Data/hora: 16/06/2024 07:50:05

Biblioteca(s): | Epagri-Sede.
Data corrente: | 10/08/2011
Data da última atualização: | 10/08/2011
Autoria: | MEZZALIRA, J. C.; OHLWEILER, L. U.; URIO, M.; GAUDENCIO NETO, S.; MARINHO, L. R. S.; ZAGO, F. C.; FORELL, F.; BERTOLINI, M.; MEZZALIRA, A.
Afiliação: | Epagri
Título: | Effect of nitrocooler negative pressure and recovery internal on cryotolerance of bovine in vitroproduced embryos.
Ano de publicação: | 2010
Fonte/Imprenta: | In: ANNUAL CONFERECE OF IETS, ., 2010, Cordoba, Argentina. Proceedings... Sydney, Australia: CSIRO, 2010. p. 210.
Idioma: | Inglês
Conteúdo: | Exposing bovine embryos and porcine oocytes to hydrostatic pressure has been shown to increase cryosurvival, possibly by a resulting expression of stress tolerance proteins. This study aimed to evaluate the effect of the negative pressure stress condition (a 5¨Cmin long embryo exposure to a negative pressure,) and the interval between vacuum exposure and vitrification (40 min or 2 h) on survival of bovine IVP embryos. The negative pressure was achieved with the same apparatus used previously for the cryopreservation of embryos (¡ä¡äNitrocooler¡ä¡ä; Mezzalira et al. 2009 Reprod Fert Dev (1) 134), in which a negative pressure (vacuum) is applied to liquid nitrogen to increase the cooling rate through the slush phenomenon, except that, in this study, the vacuum was applied to the chamber without liquid nitrogen, at room temperature. Grades 1 and 2 bovine IVP expanded blastocysts were allocated to one of five experimental groups: embryos in vitro-cultured as fresh (Control) or after vitrification (Vitri); and embryos subjected to the negative pressure for 5 min and then in vitro¨Ccultured as fresh (NP¨Cfresh) or after vitrification performed 40 min (NP¨CVitri¨C40min) or 2 h (NP-Vitri-2h) following the vacuum exposure. Embryos were vitrified in pulled glass micropipettes in a solution with 20% ethylene glycol + 20% dimethylsulfoxide + 20% fetal bovine serum and rewarmed in decreasing sucrose concentrations (Mezzalira et al. 1999 Acta Scientiae Veterinariae (27) 262¨C262). In vitro culture was carried out in all treatments for 72 h for the assessment of re¨Cexpansion and hatching rates, which were analyzed by the chi¨Csquare test, for P<0.05. No differences in re¨Cexpansion rates were observed between groups. However, the vitrification of embryos after 2 h of exposure to a 5¨Cmin long negative pressure (NP¨CVitri¨C2h) improved embryo survival expressed by a higher hatching rate than for embryos vitrified without vacuum exposure (Vitri) or after 40 min following the 5¨Cmin long exposure to vacuum. In addition, hatching rates in group NP¨CVitri¨C2h was similar to those for fresh embryos (Control and NP¨Cfresh). Our results indicated that a short exposure of embryos to a negative pressure can improve cryotolerance following vitrification, which is dependent on the time interval between NP exposure and cryopreservation. Bovine IVP embryos should be allowed to recover for at least two hours after NP exposure before the increase in cryotolerance is achieved.
Palavras-Chave: | Bovine; Cryotolerance; Embryos; Nitrocooler; Pressure.
Categoria do assunto: | --
URL: | http://intranetdoc.epagri.sc.gov.br/producao_tecnico_cientifica/DOC_6296.pdf
Registro original: | Epagri-Sede (Epagri-Sede)
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