The effects of time of first cleavage, developmental stage, and delipidation of nuclear-transferred porcine blastocysts on survival following vitrification.
The effect of removing cytoplasmic lipid droplets (delipidation) at the 2-cell and developmental stages on the survival of porcine somatic cell nuclear-transferred blastocysts developed from the enucleated oocytes receiving somatic cells from kidney of an adult female after cryopreservation was examined. Vitrification was performed using the Cryoloop method with a small volume of medium (0.5 microl). To select 2-cell embryos with a high potential to develop into blastocysts, the relationship between the timing of the first cleavage and the developmental potential was examined. The potential of nuclear-transferred oocytes to develop into blastocysts in the intermediate-cleavage group (20-24h after activation, 25%) was slightly or significantly (P<0.05) higher than that in fast-cleavage (<20 h after activation, 13%) and slow-cleavage groups (>24h after activation, 5%). Most non-delipidated blastocysts did not survive after thawing (0% for early-stage and 9% for advanced-stage blastocysts), but the survival rate of delipidated blastocysts 48 h after culture (54% and 72%, respectively) was not significantly different from that of non-vitrified blastocysts (80% and 92%, respectively). The survival rate of advanced-stage blastocysts after vitrification was slightly higher than that of early-stage blastocysts. The present study demonstrates that somatic cell nuclear-transferred porcine blastocysts developed from embryos selected at the 2-cell stage can be preserved by vitrification with a small volume of medium if the lipid droplets of the embryos are first removed.
Kawakami
M
M
Laboratory of Animal Reproduction, College of Agriculture, Kinki University, Nara 631-8505, Japan.
Kato
Y
Y
Tsunoda
Y
Y
D000818:Animals; D001755:Blastocyst / Q000737:chemistry / Q000502:physiology*; D002470:Cell Survival / Q000187:drug effects; D002970:Cleavage Stage, Ovum / Q000502:physiology*; D015925:Cryopreservation; D003593:Cytoplasm / Q000737:chemistry; D047108:Embryonic Development / Q000502:physiology*; D005260:Female; D008055:Lipids / Q000302:isolation & purification* / Q000494:pharmacology; D053652:Nuclear Transfer Techniques; D013552:Swine / Q000196:embryology / Q000502:physiology*; D013997:Time Factors
D008055:Lipids