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.

Avaliação da presença de hidrocarbonetos policíclicos aromáticos em chocolates: exposição ao consumo e implicações à saúde / Evaluation of the presence of polycyclic aromatic hydrocarbons in chocolates: exposure to consumption and health implications

Introdução - Os hidrocarbonetos policíclicos aromáticos (HPAs) são compostos que apresentam ação potencialmente carcinogênica e mutogênica, que geram risco à saúde humana. Esses contaminantes são formados a partir da combustão incompleta de matéria orgânica, podendo ocorrer a formação durante o processamento dos alimentos em âmbito industrial (secagem, torra, pré-cozimento) e doméstico (fritar, assar e grelhar) pelo emprego de altas temperaturas. Para a produção do chocolate e outros produtos derivados do cacau, etapas como a secagem, torra e conchagem, são processos que utilizam altas temperaturas e essenciais para a produção de chocolates. Não existem estudos avaliando a presença e a exposição dietética por HPAs em chocolates no Brasil. Objetivo - Otimizar e validar a metodologia de extração e quantificação de 4 HPAs (benzo[a]antraceno (BaA), criseno (Cri), benzo[b]fluoranteno (BbF) e benzo[a]pireno (BaP)) em chocolates, quantificar sua presença em amostras de chocolates comerciais e estimar a exposição dietética aos HPAs a partir do consumo de chocolate. Métodos - As amostras de chocolate (ao leite, branco e amargo com porcentagens de cacau de 40%, 53%, 55%, 60% e 70%) foram obtidas no comércio da cidade de São Paulo. Foi realizada a otimização e validação da metodologia pelos parâmetros de linearidade, seletividade, limite de detecção, limite de quantificação, recuperação e repetibilidade. As amostras foram submetidas a extração líquido-líquido, extração em fase sólida e quantificadas por cromatógrafo líquido de alta eficiência com detector de fluorescência. A estimativa de exposição dietética (DEs) para benzo[a]pireno foi avaliada para três categorias: 1) Sexo (feminino e masculino); 2) Grupos etários: adolescentes (14 a 18 anos), adultos (19 a 59 anos) e idosos (>= 60 anos); 3) Local de residência (urbana e rural). Resultados - O método obteve faixa de linearidade entre 0,50 e 5,00 µg.kg-1 para os quatro HPAs. Com relação à seletividade, houve interferência da matriz apenas para o BaP. O método também mostrou acurácia, com recuperações médias variando entre 95,25 a 108,27% e repetibilidade mostrando valores entre 0,14 e 7,25%. Benzo[a]pireno foi encontrado em todos os chocolates, variando entre 1,58 a 4,34 µg.kg-1 de gordura. As amostras de chocolate com 53-60% cacau e chocolate 70% cacau apresentaram as maiores taxas de contaminação para BaP; já as amostras de chocolate 40% cacau e chocolate ao leite apresentaram menor contaminação. Quanto a exposição dietética, as mulheres (por gênero) e os adolescentes (por idade) apresentaram maiores DEs para BaP pelo consumo de chocolate, principalmente para o chocolate 70% cacau. Os resultados apresentaram baixa contaminação por HPAs nos chocolates analisados, no entanto, o consumo aumentado por diferentes faixas etárias pode contribuir para a DEs ao BaP. Conclusões - A metodologia padronizada foi considerada seletiva e sensível, garantindo a eficiência do ensaio. As amostras analisadas apresentaram resultados abaixo dos limites estabelecidos pelo Regulamento da Comunidade Européia No. 835/2011 para o BaP e para a soma dos 4 HPAs. Frente aos grupos analisados (sexo, idade e local de residência), os chocolates 70% cacau contribuíram para a maior exposição dietética à BaP. A presença dos quatro HPAs prioritários nos chocolates analisados demonstrou a importância de programas de monitoramento da cadeia produtiva em produtos de cacau (massa de cacau, manteiga de cacau e cacau em pó) e ingredientes adicionados (açúcar e leite em pó).

Introduction - Polycyclic aromatic hydrocarbons (PAHs) are compounds that have a potentially carcinogenic and mutogenic action, which generate risk to human health. These contaminants are formed from the incomplete combustion of organic matter, which can occur during industrial (drying, roasting, pre-cooking) and domestic (frying, roasting and grilling) processing of food by the use of high temperatures. For the production of chocolate and other products derived from cocoa, steps such as drying, roasting and conching are processes that use high temperatures and are essential for the production of chocolates. There are no studies evaluating the presence and dietary exposure to PAHs in chocolates in Brazil. Objective - To optimize and validate the methodology for the extraction and quantification of 4 PAHs (benzo[a]anthracene (BaA), chrysene (Chr), benzo[b]fluoranthene (BbF) and benzo[a]pyrene (BaP)) in chocolates, quantify the presence in commercial chocolate samples and estimate dietary exposure to PAHs from the consumption of chocolate. Methods - Chocolate samples (milk, white and dark with cocoa percentages of 40%, 53%, 55%, 60% and 70%) were obtained from commercial stores in the city of São Paulo. The methodology was optimized and validated by the parameters of linearity, selectivity, limit of detection, limit of quantification, recovery and repeatability. The samples were subjected to liquid-liquid extraction, solid-phase extraction and quantified by a High Performance Liquid Chromatograph with fluorescence detector. The dietary exposure estimate (DEs) for benzo[a]pyrene was assessed for three categories: 1) Gender (female and male); 2) Age groups: adolescents (14 to 18 years), adults (19 to 59 years) and elderly (>= 60 years); 3) Place of residence (urban and rural). Results - The method obtained a linearity range between 0.50 and 5.00 µg.kg-1 for the four PAHs. Regarding selectivity, there was interference from the matrix only for BaP. The method also showed accuracy, with average recoveries ranging from 95.25 to 108.27% and repeatability showing values between 0.14 and 7.25%. Benzo[a]pyrene was found in all chocolates, ranging from 1.58 to 4.34 µg.kg-1 of fat. Chocolate samples with 53-60% cocoa and chocolate 70% cocoa showed the high contamination for BaP; the 40% cocoa and milk chocolate samples showed low contamination. As for dietary exposure, women (by gender) and adolescents (by age) had higher DEs for BaP due to chocolate consumption, especially for 70% cocoa chocolate. The results showed low contamination by PAHs in the analyzed chocolates, however, the increased consumption by different age groups can contribute to DEs to BaP. Conclusions - The standardized methodology was considered selective and sensitive, ensuring the efficiency of the test. The analyzed samples showed results below the limits established by the European Community Regulation No. 835/2011 for the BaP and for the sum of the 4 PAHs. In view of the groups analyzed (gender, age and place of residence), chocolates 70% cocoa contributed to the greater dietary exposure to BaP. The presence of the four priority PAHs in the analyzed chocolates demonstrated the importance of programs to monitor the production chain in cocoa products (cocoa mass, cocoa butter and cocoa powder) and ingredients used in chocolate formulation (sugar and powdered milk).

Effect of benzo(a)pyrene on dopaminergic neurons and α-synuclein in brain and its mechanism involved / 北京大学学报(医学版)

OBJECTIVE@#To analyze the effect of benzopyrene on the decrease of dopaminergic neurons, and the increase and aggregation of α-synuclein, which are the pathological features of Parkinson's disease, and to explore its possible mechanisms.@*METHODS@#Eight-month-old transgenic mice with human SNCA gene were randomly divided into a BaP-exposed group and a control group. BaP and solvent corn oil were injected intraperitoneally to BaP-exposed group and control group respectively, once a day for 60 days. The motor dysfunction of mice was tested by rotarod test. The effects of BaP on the decrease of dopaminergic neurons and increase and aggregation of α-synuclein were observed by immunohistochemistry and Western blot experiments respectively, and the expression of related mRNA was detected by quantitative real-time PCR (qRT-PCR). Twenty genes were tested in the study, mainly related to neurotransmitter transporter (2 genes), neurotransmitter receptor function (10 genes), cellular autophagy (5 genes), and α-synuclein aggregation and degradation (3 genes).@*RESULTS@#After BaP exposure, the movement time of the mice in the rotarod test was significantly reduced (P<0.05). The substantia nigra dopami-nergic neurons in the mice were significantly reduced, which was 62% of the control group (P<0.05), and the expression of α-synuclein in the midbrain increased, which was 1.36 times that of the control group (P<0.05). After BaP exposure, mRNA expressions of 14 genes in the midbrain of the mice were significantly down-regulated (P<0.05). Alpha-synuclein degradation and cell autophagy (5 genes), neuron transporters (2 genes), and neurotransmitter receptor functions (5 genes) were involved. The expression of one gene, Synphilin-1, was significantly up-regulated (P<0.01), which was related to α-synuclein aggregation.@*CONCLUSION@#BaP exposure not only inhibited function of neurotransmitter receptor and dopamine transporter, but also interfered cell autophagy, thereby hindering the degradation of α-synuclein, which could lead to decrease of dopaminergic neurons in substantia nigra and increase and aggregation of α-synuclein in midbrain, as the significant pathology of Parkinson's disease. Therefore, BaP exposure may increase the risk of Parkinson's disease.

Progress in study on the role of metabolomics in toxic effects of environmental pollutants and the underlying mechanism / 中南大学学报(医学版)

Metabolomics methods were applied in the study of the toxicity of environmental pollutants. It has been shown that exposure to heavy metals such as mercury, arsenic, cadmium, chromium and lead could cause significant changes in energy, lipids, nucleic acids and amino acids in mammalian cells. After exposure to benzo(a)pyrene [B(a)P], the glands of Pinctada pumila could produce various changes, such as energy metabolic disorder, cell damage, signal transduction disorder, oxidative stress and osmotic disorder. Persistent organic compounds polychlorinated biphenyls (PCBs) could exert toxic effects on Zebrafish embryos through affecting amino acid metabolism, DNA and protein methylation and biosynthesis. After exposure to endocrine disruptors, such as nonylphenol, octylenediester phthalate and bisphenol propane, goldfish showed energy, lipid and nucleic acid metabolic disorders.

Polycyclic aromatic hydrocarbons degradation by marine-derived basidiomycetes: optimization of the degradation process

ABSTRACT Pyrene and benzo[a]pyrene (BaP) are high molecular weight polycyclic aromatic hydrocarbons (PAHs) recalcitrant to microbial attack. Although studies related to the microbial degradation of PAHs have been carried out in the last decades, little is known about degradation of these environmental pollutants by fungi from marine origin. Therefore, this study aimed to select one PAHs degrader among three marine-derived basidiomycete fungi and to study its pyrene detoxification/degradation. Marasmiellus sp. CBMAI 1062 showed higher levels of pyrene and BaP degradation and was subjected to studies related to pyrene degradation optimization using experimental design, acute toxicity, organic carbon removal (TOC), and metabolite evaluation. The experimental design resulted in an efficient pyrene degradation, reducing the experiment time while the PAH concentration applied in the assays was increased. The selected fungus was able to degrade almost 100% of pyrene (0.08 mg mL-1) after 48 h of incubation under saline condition, without generating toxic compounds and with a TOC reduction of 17%. Intermediate metabolites of pyrene degradation were identified, suggesting that the fungus degraded the compound via the cytochrome P450 system and epoxide hydrolases. These results highlight the relevance of marine-derived fungi in the field of PAH bioremediation, adding value to the blue biotechnology.

Anaerobic biodegradation of benzo(a)pyrene by a novel Cellulosimicrobium cellulans CWS2 isolated from polycyclic aromatic hydrocarbon-contaminated soil

Abstract Cellulosimicrobium cellulans CWS2, a novel strain capable of utilizing benzo(a)pyrene (BaP) as the sole carbon and energy source under nitrate-reducing conditions, was isolated from PAH-contaminated soil. Temperature and pH significantly affected BaP biodegradation, and the strain exhibited enhanced biodegradation ability at temperatures above 30 °C and between pH 7 and 10. The highest BaP removal rate (78.8%) was observed in 13 days when the initial BaP concentration was 10 mg/L, and the strain degraded BaP at constant rate even at a higher concentration (50 mg/L). Metal exposure experimental results illustrated that Cd(II) was the only metal ion that significantly inhibited biodegradation of BaP. The addition of 0.5 and 1.0 g/L glucose enhanced BaP biodegradation, while the addition of low-molecular-weight organic acids with stronger acidity reduced BaP removal rates during co-metabolic biodegradation. The addition of phenanthrene and pyrene, which were degraded to some extent by the strain, showed no distinct effect on BaP biodegradation. Gas chromatography-mass spectrometry (GC-MS) analysis revealed that the five rings of BaP opened, producing compounds with one to four rings which were more bioavailable. Thus, the strain exhibited strong BaP degradation capability and has great potential in the remediation of BaP-/PAH-contaminated environments.

Dual effect of Algerian propolis on lung cancer: antitumor and chemopreventive effects involving antioxidant activity

Abstract The purpose of our study was to divulge the antiproliferative effect of an ethanolic extract of Algerian propolis (EEP) in the human lung adenocarcinoma cell line (A549) and reveal the chemopreventive role against benzo(a)pyrene-induced lung carcinogenesis in albino Wistar rats. Cytotoxicity of EEP was evaluated using the MTT assay and cell adhesion in A549 cells. Moreover, rats were given 25 mg/kg of propolis for 5 days before induction of experimental lung cancer by a single intraperitoneal dose of 200 mg/kg benzo(a)pyrene. Body weight, lung weight, lipid peroxidation, marker enzymes, and enzymatic and non-enzymatic antioxidants were estimated. The EEP demonstrated an inhibitory effect on proliferation of A549 at 24 and 72 hours in a dose-dependent manner and blocked adhesion of the cells by fibrinogen. Moreover, EEP reduced the oxidative stress generated by benzo(a)pyrene. The pre-treatment showed that enzymatic and non-enzymatic antioxidants increased and lipid peroxidation decreased. A histological analysis further supported these findings and showed a decrease in the number of side effects. These results are particularly important for both clinical applications of propolis and the possibility for its use as a potential chemotherapeutic agent.

Effects of benzo(a)pyrene on expressions of insulin-degrading enzyme and neprilysin in neuroglia cells / 北京大学学报(医学版)

OBJECTIVE@#To investigate effects of benzo(a)pyrene (BaP) on expressions of insulin-degrading enzyme (IDE) and neprilysin (NEP) which have the ability to degrade β-amyloid (Aβ) in neuroglia cells.@*METHODS@#Primary mix-neuroglia cells were cultured from newborn SD rats. After exposure to BaP, Aβ1-42 oligomer or Aβ1-42 fiber individually or jointly for 24 h, the cell survival rate was measured by cell counting kit-8 (CCK-8). Afterwards, the primary mix-neuroglia cells were divided randomly into six groups: Control group, BaP group (2.00 μmol/L), Aβ1-42 oligomer group (20.00 mg/L), BaP plus Aβ1-42 oligomer group, Aβ1-42 fiber group (20.00 mg/L) and BaP plus Aβ1-42 fiber group, of which BaP was pretreated for 12 h followed by cotreatment with different aggregated Aβ1-42. The expressions of IDE and NEP were measured by quantitative real-time polymerase chain reaction (qRT-PCR) for mRNA level and Western blotting for protein level.@*RESULTS@#The cell survival rate showed no significant differences after treatment with BaP (≤20.00 μmol/L), Aβ1-42 oligomer (20.00, 40.00 mg/L), Aβ1-42 fiber (20.00, 40.00 mg/L) or cotreatment with BaP and Aβ1-42 oligomer or BaP and Aβ1-42 fiber. Compared with the control group, expressions of IDE and NEP in BaP-treated alone group had no obvious change; however, exposure to Aβ1-42 oligomer alone significantly increased the mRNA and protein level of IDE (P<0.05), and the BaP pretreatment could significantly inhibit the up-regulated expressions of IDE by Aβ1-42 oligomer (P<0.05); on the other hand, exposure either to Aβ1-42 fiber alone or under the BaP pretreatment did not change the mRNA and protein level of IDE and NEP obviously.@*CONCLUSION@#On the premise of no significant change of cell survival rate, BaP pretreatment inhibited the up-regulated expressions of IDE in primary mixed neuroglia cells under cotreatment with Aβ oligomer, indicating that BaP may disturb degradation of Aβ oligomer and cause deposition of β-amyloid and further induce cognitive decline and acceleration of Alzheimer.

Tolerance to Polycyclic Aromatic Hydrocarbons (PAHs) by filamentous fungi isolated from contaminated sediment in the Amazon region / Tolerância a Hidrocarbonetos Policíclicos Aromáticos (HPAs) por fungos filamentosos isolados de sedimentos contaminados da região Amazônica

Tolerance to Polycyclic Hydrocarbons Aromatic (PAHs) is considered an important characteristic when assessing the bioremediation potential of microorganisms. Given this, the objective of this research was to assay filamentous fungi from the Amazon region, isolated from sediments with differents levels of contamination by PAHs, for tolerance to phenanthrene and pyrene. To achieve this, fungal cultures plugs (5 mm), obtained after 7 days growth, were transferred to petri dishes containing 20% Sabouraud dextrose agar medium, after surface innoculation with phenanthrene and pyrene crystals, separately. Radial mycelial growth was evaluated after 10 days at five different concentration levels for each contaminant and control group, all in triplicate for each treatment. Fungal growth and growth inhibition rates were calculated. The average growth of the colonies in each treatment was compared with one-way ANOVA, followed by a Tukey Test (p < 0,05). All fungi showed tolerant to phenanthrene and pyrene. However, Hypoxylon sp. showed the lowest growth inhibition rate and average growth rates significantly different of the other six tested species. Hypoxylon sp. has been shown to be a promising genetic resource for use in new studies of PAHs degradation.

A tolerância a Hidrocarbonetos Policíclicos Aromática (HPAs) é considerada como uma característica importante na avaliação do potencial de micro-organismos para biorremediação. Diante disso, o objetivo desta pesquisa foi avaliar fungos filamentosos da região amazônica, isolados de sedimentos com diferentes níveis de contaminação por HPAs, quanto à tolerância ao fenantreno e pireno. Para tanto, discos das culturas fúngicas (5 mm), obtidas após 7 dias de crescimento, foram transferidas para placas de Petri contendo meio Agar Sabouraud Dextrose a 20%, após inoculação superficial com cristais de fenantreno e pireno, separadamente. O crescimento micelial radial foi avaliado após 10 dias em cinco concentrações diferentes para cada contaminante e grupo controle, ambos em triplicata para cada tratamento. As taxas de crescimento fúngico e de inibição de crescimento foram calculadas. O crescimento médio das colônias em cada tratamento foi comparado com ANOVA one way, seguido pelo teste de Tukey (p < 0,05). Todos os fungos mostraram tolerância ao fenantreno e ao pireno. No entanto, Hypoxylon sp. apresentou menor taxa de inibição de crescimento e taxas médias de crescimento significativamente diferentes das outras seis espécies testadas. Hypoxylon sp. tem se mostrado um recurso genético promissor para uso em novos estudos sobre degradação de HPAs.

Antimutagenic and Antioxidant Activities of Thai Rice Brans

BACKGROUND: Rice bran is the outer layer of the rice grain, and contains high amounts of bioactive phytochemicals. Here, we investigated and compared chemopreventive properties of purple and white rice bran extracts. METHODS: Rice bran was extracted with dichloromethane and methanol. Chemical constituents in the extracts were analyzed by colorimetric assay and high performance liquid chromatography. The mutagenicity and antimutagenicity of the extracts were determined via the Salmonella mutation assay. The anticarcinogenic enzyme induction and antioxidant activities of the extracts were examined using Hepa1c1c7 cells and 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay, respectively. RESULTS: The methanol extracts of rice bran contained high amounts of phenolic acids, flavonoids, anthocyanins, and phytic acid, whereas large amounts of γ-oryzanol and vitamin E were presented in the dichloromethane extract. None of the extracts were mutagenic to Salmonella typhimurium. All rice bran extracts had strong antimutagenic effects against aflatoxin B1- and 2-amino-3,4-dimethylimidazo [4,5-f]quinoline-induced mutagenesis. The inhibitory effect against 2-aminofluorene-induced mutagenesis was found in the dichloromethane extract, while only the methanol extract of purple rice bran exhibited antimutagenic effects against benzo(a)pyrene. None of the extracts induced quinone reductase activity in Hepa1c1c7 cells. Additionally, the greatest antioxidant capacity was found in the methanol extract of purple rice bran. CONCLUSIONS: The methanol extract of purple rice bran containing high amount of phenolic acids, flavonoids, anthocyanins, and phytic acid showed the most effective antioxidant and antimutagenic activities by inhibiting mutagenic metabolizing enzymes and/or scavenging free radicals. These results demonstrate the nutritional and medical value of Thai rice for cancer prevention.

Protective Effect of Schisandra Extract on Embryotoxicity and Reproductive Toxicity in Early Pregnant Rats Exposed to Benzo a pyrene / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To observe protective effects of Schisandra extract (SE) on embryotoxicity and reproductive toxicity of early pregnant rats exposed to Benzo[a]pyrene (Bap).</p><p><b>METHODS</b>Pregnant rat model was prepared using periodic screening cage method. Totally 50 female pregnant SD rats were divided into five groups by randomized block design according to the weight, i.e., the BaP model group, the low dose SE group, the middle dose SE group, the high dose SE group, the normal control group, 10 rats in each group. Rats in the BaP model group were administered with BaP at a daily dose of 2 mg/kg by gastrogavage. Rats in low, middle, and high dose SE groups were administered by gastrogavage with BaP (at a daily dose of 2 mg/kg) plus SE at a daily dose of 40, 200, and 1 000 mg/kg, respectively. Equal volume of olive oil was administered to rats in the normal control group by gastrogavage. All medication was performed for 8 successive days. Changes of rat body weight in each period were observed. The uterus embryonic total quality and ovary quality were measured, and organ index calculated. The number of corpus luteum, the number of embryo implantation, and the number of absorbed embryo were statistically calculated respectively. The implantation rate and the absorbed embryos rate were calculated. Serum levels of human chorionic gonadotrophin β (β-HCG) and progesterone (PROG) were detected by ELISA.</p><p><b>RESULTS</b>Compared with the normal control group, the weight of 9-day pregnant rats, the number of embryo implantation, the uterus embryonic total index, ovary index, serum levels of β-HCG and PROG all decreased in the Bap model group with significant difference (P < 0.05, P < 0.01). Compared with the Bap model group, body weight, the uterus embryonic total index, and the PROG level increased in 3 dose SE groups (P < 0.05, P < 0.01). Ovary index and serum β-HCG increased in middle and high dose SE groups (P < 0.05, P < 0.01). The number of implantation obviously increased in the high dose SE groups (P < 0.01).</p><p><b>CONCLUSION</b>SE could reduce the embryotoxicity and reproductive toxicity of early pregnant rats exposed to Benzo[a]pyrene.</p>

Morphological changes and growth of filamentous fungi in the presence of high concentrations of PAHs

In this study, we evaluated the effect of low and high molecular weight polycyclic aromatic hydrocarbons (PAHs), i.e., Phenanthrene, Pyrene and Benzo[a]pyrene, on the radial growth and morphology of the PAH-degrading fungal strains Aspergillus nomius H7 and Trichoderma asperellum H15. The presence of PAHs in solid medium produced significant detrimental effects on the radial growth of A. nomius H7 at 4,000 and 6,000 mg L⁻¹ and changes in mycelium pigmentation, abundance and sporulation ability at 1,000–6,000 mg L⁻¹. In contrast, the radial growth of T. asperellum H15 was not affected at any of the doses tested, although sporulation was observed only up to 4,000 mg L⁻¹ and as with the H7 strain, some visible changes in sporulation patterns and mycelium pigmentation were observed. Our results suggest that fungal strains exposed to high doses of PAHs significantly vary in their growth rates and sporulation characteristics in response to the physiological and defense mechanisms that affect both pigment production and conidiation processes. This finding is relevant for obtaining a better understanding of fungal adaptation in PAH-polluted environments and for developing and implementing adequate strategies for the remediation of contaminated soils.

Vitamin E prevents the toxic effect of benzo(a)pryene on reproductive system in male SD rats / 中南大学学报(医学版)

OBJECTIVE@#To investigate the protective effects and the potential mechanisms of vitamin E (VE) on benzo(a)pryene (B[a]P)-induced toxicity in the reproductive system of male rats. 
@*METHODS@#A total of 60 male Sprague Dawley (SD) rats, weighted 70-90 g, were randomly assigned to 6 groups: a control group, a vehicle group, a B[a]P group (5 mg/kg), a VE (10 mg/kg)+ B[a]P (5 mg/kg) group, a VE (50 mg/kg) + B[a]P (5 mg/kg) group and a VE (100 mg/kg)+B[a]P (5 mg/kg) group (n=10 per group). The rats were treated with B[a]P and/or VE once a day for 30 days via intragastric administration. The sperm quality and the levels of SOD, GSH-Px, 8-OHdG and MDA were detected, respectively. The testicular tissue morphology and DNA damage were observed by HE staining and comet assay.
@*RESULTS@#The sperm count, the rate of sperm deformation, the content of MDA and 8-OHdG were all significantly increased in single B[a]P-treated group in comparison to the control groups. The activities of SOD and GSH-Px were markedly decreased by B[a]P as compared with the control groups (P<0.05). The injury of testicular tissue in B[a]P-treated rats was remarkably improved after VE treatment. The levels of oxidative stress and DNA damage indicators in the B[a]P-treated group were all attenuated by VE. These protective effects of VE were in a dose-dependent manner (P<0.05).
@*CONCLUSION@#Vitamin E can protect the male SD rats against the B[a]P-induced reproductive toxicity.

Effects of benzo(a)pyrene exposure on the ATPase activity and content of Ca²⁺ in the hippocampus of neonatal SD rats / 中南大学学报(医学版)

OBJECTIVE@#To investigate the effect of benzo(α)pyrene on the ATPase activity and content of Ca²⁺ in the hippocampus of neonatal SD rats.@*METHODS@#Sixty male and 60 female 4-days-old neonatal SD rats were randomly divided into 5 groups (n=24): a blank control group, a vehicle control group (peanut oil), 3 benzo(α)pyrene groups (0.02, 0.2 and 2 mg/kg, respectively). SD rats were given benzo(α)pyrene (dissolved in peanut oil) by gavage daily from postnatal day 4 (PND4) to PND20. The nerve reflex, the condition of neuro-muscle development and motion function were examined in the period of treatment. The colorimetric technique was used to detect the activity of Ca²⁺-ATPase and Ca²⁺-Mg²⁺-ATPase in hippocampus after the treatment. The concentration of Ca²⁺ of synapse in the hippocampus of rats was detected by fluorescent labeling.@*RESULTS@#The results from the behavior tests showed that duration of surface reflex latency in rats with medium dose of benzo(α)pyrene was longer compared with that in the control group in PND12. The duration of surface reflex latency in rats with high dose of benzo(α) pyrene is longer in PND 14 and PND 16 compared with that in the control group (P<0.05). Compared with the rats in the control group, the activities of Ca²⁺-Mg²⁺-ATPase and Ca²⁺-ATPase in hippocampus in rats with high dose benzo(α) pyrene were significantly decreased, and the degree in the decrease of Ca²⁺-ATPase activity was dose-dependent (P<0.05). The contents of Ca²⁺ in the hippocampus in rats with medium or high dose of benzo(α) pyrene were significantly increased compared with that in the control group (P<0.05), which showed a dose-dependent manner (P<0.05).@*CONCLUSION@#Benzo(α)pyrene exposure led to the decrease in ATPase activity as well as Ca²⁺ overload of the synapse in the hippocampal tissue, which in turn results in the nerve damage of newborn SD rats.

Cohort study of effects on lung function of coke oven workers exposured to coke oven emissions / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>Through comparative study on pulmonary function damage of coke oven workers exposed to coke oven emissions with the same group before and after five years, and further explore the relationship between the coke oven emissions and injury in pulmonary function of coke oven worker.</p><p><b>METHODS</b>Select a coking plant in Shanxi 165 coke oven workers (exposed group) and 52 auxiliary workers (control group) for the study, using a uniform questionnaire to collect workers' personal information. Fixed workplace air samples collected periodically. Air samples of benzo (a) pyrene concentrations was measured by high pressure liquid chromatograph. Pulmonary function of research object was measured by portable spirometer respectively in 2009 and 2013, and comparative analysis on it.</p><p><b>RESULTS</b>The concentration of B(a)P was no significant difference in the same area between 5 years in 2009-2013. Compared with 2009, 2013 control workers lung function index and the abnormal rate had no significant difference (P > 0.05). But FVC%, FEV1.0%, MVV%, VC% and FEF25% of exposed workers in 2013 was significantly lower than in 2009, FVC%, FEV1.0%, VC% and FEF25% pulmonary dysfunction rate in 2013 was also significantly higher than in 2009, difference was statistically significant (P < 0.05). Workers emerging pulmonary function abnormalities mainly distributed in furnace roof and side. furnace roof group FVC%, FEV1.0%, VC% additional abnormal number (rate) was significantly higher than furnace floor and the control group (P < 0.05), and furnace side groop was significantly higher than the control group, the difference was statistically significant (P < 0.05). Multivariate Logistic regression analysis showed that after 5 years FVC%, FEV1% and VC% of abnormal lung function emerging adjusted OR of furnace roof workers were 7.939, 5.966 and 4.956. For abnormal of FVC%, FEV1%, VC% and MVV%, the contacting coke seniority is a risk factor. There is a positive interaction between contacting coke seniority and furnace roof (P < 0.05).</p><p><b>CONCLUSION</b>Coke oven workers lung function damage associated with exposureing to coke oven emissions, coke oven emissions exposure level and exposure time are the main factors of coke oven workers in lung function damage, there is a positive interaction between the two factors.</p>

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.

Efeito da mistura de diazinon e benzo[a]pireno naS-transferase da Glutationa em Tilápias do Nilo / Effect of mixture of diazinon and benzo[a]pyrenein Glutathione S-transferase of Nile tilapia

Atualmente, com a crescente contaminação dos ecossistemas aquáticos, muitos compostos, como pesticidas e hidrocarbonetos,são lançados de forma indevida em corpos d’água. Estudos relacionando a exposição de poluentes, individualmente,com variações bioquímicas são abundantes na literatura. Entretanto, ainda são poucos os voltados às misturas complexas.Sendo assim, o objetivo do presente estudo foi analisar se a mistura diazinon e benzo[a]pireno pode afetar as atividadesbioquímicas de biomarcadores clássicos, tais como acetilcolinesterase (AChE), carboxilesterase (CbE), catalase (CAT), glutationaperoxidase (GPx) e glutationa S-transferase (GST) em Tilápias do Nilo (Oreochromis niloticus) e comparar os efeitosnos sistemas enzimáticos quando estão expostos à mistura e aos compostos separadamente. Foi medida a atividade dasenzimas em brânquias e fígados de Tilápia do Nilo após 2 e 7 dias de exposição ao Diazinon (0,5 mg/L) e ao benzo[a]pireno (1,0 mg/L) individualmente e em mistura. Os resultados mostraram que no grupo mistura do fígado após 7 dias deexposição, o benzo[a]pireno aumentou a ação inibidora do Diazinon na atividade da enzima GST. Isso indica que a toxicidadedas interações ambientais entre pesticida e hidrocarboneto policíclico aromático pode apresentar efeito sinérgico.Desse modo, é importante levar em conta esse fator, pois irá auxiliar na compreensão de resultados obtidos em estudosde campo, como em um monitoramento ambiental.

Currently, with the growing contamination of aquatic ecosystems, many compounds, such as pesticides and hydrocarbons,are improperly released into rivers and lakes. Studies about the exposure of single pollutants causing biochemical variationsare abundant in the literature. However, there are few studies focused on the biological effects of complex mixtures.The aim of this investigation was to evaluate whether mixture diazinon and benzo[a]pyrene can affect the biochemicalactivities of classic biomarkers such as acetylcholinesterase (AChE), carboxylesterase (CbE), catalase (CAT), glutathioneperoxidase (GPx) and glutathione S-transferase (GST) in Nile tilapia and compare the effects on enzymatic systems of theexposure to a mixture of compounds and the effects observed when they are exposed separately. We measured the activityof enzymes in gills and liver of Nile Tilapia (Oreochromis niloticus) after 2 and 7 days of exposure to Diazinon (0.5 mg/L)and benzo[a]pyrene (1.0 mg/L) individually and in mixture. The results showed that in the mixture group after 7 days ofexposure, the benzo[a]pyrene increased the inhibitory action of Diazinon in GST enzyme activity, in liver tissue. This indicatesthat the toxicity of the interactions between pesticide and polycyclic aromatic hydrocarbon may show synergisticeffect. These results suggest the importance of studies with mixture of compounds, because these data will help to understandthe results obtained in field studies, such as those from environmental monitoring.

El benzo(a)pireno en los alimentos y su relación con el cáncer / Benzo[a]pyrene from food and cancer

Antecedentes: el benzo(a)pireno es un hidrocarburo aromático policíclico con efectos adversos para la salud, una de las fuentes es la ingestión de alimentos, formados durante procesamiento industrial o en el hogar. Objetivo: indagar sobre la formación de benzo(a)pireno en los alimentos, su activación biológica, relación con el cáncer, contenido en los alimentos y la normativa que regula la cantidad en alimentos para humanos. Materiales y métodos: se realizó una búsqueda bibliográfica de artículos publicados en las bases de datos nacionales e internacionales. Resultados: el benzo(a)pireno ingerido con los alimentos se absorbe por el intestino, se metaboliza predominantemente en el hígado, allí se activa y puede inducir cáncer de diversa localización, como esófago, estómago, intestino, piel, vejiga, pulmón e hígado, evidenciado en estudios experimentales en animales. El benzo(a)pireno atraviesa la placenta y es potencialmente tóxico para el feto. Las cantidades en algunos alimentos exceden las máximas permitidas por la Comisión Europea entidad que periódicamente actualiza las normas sobre el tema. En Colombia no se encontró reglamentación. Conclusión: el benzo(a)pireno procedente de alimentos genera compuestos capaces de desarrollar cáncer principalmente del tracto gastrointestinal. La Comisión Europea actualiza periódicamente la normativa que regula el contenido de benzo(a)pireno en alimentos, Colombia carece de normas sobre el tema.

Background: Benzo[a]pyrene is a polycyclic aromatic hydrocarbon which has been related with adverse health outcomes. Food is a source of benzo[a]pyrene; which is produced during industrial processing or cooking. Objective: To review information about benzo(a)pyrene formation in food, biological activation, association with cancer, food content and regulation of benzo(a)pyrene content in human food. Methods: A literature search from national and international scientific databases was developed. Results: benzo[a]pyrene ingested is absorbed by the intestine metabolized and activated, predominantly, by the liver. Animal studies have associated benzo[a]pyrene with esophagus, stomach, intestine, skin, bladder, lung, and liver cancer. Benzo[a]pyrene is potentially toxic to the fetus, due to it passes trough placenta. Benzo[a]pyrene amounts in some foods exceed the maximum level allowed by the European Commission; which periodically updates legislation on this topic. In Colombia there is not regulation about benzo[a]pyrene. Conclusion: benzo[a]pyrene in food generates compounds that may be associated with cancer, mainly gastrointestinal cancer. The European Commission regularly updates regulation about benzo[a] pyrene content in foods. Colombia does not have regulation on this topic.

Effects of subchronic benzoapyrene exposure on hippocampal cholinergic system in rats / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To observe the effects of subchronic benzo[a]pyrene (B[a]P) exposure on the neurobehavior and hippocampal acetylcholine (Ach) level, acetylcholinesterase (AChE) activity, and mRNA and protein expression of nicotinic acetylcholine receptor α7 subtype (nAChR α7) in rats, and to investigate the neurotoxic mechanism of B[a]P.</p><p><b>METHODS</b>Sixty healthy male SD rats were randomly divided into blank control group, solvent control group, and B [a]P exposure groups. Each rat in the exposure groups was intraperitoneally injected with B[a]P at 1.0, 2.5, or 6.25 mg/kg once every other day for 90 days. The learning and memory ability of the rats was examined by Morris water maze test and step-down test; the hippocampal Ach level was measured by alkaline hydroxylamine method; the AChE activity was measured by DNTB method; the mRNA and protein expression levels of hippocampal nAChR α7 were measured by quantitative PCR and Western blot.</p><p><b>RESULTS</b>The 2.5 and 6.25 mg/kg B[a]P exposure groups showed significantly lower learning and memory abilities than the blank control group and solvent control group (P < 0.05); also, the two groups had significantly lower hippocampal Ach levels than the blank control group, solvent control group, and 1.0 mg/kg B[a]P exposure group (P < 0.05). The 6.25 mg/kg B[a]P exposure group showed significantly lower hippocampal AChE activity than the blank control group, solvent control group, and 1.0 mg/kg B[a]P exposure group (P < 0.05). There were no significant differences in the mRNA and protein expression levels of nAChR α7 among all groups (P > 0.05). The hippocampal Ach level was negatively correlated with the mean escape latency period and total distance travelled (r = -0.567, P < 0.01; r = -0.503, P < 0.01) but positively correlated with the time in platform quadrant (r = 0.800, P < 0.01).</p><p><b>CONCLUSION</b>Subchronic B[a]P exposure may impair the learning and memory ability in rats, which is related to the downregulation of hippocampal Ach level.</p>

The modification of apoptosis correlated gene, protein and protein activity in rat hippocampus induced by benzoa pyrene sub-chronic exposure / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To observe the effects of subchronic exposure to benzo[a]pyrene (B[a]P) on the mRNA and protein expression levels of apoptosis-related genes (bax, bcl-2, caspase-3, caspase-6, and caspase-9) and the activities of Caspase-3, Caspase-6, and Caspase-9 in the hippocampal neurons of rats and to investigate the neurotoxic mechanism by which B[a]P induces the apoptosis of neurons.</p><p><b>METHODS</b>Fifty-two healthy SD rat were randomly divided into five groups according to preliminary neurobehavioral test results: blank control group, solvent control group, and 1.0, 2.5, and 6.25 mg/kg B[a]P exposure groups; the rats in exposure groups were intraperitoneally injected with B[a]P every other day for 90 days. The Morris water maze was used to test the learning and memory ability of rats; flow cytometry was used to measure the apoptosis ratio of hippocampal neurons; real-time quantitative PCR and Western blot were used to measure the mRNA and protein expression levels of apoptosis-related genes; spectrophotometry was used to measure the activities of their en-coded proteins.</p><p><b>RESULTS</b>Compared with the blank control group, solvent control group, and 1.0 mg/kg B[a]P exposure group, the 2.5 and 6.25 mg/kg B[a]P exposure groups hada significantly longer mean escape latency period (P < 0.05) and a significantly increased number of times of platform crossing (P < 0.05), and the 6.25 mg/kg B[a]P exposure group had significantly lower length and percentage of time spent in the platform quadrant (P < 0.05). The early apoptosis ratio rose as the dose of B[a]P increased (P trend < 0.05); the early apoptosis ratios of 1.0, 2.5, and 6.25 mg/kg B[a]P exposure groups were significantly higher than those of blank control group and solvent control group (P < 0.05). Compared with the blank control group, solvent control group, and 1.0 and 2.5 mg/kg B[a]P exposure groups, the 6.25 mg/kg B[a]P exposure group had significantly increased Bax expression (P < 0.05) and significantly decreased Bcl-2 expression and Bcl-2/Bax ratio (P < 0.05). The 2.5 and 6.25 mg/kg B[a]P exposure groups had significantly higher expression levels of Caspase-3 and Caspase-6 than the blank control group, solvent control group, and 1.0 mg/kg B[a]P exposure group (P < 0.05). The activities of Caspase-3, Caspase-6, and Caspase-9 were significantly higher in the 2.5 and 6.25 mg/kg B[a]P exposure groups than in the blank control group and solvent control group (P < 0.05). There was a positive correlation between the activities of Caspase-3, Caspase-6, and Caspase-9 and early apoptosis ratio of hippocampal neurons in rats (r = 0.793, P = 0.019; r = 0.886, P = 0.006; r = 0.773, P = 0.025). There were no significant differences in the mRNA expression of Bax, Bcl-2, Caspase-3, Caspase-6, and Caspase-9 among these groups (P > 0.05).</p><p><b>CONCLUSION</b>Subchronic exposure to B[a]P can induce apoptosis of hippocampal neurons; its mechanism may be related to the fact that B[a]P can induce upregulated expression of Bax, inhibit expression of Bcl-2, lead to decrease in Bcl-2/Bax ratio, induce upregulated expression of Caspase-3 and Caspase-6, and cause increase in the activities of Caspase-3, Caspase-6, and Caspase-9.</p>