Submitted by biblioteca unifenas (biblioteca@unifenas.br) on 2017-08-24T13:10:32Z No. of bitstreams: 1 Carolina Soares Horta de Souza.pdf: 898395 bytes, checksum: 8025b51d63570bf92cd6485289fa3c65 (MD5) / Made available in DSpace on 2017-08-24T13:10:32Z (GMT). No. of bitstreams: 1 Carolina Soares Horta de Souza.pdf: 898395 bytes, checksum: 8025b51d63570bf92cd6485289fa3c65 (MD5) Previous issue date: 2015-02-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The addition of the food coloring plays an important role in the food industry under the technological point of view. Natural dyes are difficult to navigate in standard products, so we were created synthetic dyes. Among artificial synthetic dyes allowed by law, are those of azo group and its use is one of the most controversial developments in the sector. The use of these substances is still raising a lot of questions as to toxicity, because in the literature, working with this momentum is limited and controversial. In this context, the aim, with this study was to evaluate the genotoxic potential of azo dyes by the micronucleus assay (MN). The MN test is widely used and internationally accepted for evaluation of mutagenic actions. The in vivo genotoxicity test was applied to research observed in erythrocytes Polychromatic (PCE) extracted from the bone marrow of the femur 168 Swiss mice Albinus, male and female, underwent five treatments (N-nitroso-N-ethylurea: control+; 150 mM NaCl: Control–; dye at 1, 1.5 and 2 g.Kg-1) and used four azo dyes (Tartrazine, Sunset Yellow, Red 40, Ponceau 4R) for 24h and 48h (after this time euthanasia was performed). We analyzed also the PCE/NCE ratio, which it is an important marker of cytotoxicity. The data obtained in the MN assay were subjected to analysis of one-way variance (ANOVA) using a factorial scheme of 5 × 2 × 2 (treatment × sex × time), and average compared to Tukey's test (p < 0.05) using SAS® software version 9.3. The dye Tartrazine showed genotoxicity dose- and sex-dependent; Sunset Yellow was genotoxic sex-independent; Red 40, its genotoxicity was dependent on the exposure time and the sex of the animal; the dye Ponceau 4R genotoxicity depends on the dose and time until euthanasia. However, it can be concluded that studies of these food additives often must be performed in order to constantly update data that are safe for consumption, since all four dyes tested in this study showed some degree of toxicity. Recalling that they have the use regulated by specific legislation establishing the Maximum Allowable Limits (LMP) and patterns of Acceptable Daily Intake for humans, extrapolated to animals. However, despite the control required by regulatory agencies, the use of dyes in food continues to raise a number of questions, mainly due to lack of studies evaluating the toxicity of these compounds which reinforces the attention they should be given. / A adição de corantes em alimentos e rações assume papel importante na indústria alimentícia sob o ponto de vista tecnológico. Corantes naturais são difíceis de serem utilizados em produtos padronizados, portanto, foram criados corantes sintéticos. Dentre os corantes sintéticos artificiais permitidos por lei, estão aqueles do grupo Azo e seu uso é um dos avanços mais controversos no setor. A utilização destas substâncias continua levantando uma série de dúvidas quanto à toxicidade, uma vez que, na literatura, trabalhos com esse ímpeto são escassos e controversos. Neste contexto, objetivou-se, com este trabalho, avaliar o potencial genotóxico de corantes azóicos através do ensaio de micronúcleo (MN). O teste do MN é amplamente utilizado e aceito internacionalmente para avaliação de ações mutagênicas. O teste in vivo foi aplicado para investigação de genotoxicidade observada em Eritrócitos Policromáticos (PCE) extraídos da medula óssea do fêmur de 168 camundongos Swiss albinus, machos e fêmeas, submetidos a cinco tratamentos (N-Nitroso-N-etilureia: controle+; 150 mM NaCl: controle–; corante a 1, 1,5 e 2 g.Kg-1), sendo utilizados quatro corantes azóicos (Tartrazina, Amarelo Crepúsculo, Vermelho 40, Ponceau 4R) nos tempos de 24h e 48h (após estes períodos foi executada eutanásia). Foi analisada também a relação PCE/NCE, cujo se trata de um importante biomarcador de citotoxicidade. Os dados obtidos no ensaio de MN foram submetidos à análise de variância (ANOVA), utilizando um esquema fatorial de 5 × 2 × 2 (tratamento × sexo × tempo), e comparação das médias pelo teste de Tukey (p < 0,05) usando o programa computacional SAS® versão 9.3. O corante Tartrazina apresentou genotoxicidade dose e sexo dependentes; Amarelo Crepúsculo foi genotóxico independente do sexo; Vermelho 40, a sua genotoxicidade foi dependente do tempo de exposição e do sexo do animal; a genotoxicidade do corante Ponceau 4R foi dependente da dose administrada e do tempo até a eutanásia. Contudo, pode-se concluir que estudos envolvendo estes aditivos alimentares devem ser realizados frequentemente com a finalidade de atualização constante de dados que ofereçam segurança para seu consumo, uma vez que todos os quatro corantes testados nesta pesquisa apresentaram algum grau de toxicidade. Lembrando que os mesmos possuem o uso regulamentado por legislação específica, que estabelece os Limites Máximos Permitidos (LMP) e padrões de Ingestão Diária Aceitável por humanos, extrapolados para animais. Porém, apesar do controle exigido pelas agências reguladoras, a utilização de corantes em alimentos continua levantando uma série de dúvidas, principalmente devido a escassez de trabalhos avaliando a toxicidade destes compostos o que reforça a atenção que lhes deve ser conferida.

Made available in DSpace on 2016-07-18T17:53:11Z (GMT). No. of bitstreams: 1 Mariliza.pdf: 910731 bytes, checksum: 21aa8bdaf81f9c020e8cdee92ae30dcb (MD5) Previous issue date: 2013-03-26 / Studies with some local anesthetics showed that these can cause genetic damage. But local anesthetics has not been tested against the genotoxicity of repeated use. Objective: The aim of this study was to evaluate the genotoxic potential of local anesthetics with single dose and repeated, through the micronucleus test. Methods: We used 80 Wistar rats, male, 12 weeks old, divided into 6 groups: A - 16 rats received lidocaine hydrochloride intraperitoneally (4.4 mg / kg), B - 16 rats received 3% mepivacaine intraperitoneally (4.4 mg / kg), C - 16 rats received 4% articaine intraperitoneally (7.0 mg / kg) D - 16 rats received prilocaine 3% intraperitoneally (6.0 mg / kg) E - 08 rats received cyclophosphamide in single subcutaneous dose (50mg/kg) (positive control group) F - 08 rats received 0.5 ml of saline intraperitoneally (negative control group). Eight rats from Group A, B, C and D received the dose of anesthetic only once at the first day of the experiment and the remainder were dosed daily for five days. The Kruskal-Wallis test followed by a multiple comparisons Student-Newman-Keuls test was used for statistical analysis. Results: The median of micronuclei in the lidocaine group exposed for 1 day was 1.00 and by 5 days was 0.50, mepivacaine for 1 day and for 5 days was 1.00, articaine for 1 day was 1.00 and for 5 days 0.00, prilocaine for 1 day and 5 days was 0.00, cyclophosphamide was 10.00 and the negative control group exposed for 1 day was 1.00 and exposed for 5 days was 0.00 (p<0.0001). There was a statistical difference between the number of micronuclei in relation to the positive control group and all local anesthetics studied (related to the anesthetic type and duration of exposure) (p=0.0001) but not for the negative control group (p>0.05). Conclusion: There was no increase in micronuclei frequency in relation to exposure to 1 or 5 days in all local anesthetics evaluated. / Estudos com alguns anestésicos locais mostraram que estes podem causar dano genético. Porém ainda não foi testada a genotoxicidade frente ao uso repetido destes. Objetivo: O objetivo deste estudo foi avaliar o potencial genotóxico de anestésicos locais em dose única e repetida, por meio do teste de micronúcleo em ratos Wistar. Material e métodos: Foram utilizados 80 ratos Wistar, machos, com 12 semanas, divididos em 6 grupos: A 16 ratos receberam cloridrato de lidocaína via intraperitoneal (4,4 mg/kg); B 16 ratos receberam mepivacaína a 3% via intraperitoneal (4,4 mg/kg); C 16 ratos receberam articaína a 4% via intraperitoneal (7,0 mg/kg); D 16 ratos receberam prilocaína a 3% via intraperitoneal (6,0 mg/kg); E 08 ratos receberam ciclofosfamida em dose única subcutânea (50mg/kg) (grupo controle positivo); F 08 ratos receberam 0,5ml de soro fisiológico via intraperitoneal (grupo controle negativo). Oito ratos do grupo A, B, C e D receberam a dose do anestésico apenas uma vez no primeiro dia do experimento e os demais receberam doses diárias durante cinco dias. O teste de Kruskal-Wallis, seguido das comparações múltiplas de Student-Newman-Keuls, foi utilizado para análise estatística. Resultados: A mediana de micronúcleos no grupo exposto a Lidocaína por 1 dia foi de 1.00 e por 5 dias foi de 0.50, a Mepivacaína por 1 dia e por 5 dias foi de 1.00, a Articaína por 1 dia 1.00 e por 5 dias 0.00, a Prilocaína por 1 dia e por 5 dias 0.00, a ciclofosfamida foi 10.00 e no grupo de controle negativo exposto por 1 dia foi 1,00 e no exposto por 5 dias foi de 0,00 (p<0,0001). Houve diferença estatística entre o número de micronúcleos em relação ao grupo controle positivo e todos os anestésicos locais estudados (quanto ao tipo e tempo de exposição) (p=0,0001), porém não em relação ao grupo controle negativo (p>0,05). Conclusão: Não foi observado aumento da frequência de micronúcleos com relação à exposição de 1 ou 5 dias em todos os anestésicos locais avaliados.

Made available in DSpace on 2016-07-18T17:53:13Z (GMT). No. of bitstreams: 1 Gustavo Logar.pdf: 371330 bytes, checksum: 461b03ba76909955dcf6db3c8b004b60 (MD5) Previous issue date: 2014-05-23 / The Biodentine is a new material suitable for various clinical situations in dentistry. Despite being a promising material, there are few studies evaluating the characteristics of this material, especially its genotoxicity and mutagenicity. Objective: This study aims to evaluate the genotoxic and mutagenic potential of Biodentine "in vivo". Methods: We used 24 Wistar albino rats, males were divided into 3 groups: A - 8 rats where specimens of Biodentine measuring 2 mm in diameter x 10mm length on the dorsum were placed, B - 8 rats, which received cyclophosphamide in single subcutaneous dose (50mg/kg) on the first day of the experiment (positive control group), C - 8 rats where specimens measuring 2 mm in diameter x 10mm long without Biodentine on the dorsum were placed (negative control group). After 24 hours, all animals were euthanized and material from bone marrow of femurs was collected to perform the Comet assay and micronucleus test. Results: Biodentine showed levels of DNA damage (tail intensity %) in bone marrow cells of 23.57 ± 7.70, cyclophosphamide of 27,43 ± 7,40 and negative control of 24.75 ± 5 55 (p < 0.05). The average number of micronuclei in the exposed Biodentine group was 6.25 (standard deviation - SD = 3.53), in the group exposed to cyclophosphamide was 9.75 (SD = 2.49) and negative control group was 0.75 (SD = 1.03) (p < 0.0001). Conclusion: The Biodentine showed an increase in the frequency of micronuclei, but no genotoxicity effect by the Comet assay. / O Biodentine é um novo material indicado para diversas situações clínicas na odontologia. Apesar de ser um material promissor, ainda há poucos trabalhos avaliando as características deste material, em especial sua genotoxicidade e mutagenicidade. Objetivo: Este estudo visa avaliar o potencial genotóxico e mutagênico do Biodentine in vivo . Material e métodos: Foram utilizados 24 ratos Wistar albinos, machos, distribuídos em 3 grupos: A 8 ratos onde foram colocados corpos de prova medindo 2mm de diâmetro x 10mm de comprimento com Biodentine no subcutâneo do dorso; B 8 ratos, que receberam ciclofosfamida em dose única subcutânea (50mg/kg) no primeiro dia do experimento (grupo controle positivo); C 8 ratos onde foram colocados corpos de prova medindo 2mm de diâmetro x 10mm de comprimento sem Biodentine no subcutâneo do dorso (grupo controle negativo). Após 24 horas, todos os animais foram eutanasiados e material da medula óssea dos fêmures foi coletado para realização do Teste do Cometa e do Teste do micronúcleo. Resultados: O Biodentine apresentou níveis de danos no DNA (tail intensity %) em células da medula óssea de 23,57 ± 7,70, a ciclofosfamida de 27,43 ± 7,40 e o controle negativo de 24,75 ± 5,55 (p<0,05). A média de micronúcleos no grupo exposto ao Biodentine foi de 6,25 (desvio padrão DP= 3,53), no grupo exposto a ciclofosfamida foi de 9,75 (DP= 2,49) e no grupo de controle negativo foi 0,75 (DP= 1,03) (p<0,0001). Conclusão: O Biodentine apresentou aumento na frequência de micronúcleos, mas não apresentou efeito genotóxico observado pelo teste do Cometa.

Submitted by Adriana Martinez (amartinez@unoeste.br) on 2017-08-03T20:13:27Z No. of bitstreams: 1 Jamile Tomiazzi.pdf: 1140169 bytes, checksum: 85ab1353f7aab9dbdd62efcda0bc0e0c (MD5) / Made available in DSpace on 2017-08-03T20:13:27Z (GMT). No. of bitstreams: 1 Jamile Tomiazzi.pdf: 1140169 bytes, checksum: 85ab1353f7aab9dbdd62efcda0bc0e0c (MD5) Previous issue date: 2017-03-27 / The growing increase in the use of agrochemicals by small and large rural producers has generated environmental impacts and in the health of the exposed population. Another relevant public health problem, whose adverse effects have been widely documented, is smoking. Studies have indicated that isolate exposure to these xenobiotics can lead to ototoxicity and genotoxicity. Thus, the objective of this study was to evaluate the possible auditory and cytogenetic alterations in rural workers exposed to smoking and agrochemicals in isolation or in combination and to identify possible classification patterns of exposure groups. Were evaluated 127 workers of both sexes, with ages ranging from 18 to 39 years, divided into four groups: Control Group - CG; Group exposed to smoking - GT; Group exposed to agrochemicals - GA and Group exposed to the association between smoking and agrochemicals - GTA. Initially, a questionnaire was used to measure the exposure to the study compounds and general and auditory health. Auditory examinations (meatoscopy, conventional and high-frequency audiometry, logoaudiometry and imitanciometry) and cytogenetic evaluation (from cells of the bucal mucosa, stained by Giemsa method) were performed. The data were evaluated by the following pattern recognition algorithms Artificial Neural Network (ANN), Bayes Classifier (BAY) and Support Vector Machine (SVM). The results of the audiological evaluation demonstrated a lowering of high frequency thresholds, a higher incidence of descending type, type A tympanometry and absence of reflex of the stapedic muscle in the three exposed groups (GT, GA and GTA). In addition, these groups showed an increase in the total number of nuclear alterations and in the number of micronuclei, binucleate cells, karyotype, karynx, pycnotic cells and nuclear bud. The computational analysis did not recognize the GTA group as a real value, as with GT and GA in relation to GC, in which the data were distributed with standard and correctly classified. Therefore, it was concluded that exposure to agrochemicals and cigarettes, in isolation or in combination, has been shown to be potentially ototoxic and genotoxic. However, the concomitant use of xenobiotics did not lead to additive or potentiating effect. / O crescente aumento do uso de agroquímicos por pequenos e grandes produtores rurais tem gerado impactos ambientais e à saúde da população exposta. Outro problema relevante de saúde pública, cujos efeitos adversos têm sido amplamente documentados, é o tabagismo. Estudos têm indicado que a exposição isolada a estes xenobióticos pode levar a ototoxicidade e genotoxicidade. Assim, o objetivo deste estudo foi avaliar as possíveis alterações auditivas e citogenéticas de trabalhadores rurais expostos ao tabagismo e aos agroquímicos de maneira isolada ou em combinação e identificar possíveis padrões de classificação dos grupos de exposição. Foram avaliados 127 trabalhadores de ambos os sexos, com faixa etária de 18 a 39 anos, divididos em quatro grupos: Grupo Controle – GC; Grupo exposto ao tabagismo – GT; Grupo exposto a agroquímicos – GA e Grupo exposto à associação entre tabagismo e agroquímicos - GTA. Inicialmente foi aplicado um questionário, para coleta de dados sobre a exposição aos compostos de estudo e saúde geral e auditiva. Em seguida, foram realizados exames auditivos (meatoscopia, audiometria convencional e de alta frequência, logoaudiometria e imitânciometria) e avaliação citogenética (a partir de células da mucosa bucal, coradas pelo método Giemsa). Os dados foram avaliados pelos seguintes algoritmos de reconhecimento de padrões: Artificial Neural Network (ANN), Bayes Classifier (BAY) e Support Vector Machine (SVM). Os resultados da avaliação audiológica demonstraram rebaixamento de limiares auditivos em alta frequência, maior incidência de curva do tipo descendente, timpanometria tipo A e ausência de reflexo do músculo estapédico nos três grupos expostos (GT, GA e GTA). Além disso, nestes grupos foi observado aumento do número total de alterações nucleares e no número de micronúcleos, células binucleadas, cariólise, cariorréxis, células picnóticas e broto nuclear. A análise computacional não reconheceu o grupo GTA como um valor real, como ocorreu com GT e GA em relação ao GC, onde os dados foram distribuídos com padrão e classificadas corretamente. Diante disso, concluiu-se que a exposição a agroquímicos e cigarro, de maneira isolada ou em combinação, demonstrou ser potencialmente ototóxica e genotóxica. No entanto, o uso concomitante dos xenobióticos não levou a efeito aditivo ou de potencialização.

The presented doctoral thesis is focused on preparation of nanoparticles and nanofibers with natural active ingredient and testing their biological effects. Modern types of application forms were prepared from biomaterials based on one or more natural polymers. Chitosan particles were prepared from cross-linked polymer using ultrasonication. A mixture of soy lecithin and cholesterol was used for preparation of liposomes. Poly-3-hydroxybutyrate was used for preparation of combined liposomes, too. All liposome particles were prepared by ultrasonication. Nanofibers were obtained from polyhydroxybutyrate using electrospinning. Mixtures of low-molecular antioxidants obtained by extraction from natural sources were used as active ingredients. Different types of teas, barks, herbs, spices, fruits and vegetables were selected as sources of natural antioxidants. Total phenolic and flavonoid content and total antioxidant activity of extracts were determined using spectrophotometrical methods. Obtained natural extracts were subsequently used for encapsulation. Prepared application forms were characterized in terms of their physicochemical properties. Particle size was monitored by dynamic light scattering. Colloidal stability of particles in suspension was determined using zeta potential. Spectrophotometry was used to evaluate the efficiency of encapsulation of active compounds into particles. The morphology of the new type of combined PHB liposomes was monitored by electron microscopy. Chromatography was used for quantification of individual components of particles. Morphology of nanofibers and incorporation of active agent into their structure were monitored using FTIR-ATR spectroscopy and electron microscopy. Afterwards, antimicrobial, cytotoxic and genotoxic effects of preparations were evaluated. It was found that the most suitable types of extracts for liposome preparation are aqueous and lipid extracts of natural antioxidants. Prepared particles showed excellent stability and good encapsulation efficiency. The study confirmed that incorporation of polydroxybutyrate into liposome structure does not reduce neither the colloidal stability of the particle, nor the efficiency of encapsulation process. Antimicrobial and antimycotic effect of preparations against model microorganisms Micrococcus lutues, Serratia marcescens and Candida glabrata was detected. It was found that process of encapsulation increases the inhibitory effect of natural extracts of antioxidants. The safety of preparations was assessed using two human cell cultures: epidermal keratinocytes and HaCaT cell line. Assays of cell viability and plasma membrane integrity were used to determine cytotoxicity of preparations. Low toxicity of liposome particles was confirmed by a series of cytotoxic tests. Obtained data showed that association of phospholipid with PHB polymer does not cause a significant increase in cytotoxicity in human skin cells. Genotoxicity testing on model procaryotic organism confirmed zero genotoxic potential of preparations. The new type of combined particles and polymeric fibers cant thus be used as a carrier for active ingredients, complex natural extracts, antimicrobial agents and many others.

Orientador: Maria Aparecida Marin-Morales / Resumo: O crescente aumento das atividades antrópicas vem promovendo um aumento nos impactos causados ao meio ambiente. Dentre essas atividades humanas, a mineração, realizada no Brasil desde o século XVII e persistindo até os dias atuais, tem se destacado, quanto à sua potencialidade de causarem danos ambientais. O estado de Minas Gerais é um grande produtor de ouro e nele está localizado o município de Paracatu, onde se encontra a mina Morro do Ouro, que é considerada uma grande lavra a céu aberto, situada a poucos metros do perímetro urbano. Diante deste cenário, o presente estudo tem por objetivo avaliar a biodisponibilidade dos metais presentes nas amostras, as fontes poluidoras envolvidas com a contaminação desses metais e os riscos que esses metais promovem ao meio ambiente, por meio das análises químicas, extrações sequenciais e cálculos de Fator de Enriquecimento (EF), Índice de geoacumulução (Igeo) e Avaliação de Risco (RAC) e o potencial tóxico das amostras, por meio de bioensaios in vivo (Allium cepa e Lactuca sativa) e in vitro (cultura celular humana – HepG2/C3A). Para a avaliação do comprometimento dos rios que recebem influência da mineradora, foram coletadas amostras de água superficiais e de sedimentos de 3 regiões distintas: 1) jusante da mina Morro do Ouro, onde está localizado o município de Paracatu (P1, P2 e P3); 2) jusante da barragem de rejeitos da mina Morro do Ouro (P4, P5 e P6) e 3) rio de captação de água para abastecimento público de Paracatu (P7) e água... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The increase of anthropic activities has been promoting an impact increase to the environment. Among these human activities, mining, conducted in Brazil since the XVII century, has stood out for its potential to cause environmental damage. The Morro do Ouro mine, located in Paracatu (state of Minas Gerais, considered a major gold producer) is a large open mining located a few meters from the urban perimeter. According to this scenario, the present study aims to evaluate the bioavailability of the metals present in the samples, the polluting sources involved with the contamination of these metals and the risks that these metals promote to the environment by chemical analysis, sequential extractions and calculations of Enrichment Factor (EF), Geoaccumulation Index (Igeo) and Risk Assessment (RAC) and the toxic potential of samples by in vivo (Allium cepa and Lactuca sativa) and in vitro bioassays (human cell culture - HepG2 / C3A).To evaluate the impact of rivers that receive influence from the mining company, surface water and sediment samples were collected from 3 different regions: 1) downstream of the Morro do Ouro mine, located in Paracatu (P1, P2 and P3); 2) downstream of the Morro do Ouro tailings dam (P4, P5 and P6) and 3) Paracatu water supply river (P7) and water supply provided by Paracatu WTS (Water Treatment Station) (P8). Afterwards, two extracts of eachcollected sediments (solubilized and leached) were prepared. The results demonstrated that this region is highly... (Complete abstract click electronic access below) / Doutor

Les hydrocarbures aromatiques polycycliques (HAPs), tels que le benzo(a)pyrène (B[a]P), sont des contaminants environnementaux ubiquistes générés lors de la combustion de matière organique. Ces composés ont été associés au développement d'effets toxiques sur la santé humaine, notamment des effets cancérigènes et immunotoxiques, principalement liés à l'activation du récepteur aux hydrocarbures aromatiques (RAh). Parmi les cellules du système immunitaire, les lymphocytes T apparaissent comme des cibles majeures des HAPs. Des résultats antérieurs, obtenus au laboratoire, ont montré que l'activation des lymphocytes T humains en culture primaire conduit à l’augmentation de l'expression et de la fonction du RAh, suggérant la capacité accrue de ces cellules à répondre à une exposition aux HAPs. Nos objectifs sont : (1) de déterminer les effets du B[a]P sur les profils d'expression génique dans les lymphocytes humains normaux en utilisant des approches à haut débit telle que l'analyse transcriptomique sur puce à ADN, (2) d’évaluer les effets génotoxiques et immunotoxiques du B[a]P en mesurant respectivement les dommages à l'ADN induits et leurs actions immunosuppressives et (3) d’analyser la modulation de ces effets en présence d'autres HAPs. Notre travail identifie les lymphocytes T humains normaux comme un bon modèle pour étudier les effets génotoxiques et immunotoxiques des HAPs, et pour prédire les problèmes de santé humaine liés à l’exposition à ces contaminants. Il permet également de mieux comprendre la régulation par les HAPs de la réponse immune et propose de nouveaux biomarqueurs potentiels de l'exposition à ces contaminants environnementaux. / Polycyclic aromatic hydrocarbons (PAHs), such as benzo(a)pyrene (B[a]P), are ubiquitous environmental contaminants generated during organic matter combustion. These compounds have been associated with the development of toxic effects on human health, including carcinogenic and immunotoxic effects, mainly related to Aryl hydrocarbon Receptor (AhR) activation. Among the immune system cells, T lymphocytes appear as major targets of PAHs. Previous results, obtained in the laboratory, have shown that activation of primary human T lymphocytes leads to a functional AhR expression increase, suggesting their ability to respond to PAH exposure. Our specific aims are: (1) to determine the effects of B[a]P on gene expression profiles in human normal lymphocytes by using large-scale approaches such as microarray-based transcriptome analysis, (2) to monitor the genotoxic and immunotoxic effects of B[a]P by measuring DNA damage and immunosuppressive actions, respectively and, (3) to analyze the modulation of these effects by the presence of other PAHs. Our work propose primary cultures of activated human T lymphocytes as a good model for studying both genotoxic and immunotoxic effects of environmental contaminants such as PAHs and predicting human health issues. It also gains a comprehensive insight into the immune response regulation after PAH exposure and provides potential new biomarkers of exposure to these environmental contaminants.

Les êtres humains sont constamment confrontés à des agents génotoxiques issus de l’environnement ou liés aux activités humaines. Ces agents induisent différents types de lésions sur l’ADN et peuvent conduire à un risque accru de développer des cancers. Pour préserver son intégrité génétique, la cellule possède divers mécanismes de réparation permettant leur élimination. L’impact de ces agents exogènes sur l’organisme a conduit à l’émergence d’un nouveau domaine, la biosurveillance. Elle vise à évaluer l’exposition des individus par l’identification d’indicateurs biologiques de l’exposition. Cependant, à ce jour, une des limites principales dans ce domaine est le manque de méthodes et de biomarqueurs disponibles. Afin de définir de nouveaux biomarqueurs, les conséquences de l’exposition de deux agents cancérigènes reconnus, le benzo[a]pyrène et le chlorure de vinyle, ainsi que leurs métabolites toxiques ont été évaluées dans deux modèles cellulaires. Pour cela, deux méthodes ont été utilisées : la chromatographie liquide haute performance couplée à la spectrométrie de masse pour la quantification des lésions formées ainsi qu’un test de mesure des activités enzymatiques de réparation développé par la société LXRepair. Cette approche permet d’appréhender de manière globale l’exposition à ces composés en étudiant différents paramètres comme le seuil de déclenchement, la variabilité ainsi que la spécificité de la réponse cellulaire. L’étude a montré la difficulté de mettre en évidence une réponse spécifique à un agent donné. Cependant, les profils de réparation obtenus ont souligné la complexité des régulations mises en jeu et permettent de soulever de nouvelles pistes de recherches. / Humans are constantly exposed to environmental genotoxic agents. These agents can induce different types of DNA damage, which have been associated with an increased risk of developing cancer. In order to maintain genomic integrity, cells have multiple DNA repair mechanisms that help protect their DNA from injury. Investigation of the impact of these exogenous genotoxic agents on individuals leads to the emergence of a new field, biomonitoring. This field allows researchers to evaluate individual exposure to genotoxic agents based on the detection of biological markers of exposure. However, up to now, the major limitations in this area are the lack of relevant biomarkers, as well as the availability of methods to detect them. In order to define new biomarkers, two cell lines were exposed to two well-known carcinogenic compounds, benzo[a]pyrene and vinyl chloride, as well as their toxic metabolites, in order to determine the consequences of these exposures. Two methods were used: DNA lesions were quantified by HPLC-MS/MS and DNA repair activities were evaluated using a microarray assay developed by the start-up company, LXRepair. This approach allowed us to gain a global understanding related to the exposure of these compounds by considering different parameters, such as the specificity of different cellular responses to a given genotoxic agent and the minimum concentration needed to observe an effect with respect to its toxicity. This study underlines the complexity to obtain specific cellular responses to a given genotoxic agent. However, DNA repair signatures bring on the intricacy of the regulations of DNA repair mechanisms and open up new research avenues.

This review focuses on the roles antioxidants and pro-oxidants in colorectal cancer (CRC). Considerable evidence suggests that environmental factors play key roles in the incidence of sporadic CRC. If pro-oxidant factors play an etiological role in CRC it is reasonable to expect causal interconnections between the well-characterized risk factors for CRC, oxidative stress and genotoxicity. Cigarette smoking, a high dietary consumption of n-6 polyunsaturated fatty acids and alcohol intake are all associated with increased CRC risk. These risk factors are all pro-oxidant stressors and their connections to oxidative stress, the intestinal microbiome, intestinal microfold cells, cyclooxygenase-2 and CRC are detailed in this review. While a strong case can be made for pro-oxidant stressors in causing CRC, the role of food antioxidants in preventing CRC is less certain. It is clear that not every micronutrient with antioxidant activity can prevent CRC. It is plausible, however, that the optimal food antioxidants for preventing CRC have not yet been critically evaluated. Increasing evidence suggests that RRR-gamma-tocopherol (the primary dietary form of vitamin E) or other "non-alpha-tocopherol" forms of vitamin E (e.g., tocotrienols) might be effective. Aspirin is an antioxidant and its consumption is linked to a decreased risk of CRC.

This project focuses on two important topics which may pose hazards to human health. Firstly, drinking water disinfection by-products (DBPs), which are generated by the chemical disinfection of water have been investigated. What has not been shown is the effect of DBPs in human germ cells as well as somatic cells and whether oxidative stress is involved in the mechanism of genotoxic action. Three different DBPs (halo acetic acids: HAAs), together with the antioxidants – catalase and butylated hydroxyanisole (BHA), were investigated in peripheral blood cells and sperm from healthy individuals using the Comet assay and lymphocytes only using the micronucleus assay. Secondly, nanoparticles of the non-steroidal anti-inflammatory drugs (NSAIDs), aspirin and ibuprofen, have been investigated in patients with respiratory diseases, in the micronucleus assay and the Comet repair assay. NSAIDs inhibit cyclooxygenase enzyme activity, which plays part in tumour progression. In the Comet assay, BHA and catalase were able to reduce DNA damage in both cell types compared to HAAs alone. Similarly, in the micronucleus assay, micronuclei were reduced with the antioxidants, suggesting oxygen radical involvement in both assays. With the NSAIDs, reductions were seen for DNA damage in the micronucleus assay with aspirin and ibuprofen nanoparticles compared to their bulk forms. Using the Comet repair assay, aspirin and ibuprofen nanoparticles aided repair of DNA to a greater extent than their bulk counterparts, which in turn showed better repair compared to samples repaired without NSAIDs. These observations show the importance of DBPs and NSAIDs in genotoxic public health issues. / United Kingdom India Education and Research Initiative (UKIERI).