Please use this identifier to cite or link to this item: http://dspace.unipampa.edu.br:8080/jspui/handle/riu/178
metadata.dc.type: Dissertação
Title: Efeito da Tensão de Oxigênio e da Densidade de Oócitos na Maturação In Vitro de Oócitos Bovinos e a Relação com o Estresse Oxidativo
Effect of Oxygen Tension and Oocyte Density Utilized on In Vitro Maturation of Bovine Oocytes and the Relationship with the Oxidative Stress
metadata.dc.creator: Giotto, Angelo Bertani
metadata.dc.contributor.advisor1: Leivas, Fábio Gallas
Brum, Mário Celso Sperotto
Abstract: A maturação in vitro (MIV) é um dos pontos críticos da produção in vitro de embriões bovinos, sendo que vários fatores podem interferir na MIV, como a tensão de oxigênio e a densidade de oócitos por volume de meio. O objetivo deste estudo foi avaliar o efeito da tensão de oxigênio associada a diferentes densidades de oócitos durante a MIV. Para tanto, três experimentos foram conduzidos com oócitos bovinos obtidos de ovários de abatedouro. O experimento I consistiu na avaliação da maturação citoplasmática e nuclear, o experimento II na avaliação da produção de espécies reativas de oxigênio (ROS) e atividade antioxidante, e o experimento III na avaliação das taxas de fecundação in vitro. Após a seleção, os oócitos foram submetidos a MIV distribuídos aleatoriamente em 4 tratamentos: Tratamento 1:10/5%: 1 oócito em 10μl de meio de MIV em 5% de O 2 ; Tratamento 1:10/20%: 1 oócito em 10μl de meio em 20% de O 2 ; Tratamento 1:20/5%: 1 oócito em 20μl em 5% de O 2 e Tratamento 1:20/20%: 1 oócito em 20μl de meio em 20% de O 2 . A MIV foi conduzida em grupos de 15 oócitos em meio TCM 199 modificado, acrescido de FSH, LH, EGF, soro de égua em estro (SEE) e piruvato por 24h. Decorrido o período de MIV foi conduzida a fecundação in vitro em gotas de 300μl de meio Fert-TALP, sendo realizada pelo co-cultivo de oócitos e espermatozóides (2x10 6 sptz/mL) selecionados por gradientes de mini-Percoll por 18h. No experimento I, as taxas de maturação nuclear (69,66%) e maturação citoplasmática (71,55%) foram similares entre os tratamentos (P>0,05). No experimento II, a produção de ROS foi avaliada nos oócitos e no meio de MIV, assim como a atividade antioxidante foi avaliada após 24 h de MIV. A produção de ROS pelos oócitos foi superior nos tratamentos com baixa tensão de oxigênio (5%; 13,3UF) em relação a alta tensão de oxigênio (20%; 7,0UF) independentemente da densidade de oócitos (P<0,05). Os níveis de ROS detectados no meio de MIV foram superiores nos tratamentos com alta densidade de oócitos (1:10) independentemente da tensão de oxigênio (P<0,05). A atividade da SOD (21,3UI) e os níveis de GSH (6,95 nmol GSH/ml) mensurados nos oócitos foram similares entre os tratamentos (P>0,05). As taxas de fecundação e penetração foram superiores nos tratamentos com 20% de O 2 e com alta densidade de oócitos (1:10; 48,8%) em relação aos tratamentos 1:10/5% (29,5%) e 1:20/20% (29,1%; P<0,05). Adicionalmente a taxa de polispermia foi maior no tratamento com alta tensão de oxigênio e baixa densidade de oócitos. (1:20/20%; 27.8%) em relação ao tratamento 1:10/20% (13,41%; P<0,05). Os resultados deste estudo mostram interação entre a tensão de oxigênio e a densidade de oócitos aumentando a produção de ROS em determinadas associações e influenciando posteriormente as taxas de fecundação in vitro de oócitos bovinos.
The in vitro maturation is one of the critical points on in vitro production of bovine embryos so many factors can do an interference on IVM, like oxygen tension and oocyte density by volume of medium. The aim of this study was evaluate the effects of association of oxygen tension with different oocyte density during IVM Three experiments were performed with bovine oocytes obtained from abattoir ovaries, on experiment I was performed the nuclear and cytoplasmic evaluation, on the experiment III the biochemical assay of ROS production and antioxidant activity and on experiment III was realized the evaluation of in vitro fertilization. After selection, the oocytes were randomly distributed in 4 treatments: Treatment 1:10/5%: 1:10µl in 5% of O2; Treatment 1:10/20%: 1:10µl in 20% of O2; Treatment 1:20/5%: 1:20µl in 5% of O2; Treatment 1:20/20%: 1:20µl in 20% of O2. The IVM was performed in droplets (150µl or 300µl) of TCM 199 plus FSH, LH, EGF, EMS and pyruvate. The IVF were performed in droplets (300µl) of Fert-TALP. Was realized IVF with oocytes and spermatozoa (2x106 sptz/mL) selected by Percoll density gradients for 18h. On experiment I, the nuclear maturation rates (69.66%) and reorganization mitochondrial (71.55%) rates were similar among treatments (P>0.05). In Experiment II, the ROS production in oocytes, IVM medium and antioxidant activity were evaluated after 24 h of IVM. ROS production in oocytes was higher on treatments with low tension (5%; 13.3 UF) than 20% oxygen tension (7.0 UF) independently of oocyte density (P<0.05). ROS levels on IVM medium was higher on treatments with high oocyte density (1:10) independently of oxygen tension (P<0.05). The GSH levels (6.95 nmol GSH/ml) and SOD activity (21.3UI) were similar among treatments (P>0.05). The rates of normal fertilization and normal penetration were higher in treatments with 20% of O2 with high oocyte density (1:10;48.8%) than treatments 1:10/5% (29.5%) and 1:20/20% (29.1%; P<0.05). In addiction the polysperm rates were higher on treatment with high oxygen tension and low oocyte density (1:20/20%; 27.8%) than treatment 1:10/20% (13.4%; P<0.05). The results of this study show an interaction between oxygen tension and oocyte density, that increase ROS production on certain associations and subsequently affects the IVF rates.
The viruses are significant important pathogenic agents of several animal species, including cattle. In Brazil, several viral agents causing infections have been described in cattle and they produce significant economic losses. The identification of animals infected by a virus can be performed in different ways; however, definitive confirmation requires demonstration of the agent or immune response. For this purpose, various methods with the capacity to detect the viral particle, biological activity, genome, viral antigens, or specific immune response have been developed. Immunoassays are widely used in laboratory routine for detection of viral antigens in clinical or research. These assays exhibit good sensitivity, specificity and easy for implantation. The immunoassay methodologies are based on the employment of monoclonal or polyclonal antibodies specific to the viral antigens. Therefore, the aim of this study was to produce polyclonal antibodies for some bovine virus, and evaluate their reactivity in immunofluorescence, immunoperoxidase and slot blot tests. For this purpose, strains and/or isolates of bovine herpesvirus type 1 (BoHV-1), bovine herpesvirus type 2 (BoHV-2), bovine herpesvirus type 5 (BoHV-5), bovine herpesvirus type 5 gE deleted (BoHV-5 gEΔ), bovine viral diarrhea virus (BVDV), bovine respiratory syncytial virus (BRSV), bluetongue virus (BTV), and vaccinia virus (VACV) were amplified in cell culture and the supernatant were used to immunize rabbits. The animals were immunized five times by the subcutaneous route, and five days after the last boost the blood was collected. The serum was obtained by centrifugation. The serum was diluted (1:100 a 1:204.800) and used as primary antibodies in the immunofluorescence, immunoperoxidase and slot blot assays. The working dilution was selected among those produced specific reaction with infected cells and absent or weak background in control cells. The antiserum showed higher reactivity in immunoperoxidase technique than the immunofluorescence and slot blot. The antiserum of the BoHV-1, BoHV-5, BVDV and BRSV presented the reactivity when tested with heterologous isolates in immunofluorescence, immunoperoxidase assays. In summary, that the polyclonal antibodies raised in rabbits have high concentrations of specific antibodies, which were demonstrated by the reactivity in immunofluorescence, immunoperoxidase and slot blot assays. Additionally, these reagents can be considered an important tool for the detection and characterization of various bovine viruses in diagnostic and research routine.
Keywords: Maturação in vitro
Espécies reativas de oxigênio
Tensão de oxigênio
Densidade de oócitos
Fecundação in vitro
Bovinos
In vitro maturation
Oxygen tension
Oocyte density
in vitro fertilization
Bovine
Bovine viruses
Diagnostic
Immunoassay
Polyclonal antibodies
Publisher: Universidade Federal do Pampa
URI: http://hdl.handle.net/riu/178
Issue Date: 2-Aug-2013
Appears in Collections:Mestrado e Doutorado em Ciência Animal

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