Viability of one-cell bovine embryos cultured in vitro: comparison of cell-free culture with co-culture.
In this study, the quality (number of cells) and pregnancy rates of bovine blastocysts produced by in vitro maturation/in vitro fertilization (IVM/IVF) following cultivation in either cell-free culture or co-culture were compared. Bovine one-cell IVM/IVF embryos obtained 6 h after insemination were stripped of cumulus cells and assigned to either cell-free culture or co-culture with granulosa cell monolayers for 9 days (Expt 1) or 10 days (Expts 2 and 3). In Expt 3, day-7 (day 0 = day of insemination) blastocysts, day-8 expanded blastocysts and day-9 hatched blastocysts were air-dried, fixed and stained to determine the number of cells. Expanded blastocysts obtained in Expt 1 were cryopreserved using propylene glycol as a cryoprotectant and were used later for embryo transfer. There were no significant differences between cell-free culture and co-culture in the percentage of one-cell embryos that developed to 2- to 16-cells (66.7% versus 72.4% for Expt 1, 71.0% versus 78.2% for Expt 2). However, significantly more (P < 0.05) of the one-cell embryos co-cultured with granulosa cell monolayers developed to morula, blastocyst and expanded blastocyst stages compared with those in cell-free culture (35.0 versus 27.1%, 25.1 versus 14.2%, 15.6 versus 5.4% for Expt 1; 37.6 versus 24.0%, 25.7 versus 11.0%, 16.8 versus 3.0% for Expt 2). Only embryos co-cultured with granulosa cell monolayers hatched (Expt 2). Embryos co-cultured with granulosa cell monolayers also had higher (P < 0.01) numbers of cells (92 +/- 42 versus 56 +/- 21 for blastocysts, 149 +/- 53 versus 81 +/- 29 for expanded blastocysts).(ABSTRACT TRUNCATED AT 250 WORDS)
Goto
K
K
Laboratory of Animal Reproduction, Faculty of Agriculture, Kagoshima University, Japan.
Iwai
N
N
Ide
K
K
Takuma
Y
Y
Nakanishi
Y
Y
D000818:Animals; D001755:Blastocyst / Q000502:physiology*; D002417:Cattle; D002474:Cell-Free System; D002478:Cells, Cultured; D015925:Cryopreservation; D004624:Embryo Transfer; D005260:Female; D005307:Fertilization in Vitro; D005328:Fetal Viability / Q000502:physiology*; D006107:Granulosa Cells / Q000166:cytology