In vitro development and cell allocation of porcine blastocysts derived by aggregation of in vitro fertilized embryos.
In pigs, the morphology and cell number of in vitro-produced blastocysts are inferior to those of their in vivo counterparts. The objective of this study was to increase developmental competence and to gain an understanding of cell allocation in blastocysts derived from the aggregation of four-cell stage porcine embryos produced in vitro. After removal of the zona pellucida, two (2x) and three (3x) four-cell stage embryos were aggregated by co-culturing them in aggregation plates. Five days after aggregation, the developmental ability and the number of cells in the aggregated embryos were determined. The percentage of blastocysts was higher (P < 0.05) in both the 2x and 3x aggregated embryos (66.6% and 72.0%, respectively) compared to that of the 1x embryos and the intact controls (43.1% and 36.4%, respectively). The total cell number of blastocysts also increased in aggregated embryos compared to that of intact controls (2.6-fold for 2x and 3.4-fold for 3x) (P < 0.05). The cells of two differentially stained embryos were started to mix at 72 hr after aggregation. In vitro-fertilized porcine aggregates (2x) were developed to blastocyst with a random distribution of cells from each embryo. The mRNA levels for the oct-4, bcl-xL and connexin 43 genes were higher (P < 0.05) and bak gene were lower (P < 0.05) in both the 2x and 3x aggregated embryos than the intact controls. Therefore, the aggregation of the four-cell stage embryos could be used to improve the quality of porcine preimplantation stage embryos produced in vitro.
Lee
Sang-Goo
SG
Department of Food and Animal Biotechnology, College of Agriculture and Life Science, Seoul National University, Seoul, Korea.
Park
Chi-Hun
CH
Choi
Don-Ho
DH
Kim
Hye-Sun
HS
Ka
Hak-Hyun
HH
Lee
Chang-Kyu
CK
D000818:Animals; D001755:Blastocyst / Q000737:chemistry / Q000166:cytology* / Q000502:physiology*; D002452:Cell Count; D047108:Embryonic Development / Q000235:genetics; D005260:Female; D005307:Fertilization in Vitro; D008297:Male; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D034421:Sus scrofa / Q000196:embryology*
D012333:RNA, Messenger