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1.
JBRA Assist Reprod ; 2023 Aug 14.
Article in English | MEDLINE | ID: mdl-37579265

ABSTRACT

OBJECTIVE: The use of animals as experimental models has been proposed to improve the techniques applied in human reproduction clinics. This prospective and observational study evaluates the effects of the use of cumulus cells and collagen membrane on the maturation process of bovine oocytes. METHODS: Design and Setting: Bovine oocytes with or without cumulus cells were cultured in maturation medium for 24 hours in the conventional system (2D), central well plates and in the three-dimensional (3D) system. Intervention: The oocytes were positioned in the collagen membrane and matured for the same period. The morphological evaluation was carried out with the parameters of maturation. Main Outcome Measure: Presence or absence of the first polar corpuscle, which were observed and classified as germinal vesicle (GV), meiosis I (MI) and meiosis II (MII). RESULTS: The percentage of oocytes in GV was higher (p<0.05) in treatments without cumulus cells than those with cells. The rates of MII were higher (p<0.05) in the treatments with cumulus cells, independent of the culture system. In general, oocytes with presence of cumulus cells have approximately 1.7 times more chances (p<0.001) of reaching MII after MIV than those matured without cells. CONCLUSIONS: The presence of the cells in the cumulus is essential for the maturation process of bovine oocytes; the three-dimensional collagen membrane culture system is favorable for the maturation process of bovine oocytes.

2.
Reprod Biol ; 21(4): 100575, 2021 Dec.
Article in English | MEDLINE | ID: mdl-34808453

ABSTRACT

Cryopreservation and transplantation of ovarian tissue are proposed methods for the restoration of endocrine function and reproductive potential. Therefore, this study aimed to evaluate the effects of vitrification and xenotransplantation on follicle viability, activation, stromal cell integrity, vascularization, and micronuclei formation. Bovine fetal ovaries were fragmented and assigned to the following groups: Fresh control (FC), ovarian fragments immediately fixed; Vitrified control (VC), ovarian fragments vitrified; Vitrified xenotransplanted (VX), ovarian fragments vitrified and xenotransplanted; and Fresh xenotransplanted (FX), ovarian fragments xenotransplanted. Ovarian fragments were grafted in female BALB/c mice and recovered after 14 days. Follicular viability was preserved (P > 0.05) in VC group. The rate of developing follicles was greater (P < 0.05) in the FX group compared to other groups. Follicular density was higher (P < 0.05) in the VC group than the FC, VX, and FX groups. A decrease (P < 0.05) of stromal cell density was recorded after vitrification (VC vs. FX). Blood vessel density decreased in VC, VX, and FX groups compared with the FC group, and blood vessel density was correlated with follicular viability (positively; P = 0.07) and developing follicles (negatively; P < 0.001). Both vitrification and xenotransplantation groups (VC, VX, and FX) had a greater (P < 0.05) number of cells with one MN compared to the FC group. In summary, our findings showed that both vitrification and xenotransplantation modified blood vessel, follicular and stromal cell densities, follicular viability and activation, and micronuclei formation in ovarian tissue.


Subject(s)
Cryopreservation/veterinary , Ovary/physiology , Tissue Preservation/veterinary , Transplantation, Heterologous/veterinary , Animals , Cattle , Female , Fetus , Mice , Mice, Inbred BALB C , Pregnancy , Tissue Preservation/methods , Vitrification
3.
Reprod Biomed Online ; 38(3): 300-311, 2019 Mar.
Article in English | MEDLINE | ID: mdl-30639159

ABSTRACT

RESEARCH QUESTION: Does a three-dimensional culture system based on magnetic levitation with nanoparticles assembly maintain the follicular structure and viability with adequate growth rates leading to oocyte maturation after long-term culture? DESIGN: Randomized-controlled trial of treatments in a bovine model. Secondary follicles (n = 213) isolated from bovine ovaries were cultured in a two-dimensional system (two-dimensional control) or three-dimensional levitation system with different concentrations (three-dimensional 50 µl/ml, 100 µl/ml and 200 µl/ml) of magnetic nanoparticles. Follicular growth (diameter, daily growth and growth patterns), morphology (normal, degenerated and extruded follicles), antrum formation, oocyte viability and chromatin configuration were assessed. RESULTS: Secondary follicles of three-dimensional 200-µl/ml treatment showed higher viability, antrum formation and lower degeneration rates than two-dimensional control. Also, follicles cultured in the three-dimensional 200-µl/ml treatment presented a most homogenous daily growth rate as shown by the lowest variance and standard deviation. Compared with the two-dimensional control, the proportion of non-growing and slow-growing follicles were 3.8-fold lower and 1.6-fold higher, respectively, in the three-dimensional 200-µl/ml treatment. After in-vitro maturation, the three-dimensional 200-µl/ml had a greater proportion of viable oocytes (1.7-fold) and meiotic resumption rates (2.4-fold) than the two-dimensional control treatment. CONCLUSION: The three-dimensional levitation culture system improves the viability of in-vitro development of bovine secondary follicles, antrum formation and lower extrusion and degeneration rates and adequate growth rate leading to relevant oocyte viability and meiotic resumption after in-vitro maturation. This approach does not require a specific medium, and has the potential as an alternative method to in-vitro follicle culture in several species, including humans.


Subject(s)
In Vitro Oocyte Maturation Techniques/veterinary , Oocytes/growth & development , Ovarian Follicle/growth & development , Animals , Cattle , Female , In Vitro Oocyte Maturation Techniques/methods , Oocyte Retrieval/methods , Oocyte Retrieval/veterinary
4.
Theriogenology ; 114: 244-251, 2018 Jul 01.
Article in English | MEDLINE | ID: mdl-29660627

ABSTRACT

This study aimed to evaluate whether the addition of resveratrol to vitrification/thawing medium improves the cryotolerance of preantral follicles enclosed in bovine ovarian fragments. Ovarian fragments were obtained from bovine fetuses and distributed to the following groups: fresh ovarian fragments (control), vitrified (VIT), and vitrified with resveratrol (VIT + RESV). Overall, the mean percentage of normal follicles was greater (P < 0.05) in the VIT + RESV compared to the VIT group. Moreover, the probability of finding normal follicles was 2.5 greater (P < 0.05) in the VIT + RESV group. In class comparison, the primordial and transitional follicles have ∼3.0 times (P < 0.05) greater odds of being normal after vitrification compared to the secondary follicles. Additionally, a negative association (P < 0.05) was observed between the proportion of viable follicles and the stage of follicular development. ROS levels were similar (P > 0.05) between the VIT and VIT + RESV groups, and both were lower (P < 0.05) than the control group. The tissue viability in the VIT + RESV group was similar (P > 0.05) to the control group. In summary, the resveratrol provided greater ovarian tissue viability and has a positive effect against degeneration of preantral follicles enclosed in ovarian fragments.


Subject(s)
Cryopreservation/veterinary , Ovarian Follicle/drug effects , Stilbenes/pharmacology , Tissue Preservation/veterinary , Vitrification/drug effects , Animals , Antioxidants/pharmacology , Cattle , Female , Resveratrol
5.
Ciênc. rural ; 39(1): 215-220, Jan.-Feb. 2009. graf, tab
Article in Portuguese | LILACS | ID: lil-502649

ABSTRACT

Este trabalho teve por objetivo estudar as causas de variação nos preços de bovinos da raça nelore pertencentes a rebanhos de seleção, os quais foram comercializados em leilões, para verificar as influências das avaliações genéticas e dos julgamentos de exterior sobre esses preços. Para tanto, foram computados os preços de venda de 426 bovinos da referida raça em 12 leilões ocorridos em diversas localidades brasileiras (regiões Centro-Oeste, Norte e Sudeste), entre os anos de 2002 e 2005. O valor médio foi de R$ 3.325,49, sendo o mínimo de R$ 1.400,00 e o máximo de R$ 10.500,00. Esses dados foram digitados juntamente com outras informações que eram apresentadas nos catálogos dos leilões. As informações registradas incluíram o sexo de cada animal, o nome do leilão e as DEPs informadas nos catálogos. Além da avaliação da influência das informações dos catálogos, também foi avaliada a influência das informações dos reprodutores, pais dos animais vendidos nos leilões, envolvendo suas DEPs publicadas em um sumário de reprodutores da raça e as pontuações de suas progênies em julgamentos. Os métodos estatísticos aplicados foram análises de variâncias e análises de agrupamento (método K-médias). Como resultado, foi observado que animais com superioridade genética em características relacionadas a desempenho ponderal, considerando-se os efeitos diretos e maternos, foram valorizados ao serem comercializados nos leilões. Em contra-partida, a pontuação dos reprodutores nos julgamentos não teve influência significativa sobre os preços médios de venda de suas progênies nos leilões.


This study aimed to understand the causes of variation in the marketing prices of elite flock nelore cattle commercialized by auction, especially to verify the influences of EPDs and visual assessment. The selling prices of 426 animals from the nelore breed commercialized during 12 auctions held in various Brazilian locations, between the years 2002 and 2005, were considered in the analysis. The average price was R$ 3.325,49, with a minimum of R$ 1.400,00 and a maximum of R$ 10.500,00. The data used in a first analysis included the sex of each animal, the name of the auction and the EPDs of each animal informed in a catalog provided to the buyers during the auctions. A second analysis considered the EPDs of the sires of the commercialized animals, and the accumulated punctuation of these sires through their progeny judged through visual assessment during traditional animal shows in Brazil. Variance analysis and k-means clustering were applied to run the statistical analysis of the data. It was observed that animals with better EPDs, direct and maternal effects, on growth traits were sold with higher prices during the auctions. The punctuation by visual assessment did not significantly affect the prices.

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