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Publication
Implementation of immature oocytes by cryopreservation technique and subsquent in vitro maturation and fertilization post-thawing
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Authors
Abstract(s)
The aim of this study was to cryopreserve by vitrification by propylene glycol (PROH) and dimethylsulfoxide (DMSO) immature bovine oocytes in straws and to investigate the effects of vitrification on post-thaw oocyte maturation and fertilization. A total of 983 cumulus oocyte complexes were obtained by follicle aspiration from 263 ovaries of cows slaughtered at a local slaughterhouse. Following selection, oocytes with compacted cumulus cells and evenly granulated ooplasm were vitrified using one of the two different solutions with a non vitrified group served as control. The first step vitrification solution contained 10% PROH while the second step solution contained 20% PROH+1M sucrose in a basic media used in group of PROH. Oocytes were matured in N-2-hidroxyethyl piperazine-N-2-ethanosulfonic acid (HEPES) buffered tissue culture medium (TCM) 199 supplemented with 10% FCS, 0.02 IU/ml FSH (Sigma), 1μg/ml E2 (Sigma), 0.15mg/ml Glutamine, 22μg/ml Na-Pyruvate, 10μg/ml Gentamycin, 10μg/ml Streptomycin and 10μg/ml Nistamycin. for 24 h at 38 ◦C in a humidified atmosphere of 5% CO2 in air. Oocytes were then fertilized and cultured. The numbers of developed embryos observed were 98 (70.1%), 73 (59.9%), and 80 (67.7%) in groups Control, PROH and DMSO, respectively, without co-culture. With co-culture were observed 141 (69.5%), 54 (61.7%), and 45 (49%), also in Control, PROH and DMSO. Developed embryos rate from control, without co-culture, was not statistically different when compared with PROH and DMSO (p< 0.05), but with co-culture present statistical differences with DMSO. However, better results were obtained in DMSP group compared to PROH, without co-culture. The lowest number of developed embryos was obtained in DMSO group, with co-culture. Immature bovine oocytes can be vitrified in straws, but success differs with the cryoprotectant and without co-culture.
Description
Dissertação de Mestrado em Engenharia Zootécnica.
Keywords
Cattle Cryopreservation Embryo In Vitro Fertilization Vitrification Bovinos Criopreservação Embriologia Animal Fertilização Animal in vitro Vitrificação