Protección del ácido clorogénico frente a lesiones inducidas por venzo(a)pireno en Saccharomyces cerevisiae / Protection of chlorogenic acid against benzo(a)pyrene-induced lesions in Saccharomyces cerevisiae / Proteção do ácido clorogênico contra lesões induzidas por benzo(a)pireno em Saccharomyces cerevisiae

El objetivo del presente estudio fue analizar el efecto del ácido clorogénico, uno de los compuestos polifenólicos con mayor concentración en la infusión de Ilex paraguariensis, sobre el daño celular y molecular inducido por el benzo(a)pireno. La infusión de Ilex paraguariensis ("mate") es bebida por la mayoría de los habitantes de Argentina, Paraguay, sur de Brasil y Uruguay. La levadura Saccharomyces cerevisiae (cepas SC7K lys2-3; SX46A y SX46Arad14() se utilizó como modelo eucariota. Las células en crecimiento exponencial se expusieron a concentraciones crecientes de benzo(a)pireno y a tratamientos combinados con una concentración de 250 ng/mL de benzo(a)pireno y ácido clorogénico a una concentración igual a la encontrada en la infusión de yerba mate. Luego de los tratamientos se determinaron fracciones de sobrevida, frecuencia mutagénica y roturas de doble cadena de ADN así como la modulación en la expresión de la proteína Rad14 a través de un análisis de Western Blot. Se observó un aumento significativo en las fracciones de sobrevida así como una disminución en la frecuencia mutagénica después de la exposición combinada con benzo(a)pireno y ácido clorogénico en comparación con los tratamientos con benzo(a)pireno como único agente. En la cepa mutante deficiente en la proteína Rad14 se observó un aumento significativo en la sensibilidad a benzo(a)pireno en comparación con la cepa SC7K lys2-3. En los tratamientos combinados de benzo(a)pireno y ácido clorogénico se observó una importante disminución de la letalidad. Con respecto a la determinación de roturas de doble cadena de ADN no se observó fraccionamiento cromosómico a la concentración de benzo(a)pireno utilizada en los experimentos. Los análisis de Western Blot mostraron un aumento en la expresión de la proteína Rad14 en las muestras tratadas con benzo(a)pireno como único agente en comparación con la muestra control. Adicionalmente se observó una disminución en la expresión de la proteína cuando en los tratamientos se utilizaron benzo(a)pireno y ácido clorogénico combinados. Los resultados indican que el ácido clorogénico disminuye significativamente la actividad mutagénica producida por el benzo(a)pireno, la cual no se encuentra relacionada con un incremento en la remoción de las lesiones inducidas por el sistema de reparación por escisión de nucleótidos.

The aim of this study was to analyze the effect of chlorogenic acid, a polyphenolic compound found at high concentrations in Ilex paraguariensis infusions, on cellular and molecular damage induced by benzo(a)pyrene. Ilex paraguariensis infusions ("mate") are consumed by most of the population in Argentina, Paraguay, southern Brazil and Uruguay. Saccharomyces cerevisiae yeast (SC7K lys2-3; SX46A and SX46Arad14( strains) were used as eukaryotic model organisms. Cells in an exponential growth phase were exposed to increasing concentrations of benzo(a)pyrene, as well as combined treatments of benzo(a)pyrene at a concentration of 250 ng/mL and chlorogenic acid at a concentration matching that which is commonly found in mate. Determinations of surviving fraction, mutagenic frequency and double strand DNA breaks induction were performed, along with the assessment of the modulation of the expression of protein Rad14 by Western Blot. A significant increase of surviving fractions and a decrease in mutagenic frequency were observed after exposure to benzo(a)pyrene plus chlorogenic acid, contrary to benzo(a)pyrene alone. A substantial increase in sensitivity to benzo(a)pyrene was observed for the Rad14 protein-deficient mutating strain when compared to the SC7K lys2-3 strain. An important decrease in lethality was observed when combined benzo(a)pyrene and chlorogenic acid treatments were applied. As for the determination of DSBs, no chromosomic fractionation was observed at the benzo(a)pyrene concentration tested in the experiments. Western Blot analysis showed an increase in the expression of protein Rad14 for samples treated with benzo(a)pyrene as a single agent when compared against the control sample. Additionally, the expression of this protein was observed to diminish when combined treatments with benzo(a)pyrene and chlorogenic acid were used. Results obtained indicate that chlorogenic acid significantly decreases the mutagenic activity of benzo(a)pyrene, which is not related to an increase in the removal of lesions induced by nucleotide excision repair system.

O objetivo deste estudo foi analisar o efeito do ácido clorogênico, um dos compostos polifenólicos com maior concentração na infusão de Ilex paraguariensis, sobre o dano celular e molecular induzido pelo benzopireno. A infusão de Ilex paraguariensis ("mate") é consumida pela maioria dos habitantes da Argentina, Paraguai, sul do Brasil e Uruguai. A levedura Saccharomyces cerevisiae (cepas SC7K lys2-3; SX46A e SX46Arad14() foi utilizada como modelo eucariótico. Células em crescimento exponencial foram expostas a concentrações crescentes de benzopireno e tratamentos combinados foram realizados com uma concentração de 250 ng/mL de benzo(a)pireno e ácido clorogênico, igual à encontrada na infusão de erva-mate. Após os tratamentos, foram determinadas as frações de sobrevivência, frequência mutagênica e quebras de fita dupla do DNA, bem como a modulação na expressão da proteína Rad14 por meio de análise de Western Blot. Um aumento significativo nas frações de sobrevivência, bem como uma diminuição na frequência mutagênica foram observados após a exposição combinada de benzo(a)pireno e ácido clorogênico em comparação com tratamentos de agente único de benzo(a)pireno. Um aumento significativo na sensibilidade ao benzo(a)pireno foi observado na cepa mutante deficiente em proteína Rad14 em comparação com a cepa SC7K lys2-3. Nos tratamentos combinados de benzo(a)pireno e ácido clorogênico, observou-se uma diminuição significativa na letalidade. Com relação à determinação das quebras de fita dupla de DNA, não foi observado fracionamento cromossômico na concentração de benzo(a)pireno utilizada nos experimentos. A partir da análise de Western Blot, observou-se um aumento na expressão da proteína Rad14 nas amostras tratadas com benzo(a)pireno como agente único em relação à amostra controle. Além disso, uma diminuição na expressão da proteína foi observada quando combinados de benzo(a)pireno e ácido clorogênico foram usados ​​nos tratamentos. Os resultados obtidos neste trabalho indicam que o ácido clorogênico diminui significativamente a atividade mutagênica produzida pelo benzo(a)pireno, a qual não está relacionada a um aumento na remoção de lesões induzidas pelo sistema de reparo por excisão de nucleotídeos.

Equivalentes tóxicos de hidrocarburos aromáticos políciclicos en particulado atmosférico en Valencia, Venezuela / Toxic equivalency factors of polycyclic aromatic hydrocarbons (PAHS) in Valencia, Venezuela

El particulado atmosférico de las áreas urbanas contiene mezclas de compuestos contaminantes con diferentes grados de toxicidad como los Hidrocarburos Aromáticos Policíclicos (HAPs), provenientes de las emisiones de combustión incompleta de diversas fuentes no naturales. Los HAPs pueden provocar cáncer, malformaciones congénitas, trastornos del sistema nervioso, entre otros, al ser absorbidos, ya sea por inhalación o ingesta. El factor de equivalencia de toxicidad (FET), es un parámetro estimativo que relaciona la toxicidad de un compuesto con un componente de referencia, cuyo objetivo es evaluar la toxicidad y el riesgo de diversas sustancias y, en el caso de HAPs, el benzo(a)pireno (BaP) es el compuesto de referencia. El objetivo de este trabajo fue estimar el riesgo potencial de exposición a HAPs en habitantes de la zona de estudio a través de los FET. Catorce HAPs fueron extraídos del particulado atmosférico colectado en filtros y analizados por Cromatografía Líquida de Alta Eficiencia con detector de fluorescencia. Se determinó la concentración de los HAPs, se calculó la concentración tóxica equivalente para cada compuesto y de la mezcla total de acuerdo al método propuesto por la Agencia de Protección Ambiental (EPA) de Estados Unidos. La concentración promedio total de HAPs en el particulado fue de 1,97 ng/m³. La contribución del BaP fue del 2,54% en la mezcla total de HAPs. La concentración tóxica equivalente total fue de 0,08 ng/m³ de la mezcla de aire. Las concentraciones tóxicas equivalentes para cada HAP y para el total en el particulado atmosférico no exceden el valor de 1 ng/m³ en equivalentes de BaP, indicado en diversas regulaciones internacionales.

The atmospheric particulate from urban areas contains mixtures of contaminants with different degrees of toxicity such as Polycyclic Aromatic Hydrocarbons (PAHs) derived from emissions from incomplete combustion of various natural sources. PAHs can cause cancer, birth defects and nervous system disorders when they are absorbed either by inhalation or ingestion. The toxic equivalency factor (TEF) is a parameter that relates the toxicity of a compound with a reference component in order to evaluate the toxicity and risk of various substances. The benzo(a)pyrene (BaP) is the reference compound in the case of PAHs mixture. The aim of this study was to estimate the potential risk of exposure to PAHs in people of the study area through the TEF. Fourteen PAHs were extracted from particulate filters and analyzed by liquid chromatography- fluorescence detection. The concentration of PAHs was calculated. The total average concentration of PAHs in the particulate was 1.97 ng/m³. Then, the equivalent toxic concentration of each compound and the total mixture were calculated too according to the method proposed by the United States Environmental Protection Agency (EPA). The contribution of BaP was 2.54% in the total mixture of PAHs. The total equivalent toxic concentration was 0.08 ng/m³ in the air mixture. The toxic equivalent concentrations for each PAH and the total in the atmospheric particulate were not exceeding the value of 1 ng/m3 in BaP equivalent that is the level indicated in international regulations.

Interacciones genotóxicas de mutágenos en mezclas binarias mediante ensayo cometa alcalino en linfocitos humanos / Interaction of mutagens in binary mixtures using the alkaline comet assay in human lymphocytes

Introducción. Los mutágenos contenidos en mezclas complejas presentan interacciones de sinergismo, aditivas o antagónicas. Se han desarrollado enfoques experimentales que permitan dilucidar el responsable de las interacciones en la mezcla. Objetivo. Desarrollar un diseño experimental para comprender los procesos que se llevan a cabo entre los compuestos presentes en las mezclas complejas. Materiales y métodos. Se expusieron linfocitos humanos a mezclas binarias de mutágenos B[a]P, DMBA, Trp-P-1 y MX durante una hora, con activación metabólica y sin ella. La viabilidad se evaluó con azul de tripano y, la genotoxicidad, con cometa alcalino. Resultados. Ningún hidrocarburo tuvo efecto con furanona. Con S9 y sin él, se observó que se presentaban interacciones tóxicas entre hidrocarburos. Se observó sinergismo sin S9 entre B[a]P y Trp-P-1 y, con actividad metabólica, entre DMBA y Trp-P-1. Sin S9 se observó interacción antagónica entre Trp-P-1 y DMBA y, con S9, entre Trp-P-1 y MX y entre MX y DMBA. Se observó un incremento dependiente de la dosis en la longitud de la cola. Hubo daño genotóxico medio y aumento de las células dañadas. Para todas las mezclas se pudo determinar la concentración mínima en la que se observaban efectos adversos y solo para algunas se determinó la concentración máxima en la cual no se observaron efectos adversos. Conclusión. Se hace un aporte para comprender los procesos que ocurren cuando en una mezcla hay presentes, al menos, dos mutágenos y se valida un modelo de análisis que permite dilucidar el compuesto que tiene efecto sobre otro. También, se demostró que según el tipo de compuestos en la mezcla, se tendrá o no un umbral de riesgo.

Introduction. Mutagens contained in complex mixtures can present synergistic interactions, either additive or antagonistic. Therefore, development of experimental approaches is necessary to elucidate which is the responsible agent for the effect in the mixtures. Objective. An experimental design was developed that allowed an understanding of the processes between the compounds of complex mixtures. Materials and methods. Human lymphocytes were exposed to binary mixtures of the mutagens B[a]P, DMBA, Trp-P-1 and MX for 1 hour with or without S9. Viability was assessed with trypan blue dye and the genotoxicity by the comet assay. Results. All of the hydrocarbon showed an effect with furanone. With and without S9, the most toxic interactions were observed between hydrocarbons. Synergistic interaction was observed without S9 between B [a] P and Trp-P-1 and between DMBA and Trp-P-1 with metabolic activity. Without S9 antagonistic interaction was observed only between Trp-P-1+DMBA, and with S9 between Trp-P-1+MX and MX+DMBA. It observed an increase dose dependent in tail length. Half the cultures showed genotoxic damage and increased cell damage. For each mixture, minimum concentrations were determined at which adverse effects are observed; for some only the maximum concentration was determined at which no adverse effects are observed. Conclusion. The processes between mutagens present in a mixture have become better understood, and the results validated an analytical model that determined which component had an effect on another. The results also showed that the type of compounds in the mixture determined whether or not a risk threshold was present.

Azadirachta indica leaf extract modulates initiation phase of murine forestomach tumorigenesis.

The effects of aqueous Azadirachta indica leaf extract (AAILE) on benzo(a)pyrene [B(a)P]-induced forestomach tumorigenesis, B(a)P-DNA adduct formation and certain parameters of carcinogen biotransformation system in mice have been reported earlier from our laboratory. In this study, the effects of AAILE on the enzymes of B(a)P biotransformation, which play crucial role in initiation of chemical carcinogenesis - aryl hydrocarbon hydroxylase (AHH) and uridinediphosphoglucuronosyltransferase (UDP-glucuronosyltransferase) have been evaluated in murine forestomach and liver. In addition, lipid peroxidation (LPO) levels in forestomach as well as liver and the activities of tissue injury marker enzymes - lactate dehydrogenase, aspartate aminotransferase and alkaline phosphatase in the serum have also been evaluated. Oral administration of AAILE (100 mg/kg body wt for 2 weeks) reduces the AHH activity and enhances the UDP-glucuronosyltransferase activity in both the tissues, suggesting its potential in decreasing the activation and increasing the detoxification of carcinogens. The LPO levels decrease upon AAILE treatment in the hepatic tissue, suggesting its antioxidative and hence anti-carcinogenic effects. Non-significant alterations have been observed in tissue injury marker enzymes upon AAILE treatment, suggesting its safety at the given dose. In conclusion, AAILE appears to modulate initiation phase of carcinogenesis and may be suggested as safe and an effective agent for chemoprevention.

Experimental model of pulmonary carcinogenesis in Wistar rats

PURPOSE: To elaborate an experimental model of pulmonary carcinogenesis in Wistar rats. METHODS: Male Rattus norvegicus albinus, Wistar lineage was carried through an intra-pulmonary instillation of the Benzo[a]pyrene (B[a]P) dilution in alcohol 70 percent, a polycyclic aromatic hydrocarbon widely known by its power of tumoral induction. Three experimental groups had been formed with 08 animals each: Control Group (Alcohol 70 percent); B[a]P Group 10 mg/kg; e B[a]P Group 20mg/kg, submitted to euthanasia 08, 10, 12 and 14 weeks after the experimental procedure. The pulmonary sections had been colored by hematoxilin-eosin (HE) and submitted to the morphometrical analysis to describe the tissue alterations. RESULTS: The presence of diffuse inflammatory alterations was observed in all groups, however, at the analysis of the pulmonary tissue of the experimental groups, it had been observed hyperplasic alterations (BALT hyperplasia), and in one of the animals of the experimental group 20mg/kg (12 weeks), it was noticed the presence of cellular epithelial tracheal pleomorphism, suggesting the adenocarcinoma formation in situ. CONCLUSION: The main secondary alterations to the intra-pulmonary instillation of B[a]P in Wistar rats were: cellular proliferation, inflammatory alterations of several degrees and nodular lymphoid hyperplasias. The association of an activator agent of the pulmonary metabolic reply is necessary to establish the ideal reply-dose to the development of the lung cancer.

OBJETIVO: Elaborar um modelo experimental de carcinogênese pulmonar em ratos wistar. MÉTODOS: Rattus norvegicus albinus, linhagem Wistar foram submetidos a instilação intra-pulmonar da diluição em álcool 70 por cento de Benzo[a]pireno (B[a]P), um hidrocarboneto aromático policíclico amplamente conhecido por seu poder de indução tumoral. Foram formados três grupos experimentais com 08 animais cada: Grupo Controle (álcool 70 por cento); Grupo B[a]P 10 mg/kg; e Grupo B[a]P 20mg/kg, submetidos a eutanásia 08, 10, 12 e 14 semanas após o procedimento experimental. As secções pulmonares foram coradas por HE e submetidas a análise morfométrica para descrição das alterações teciduais. RESULTADOS: em todos os grupos observou-se a presença de alterações inflamatórias difusas, porém na análise do tecido pulmonar dos grupos experimentais, observou-se alterações hiperplásicas (hiperplasia de BALT), e em um dos animais do grupo experimental 20mg/kg (12 semanas) notou-se a presença de pleomorfismo celular epitelial traqueal, sugerindo a formação de adenocarcinoma in situ. CONCLUSÃO: as principais alterações secundárias à instilação intra-pulmonar de B[a]P em ratos Wistar foram: proliferação celular, alterações inflamatórias de diversos graus e hiperplasias nodulares linfóides. A associação de um agente ativador da resposta metabólica pulmonar pode ser necessária para estabelecimento da dose-resposta ideal ao desenvolvimento do câncer de pulmão.

Antimutagenic effects of black tea in the Salmonella typhimurium reverse mutation assay.

Black tea (Camellia sinensis) is one of the most widely consumed beverages worldwide. Its chemopreventive effects are well documented in the literature. In the present set of investigations antimutagenic effects of aqueous black tea extract (ATE) and black tea polyphenols (BTP) were evaluated in the Ames test using Salmonella typhimurium tester strains TA 98 and TA 100. Addition of benzo(a)pyrene (BaP) and cyclophosphamide (CP), two well known mutagens, at the concentrations of 20 and 15 microg/plate, respectively, in an S-9 metabolically activated system resulted in significant induction of his+ revertant colonies. However, addition of 500 microl 1, 2 and 4% ATE to the BaP and CP treated plates resulted in a dose dependent inhibition in the number of his+ revertant colonies. Furthermore in another set of experiments, supplementation with BTP at the concentrations of 100, 200 and 400 microg/plate also led to a significant inhibition in BaP and CP induced colony formation. The antimutagenic activity of BTP was found to be higher than that of ATE, which may be attributable to the higher amount of polyphenolic ingredients. Hence the study revealed that black tea has a protective efficacy in suppressing BaP and CP induced mutagenicity in a microbial test system.

Effects of Benzoapyrene, 2-Bromopropane, Phenol and 2,3,7,8-Tetrachlorodibenzo-p-Dioxin on Proinflammatory Cytokines Gene Expression by Mice Spleen Cells

The detrimental effects of environmental pollutants on the health of the individual are generally accepted, although the mechanisms of these effects remain to be incompletely understood. In the present study, we examined the effects of B[a]P, 2-BP, phenol and TCDD on proinflammatory cytokine gene expression in mice spleen cells which were stimulated with anti-CD3. 10-9M TCDD increased IFN gammar and TNF alpha gene expression, but suppressed IL-1 gene expression. 10-6M phenol inhibited IL-1, IL-6 and TNF alpha gene expression, and 10-6M of 2-BP downregulated TNF alpha gene expression. However, 10-6M of B[a]P did not influence on IL-1, IL-6, IFN gammar and TNF alpha gene expression. These findings suggest that TCDD may impair the immune functions of mice by enhancing proinflammatory cytokines production, whereas phenol and 2-BP may impair the functions by inhibiting the production of these cytokines.

Benzoapyrene-Induced DNA-Protein Crosslinks in Cultured Human Lymphocytes and the Role of the GSTM1 and GSTT1 Genotypes

We investigated the influence of glutathione S-transferase M1 (GSTM1) and glutathione S-transferase T1 (GSTT1) polymorphisms upon DNA-protein crosslinks (DPC) induced by benzo[a]pyrene (B[a]P) in cultured human lymphocytes. Lymphocyte samples were collected from 30 healthy nonsmoking hospital administrative workers. DPC was detected with KCl-SDS assay and the distributions of GSTM1 and GSTT1 were determined by polymerase chain reaction. B[a]P was found to induce a significant dose-responsive increase in cytotoxicity and DPC regardless of the genotypes (p0.05). In terms of the genes examined, the level of cytotoxicity and DPC formation were found to be highest in the GSTM1-null and GSTT1-null cells. In conclusion, B[a]P induced a significant increase in the cytotoxicity and the level of DPC formation in cultured human lymphocytes. Our findings suggest that DPC could be used as a biomarker of B[a]P exposure.

Abnormal pattern of lung functions in rubber factory workers.

The influence of suspended particulate matter, benzo(e) pyrene, benzo(e) pyrene and benzo(a) anthracene concentration on pulmonary lung functions ie, residual volume, total lung capacity, residual volume/total lung capacity, forced residual capacity were studied in 667 rubber factory workers during 1990-91. The respirable fraction of the particulate size (< 0.5 micron) showed high mean concentration of suspended particulate matter, benzo(a) pyrene, benzo(e) pyrene and benzo(a) anthracene in the compounding section (group III), when compared with vulcanising (group II) and packing loading (group I) units. While comparing the lung functions amongst these groups, the higher results of residual volume, residual volume/total lung capacity ratio, forced respiratory capacity and lower values of total lung capacity were observed in group III workers as compared with other two groups. And also these results seem to be correlated with the high pollutant concentrations to which group III workers were exposed, and reflect a clear combination of obstructive and restrictive pattern of lung functions in them.

Niveles de benzo (a) pireno en la atmósfera y suelos del Aeropuerto Internacional "José Martí" / Benzo (a) pyrene levels in the air and soils of the \"José Martí\" International Airport

Se estudian los niveles medios de contaminación atmosférica producida por la aviación en nuestro país, tomando como ejemplo el Aeropuerto Internacional "José Martí". Se compara con las normas establecidas por el Consejo de Ayuda Mutua Económica y se indica las características que estos presentan en relación con nuestro clima