Human oocyte ultravitrification with a low concentration of cryoprotectants by ultrafast cooling: a new protocol.
OBJECTIVE
To evaluate the efficacy of a new ultravitrification technique with a low concentration of cryoprotectants.


METHODS
Ultravitrification research.


METHODS
Private assisted reproduction center.


METHODS
Oocytes donated voluntarily with the aim of research.


METHODS
Ultravitrification with different protocols of 100 mature oocytes and 100 immature oocytes divided in four groups to determine which is the adequate cryoprotectant concentration and the appropriate cooling solution.


METHODS
Human oocytes survival rate with low concentration of cryoprotectants by ultravitrification technique.


RESULTS
We obtained higher survival rates with slush nitrogen than with liquid nitrogen (92% vs. 56%) and better results with 2 M of cryoprotectants than with 1.5 M (92% vs. 60%). The best protocol was 2 M PrOH + 0.5 M sucrose + slush nitrogen with a mature oocytes survival rate of 92% (23 of 25) and immature of 88% (22 of 25).


CONCLUSIONS
This ultravitrification technique is a new option to preserve human oocytes that avoids the use of a high cryoprotectant concentration while obtaining a high survival rate with a concentration of cryoprotectants typical of slow freezing.
Department of Gynecology and Reproductive Medicine, IRCCS Istituto Clinico Humanitas, Rozzano, Milan, Italy. ecriados@yahoo.es
Enrique
E
Criado
Elena
E
Albani
Paola Vittoria
PV
Novara
Antonella
A
Smeraldi
Amalia
A
Cesana
Valentina
V
Parini
Paolo Emanuele
PE
Levi-Setti
D002470:Cell Survival / Q000187:drug effects; D015925:Cryopreservation / Q000379:methods*; D003451:Cryoprotective Agents / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D009584:Nitrogen / Q000494:pharmacology*; D009865:Oocytes / Q000166:cytology* / Q000187:drug effects; D012996:Solutions; D013997:Time Factors; D058989:Vitrification
D003451:Cryoprotective Agents; D012996:Solutions; D009584:Nitrogen