Development of vitrified matured caftle oocytes after thawing and culture in vitro

Abstract

Bovine oocytes were partly denuded either at the beginning (t0) or six hours (t6) after the beginning of maturation and vitrified by the open pulled straw method at the end of the maturation process. After warming and fertilisation, their development in vitro and in vivo was assessed. The rates of production of blastocysts achieved in vitro were 3.4 per cent for the t0 group and 0.9 per cent for the t6 group compared with 40.4 per cent for the control oocytes. After transfer at the blastocyst stage pregnancies have been established in the three groups. Some of these pregnancies originated from vitrified oocytes which were further vitrified at the blastocyst stage before being transferred into synchronised recipients.

Morphological survival and subsequent in vitro maturation of denuded and cumulus compact Bubaline oocytes cryopreserved by ultra rapid cooling

“…The cumulus cell removal is known to increase the MPF activity and accelerate the transition to the metaphase stage and the redistribution of cortical granules [33]. The presence of cumulus cells affects many processes of oocyte growth and Le Gal [34] found a higher blastocyst rate for oocytes denuded at the start of vitrification compared to those denuded later. Smith and associates [35] had stressed that many structural components of oocytes have cell to cell communication and essential functional roles in development.…”

Effect of vitrification method on survivability, follicular growth and ovulation of preantral follicles in mice

“…The cryopreservation of human gametes could allow patients who are at risk of premature ovarian failure to preserve their fecundity 1–3 . However, to date, attempts to cryopreserve mature oocytes have met with limited success, because they are highly susceptible to freezing damage; this might also account for the poor post‐thaw survival and fertilization rates 4,5 . An alternative option could be to preserve the gametes at an earlier stage of development, when they might be more resistant to the damage induced by freezing and thawing 6 .…”