed, washed, weighed and divided into two, then fixed in 10 percent buffered formalin. By conventional histology samples were obtained serially every 4 thymus, 5 microns thick and separated by 100 microns each, then were stained with HE. We analyzed 30 fields (120 fields per organ). The results showed that As2O3 causes loss of cellularity in both compartments of the thymus, both in the cortex and in the bone, medullary compartment was more affected (near the corticomedullary junction). There was a significant reduction in the size of the medulla in both groups (5 and 10 mg As2O3 respectively), probably the decrease of the tissue responsible for thymic atrophy. We observed an increase in the size of the cortex in female rats treated with 10 mg of As2O3. The corticomedullary junction of the treated rats showed diffuse or difficult to distinguish.
Assuntos
Animais , Feminino , Ratos , Arsênio/toxicidade , Timo , Timo/patologia , Atrofia , Arsênio/administração & dosagem , Intoxicação por Arsênico/patologia , Óxidos/toxicidade , Peso Corporal , Ratos Sprague-DawleyRESUMO
BACKGROUND: The aim of this study was to evaluate the intake of selenium, total and inorganic arsenic and the bioaccessibility of arsenic in diets of Mexican schoolchildren using an in vitro method. RESULTS: Total and inorganic arsenic concentrations in the diets ranged from 0.05 to 1.15 mg kg(-1) dry weight (DW) and from 0.023 to 0.088 mg kg(-1) DW respectively, while selenium levels were between 0.08 and 0.20 mg kg(-1) DW. Daily intake of total and inorganic arsenic ranged from 0.15 to 10.49 µg day(-1) kg(-1) body weight (BW) and from 0.06 to 1.11 µg day(-1) kg(-1) BW respectively, while that of selenium varied from 0.29 to 2.63 µg day(-1) kg(-1) BW. Bioaccessibility of total and inorganic arsenic ranged from 4 to 97% (mean 44 ± 21.5%) and from 33 to 97% (mean 71 ± 22.5%) respectively. CONCLUSION: Inorganic arsenic levels in the diets were low. Therefore there appears to be a low risk of adverse effects resulting from excess inorganic arsenic intake from these diets.
Assuntos
Arsênio/administração & dosagem , Dieta , Monitoramento Ambiental/métodos , Selênio/administração & dosagem , Arsênio/metabolismo , Disponibilidade Biológica , Criança , Ingestão de Energia , Humanos , México , Medição de Risco , Selênio/metabolismoRESUMO
Rice is an important source of essential elements. However, rice may also contain toxic elements such as arsenic. Therefore, in the present study, the concentration of total arsenic and five main chemical species of arsenic (As(3+), As(5+), DMA, MMA and AsB) were evaluated in 44 different rice samples (white, parboiled white, brown, parboiled brown, parboiled organic and organic white) from different Brazilian regions using high-performance liquid chromatography hyphenated to inductively coupled plasma mass spectrometry (HPLC-ICP-MS). The mean level of total arsenic was 222.8 ng g(-1) and the daily intake of inorganic arsenic (the most toxic form) from rice consumption was estimated as 10% of the Provisional Tolerable Daily Intake (PTDI) with a daily ingestion of 88 g of rice. Inorganic arsenic (As(3+), As(5+)) and dimethylarsinic acid (DMA) are the predominant forms in all samples. The percentages of species were 38.7; 39.7; 3.7 and 17.8% for DMA, As(3+), MMA and As(5+), respectively. Moreover, rice samples harvested in the state of Rio Grande do Sul presented more fractions of inorganic arsenic than rice in Minas Gerais or Goiás, which could lead to different risks of arsenic exposure.
Assuntos
Arsênio/classificação , Dieta , Oryza/química , Arsênio/administração & dosagem , Arsênio/análise , Brasil , Cromatografia Líquida de Alta Pressão , Exposição Ambiental , Humanos , Limite de Detecção , Espectrometria de Massas , Medição de RiscoRESUMO
The urothelium covering the luminal surface of the urinary bladder has developed an efficient permeability barrier that protects it against the back-flow of toxins eliminated in the urine. The subapical endocytic vesicles containing the urinary bladder fluid phase are formed during the micturition cycle by endocytosis processes of the superficial cells. In normal conditions, the permeability barrier of the endocytic vesicles blocks the passage of the fluid phase to the cellular cytoplasm and the fluid is recycled to the bladder lumen. The aim of this work was to investigate the alteration of the endocytic vesicle membrane permeability barrier to toxins such as iAs (inorganic arsenic) administered in drinking water. By using an induced endocytosis model and the fluorescence requenching technique, it is shown that the exposure of rats to ingestion of water containing iAs not only induced pre-cancerous morphological changes, but allowed the differential leakage of an endocytosed fluorescent marker, HPTS, and its quencher, DPX, (hydroxypyrene-1,3,6-trisulfonic acid and p-xylene-bis-pyridinium bromide, respectively) out of the vesicular lumen. The leakage of the cationic DPX was almost complete, while the release of the anionic HPTS molecule was partial and higher in arsenic-treated-rats than in controls. Such membrane alteration would allow the toxins to elude the permeability barrier and to leak out of the endocytic vesicles, thus establishing a "bypass" to the permeability barrier. The retention of As in the urinary bladder, assessed by synchrotron radiation X-ray fluorescence spectrometry (SR-µXRF), was lower than the kidney accumulation of arsenic previously observed by our group and was accompanied by altered concentrations of K, Ca, Fe, Cu and Zn, all ions related to cellular metabolism. The results support the hypothesis that low amounts of endocytosed As can accumulate in the interior of the urothelial superficial cells and initiate the cytotoxic effects reflected in the morphological alterations observed.
Assuntos
Arsênio/toxicidade , Ácidos Graxos/metabolismo , Lesões Pré-Cancerosas/metabolismo , Vesículas Transportadoras/metabolismo , Bexiga Urinária/metabolismo , Urotélio/metabolismo , Animais , Arsênio/administração & dosagem , Arsênio/metabolismo , Permeabilidade da Membrana Celular/efeitos dos fármacos , Masculino , Lesões Pré-Cancerosas/induzido quimicamente , Lesões Pré-Cancerosas/patologia , Ratos , Ratos Wistar , Vesículas Transportadoras/efeitos dos fármacos , Bexiga Urinária/efeitos dos fármacos , Bexiga Urinária/patologia , Urotélio/efeitos dos fármacos , Urotélio/patologiaRESUMO
Epigenetic mechanisms are crucial to regulate the expression of different genes required for neuronal plasticity. Neurotoxic substances such as arsenic, which induces cognitive deficits in exposed children before any other manifestation of toxicity, could interfere with the epigenetic modulation of neuronal gene expression required for learning and memory. This study assessed in Wistar rats the effects that developmental arsenic exposure had on DNA methylation patterns in hippocampus and frontal cortex. Animals were exposed to arsenic in drinking water (3 and 36ppm) from gestation until 4 months of age, and DNA methylation in brain cells was determined by flow cytometry, immunohistochemistry and methylation-specific polymerase chain reaction (PCR) of the promoter regions of reelin (RELN) and protein phosphatase 1 (PP1) at 1, 2, 3 and 4 months of age. Immunoreactivity to 5 methyl-cytosine was significantly higher in the cortex and hippocampus of exposed animals compared to controls at 1 month, and DNA hypomethylation was observed the following months in the cortex at high arsenic exposure. Furthermore, we observed a significant increase in the non-methylated form of PP1 gene promoter at 2 and 3 months of age, either in cortex or hippocampus. In order to determine whether this exposure level is associated with memory deficits, a behavioral test was performed at the same age points, revealing progressive and dose-dependent deficits of fear memory. Our results demonstrate alterations of the methylation pattern of genes involved in neuronal plasticity in an animal model of memory deficit associated with arsenic exposure.
Assuntos
Arsênio/toxicidade , Encéfalo/crescimento & desenvolvimento , Ilhas de CpG/fisiologia , Metilação de DNA/efeitos dos fármacos , Metilação de DNA/fisiologia , Plasticidade Neuronal/fisiologia , Fatores Etários , Animais , Arsênio/administração & dosagem , Encéfalo/efeitos dos fármacos , Ilhas de CpG/efeitos dos fármacos , Feminino , Masculino , Plasticidade Neuronal/efeitos dos fármacos , Regiões Promotoras Genéticas/efeitos dos fármacos , Regiões Promotoras Genéticas/fisiologia , Ratos , Ratos Wistar , Proteína ReelinaRESUMO
The dietary intake of total arsenic (tAs), inorganic arsenic (iAs) and total mercury (tHg) in lunch and breakfast servings provided by the Chilean School Meal Program (SMP) was estimated, using the duplicate-portion variant of the total diet study. Lunch and breakfast samples were collected from 65 schools throughout the country in 2006. The population sample was a group of girls and boys between 6 and 18 years old. The tAs concentration was measured via hydride-generation atomic absorption spectrometry. The total mercury concentration was measured via cold-vapor atomic absorption spectroscopy. The estimated iAs intake was 12.5% (5.4 µg/day) of the Provisional tolerable daily intake (PTDI) as proposed by the FAO/WHO, and the tHg intake was 13.2% (1.9 µg/day) of the PTDI as proposed by the FAO/WHO. It was therefore concluded that tAs, iAs and tHg intake from food provided by the SMP do not pose risks to student health.
Assuntos
Arsênio/administração & dosagem , Arsênio/química , Contaminação de Alimentos/análise , Mercúrio/administração & dosagem , Mercúrio/química , Adolescente , Criança , Chile , Exposição Ambiental , Poluentes Ambientais , Feminino , Análise de Alimentos , Humanos , Masculino , Instituições AcadêmicasRESUMO
Toxic agents can interfere with the male reproductive system at many targets. One of the major unresolved questions concerning male infertility is identification of its molecular origins. Clinical and animal studies indicate that abnormalities of spermatogenesis result from exposure to three toxic metals (lead acetate, cadmium chloride, and arsenic trioxide), but the effects on primary spermatocyte DNA of the male rat after chronic exposure to these metals have not been identified. The aims of this study were to analyze, in three independent experiments, the DNA damage induced by lead (Pb), cadmium (Cd), and arsenic (As) in rat germinal cells during three time periods, and to determine the relationship between DNA damage and blood Pb, blood Cd, and urine As levels. For lead acetate and cadmium chloride experiments, blood was collected by cardiac puncture, while for arsenic trioxide a 24-h urine sample was collected. Afterward, the animals were sacrificed by decapitation. Pachytene spermatocytes from rat testes were purified by trypsin digestion followed by centrifugal elutriation. After establishment of cell purity and viability, DNA damage (tail length) was measured employing a single cell gel/comet assay. Significant DNA damage was found in primary spermatocytes from rats with chronic exposure (13 weeks) to toxic metals. In conclusion, these findings indicate that exposure to toxic metals affects primary spermatocyte DNA and are suggestive of possible direct testicular toxicity.