Experimental vitrification of human compacted morulae and early blastocysts using fine diameter plastic micropipettes.
BACKGROUND
Vitrification of human blastocysts has been successfully applied using grids, straws and cryoloops. We assessed the survival rate of human compacted morulae and early blastocysts vitrified in pipette tips with a smaller inner diameter and solution volume than the previously described open pulled straw (OPS) method.


METHODS
Excess day 5 human embryos (n = 63) were experimentally vitrified in vessels. Embryos were incubated at 37 degrees C with sperm preparation medium (SPM) for 1 min, SPM + 7.5% ethylene glycol (EG)/dimethylsulphoxide (DMSO) for 3 min, and SPM + 16.5% EG + 16.5% DMSO + 0.67 mol/l sucrose for 25 s. They were then aspirated (0.5 microl) into a plastic micropipette tip (0.36 mm inner diameter), exposed to liquid nitrogen (LN(2)) vapour for 2 min before being placed into a pre-cooled cryotube, which was then closed and plunged into LN(2). Embryos were warmed and diluted using 0.33 mol/l and 0.2 mol/l sucrose.


RESULTS
The survival rate for compacted morulae was 73% (22/30) and 82% (27/33) for early blastocysts.


CONCLUSIONS
The survival rates of human compacted morulae and early blastocysts after vitrification with this simple technique are similar to those reported in the literature achieved by slow cooling and other vitrification protocols.
Cremades
N
N
Unidad de Reproduccion, Servicio de Ginecologia y Obstetricia, Hospital General Universitario de Alicante, Alicante, Spain.
Sousa
M
M
Silva
J
J
Viana
P
P
Sousa
S
S
Oliveira
C
C
Teixeira da Silva
J
J
Barros
A
A
D001755:Blastocyst / Q000502:physiology; D015925:Cryopreservation / Q000295:instrumentation* / Q000379:methods*; D003451:Cryoprotective Agents; D046508:Culture Techniques; D004121:Dimethyl Sulfoxide; D019855:Ethylene Glycol; D006358:Hot Temperature; D006801:Humans; D009028:Morula / Q000502:physiology; D010969:Plastics
D003451:Cryoprotective Agents; D010969:Plastics; D019855:Ethylene Glycol; D004121:Dimethyl Sulfoxide