Proefschrift Rijksuniversiteit Limburg, Maastricht. / Met bibliogr., lit. opg. - Met samenvatting in het Nederlands.

Proefschrift Rijksuniversiteit Limburg, Maastricht. / Met bibliogr., lit. opg. - Met een samenvatting in het Nederlands.

Texte remanié de: Th. Ph. D.--Utrecht--Rijksuniversiteit te Utrecht, 1988. / Bibliogr. p. 233-242. Index.

Resumo: O presente projeto objetivou investigar os efeitos da combinação, em baixas doses, de cinco praguicidas (dieldrin, dicofol, endosulfan, diclorvos e permetrina) sobre o sistema reprodutor de ratas Sprague-Dawley, Wistar e Lewis. Ratas de cada linhagem, com seis semanas de idade, foram randomizadas em três grupos: GI: controle negativo; GII: praguicidas adicionados à ração em doses de NOEL (mg/Kg/dia) - diclorvos (0,23), dicofol (0,5), dieldrin (0,025); endosulfan (0,7), permetrina (5); GIII: praguicidas adicionados à ração em doses de LOEL (mg/Kg/dia) - diclorvos (2,3), dicofol (2,1), dieldrin (0,05), endosulfan (3,8), permetrina (25). A eutanásia foi realizada entre a 10ª e a 12ª semana experimental, na fase de estro. Os parâmetros de avaliação foram: peso de fígado, útero e ovários; análise histológica qualitativa de fígado, útero e ovários; morfometria do endométrio; avaliação do ciclo estral; dosagem de LH, FSH e progesterona; e contagem de folículos ovarianos. Animais das três linhagens tratados com a LOEL apresentaram toxicidade sistêmica, evidenciada pela diminuição de peso corpóreo e aumento de peso de fígado. A análise qualitativa de útero e ovários, assim como a avaliação do ciclo estral e níveis hormonais não indicaram sinais de toxicidade reprodutiva exercida pelas misturas. A contagem de folículos ovarianos indicou ausência de resposta dose dependente e alta variabilidade entre os animais de mesmo grupo experimental. Desta forma concluímos que, embora os resultados tenham mostrado diminuição de algumas populações foliculares nas doses de NOEL e LOEL, este parâmetro não pode ser utilizado isoladamente como indicativo de toxicidade reprodutiva. Estes achados remetem à necessidade de maiores estudos para o esclarecimento dos efeitos destes compostos nas populações foliculares / Abstract: This project aimed to investigate the effects of the combination, in low doses, of five pesticides (dieldrin, dicofol, endosulfan, dichlorvos and permethrin) on the reproductive system of Sprague- Dawley, Wistar and Lewis rats. Six-weeks-old rats from each strain were randomized into three groups: GI: negative control; GII: pesticides added to the feed at NOEL doses (mg/kg/day) - dichlorvos (0.23), dicofol (0.5), dieldrin (0.025), endosulfan (0.7), permethrin (5), GIII: pesticides added to the feed at LOEL doses (mg / kg / day) - dichlorvos (2.3), dicofol (2.1), dieldrin (0.05), endosulfan (3.8), permethrin (25). Euthanasia was performed between the 10th and 12th experimental week, in the estrous stage. The evaluation parameters were: weight of liver, uterus and ovaries; qualitative histological analysis of liver, uterus and ovaries; endometrium morphometry; estrous cycle assessment; dosage of LH, FSH and progesterone; and counting of ovarian follicles. Animals from all three strains showed systemic LOEL toxicity, as evidenced by decreased body weight and increased liver weight. Qualitative analysis of the uterus and ovaries, as well as estrous cycle and hormone levels evaluations indicated no signs of reproductive toxicity exerted by the mixtures. Counting of ovarian follicles indicated lack of dose-dependent response and high variability among animals from the same experimental group. Hence, we concluded that, although our results have shown a decrease of some follicular populations at the NOEL and LOEL doses, this parameter can not be used alone as an indicator of reproductive toxicity. These findings underscore the need for more studies to clarify the effects of these compounds on follicular populations / Orientador: Noeme Sousa Rocha / Coorientador: Carla Adriene da Silva Franchi / Banca: Clarissa Scolastici / Banca: Antonio Francisco Godinho / Mestre

abstract: Spinal cord injury (SCI) disrupts the communication between supraspinal circuits and spinal circuits distal to the injury. This disruption causes changes in the motor abilities of the affected individual, but it can also be used as an opportunity to study motor control in the absence or limited presence of control from the brain. In the case of incomplete paraplegia, locomotion is impaired and often results in increased incidence of foot drag and decreased postural stability after injury. The overall goal of this work is to understand how changes in kinematics of movement and neural control of muscles effect locomotor coordination following SCI. Toward this end, we examined musculoskeletal parameters and kinematics of gait in rats with and without incomplete SCI (iSCI) and used an empirically developed computational model to test related hypotheses. The first study tested the hypothesis that iSCI causes a decrease in locomotor and joint angle movement complexity. A rat model was used to measure musculoskeletal properties and gait kinematics following mild iSCI. The data indicated joint-specific changes in kinematics in the absence of measurable muscle atrophy, particularly at the ankle as a result of the injury. Kinematic changes manifested as a decrease in complexity of ankle motion as indicated by measures of permutation entropy. In the second study, a new 2-dimensional computational model of the rat ankle combining forward and inverse dynamics was developed using the previously collected data. This model was used to test the hypothesis that altered coordination of flexor and extensor muscles (specifically alteration in burst shape and timing) acting at the ankle joint could be responsible for increases in incidence of foot drag following injury. Simulation results suggest a time course for changes in neural control following injury that begins with foot drag and decreased delay between antagonistic muscle activations. Following this, beneficial adaptations in muscle activation profile and ankle kinematics counteract the decreased delay to allow foot swing. In both studies, small changes in neural control caused large changes in behavior, particularly at the ankle. Future work will further examine the role of neural control of hindlimb in rat locomotion following iSCI. / Dissertation/Thesis / Ph.D. Bioengineering 2012

Subterranean rodents are interesting model group for studying of the circadian timing system due to their cryptic lifestyle and challenging living conditions. The filed data indicate that the locomotor activity of the silvery mole-rat (Heliophobius argenteocinereus) is influenced by temperature cycle, but the confirmation in laboratory study was to date missing.

O transplante de hepatócitos é uma modalidade terapêutica atrativa para as doenças hepáticas, assim como uma alternativa para o transplante hepático. O objetivo do presente estudo é investigar a efetividade do transplante de hepatócitos de ratos nos modelos de hepatotoxicidade aguda induzida por paracetamol (1g/kg e 1,5g/kg). Os hepatócitos foram isolados de ratos Wistar machos e transplantados 24 horas após em receptoras fêmeas com hepatotoxicidade de 1g/kg. Os ratos fêmeas receberam 1x107 hepatócitos (grupo 1, n=20) ou PBS (grupo 2, n=24) através da veia porta ou no baço. A análise de sobrevida em 3 dias demonstrou que todos os animais do grupo 1 sobreviveram, enquanto 5 animais do grupo 2 morreram (P=0,03), todas as mortes ocorreram nos ratos que receberam PBS através da veia porta (P=0,001). Os níveis de alanina aminotransferase e fator V que foram medidos no experimento não mostraram diferença entre o grupo 1 e o grupo 2 em nenhum momento. A análise molecular e a histologia mostraram a presença de hepatócitos no fígado de animais transplantados através da veia porta ou pelo baço. O modelo de hepatotoxicidade aguda induzida por paracetamol (1g/kg) demonstrou que o transplante de hepatócitos de ratos aumenta a sobrevida quando o local de injeção é na veia porta. No modelo de hepatotoxicidade aguda induzida por paracetamol (1,5g/kg), os hepatócitos foram isolados de ratos Wistar machos, e transplantados 6 horas após em receptoras fêmeas. Os ratos fêmeas receberam 1x107 hepatócitos (grupo 1, n=33) ou PBS (grupo 2, n=24) no baço. A análise de sobrevida em 3 dias demonstrou que 9 animais do grupo 1, e 9 animais do grupo 2 morreram no dia 2. Não houve diferença estatística significativa na análise de sobrevida entre o grupo 1 e o grupo 2. Nossos dados demonstram que o isolamento de hepatócitos é um procedimento factível. O transplante de hepatócitos é uma técnica que pode ser aplicada em modelos animais de IHA levando ao aumento da sobrevida. Entretanto, o modelo utilizado no presente estudo apresentou um alto grau de variabilidade, tornando necessária a avaliação do transplante de hepatócitos em um modelo mais reprodutível. / Hepatocyte transplantation is an attractive therapeutic modality for liver disease as an alternative for liver transplantation. The aim of the current study was to investigate the effectiveness of rat hepatocyte transplantation in the acetaminophen-induced acute hepatotoxicity models (1g/kg and 1,5g/kg). Hepatocytes were isolated from male Wistar rats and transplanted 24 hours later in female recipients with hepatotoxicity of 1g/kg of acetaminophen. Female rats received either 1x107 hepatocytes (group1, n=20) or PBS (group 2, n=24) through the portal vein or into the spleen. Survival analyses in 3 days showed that all animals from group 1 survived, whereas 5 rats from group 2 died (P=0.03), all deaths occurred in rats that received PBS into the portal vein (P=0.001). Alanine aminotransferase and factor V levels measured within the experiment did not differ between groups 1 and 2 at any time point. Molecular analysis and histology showed presence of hepatocytes in liver of transplanted animals injected either through portal vein or spleen. Our data in acetaminophen-induced hepatotoxicity model (1g/kg) demonstrate that rat hepatocyte transplantation increases survival when the site of injection is into portal vein in this hepatotoxicity model. In the acetaminophen-induced acute hepatotoxicity model (1,5g/kg), hepatocytes were isolated from male Wistar rats and transplanted 6 hours later in female recipients. Female rats received either 1x107 hepatocytes (group1, n=33) or PBS (group 2, n=24) into the spleen. Survival analyses in 3 days showed that 9 rats from group 1 and 9 rats from group 2 died at day 2. There was no statistical significance in survival between group 1 and group 2. Our data demonstrate that hepatocyte isolation is a feasible procedure. Hepatocyte transplantation can be used in animal models of acute liver failure increasing survival. The model of the present study show a higher variability, therefore it´s necessary to evaluate hepatocyte transplantation in a more reproducible model.

Submitted by Ana Maria Fiscina Sampaio (fiscina@bahia.fiocruz.br) on 2012-12-05T19:54:22Z No. of bitstreams: 1 Rhyna Carla da Cunha Costa Avaliação in vitro... 2008.pdf: 63652316 bytes, checksum: b5b47c90094bcc1316f3f0c6a163aa92 (MD5) / Made available in DSpace on 2012-12-05T19:54:22Z (GMT). No. of bitstreams: 1 Rhyna Carla da Cunha Costa Avaliação in vitro... 2008.pdf: 63652316 bytes, checksum: b5b47c90094bcc1316f3f0c6a163aa92 (MD5) Previous issue date: 2008 / Fundação Oswaldo Cruz. Centro de Pesquisas Gonçalo Moniz. Salvador, Bahia, Brasil / Na primeira parte desse estudo, foi avaliada in vitro a influência de 2 diferentes graus de N-acetilação (DA) de matrizes tridimensionais (3D) de quitosana sobre a viabilidade, adesão, distribuição e proliferação de células mesenquimais extraídas da medula óssea de ratos (rBMSC's), assim como, a influência do soro autólogo de rato (RS), sobre os mesmos aspectos, como fonte de proteínas e fatores de crescimento. Para tanto, 10 animais foram utilizados para extração do RS e das rBMSC's. As células foram semeadas e induzidas a osteodiferenciação sobre matrizes 3D de quitosana, com FBS (Soro Fetal Bovino) e sem adição do RS. Na segunda parte dessa análise, foi analisado in vivo o comportamento biológico de matrizes 3D de quitosana para a regeneração óssea, com DA's de 4 e 15%, quando implantadas em defeitos com morfologia e dimensões criticas, criados em calvária de rato. Utilizou-se 80 animais, distribuídos em 4 grupos, com 5 animais cada, avaliados nos pontos biológicos de 7, 15, 45 e 120 dias. Os grupos foram divididos em: Gl Controle - Sem implantação de biomaterial; Gil - Implantação de matriz de quitosana 4%; GUI - Implantação de matriz de quitosana 15%; GIV - Implantação de matriz de colágeno tipo I. Os espécimes foram fixados e incluidos em blocos de resina e cortados em micrótomo de alto impacto, para tecidos não descalcificados e corados em H/E, Picrosírius Red e Tricrómio de Masson Goldner para avaliação histológica em microscopía de Luz. Também, foram confeccionados blocos em parafina para análise imunohistoquímica da formação vascular utilizando-se PECAM-1. Os resultados in vitro demonstraram que as rBMSC's apresentaram-se viáveis quando cultivadas nos 2 tipos de soro. Mais ainda, as rBMSC's aderiram e proliferaram sobre as matrizes de quitosana, em especial sobre a de 4%. Em adição, os achados sugeriram que o RS apresenta as proteínas e fatores necessários para o crescimento das rBMSC's. Quando analisado o comportamento biológico das matrizes 3D in vivo, concluiu-se que, muito embora, as matrizes tenham sido consideradas biocompatíveis, e que tenham tido a sua região central permeada por vasos sangüíneos, não foi encontrada formação óssea de novo nos sítios de implantação. / In the first part of this study, an in vitro evaluation was made of the influence of 2 different grades of N-acetylation (DA) of tridimensional matrixes (3D) of chitosan on the viability, adhesion, distribution and proliferation of mesenchyme cells extracted from the bone marrow of rats (rBMSC's), as well as the influence of autologous rate serum (RS), on the same aspects, as a source of proteins and growth factors. For this purpose, 10 animals were used for the extraction of RS and rBMSC's. The cells were seeded and induced to osteodifferentiate on 3D chitosan matrixes, with FBS (Fetal Bovine Serum) and with the addition of RS. In the second part of this analysis, the biologic behavior of the 3D chitosan matrixes was analyzed in vivo for bone regeneration, with DA's of 4 and 15%, when implanted in defects with critical morphology and dimensions, created in rat calvarlas. Eighty animals distributed into 4 groups with 5 animals in each were used, and evaluated at the biological time points of 7, 15, 45 and 120 days. The groups were divided as follows: Gl Control - Without biomaterial implantation; Gil - Implantation of chitosan matrix at 4%; Gill - Implantation of chitosan matrix at 15%; GIV - Implantation of collagen type I matrix. The specimens were fixed and embedded in blocks of resin, and cut in a high impact microtome for non decalcified tissues, and stained with H/E, Picrosirius Red and Goldner’s Masson Trichrome for histomorphometric evaluation under light microscopy. Paraffin blocks were also made for immunohistochemical analysis of the vascular formation, using PECAM-1. The results in vitro demonstrated that the rBMSC's presented as viable when cultivated in the 2 types of serum. Furthermore, the rBMSC's adhered and proliferated on the chitosan matrixes, especially on the one with 4%. In addition, the findings suggest that RS presents the proteins and growth factors necessary for the growth of the rBMSC's. When the biologic behavior of the 3D matrixes were analyzed in vivo, it was concluded that although the matrixes had been considered biocompatible, and also had their central regions permeated by blood vessels, no de novo bone formation was found at the implantation sites.

Until recently, it was assumed that African mole-rats search for food randomly, as it is in concordance with Aridity food distribution hypothesis. However, recent studies indicate that some subterranean rodent species including mole-rats could be able to use plant chemicals (kairomones) for food localization. In my master thesis I conducted a battery of experiments on four mole-rat species to prove, that these species also posses the ability of kairomone guided foraging independently of their social organization.

Life underground is one of the most challenging tasks for animals. The subterranean environment is seasonally and diurnally stable and provides shelter from predators. On the other hand food is scarce, the cost of digging is very high and closed burrows create hypoxic and hypercapnic conditions. Thus the physiological and behavioral adaptations to save energy are very important for underground dwellers. Social thermoregulation is such behavioral adaptation. Additionally, it has been suggested that social animals suffer from ?isolation stress? and that they decrease their metabolic rates when other family members are present = socio-physiological effect. In this study I measured the resting metabolic rates (RMR) of social Mashona mole-rats (Fukomys darlingi) in isolated individuals, pairs and groups of three to eight individuals. Measurements were carried out at two ambient temperatures, in the thermoneutral zone (TNZ; 30°C) to test the presence of a socio-physiological effect and below their TNZ (20°C) to test the effect of social thermoregulation. A socio-physiological effect was distinctive neither in pairs nor in larger groups. At temperature below the TNZ the Mashona mole-rat saved 21% of its energetic expense in pairs due to social thermoregulation. With an increase in group size, energetic savings rose up to four animals. In larger groups, social thermoregulation did not influence the energetic expenditure, possibly because Mashona mole-rat´s families naturally contain around four to five adults.