Influência de diferentes suplementos na maturação oocitária sobre o acúmulo de lipídeos citoplasmáticos em oócitos e embriões bovinos cultivados in vitro
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Data
2013-07-05
Autores
Del Collado Barrondo, Maite [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
O excessivo acúmulo lipídico que acontece ao longo da produção in vitro de embriões (PIVE) tem sido apontado como prejudicial à criopreservação. Como o soro fetal bovino (SFB) é um dos fatores que provoca maior impacto neste acúmulo, e pelo mesmo ser de composição indefinida, procura-se substituí-lo nos meios de cultivo. Entre os possíveis substitutos, está o composto semi-definido, livre de ácidos graxos, a albumina sérica bovina (BSA). O presente estudo teve como objetivo avaliar a influência da BSA e/ou SFB na MIV sobre o acúmulo lipídico nos oócitos e embriões bovinos, e para isso, cinco experimentos foram realizados. No primeiro experimento, demostrou-se que o meio contendo SFB possui dezoito vezes mais lipídeos que o meio contendo apenas BSA como fonte proteica. No segundo experimento, confirmou-se que, ao contrário da maturação in vivo, a maturação in vitro (MIV) provoca acúmulo lipídico, sendo este acúmulo mais acentuado no grupo suplementado exclusivamente com SFB, comparado ao grupo suplementado com BSA, sem observar-se diferença nos tamanhos das gotas oocitárias entre os grupos. Oócitos maturados na presença do SFB apresentaram melhores taxas de maturação nuclear e citoplasmática, porém, mostraram diferenças com relação à quantidade e migração de lipídeos e mitocôndrias em comparação àqueles obtidos após maturação in vivo. Nos experimentos III e IV, observou-se que, além de não levar a uma esperada diminuição da quantidade de lipídeos nos blastocistos produzidos, a BSA na MIV levou a menores taxas de desenvolvimento embrionário. Sobre o tamanho das gotas embrionárias, constatou-se que a MIV suplementada com SFB provoca maior porcentagem de gotas entre 2 a 6 μm de diâmetro comparada a MIV suplementada por ambas as substancias. Além do mais, percebeu-se um aumento do tamanho das gotas ao longo da PIVE independente da suplementação...
The excessive lipid accumulation that occurs during in vitro production of embryos (IVPE) has been described as harmful to cryopreservation. Because fetal bovine serum (FBS) is one of the factors that cause the greatest impact in this accumulation, and because it is an undefined medium supplement, current research is aimed at replacing this supplement in culture media. Among the possible substitutes, there is a semi defined compound, fatty acid free bovine serum albumin (BSA). The present study aimed to evaluate the influence of BSA and/or FBS during IVM on lipid accumulation in oocytes and embryos, and for that, five experiments were performed. The first experiment demonstrated that the medium containing FBS has eighteen times more lipids than the medium containing only BSA as a protein source. In the second experiment, it was confirmed that, unlike in vivo maturation, in vitro maturation (IVM) causes a lipid accumulation, which is more pronounced in the group supplemented only with FBS, compared with BSA group, without showing difference in oocytes droplets sizes between groups. Oocytes matured in the presence of FBS showed better rates of nuclear and cytoplasmic maturation, however, they also showed differences relative to the amount and migration of lipids and mitochondrias in comparison to those obtained after in vivo maturation. In the experiments III and IV, it was observed that the expected decrease in the amount of lipids produced in blastocysts, supplemented solely with BSA, did not take place, and the use of BSA alone in IVM led to lower rates of embryo development. Furthermore, for embryos lipid droplets sizes, a higher percentage of droplets between 2-6μm was observed in IVM supplemented with FBS compared to supplemented with both substances.The last experiment determined the expression of genes involved in lipid synthesis, DGAT2 and PLIN2. Increased expression of PLIN2 and ...
The excessive lipid accumulation that occurs during in vitro production of embryos (IVPE) has been described as harmful to cryopreservation. Because fetal bovine serum (FBS) is one of the factors that cause the greatest impact in this accumulation, and because it is an undefined medium supplement, current research is aimed at replacing this supplement in culture media. Among the possible substitutes, there is a semi defined compound, fatty acid free bovine serum albumin (BSA). The present study aimed to evaluate the influence of BSA and/or FBS during IVM on lipid accumulation in oocytes and embryos, and for that, five experiments were performed. The first experiment demonstrated that the medium containing FBS has eighteen times more lipids than the medium containing only BSA as a protein source. In the second experiment, it was confirmed that, unlike in vivo maturation, in vitro maturation (IVM) causes a lipid accumulation, which is more pronounced in the group supplemented only with FBS, compared with BSA group, without showing difference in oocytes droplets sizes between groups. Oocytes matured in the presence of FBS showed better rates of nuclear and cytoplasmic maturation, however, they also showed differences relative to the amount and migration of lipids and mitochondrias in comparison to those obtained after in vivo maturation. In the experiments III and IV, it was observed that the expected decrease in the amount of lipids produced in blastocysts, supplemented solely with BSA, did not take place, and the use of BSA alone in IVM led to lower rates of embryo development. Furthermore, for embryos lipid droplets sizes, a higher percentage of droplets between 2-6μm was observed in IVM supplemented with FBS compared to supplemented with both substances.The last experiment determined the expression of genes involved in lipid synthesis, DGAT2 and PLIN2. Increased expression of PLIN2 and ...
Descrição
Palavras-chave
Bovino, Bovino - Embrião, Albumina, Lipidios, Técnicas de maturação in vitro de oócitos, Fertilização in vitro, Mitocondria, Embryos
Como citar
DEL COLLADO BARRONDO, Maite. Influência de diferentes suplementos na maturação oocitária sobre o acúmulo de lipídeos citoplasmáticos em oócitos e embriões bovinos cultivados in vitro. 2013. xix, 69 p. Dissertação (mestrado) - Universidade Estadual Paulista, Faculdade de Ciências Agrárias e Veterinárias de Jaboticabal, 2013.