Vitrification of cleavage stage mouse embryos by the cryoloop procedure.
By decreasing the volume of the cryoprotective solution it is possible to increase dramatically the freezing speed and - at the same time - reduce the toxicity and osmotic side effects of cryoprotectants (CPA). The objective of our study was to vitrify Day-3 cleavage stage mouse embryos (n = 229) with the cryoloop technology using a new composition of vitrification media. Embryos were exposed to a 2-step loading of CPA, ethylene glycol (EG) and propylene glycol (PG), before being placed on the surface of a thin filmy layer formed from the vitrification solution in a small nylon loop, then they were rapidly submerged into liquid nitrogen. After warming, the CPA was diluted out from the embryos by a 3-step procedure. Survival of embryos was based on morphological appearance after thawing and continued development to expanded blastocysts upon subsequent 48-hour culture. Embryos of the two control groups were either treated likewise except that they were not vitrified, or cultured in vitro without any treatment. Our data show that a high percentage of embryos survived (92.7%) vitrification in the mixture of EG and PG combined with cryoloop carrier and developed normally (89.1%) in vitro after thawing. To our knowledge this is the first report of the successful vitrification of cleavage stage mouse embryos using VitroLoop vitrification procedure.
Klambauer
Philip
P
Department and Clinic of Obstetrics and Reproduction, Faculty of Veterinary Science, Szent István University, István u. 2, H-1078 Budapest, Hungary.
Keresztes
Zsuzsa
Z
Kanyó
Katalin
K
Varga
Erika
E
Kriston
Rita
R
Vass
Nóra
N
Jávor
András
A
Konc
János
J
Solti
László
L
Cseh
Sándor
S
D000818:Animals; D002970:Cleavage Stage, Ovum / Q000502:physiology*; D015925:Cryopreservation / Q000295:instrumentation* / Q000379:methods*; D003451:Cryoprotective Agents; D004622:Embryo, Mammalian; D051379:Mice; D013048:Specimen Handling
D003451:Cryoprotective Agents