984 resultados para Assisted reproduction techniques
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Cryopreservation of spermatozoa is a pivotal tool in assisted reproduction, and studies aiming to establish optimal freezing/thawing protocols are essential to enhance sperm survival. The objectives of the present study were to (1) compare the cryoprotective efficiency of three different glycerol concentrations (3%, 5%, and 7%) on the basis of post-thaw sperm quality and (2) investigate whether the incidence of morphologically abnormal sperm in fresh samples is related to cryodamage sensitivity. Semen was collected from six tomcats using an artificial vagina (total 18 ejaculates). Each ejaculate was diluted using Tris-egg yolk-based extender (TEY), evaluated, equally divided into three aliquots, and rediluted using TEY with and without glycerol to achieve final concentrations of 3%, 5%, and 7%. Samples were loaded into 0.25 mL straws, equilibrated for 60 minutes at 5 °C, frozen, and then thawed at 46 °C for 12 seconds. Fresh and frozen-thawed samples were evaluated for sperm motion parameters (computer-assisted sperm analysis), plasma membrane integrity (PMI; propidium iodide and carboxyfluorescein diacetate), and DNA integrity (acridine orange). Plasma and acrosomal membrane integrity were assessed by flow cytometry (propidium iodide and fluorescein isothiocyanate-conjugated pea (Pisum sativum) agglutinin) immediately after thawing. Sperm motion parameters were also evaluated at 30 and 60 minutes of postincubation. For all treatment groups, cryopreservation significantly impaired the PMI and sperm motion parameters, except for straightness and amplitude of lateral head displacement. DNA integrity showed a slight reduction (P < 0.05) when 3% glycerol was used. The percentage of total motility, progressive motility, and rapid spermatozoa were significantly lower immediately after thawing and up to 60 minutes of incubation for the 3% glycerol group when compared with 5% and 7%. No difference (P > 0.05) was found for PMI, acrosome integrity, and DNA integrity among post-thaw groups. However, higher (P < 0.05) incidence of viable cells with reacted acrosome and dead cells with intact acrosome were observed with 7% and 3% glycerol, respectively. Percentage of morphologically abnormal spermatozoa in fresh sample was positively correlated with PMI only in the 3% glycerol group and negatively correlated with sperm motility in the 5% and 7% groups. In conclusion, the final concentration of 5% glycerol offered better cryoprotective effect for ejaculated cat sperm, and the relationship found between prefreezing sperm morphology and post-thaw sperm quality showed to be dependent on final glycerol concentration. © 2013 Elsevier Inc.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Pós-graduação em Ginecologia, Obstetrícia e Mastologia - FMB
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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A biotecnologia aplicada à reprodução é uma ferramenta também importante para conservação de espécies ameaçadas de extinção. Algumas espécies de primatas não-humanos neotropicais têm sido amplamente agredidas por ações antrópicas, ocasionando a inclusão de 26 espécies brasileiras na lista oficial de animais ameaçados de extinção do IBAMA. As espécies de primatas não humanos Ateles belzebuth e Ateles paniscus, participantes do gênero Ateles, popularmente chamados de macaco-aranha, encontram-se particularmente ameaçadas. Poucos estudos são realizados acerca do status populacional destas espécies e menos ainda sobre dados reprodutivos e reprodução assistida. O presente trabalho pretendeu avaliar as características andrológicas de exemplares de primatas não humanos do gênero Ateles em cativeiro e comparar a performance dos diluentes TES e CEBRAN II, este último à base de ringer lactato, como criopreservadores de sêmen destas espécies. O experimento foi realizado utilizando 06 exemplares machos de primatas não humanos do gênero Ateles (02 exemplares de Ateles marginatus e 04 exemplares de Ateles paniscus) mantidos sob as mesmas condições de cativeiro no Centro Nacional de Primatas (CENP-SVS/MS), em Ananindeua, Pará. Os animais utilizados foram submetidos a exame clínico-andrológico e biometria testicular, antes da colheita seminal realizada por eletroejaculação. Foram realizadas avaliações físicoquímicas e de patologias espermáticas, além de avaliação de motilidade e vigor no sêmen a fresco e pós-diluição com os diluentes TES e CEBRAN II. As alíquotas de sêmen diluídas com os dois diluentes, na proporção 2:1, foram envasadas em minitubos com capacidade para 0,25 ml e criopreservados em nitrogênio líquido. Após descongelação, as doses envasadas foram avaliadas em teste de termo-resistência (T.T.R.). As médias de volume e concentração espermáticas obtidas foram, respectivamente, 1,94 ml (± 0,83) e 3.020.000 sptz/ml (±275,97). O pH 8 foi observado em todas as amostras e todos os exemplares apresentaram coagulação seminal. O índice de patologias espermáticas encontrados foi alto (69,8% ± 9,05) indicando que pode haver influência da sazonalidade reprodutiva nas características seminais encontradas nos animais deste experimento. Os resultados de avaliação de motilidade e vigor do sêmen a fresco, diluído e no T.T.R. não puderam ser analisadas estatisticamente, pois somente o sêmen de 03 animais demonstrou espermatozóides viáveis pós-descongelação, com resultados que sugerem que o diluente TES apresenta melhor eficiência na preservação de sêmen de Ateles do que o diluente CEBRAN II.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The aim of this study was to characterise the methylation pattern in a CpG island of the IGF2 gene in cumulus cells from 1-3 mm and a parts per thousand yenaEuro parts per thousand 8.0 mm follicles and to evaluate the effects of in vitro maturation on this pattern.Genomic DNA was treatment with sodium bisulphite. Nested PCR using bisulphite-treated DNA was performed, and DNA methylation patterns have been characterised.There were no differences in the methylation pattern among groups (P > 0.05). Cells of pre-IVM and post-IVM from small follicles showed methylation levels of 78.17 +/- 14.11 % and 82.93 +/- 5.86 %, respectively, and those from large follicles showed methylation levels of 81.81 +/- 10.40 % and 79.64 +/- 13.04 %, respectively. Evaluating only the effect of in vitro maturation, cells of pre-IVM and post-IVM COCs showed methylation levels of 80.17 +/- 12.01 % and 81.19 +/- 10.15 %.In conclusion, the methylation levels of the cumulus cells of all groups were higher than that expected from the imprinted pattern of somatic cells. As the cumulus cells from the pre-IVM follicles were not subjected to any in vitro manipulation, the hypermethylated pattern that was observed may be the actual physiological methylation pattern for this particular locus in these cells. Due the importance of DNA methylation in oogenesis, and to be a non-invasive method for determining oocyte quality, the identification of new epigenetic markers in cumulus cells has great potential to be used to support reproductive biotechniques in humans and other mammals.
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The canine species has been used as an experimental model for preservation of endangered species. Biotechnologies of reproduction, such as in vitro maturation (IVM), have been used to meet this objective. Several protocols for in vitro embryo production (IVEP) in swine and bovine species have been adapted for canids. However, the highest rate reported for in vitro maturation in canids is only 39%, which is still lower than those in other species. Therefore, current research on assisted reproduction in canids have focused on several IVM protocols, including the addition of proteins, hormones, meiosis inhibitors, growth factors and antioxidants to the maturation media and the determination of suitable timing for culture, so that variables involved in the process can be fine-tuned. This review has the main objective of describing major developments and limitations in the process of oocyte maturation in bitches.
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The acceptance of biotechnology for the most equine breeders association had a significant effect in the horse industry, gaining popularity around the world, because the increasing on the genetic gain, allowing the use of sub fertile mares and stallions with high genetics value on reproduction. The embryos in vitro production of human and cattle has been used with success, however in vitro embryo production is not efficient in the horse, as oocyte transfer (OT) and intracytoplasmatic sperm injection (ICSI). The oocyte transfer has been used especially in subfertile old mares presenting reproductive pathologies as: endometrite, cervical and uterine adhesions, blocked oviduct, perineal laceration and ovulation failures. During oocyte recovery process, the oocytes must be collected from immature follicles that need be matured in vitro or in vivo matured oocytes from pre-ovulatory follicles through the transvaginal aspiration guided by ultrasound. The recovered oocyte is transferred to a previously inseminated recipient mare, through the flank laparotomy. The intracytoplasmatic sperm injection (ICSI) is a procedure of in vitro fertilization that needs only one sperm that is aspirated and injected inside the oocyte. The oocytes used, can be from mature and immature follicles. Fresh, cooled and frozen semen can be used, because the procedure not requires a functional sperm. The use of Piezo drill resulted in a breakthrough the pellucid zone, allowing the vibration per minute provided in the sperm injection pipette, a major result of cleaved oocytes, due to a better sperm injection in the oocyte. The embryo transfer can be straight inside the oviduct, as also transcervical transferred after embryo culture produced in vitro. In conclusion both procedures (OT and ICSI) are effective to be used on equine assisted reproduction, getting results even lower than expected, but satisfactory from animal genetically superior
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In vitro production of bovine embryo (IVP) has become a remarkable assisted reproduction biotechnology in Brazil, once it is considered an important tool for the genetic improvement of the herd. However, many abnormalities are associated with IVP technologies, such as higher incidences of embryo loss, abortions, hydrallantois and dystocia, prolonged gestation, increased birth weight and high perinatal mortality. Collectively, these abnormalities are known as “Large Offspring Syndrome”, which has limited the large-scale use of IVP technologies in cattle industry
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Sonohysterography was firstly described three decades ago. The saline solution infusion into the uterine cavity favors its use and provides excellent visualization of the anatomy and the inner cavity of the uterus better than the conventional transvaginal sonography To check the current role of sonohysterography in the uterine cavity assessment in women with abnormal uterine bleeding and asymptomatic, a literature review comparing sonohysterograph with conventional transvaginal sonography and/or ambulatory diagnostic hysteroscopy was carried out. To this end, relevant studies were researched in electronic databases Medline/PubMed, SciELO/LILACS. The sonohysterography is an ambulatory procedure, non-invasive, better cost-benefit, better sensitivity and specificity to identify uterine abnormalities, causing minimal discomfort and low complications rate. It was subject to revision which there is no more doubt about its accuracy. It can be concluded that the sonohysterography is a useful tool in the propedeutics to assess uterine cavity of symptomatic patients with abnormal uterine bleeding, infertility, recurrent miscarriages, and embryonic implantation failures in assisted reproduction treatment / in vitro fertilization and in any other intra and extra uterine cavity alteration. Hence, conventional transvaginal sonography is indicated as an initial method of assessment of the uterine cavity previously to ambulatory diagnostic hysteroscopy.
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Clinical application of human embryonic stem cells will be possible, when cell lines are created under xeno-free and defined conditions. We aimed to establish methodologies for parthenogenetic activation, culture to blastocyst and mechanical isolation of the inner cell mass (ICM) using bovine oocytes, as a model for derivation and proliferation of human embryonic stem cells under defined xeno-free culture conditions. Cumulus-oocyte-complexes were in vitro matured and activated using Ca(2+)Ionophore and 6-DMAP or in vitro fertilized (IVF). Parthenotes and biparental embryos were cultured to blastocysts, when their ICM was mechanically isolated and placed onto a substrate of fibronectin in StemProA (R) medium. After attachment, primary colonies were left to proliferate and stained for pluripotency markers, alkaline phosphatase and Oct-4. Parthenogenesis and fertilization presented significantly different success rates (91 and 79 %, respectively) and blastocyst formation (40 and 43 %, respectively). ICMs from parthenogenetic and IVF embryos formed primary and expanded colonies at similar rates (39 % and 33 %, respectively). Six out of eight parthenogenetic colonies tested positive for alkaline phosphatase. Three colonies were analyzed for Oct-4 and they all tested positive for this pluripotency marker. Our data show that Ca2+ Ionophore, and 6-DMAP are efficient in creating large numbers of blastocysts to be employed as a model for human oocyte activation and embryo development. After mechanical isolation, parthenogetic derived ICMs showed a good rate of derivation in fibronectin and Stem-Pro forming primary and expanded colonies of putative embryonic stem cells. This methodology may be a good strategy for parthenogenetic activation of discarded human oocytes and derivation in defined conditions for future therapeutic interventions.
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To detect expression of bone morphogenetic protein 15 (BMP15) and growth differentiation factor 9 (GDF9) in oocytes, and their receptor type 2 receptor for BMPs (BMPR2) in cumulus cells in women with polycystic ovary syndrome (PCOS) undergoing in vitro fertilization (IVF), and determine if BMPR2, BMP15, and GDF9 expression correlate with hyperandrogenism in FF of PCOS patients. Prospective case-control study. Eighteen MII-oocytes and their respective cumulus cells were obtained from 18 patients with PCOS, and 48 MII-oocytes and cumulus cells (CCs) from 35 controls, both subjected to controlled ovarian hyperstimulation (COH), and follicular fluid (FF) was collected from small (10-14 mm) and large (> 18 mm) follicles. RNeasy Micro Kit (Qiagen(A (R))) was used for RNA extraction and gene expression was quantified in each oocyte individually and in microdissected cumulus cells from cumulus-oocyte complexes retrieved from preovulatory follicles using qRT-PCR. Chemiluminescence and RIA assays were used for hormone assays. BMP15 and GDF9 expression per oocyte was higher among women with PCOS than the control group. A positive correlation was found between BMPR2 transcripts and hyperandrogenism in FF of PCOS patients. Progesterone values in FF were lower in the PCOS group. We inferred that BMP15 and GDF9 transcript levels increase in mature PCOS oocytes after COH, and might inhibit the progesterone secretion by follicular cells in PCOS follicles, preventing premature luteinization in cumulus cells. BMPR2 expression in PCOS cumulus cells might be regulated by androgens.
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Although some patients may benefit from reduced follicle-stimulating hormone (FSH) application, in-vitro maturation (IVM) belongs to the rare treatment options in assisted reproduction. We summarize our five-year IVM experience.