Abstract
During the past few decades, significant progress in cryopreservation of mammalian oocytes and embryos has been observed. Transfer of cryopreserved embryos or oocytes resulted in live offspring in at least 25 species. So far, two major methods have been used for oocyte and embryo cryopreservation: conventional slow-rate freezing and vitrification. This review summarizes the progress in cryopreservation of mammalian oocytes and embryos that has been achieved by modifying oocyte/embryo susceptibility to cryopreservation or vitrification technology through such techniques as solid-surface vitrification, cryoloop, microdrop, cryotop, electron microscopy grids, nylon mesh, open pulled straw method or removal of lipids, addition of antifreeze protein or cytoskeleton- stabilizing agents, cholesterol or liposomes, centrifugation prior to cryopreservation or application of high hydrostatic pressure. In conclusion, the vitrification method opened new perspectives in cryopreservation of embryos and oocytes, both for in vitro fertilized and somatic nuclear transfer. Authors believe that new cryopreservation procedures which modify the susceptibility of oocytes and embryos to cryopreservation will gain importance as a major tool in mammalian gamete and embryo cryopreservation.
Highlights
OOCYTE AND EMBRYO CRYOPRESERVATIONTwo major methods have been used for oocyte and embryo cryopreservation: conventional slow-rate freezing and vitrification
During the past few decades, significant progress in cryopreservation of mammalian oocytes and embryos has been observed
Cryopreservation of mammalian embryos is a routine procedure, but considerable differences in efficiency exist depending on the origin of embryos, i.e. whether they are produced in vivo or in vitro, and on the stage of development and species involved
Summary
Two major methods have been used for oocyte and embryo cryopreservation: conventional slow-rate freezing and vitrification. Conventional slow freezing was the first system to be used for embryo cryopreservation In this system, controlled cooling rates allow extracellular and intracellular water exchange without serious osmotic effects or changes in cell shape. This technology has been used successfully to cryopreserve embryos of various species (Dobrinsky, 2002; Fuller and Paynter, 2007). Unsatisfactory results have been reported for cells more sensitive to chilling, such as oocytes of different species or pig embryos. Cryopreservation of mammalian embryos is a routine procedure, but considerable differences in efficiency exist depending on the origin of embryos, i.e. whether they are produced in vivo or in vitro, and on the stage of development and species involved
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
