Modified vitrification of human pronuclear oocytes: efficacy and effect on ultrastructure.
The efficacy of cryopreservation by direct plunging into liquid nitrogen (vitrification) of human pronuclear oocytes using open pulled straws with a super-finely pulled tip, as well as the ultrastructural changes caused by cooling and vitrification, were evaluated. Clinical and electron microscopic studies of cooled and vitrified oocytes were performed. Oocytes were cooled to 4 degrees C in the presence and absence of cryoprotectants, vitrified, warmed, cultured and transferred. Abnormally fertilized oocytes were examined by electron microscopy. Vitrified and warmed 2-pronuclear oocytes showed 71.1% survival rate and 83.3% developmental rate. One- and 3-pronuclear oocytes, after cooling without cryoprotectants (presumably non-viable), showed progressive swelling of mitochondrial smooth endoplasmic reticulum (SER). After vitrification, oocytes (presumably viable) showed the formation of large SER vesicles associated with mitochondria. The described protocol of vitrification of human pronuclear oocytes was shown to be effective in producing pregnancy. Normal ultrastructure after undergoing the described vitrification protocol was confirmed.
Isachenko
Vladimir
V
Department of Obstetrics and Gynecology, University of Cologne, Kerpener Strasse 34, 50931 Cologne, Germany. vovaisachenko@yahoo.com
Selman
Helmy
H
Isachenko
Eugenia
E
Montag
Markus
M
El-Danasouri
Imam
I
Nawroth
Frank
F
D000328:Adult; D015925:Cryopreservation / Q000379:methods*; D003451:Cryoprotective Agents / Q000494:pharmacology; D018871:Endoplasmic Reticulum, Smooth / Q000648:ultrastructure; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D008854:Microscopy, Electron; D008928:Mitochondria / Q000648:ultrastructure; D009584:Nitrogen; D009865:Oocytes / Q000648:ultrastructure*; D011247:Pregnancy; D018873:Pregnancy Rate
D003451:Cryoprotective Agents; D009584:Nitrogen