Ultra-rapid freezing of human multipronuclear zygotes using electron microscope grids

• Published in: Human reproduction (Oxford) Vol. 15; no. 8; pp. 1787 - 1790
• Main Authors: Park, Se-Pill, Kim, Eun Young, Oh, Jong Hoon, Nam, Hwa Kyung, Lee, Keum Sil, Park, Sae Young, Park, Eun Mi, Yoon, San Hyun, Chung, Kil Saeng, Lim, Jin Ho
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01-08-2000
• Subjects: Biological and medical sciences; Birth control; Cell Nucleus; Cell Survival; Cryopreservation - instrumentation; Cryopreservation - methods; developmental capacity; EM grid; Gynecology. Andrology. Obstetrics; human; Humans; Medical sciences; Microscopy, Electron - instrumentation; multipronuclear zygotes; Sterility. Assisted procreation; Time Factors; ultra-rapid freezing; Zygote - physiology; EM grid; multipronuclear zygotes; ultra-rapid freezing; developmental capacity; human; Human; Electron microscope; Cryopreservation; Metal grid; Zygote; Development; Rapid process; Assisted procreation; Freezing; Pronucleus
• ISSN: 0268-1161; 1460-2350; 1460-2350
• DOI: 10.1093/humrep/15.8.1787

Developmental capacity of human multipronuclear (PN) zygotes cryopreserved using an ultra-rapid freezing method and electron microscope (EM) grids was studied. Multipronuclear zygotes obtained from a human IVF programme were used as an alternative to normal 2PN zygotes; they were divided into 3PN or ≥4PN zygotes and their in-vitro development and cryo-injury were compared according to PN number. EFS30, which consisted of 30% ethylene glycol, 18% Ficoll, 0.5 mol/l sucrose and 10% fetal bovine serum with added modified Dulbecco's phosphate buffered saline was used as the freezing solution. After ultra-rapid freezing and thawing 85.5% of multipronuclear zygotes survived. A comparison of cleavage rates between the control and cryopreserved groups showed no significant difference (3PN; 81.3 and 85.4% and ≥4PN; 90.0 and 95.7% respectively). Comparing the in-vitro development after thawing up to blastocyst formation on day 5 after IVF, the outcome of the frozen 3PN group (22.0%) was not different from that of control 3PN group (38.5%), while the outcome of the frozen ≥4PN group (4.5%) was significantly lower than that of control ≥4PN group (44.4%) (P < 0.05).