Orientador: Anthony César de Souza Castilho / Resumo: A fim de mimetizar melhores condições do sistema in vivo, um meio de cultura mais proximo à composição do fluido do oviduto foi criado, denominado fluido ovidutal sintético (SOF), este foi formulado com base na análise bioquímica do oviduto das ovelhas. In vivo os momentos finais de maturação oocitária ocorrem em contato com o FO, já in vitro a maturação oocitária é realizada com protocolos de maturação 24h sem nenhuma alteração no meio de maturação. Portanto, o presente estudo investigou o impacto do meio de cultivo SOF durante as últimas quatro horas da maturação in vitro (MIV) e seus efeitos sobre a progressão meiótica e taxa de produção embrionária. Para tanto, os CCOs foram recuperados de ovário de vacas abatidas e maturados in vitro, nos seguintes grupos: SFB/ SFB; SFB/ SFB+SOF; BSA/BSA; BSA/BSA+SOF, todos submetidos há uma troca total de meio nas últimas quatro horas de maturação, adicionando o meio SOF de acordo com os grupos citados anteriormante. Os CCOs maturados foram fertilizados e cultivados em atmosfera e umidade controlada até o estágio de blastocisto (7 e 8 dias após a fertilização). A análise estatística foi realizada transformando os dados em arcoseno e as médias foram comparadas pelo teste T usando JMP (software JMP, SAS Institute Cary, NC). Diferenças significativas foram consideradas quando p≤ 0,05. O resultado obtido mostrou que o tratamento com SOF não tem efeito na progressão da meiose (p= 0,5944). Entretanto, quando analisamos as taxas embrionárias e... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The oviduct and its secretion, the ovidutal fluid (OF), promote an adequate environment for the final maturation of the oocyte, sperm training, fertilization, transport and initial development of the embryo. In this context, in order to mimic better conditions of in vivo mechanisms, a culture medium similar to the composition of the oviduct fluid, called synthetic ovidutal fluid (SOF), was formulated based on biochemical analysis of the oviduct of sheep. Specifically, regarding the importance of OF for the final maturation of the oocyte in cattle, only the last four hours of oocyte maturation occur in the oviduct, which therefore pemits a new strategy of oocyte maturation in vitro (MIV) in the bovine species. Therefore, the present study aimed to investigate the impact of SOF culture medium during the last four hours of IVM and its effects on the meiotic progression and embryonic production rate. Therefore, the COCs were recovered from ovaries of slaughtered and matured cows in vitro, in base medium (composed of 199 MCT with Earles salts supplemented with pyruvate, amicacin, BSA, follicle stimulating hormone and luteinizing hormone, and another group in 199 MCT medium with Earles salts supplemented with 10% fetal bovine serum (FBS), pyruvate, both in moist atmosphere at 5% CO2 for 20 hours (4 replicates with 20 COCs/group). In the last four hours of maturation, the medium was completely changed by adding the SOF medium. Matured COCs were fertilized and cultivated in a control... (Complete abstract click electronic access below) / Mestre

Meiosis is a specialized cell division that produces haploid cells (gametes) from diploid progenitors. During meiosis parental chromosomes (homologs) need to pair, synapse and eventually segregate. Faithful chromosome segregation depends on chromosome recombination. In the beginning of prophase I programmed double strand breaks (DSBs) are introduced in meiotic cells by SPO11 enzyme. DSBs are positioned at hotspot sites that are specified by that action of DNA-binding histone methyltransferase PRDM9. Specific enzymes act at the site of breaks to create 5’ single stranded DNA ends. With the assistance of the strand exchange proteins DMC1 and RAD51 these ends invade homologous DNA sequence and DSB repair is initiated. DSB repair can be completed either as a crossover (reciprocal exchange of DNA) or as a non-crossover. Crossover events lead to the formation of chiasmata between homologs and ensure proper segregation during the first meiotic division. An interesting feature in male meiosis is the XY chromosomes. The shared region between sex chromosomes is short and is called pseudoautosomal region (PAR). Due to their large non synapsed region, XY chromosomes need to be transcriptionally silenced. Thus they are covered with the phosphorylated histone variant H2AX (γH2AX) forming the so called sex body. PAR region has higher density of DSBs than autosomes and it had been shown that sex chromosomes undergo delayed homologous pairing. Nevertheless little is known how meiotic recombination is regulated in PAR region of sex chromosomes. In close proximity with sex body it has been found a structure named dense body (DB). There are few reports suggesting that DB contains RNAs/proteins but no DNA. Its role in meiosis was unclear because no structural component had been described. In the present thesis the role of two meiotic expressed genes is described. In our group after performing RNA screens we identified several genes that are highly expressed during meiotic prophase I. Based on the expression profile we selected polycomb-related sex comb on midleg like 1 (Scml1) gene and the ankyrin repeat domain 31 (Ankrd31) to study their role in mammalian meiosis.:List of figures i List of abbreviations ii 1. Introduction 1 1.1 Gametogenesis 1 1.2 Meiotic prophase I 2 1.2.1 Meiotic recombination 4 1.2.2 Regulation of meiotic recombination 7 1.2.2.1 Meiotic recombination hotspots and PRDM9 activity 7 1.2.2.2 Meiotic surveillance mechanisms 8 1.3 Unique properties of XY recombination 9 1.4 Sex chromatin associated structure: The dense body 10 1.5 Aim of the thesis 11 2. Publications 12 3. Discussion 92 4. Summary 98 5. References 102 Acknowledgements 108 Declarations 109

The production of germ cells is an essential process in all sexually reproducing eukaryotes. During male meiosis, four haploid sperm cells are formed from one primary spermatocyte, thereby undergoing two consecutive cell divisions after only one round of chromosome duplication. This process was studied in the nematode Caenorhabditis elegans, as this model organism offers a number of experimental advantages to simultaneously analyze spindle dynamics and ultrastructure. The worm is easy to cultivate, completely sequenced and numerous mutants are available, the worm is small and thus ideal for light and electron microscopic investigations, and the transparent body allows live-cell imaging within living animals. Importantly, meiotic spindles in C. elegans males are organized by centrosomes and show a lagging X-chromosome, which is always segregated after the autosomes have been partitioned to the newly forming secondary spermatocytes. The aim of this thesis was to systematically investigate this characteristic feature of chromosome segregation in male meiotic spindles. For that, spindle dynamics in the first and second meiotic division was analyzed with fluorescence light microscopy. Furthermore, the spindle ultrastructure was investigated in spindles of various stages of meiosis I using electron tomography. Light microscopy revealed a shortening of the distance between centrosomes and chromosomes (anaphase A) and an increase in the pole-to-pole distance (anaphase B). Moreover, spindles in male meiosis I and II showed differences in certain aspects of spindle dynamics. In addition it was demonstrated that spindles in metaphase II in the presence of a single X-chromosome were shorter compared to spindles without the X-chromosome. In addition, it was found that the process of aging had an impact on spindle length in both metaphase I and II. By manipulating the number of unpaired chromosomes, it could be demonstrated that the lagging behavior of univalent chromosomes is caused by the incapability of pairing in meiotic prophase. After performing a quantitative analysis of the light microscopic data it was further shown that a dynamic microtubule bundle is connecting the X-chromosome to the spindle poles. Using laser microsurgery it could be demonstrated that this bundle exerts a pulling force to the univalent chromosome throughout anaphase. Unexpectedly, electron tomography showed that anaphase-type movements of the autosomes were not accompanied by a shortening of the kinetochore microtubules. Instead, three findings indicated a shortening of the centrosome-chromosome distance itself: (1) upon anaphase onset, tension is released on the beforehand stretched autosomes; (2) centrosomes shrink in preparation for meiosis II and (3) the attachment angle of end-on microtubules changes. Interestingly, microtubules connecting the X-chromosome to the spindle poles showed a high curvature around the kinetochore region of the X-chromosome, suggesting an involvement of motor proteins in the process of segregation. Taken together, this thesis gives the first detailed quantitative analysis of spindle dynamics and architecture during male meiosis in the nematode C. elegans. This wild-type data will serve as a basis for future mutant analyses and should help to further understand the complex dynamic and ultrastructural aspects of spindle organization in the meiotic divisions in C. elegans males.

Yes / Abstract The budding yeast genome contains regions where meiotic recombination initiates more frequently than in others. This pattern parallels enrichment for the meiotic chromosome axis proteins Hop1 and Red1. These proteins are important for Spo11-catalyzed double strand break formation; their contribution to crossover recombination remains undefined. Using the sequence-specific VMA1-derived endonuclease (VDE) to initiate recombination in meiosis, we show that chromosome structure influences the choice of proteins that resolve recombination intermediates to form crossovers. At a Hop1-enriched locus, most VDE-initiated crossovers, like most Spo11-initiated crossovers, required the meiosis-specific MutLγ resolvase. In contrast, at a locus with lower Hop1 occupancy, most VDE-initiated crossovers were MutLγ-independent. In pch2 mutants, the two loci displayed similar Hop1 occupancy levels, and VDE-induced crossovers were similarly MutLγ-dependent. We suggest that meiotic and mitotic recombination pathways coexist within meiotic cells, and that features of meiotic chromosome structure determine whether one or the other predominates in different regions.

Résumé: Les cellules germinales mâles remodèlent leur chromatine pour compacter leur noyau afin de protéger leur matériel génétique et assurer un transit optimal vers le gamète femelle. Il a été démontré que tous les spermatides de plusieurs mammifères, incluant l’homme et la souris, présentaient ce mécanisme de remodelage de la chromatine. Celui-ci est caractérisé par une augmentation transitoire de cassures d’ADN dont une quantité importante sont bicaténaires. Ce remodelage chromatinien a été étudié et semble être conservé chez plusieurs espèces, allant de l’algue à l’humain. Dans le contexte de la recherche fondamentale sur le phénomène de la spermiogenèse, il devient parfois très difficile d’investiguer certains aspects importants en vertu de l’impossibilité de réaliser des manipulations génétiques simples. Il est donc impératif de développer un nouveau modèle d’étude plus permissif afin de palier à ces difficultés encourues. Comme le processus de maturation des spores chez la levure à fission présente de grandes similitudes avec la spermiogenèse des mammifères, l’utilisation d’un modèle d’étude basé sur la sporulation de la levure à fission Schizosaccharomyces pombe a été proposée comme modèle comparatif de la spermatogenèse murine. À la suite de la synchronisation de la méiose de la souche S. pombe pat1-114, des analyses d’électrophorèse en champ pulsé (PFGE) et de qTUNEL ont permis de déterminer la présence de cassures bicaténaires transitoires de l’ADN lors de la maturation post-méiotique des ascospores nouvellement formés (t>7h). Des analyses par immunobuvardages dirigés contre le variant d’histones H2AS129p suggère la présence d’un remodelage chromatinien postméiotique dix heures suivant l’induction de la méiose, corroborant le modèle murin. Enfin, des analyses protéomiques couplées à l’analyse par spectrométrie de masse ont permis de proposer l’endonucléase Pnu1 comme candidat potentiellement responsable des cassures bicaténaires transitoires dans l’ADN des ascospores en maturation. En somme, bien que le processus de maturation des spores soit encore bien méconnu, quelques parallèles peuvent être tracés entre la maturation des ascospores de la levure à fission et la spermiogenèse des eucaryotes supérieurs. En identifiant un modèle simple du remodelage chromatinien au niveau de la spermiogenèse animale, on s’assurerait ainsi d’un outil beaucoup plus malléable et versatile pour l’étude fondamentale des événements survenant lors de la spermiogenèse humaine. / Abstract : The male germ cells undergo a major chromatin remodeling process in order to protect their genetic material and ensure optimal transit to the female gamete. It has been demonstrated that all spermatids from several mammals, including humans and mice, require this structural transition in order to reach their full maturity and fertilizing potential. This mechanism is characterized by a transient surge in DNA breaks, including a significant number of double-stranded breaks. This feature has been studied and seems conserved in many species, ranging from algae to humans. In the context of basic research on the phenomenon of spermiogenesis, it is sometimes very difficult to investigate important aspects due to the impossibility of carrying out simple genetic manipulations. A more flexible model to overcome the incurred difficulties is therefore needed. Since the process of ascospore maturation of the fission yeast presents great similarities with mammal spermiogenesis, the use of a model based on the sporulation of the fission yeast Schizosaccharomyces pombe has been proposed as a comparative model to the murine spermatogenesis. Following synchronization of meiosis in the S. pombe diploid strain pat1-114, pulsed field gel electrophoresis and qTUNEL assay were used to determine the presence of transient double-stranded breaks in DNA during the post-meiotic maturation of newly formed ascospores (t> 7h). Analyses by immunoblotting directed against the histone variant H2AS129p suggests the presence of a post-meiotic chromatin remodeling to t=10h, that may share similarities with higher eu karyotes. Finally, proteomic analyzes coupled with mass spectrometry allowed us to propose the Pnu1 endonuclease as a potential candidate responsible for the transient DNA double-stranded breaks during ascospore morphogenesis. In sum mary, although the spore maturation process is still under investigation, some parallels can be drawn between the maturation of ascospores of fission yeast s and higher eukaryotic spermio genesis. Thus, identifying a simple eukaryotic model for chromatin remodeling in animal spermiogenesis would ensure a flexible genetic tool to decipher the molecular events occurring during human spermiogenesis.

La recombinaison méiotique initiée en prophase I de méiose génère soit des crossing-over (COs), qui sont des échanges réciproques entre segments chromosomiques, ou des conversions géniques non associées aux COs (NCOs). Les deux types d'événements se produisent dans de petites régions (moins de 10 kilobases) appelées points chauds, qui sont distribuées de manière non homogène le long des chromosomes. L'objectif de ma thèse était la caractérisation d'un point chaud de recombinaison méiotique (nommée 14a) chez Arabidopsis thaliana (i) dans différentes accessions (ii) dans le mutant msh4, un gène impliqué dans la formation des COs. Dans les deux hybrides ColxLer et ColxWs (i) 14a a un taux très élevé de COs 0,85% et 0,49%, respectivement (ii) Les COs sont regroupés dans deux petites régions de quelques kilobases, 14a1 et 14a2 avec une distribution de type gaussienne observée aux points chauds décrits dans d'autres espèces (iii) 14a1 est aussi un point chaud de NCO avec un taux aussi élevé que celui des COs (0,5%) dans ColxLer (iv) un biais de l'initiation de recombinaison a été trouvé dans 14a1 aussi bien pour les COs que les NCOs dans le fond génétique ColxLer.Une réduction de la fréquence de CO a été observée dans le mutant msh4 dans le fond génétique ColxLer à 14a1 et 14a2 (6,4% et 18,7% par rapport au sauvage). Cela confirme le rôle précédemment connu de la protéine MSH4 impliqué dans la formation de CO. La fréquence de NCO à 14a1 est similaire à celle observéedans le fond sauvage. Le rôle des H3K4 histones trimethyltransferase d’Arabidopsis dans la recombinaison méiotique (comme précédemment observé comme Set1 chez S. cerevisiae ou PRDM9 chez les mammifères) a également été étudiée. Aucun des dix gènes d’histones méthyltransférase étudié n'a montré de rôle dans la méiose. Cela pourrait être dû à (i) une forte redondance de la fonction entre les protéines (ii) une autre histone méthyltransférase en charge de l'étiquetage des points chauds de recombinaison méiotique (plus de 29 putatif histone méthyltransférase ont été identifiés dans le génome d'Arabidopsis!) (iii) contrairement à S. cerevisiae, les souris et l'homme, un autre mécanisme de contrôle épigénétique de la recombinaison méiotique. / Meiotic recombination initiated in prophase I of meiosis generates either crossovers (COs), which are reciprocal exchanges between chromosome segments, or gene conversion not associated to crossovers (NCOs). Both kinds of events occur in narrow regions (less than 10 kilobases) called hotspots, which are distributed non-homogenously along chromosomes. The aim of my PhD was the characterization of a hotspot of meiotic recombination (named 14a) in Arabidopsis thaliana (i) across different accessions (ii) in msh4 mutant, a gene involved in CO formation. In both ColxLer and ColxWs hybrids (i) 14a had a very high rate of COs 0.85% and 0.49%, respectively (ii) COs clustered in two small regions of a few kilobases, 14a1 and 14a2 with typical Gaussian curve distribution observed in other organisms (iii) 14a1 was also a hotspot of NCO with high rate (0.5%) in ColxLer (iv) a bias of recombination initiation at 14a1 CO and NCO hotspot was found in ColxLer. A reduction of CO frequency was observed in msh4 mutant in ColxLer background at 14a1 (6.4%) and 14a2 (18.7%) compared to wild type. This confirmed previously known role of MSH4 protein in CO formation. Frequency of NCO at 14a1 was similar to wild type. The role of putative Arabidopsis histone H3K4 trimethyltransferase in meiotic recombination as previously observed like Set1 in S.cerevisiae or PRDM9 in mammals (mice and human) was also studied. None of ten putative histone methyltransferase genes was involved in meiosis. This could be due to (i) a strong redundancy of function between gene products (ii) another histone methyltransferase in charge of labeling meiotic recombination hotspots (more than 29 putative histone methyltransferase have been identified in the Arabidopsis genome!) (iii) contrary to S. cerevisiae, mice and humans, another mechanism for epigenetic control of meiotic recombination

During early embryonic development oocytes are arrested in prophase I of the first meiotic division, in which they can persist for years. After reaching sexual maturity and the luteinizing hormon surge resumption of meiosis and meiotic maturation occur. Oocytes are arrested again at metaphase of the second meiotic division. At this stage they are ovulated and waiting for a fertilisation. Oocytes are during their development exposed to factors that cause DNA damage, of which DNA double-strand breaks (DSBs) are the most serious threat. The maintaining of genome integrity is crucial for quality of oocytes, fertility and proper embryonic development. The mechanism of the oocyte response to DSBs presence is not fully understood and it seems to differ from somatic cells. We assume that DSBs are repaired during meiotic maturation probably by a mechanism of homologous recombination (HR). In this thesis we focuse on essencial recombinase RAD51, which participates in the repair by HR. We found that RAD51 inhibition leads to an increase of segregation errors in anaphase I. Using high resolution live cell imaging we observed chromosomal fragments and anaphase bridges. Immunofluorescence detection of DSBs-marker γH2AX showed increased amount of DSBs in prophase I and MII stage after RAD51 inhibition. Our data...

Introdução: Apesar de controverso, questiona-se um papel deletério da endometriose nos resultados de procedimentos de reprodução assistida, o que pode estar relacionado ao comprometimento da qualidade oocitária. Para que o oócito maduro esteja preparado para a fertilização, é necessário que o fuso meiótico mantenha a sua integridade e funcionabilidade. Objetivos: Comparar a presença e localização do fuso meiótico e o estágio de maturação nuclear de oócitos com o primeiro corpúsculo polar (CP) visível de pacientes inférteis sem e com endometriose. Comparar os resultados de Injeção Intracitoplasmática de espermatozóides (ICSI) entre os oócitos em telófase I e metáfase II, e entre aqueles com e sem fuso celular visível, nos grupos analisados. Metodologia: Estudo prospectivo e controlado com pacientes inférteis, submetidas à estimulação ovariana para realização de ICSI, selecionadas consecutivamente e divididas em dois grupos: Controle (fator tubário e/ou masculino) e Endometriose (subdividido em endometriose mínima e leve I/II versus moderada e severa III/IV). Os oócitos com extrusão do primeiro CP foram avaliados pela microscopia de polarização imediatamente antes da realização da ICSI e caracterizados quanto à presença/localização do fuso celular em relação ao primeiro CP e ao estágio de maturação nuclear (telófase I ou metáfase II). Foram analisados as taxas de fertilização, clivagem, número de embriões de boa qualidade no segundo (D2) e terceiro (D3) dia de desenvolvimento oriundos dos oócitos em telófase I versus metáfase II, e metáfase II com fuso visível versus sem fuso visível, nos grupos controle, endometriose, endometriose I/II e endometriose III/IV. Resultados: Foram analisados 441 oócitos, sendo 254 do grupo controle e 187 do grupo endometriose (115 do grupo endometriose I/II e 72 do grupo endometriose III/IV). Não observamos diferença significativa entre a percentagem de oócitos em metáfase II com fuso celular visível e não visível (88,6%, 91,3%, 88,2%, respectivamente, nos grupos controle, endometriose I/II e endometriose III/IV) e entre a percentagem de oócitos com fuso celular nas diferentes localizações nos grupos avaliados. Entre os oócitos aparentemente maduros, observamos um aumento significativo de oócitos em telófase I no grupo endometriose III/IV (5,6%) quando comparado ao grupo endometriose I/II (0%). Observamos uma tendência a menores taxas de fertilização dos oócitos injetados em telófase I quando comparados aos em metáfase II, nos grupos controle (p=0,08), endometriose (p=0,05) e endometriose III/IV (p=0,09). Comparando-se os oócitos com e sem fuso celular visível, não observamos diferença significativa nos resultados de ICSI entre os grupos analisados. Conclusão: Não observamos diferença significativa entre os grupos analisados quanto à visualização e localização do fuso celular em oócitos maturados in vivo com o primeiro CP visível. Todavia, observamos um aumento significativo de oócitos em telófase I nas portadoras de endometriose moderada e severa, sugerindo um retardo ou comprometimento na conclusão da meiose I. Considerando que os oócitos injetados em telófase I apresentam piores taxas de fertilização do que os injetados em metáfase II, este achado poderia justificar o comprometimento dos resultados de reprodução assistida em mulheres inférteis com endometriose moderada e severa, além de ser utilizado com ferramenta prognóstica pós-ICSI. / Introduction: Although it has been a controversial issue for decades, a deleterious role of endometriosis on assisted reproductive techniques (ART) outcomes is questioned, which may be related to oocyte quality. For a mature oocyte be prepared for fertilization is necessary that the meiotic spindle keeps its integrity and its function. Objectives: To compare the presence and localization of the meiotic spindle and the oocyte nuclear maturation with the visible first polar body of infertile patients with and without endometriosis. To compare ICSI outcomes between oocytes on telophase I and metaphase II, and the ones with and without visible meiotic spindle, on those two groups. Methodology: A prospective and controlled study with infertile patients who underwent ovarian stimulation for purposes of ICSI, selected consecutively and divided into two groups: control (tubal and/or male factor) and endometriosis (subdivided in minimum and mild stage I/II versus moderate and severe stage III/IV). The oocytes with the first polar body extruded (in vivo matured oocytes) were imaged using a polarization microscopy immediately before ICSI and characterized according to the presence and localization of meiotic spindle and its relation to the first polar body and the nuclear maturation stage (telophase I and metaphase II). We have analyzed the fertilization rates, clivage, number of good quality embryos on the second (D2) and third (D3) day of development from oocytes on telophase I versus the ones on metaphase II, and metaphase II visible spindle versus the non-visible ones, on the control groups, endometriosis, endometriosis stage I/II and endometriosis stage III/IV. Results: A total of 441 oocytes were analyzed, 254 oocytes form the control group and 187 from the endometriosis one (115 from endometriosis stage I/II and 72 from endometriosis stage III/IV). No significant differences between the percentage of metaphase II with visible and non-visible meiotic spindle were found (88,6%, 91,3%, and 88,2%, in the control, endometriosis I/II and endometriosis III/IV groups, respectively). Among the apparently matured oocytes, we have observed a significant increase of oocytes on telophase I on the endometriosis III/IV group (5,6%) when compared with the endometriosis I/II group (0%). We have observed a tendency to fewer fertilization rates from the injected oocytes on telophase I when compared with the ones on metaphase II, on the control group (p=0,08), endometriosis (p=0,05) and endometriosis III/IV group (p=0,09). When we compared oocytes with and without visible meiotic spindle, we found no significant difference on ICSI outcomes among the studied groups. Conclusions: We have found no significant difference among the studied groups regarding the visualization and localization of the meiotic spindle from in vivo matured oocytes with a visible first polar body. However, we have observed a significant increase on the number of oocytes on telophase I from patients with moderate and severe endometriosis, suggesting a delay or an impairment in the completion of meiosis I. Since the injected oocytes on telophase I present a worse fertilization rates than the ones injected on metaphase II, this finding could explain the impairment on the outcomes of ART in infertile women with moderate and severe endometriosis, besides it could be used as a prognosis tool after ICSI procedures.

Os mecanismos envolvidos na etiopatogênese da infertilidade em pacientes com endometriose não foram totalmente elucidados. A infertilidade apresentada por pacientes com as formas moderada e grave (estadios III e IV, respectivamente) seria, parcialmente, decorrente de alterações anatômicas pélvicas associadas à endometriose. Entretanto, há evidências de que lesões sutis ou implantes endometrióticos em estágios iniciais (estágio mínimo e leve) também poderiam contribuir com a etiopatogênese da infertilidade. Uma pior qualidade oocitária pode estar envolvida nas menores taxas de implantação após fertilização in vitro encontradas nessas pacientes. Questionamos a possibilidade de haver alterações no microambiente folicular de pacientes inférteis com endometriose, as quais poderiam afetar a aquisição de competência oocitária e, consequentemente, comprometer a fertilidade natural e os resultados dos tratamentos de reprodução assistida em mulheres com esta doença. Sabe-se que, para ser competente e poder ser fertilizado, o oócito precisa estar maduro e ter um fuso morfologicamente funcional, que garanta a fidelidade da segregação cromossômica durante a meiose. Dessa forma, o objetivo deste estudo foi avaliar o potencial impacto de diferentes concentrações de fluido folicular (FF) de mulheres inférteis com e sem endometriose leve sobre a integridade do fuso, alinhamento cromossômico e organização dos microfilamentos de actina de oócitos bovinos maturados in vitro. Realizou-se um estudo experimental, onde amostras de fluido follicular foram consecutivamente obtidas de 22 pacientes inférteis (11 com endometriose leve e 11 com infertilidade por fator tubário e/ou masculino) submetidas à estimulação ovariana para injeção intracitoplasmática de espermatozóide. Oócitos bovinos imaturos foram submetidos à maturação in vitro (MIV) sem adição de fluido follicular (sem fluido) e com 4 concentrações (1%, 5%, 10%, e 15%) de duas amostras de fluido folicular (uma de paciente com endometriose e outra de paciente sem endometriose). Foram realizadas 11 MIVs e cada amostra de fluido follicular foi usada apenas uma vez. Os oócitos foram fixados, marcados por imunofluorescência para visualização morfológica de microtúbulos, cromatina e microfilamentos de actina e, então, analisados por microscopia confocal. A porcentagem de anormalidade de oócitos em MII (fuso normal e cromossomos desalinhados, fuso anormal e cromossomos desalinhados, fuso anormal e cromossomos alinhados) foi significativamente maior naqueles maturados com FF de pacientes com endometriose (1%: 55,56%, 5%: 63,26%, 10%: 54,54%, 15%: 48,84%) quando comparados com oócitos maturados com FF de pacientes controles (1%: 19,15%, 5%: 23,44%, 10%: 25%, 15%: 23,81%) e oócitos maturados sem fluido (23,53%), sem haver diferença entre as concentrações testadas em cada grupo. Pode-se concluir que oócitos bovinos maturados in vitro na presença de FF de mulheres inférteis com endometriose leve têm maior freqüência de anormalidade meiótica. Estes dados sugerem que o FF de mulheres com endometriose pode comprometer a qualidade oocitária por promover danos ao fuso e/ou cromossomos / The mechanisms involved in the etiopathogenesis of infertility in patients with endometriosis have not been fully elucidated. The infertility presented by patients with moderate and severe disease (stages III and IV, respectively) would be partly due to anatomical pelvic changes associated with endometriosis. However, there are evidences that subtle lesions or endometriosis implants in the early stages (stages I and II) might also contribute to the etiophatogenesis of infertility. Impaired oocyte quality may be involved in lower implantation rates after in vitro fertilization in these patients. We question if alterations in the follicular microenvironment of infertile patients with endometriosis might affect oocyte competence acquisition and compromise the natural fertility and assisted reproduction treatment outcomes in women with this disease. It is known that to be competent and capable of fertilizing, the oocyte must be mature and have a morphologically functional spindle, which ensure the fidelity of chromosome segregation during meiosis. Thus, the aim of this study was to evaluate the potential impact of different concentrations of follicular fluid (FF) of infertile women with and without mild endometriosis on spindle integrity, chromosomes alignment and actin microfilaments organization of bovine oocytes in vitro matured. We performed an experimental study, where FF samples were consecutively obtained from 22 infertile patients (11 with mild endometriosis and 11 with tubal or male factors of infertility) submitted to ovarian stimulation for intracytoplasmic sperm injection. Immature bovine oocytes were submitted to in vitro maturation (IVM) without FF and with 4 concentrations (1%, 5%, 10%, and 15%) of 2 samples of FF (1 from a woman with endometriosis and one from a woman without endometriosis). We performed 11 IVM and each FF sample was used only once. The oocytes were then fixed, stained by immunofluorescence for morphological visualization of microtubules, chromatin and actin microfilaments, and then, analyzed by confocal microscopy. The percentage of abnormal MII oocytes was significantly higher for those matured with FF from patients with endometriosis (1%: 55.56%, 5%: 63.26%, 10%: 54.54%, 15%: 48.84%) when compared with oocytes matured with FF from patients without endometriosis (1%: 19.15%, 5%: 23.44%, 10%: 25%, 15%: 23.81%) and those matured without FF (23.53%), with no differences among the tested concentrations in each group. We can conclude that bovine oocytes matured in vitro in the presence of FF from infertile women with mild endometriosis have higher frequency of meiotic abnormalities. These data suggest that FF from women with endometriosis may compromise oocyte quality by promoting spindle and/or chromosomal damage

Objetivos: Avaliar o fuso meiótico e a distribuição cromossômica de oócitos maturados in vitro obtidos de ciclos estimulados de mulheres inférteis com Síndrome dos Ovários Policísticos (SOP) e fatores masculino e/ou tubário de infertilidade. Métodos: Vinte e seis pacientes inférteis com SOP e 48 pacientes com fator tubário e/ou masculino de infertilidade, submetidas a ciclos estimulados para captação oocitária para injeção intracitoplasmática de espermatozóide, foram selecionadas prospectiva e consecutivamente e divididas em grupos de estudo e controle, respectivamente. Oócitos imaturos (34 e 56 oócitos) foram obtidos de 13 e 27 pacientes, respectivamente, dos grupos SOP e controle, sendo submetidos à maturação in vitro (MIV), respectivamente, por 19 horas ± 1 hora (VG) e 4 horas ± 30 minutos (MI), conforme curva de MIV previamente realizada no presente serviço. Oócitos em metáfase II (MII) após MIV, foram fixados, submetidos a imunocoloração e microscopia de fluorescência para avaliação morfológica do fuso e da distribuição cromossômica. Resultados: Não observamos diferença significativa nas taxas de MIV entre os dois grupos avaliados (50% e 42,8%, respectivamente, para os grupos SOP e controle). Na análise por microscopia de imunofluorescência, detectaram-se 3 e 2 oócitos, respectivamente, no grupo de estudo e no grupo controle, em estágio de Telófase I e 3 oócitos ativados partenogeneticamente no grupo controle. Ocorreu a impossibilidade de análise de 4 oócitos do grupo controle em virtude de dificuldades técnicas durante o processo de imunocoloração. Não houve diferença significativa nas proporções de anomalias meióticas entre os grupos SOP e controle (57,1 e 46,7%, respectivamente). Conclusões: Os dados preliminares do presente estudo, apesar de não demonstrarem aumento significativo na incidência de anomalias meióticas nas portadoras de SOP, sugerem uma tendência a maior ocorrência de anomalias meióticas nos oócitos deste grupo de pacientes, quando comparados aos de portadoras de fator masculino e/ou tubário de infertilidade, o que deverá ser mais bem avaliado em estudos com maiores casuísticas. Estes achados têm potencial clínico para apontar uma possível explicação para as controversas menores taxas de fertilização observadas em pacientes com SOP submetidas às Técnicas de Reprodução Assistida. / Objectives: To evaluate the meiotic spindle and the chromosome distribution of in vitro matured oocytes obtained during stimulated cycles from infertile women with Polycystic Ovary Syndrome (PCOS) and with male factor and/or tubal infertility. Methods: Twenty six infertile patients with PCOS and 48 patients with infertility due to tubal and/or male factor, submitted to stimulated cycles for oocyte retrieval for intracytoplasmic sperm injection, were selected prospectively and consecutively and respectively assigned to the study group and the control group. Imature oocytes (34 and 56 oocytes) were obtained from 13 and 27 patients, respectively, of PCOS and control groups, and submitted to in vitro maturation (IVM) for 19 hours ± 1 hour (GV) and 4 hours ± 30 minutes (MI) according to the IVM curve previously constructed in the present service. After IVM, oocytes in metaphase II (MII) were fixed and submitted to immunostaining and fluorescence microscopy for morphological evaluation of the spindle and of chromosome distribution. Results: IVM rates were similar between the two analyzed groups (50% e 42.8%, respectively, in PCOS e control groups). By immunofluorescence analysis, there were 3 and 2 oocytes, respectively, in PCOS e control groups, in telophase I stage, and 3 parthenogenetic activated oocytes in control group. Because of technical difficulties during the execution of the immunofluorescence protocol, 4 oocytes from the control group could not be analyzed. The difference in the proportions of meiotic anomalies between the two groups was not statistically significant (57.1 e 46.7%, respectively, in PCOS e control groups). Conclusions: The present preliminary data, although not showing a significant increase in the incidence of meiotic anomalies in women with PCOS, suggest a tendency to a higher occurrence of meiotic anomalies in the oocytes of this group of patients compared to women with male and/or tubal infertility, a fact to be better evaluated in studies on larger patient series. The present findings have the clinical potential to provide a possible explanation for the controversial lower fertilization rates observed in patients with PCOS submitted to Assisted Reproduction Techniques